I think this is an important issue, not just in terms of sex bias, but that the whole peer-review process could probably be improved.
This study (http://dx.doi.org/10.1016/j.tree.2007.07.008) by Amber Budden at U. Toronto, suggests that female authors are more successful in a double-blind peer review process rather than the more conventional single-blind review.
Just to be clear, double-blind means that the author doesn't know who the reviewers are and the reviewer does not see the name or affiliation of the author(s). Single-blind means the author submits the paper and the journal/editor finds reviewers (the author doesn't know who they are), but the reviewers see the author's name(s). Almost every scientific journal uses this single-blind approach; for no good reason.
From where I sit, there seems no good reason to maintain this single-blind review process. Not only does it possibly discriminate against women, I think there are likely many more negative effects. The most obvious one is that "prestigious" scientists, those who might have published a lot or have contributed seminal work in a field, seem more likely to get through the process less critically. This is part because they are good scientists, of course, but it can also be because there really are not enough reviewers to go around, and much more junior scientists (sometimes grad students) end up reviewing papers. It is intimidating as an inexperienced scientists to be critical of work by someone you know/respect/fear/want-to-work-with/etc. Also, many sub-disciplines are populated by a fairly small number of experts, who end up being asked to review each other's papers all the time. This can go either way: people are likely to be extra critical of rivals and less critical of friends.
Recently, there has been some open discussion of the review process (e.g., DOI: 10.1126/science.319.5859.32b and DOI: 10.1126/science.319.5859.32c), which is good. However, I haven't noticed any large-scale call for double-blind review. This is amazing, since double-blind studies are a foundation of modern science. I honestly can't think of a single reason that every journal should not immediately switch to double-blind reviews.
2008-01-22
2007-11-26
Watch a YouTube video
This guy on YouTube has spelled out a very nice approach to how "skeptics" should look at the possibility of a changing climate.
2007-10-10
blog action day
If time permits, which is a big if right now, I will try to participate in blog action day.
2007-10-04
Shipping Lanes
I've been sitting on the idea for this post for almost a week, but haven't had a chance to work it up. Since it doesn't look like I'm going to get to do it the way I originally wanted, I'm giving in and just going for the gusto. Maybe (yeah right) I'll come back and round out the rough edges later, but for now I want to get the basic ideas out there.
Ship tracks are the contrails of the sea. Perhaps more accurately, ship tracks are to the marine atmospheric boundary layer what contrails are to the upper troposphere. They are lines of what we will call clouds that form behind a ship. They are the focus of a recent article that I found very interesting. A news summary can be found on the Science (LINK) web site, while the paper appears in GRL. For a good picture of ship tracks, NASA's MODIS is a good resource.
The idea in the paper is to establish the radiative forcing associated with ship tracks on the global scale. This hasn't been done before using observations because ship tracks are very low, very small clouds that cover a tiny amount of Earth's surface area. However, they are common, as the paper points out, in several regions, notably off the coast of Africa and in the North Pacific. These are, somewhat coincidentally (but not really), the same regions where we think about extensive stratocumulus decks.
Schreier et al. use one year of satellite imagery, from the ENVISAT-AATSR, and go through a straight forward but intensive process of identifying ship tracks and then estimating their radiative forcing. The bottom line is that in some regions the radiative impact of ship tracks, lets call it the local radiative effect, can be a non-trivial -0.05 W/m2, but on the global scale the effect is miniscule at -0.4 to -0.6 mW/m2 (plus or minus 40%). Note that the global value is in milliWatts, so is 100 time smaller than the largest regional radiative effect (-0.05 W/m2 = -50 mW/m2). The negative sign arises because ship tracks are very low clouds that are very white (i.e., reflective), so when they appear they provide a more reflective surface for sunlight to bounce off, which to first order reduces the amount of energy in the climate system (because most of the reflected light goes back out to space) and cools the climate. This is familiar if you've been exposed to cloud "feedback" ideas, in which more low cloud cover increases the albedo of Earth and cools it. In fact, this is a terrific example of that effect, but we'll come to that shortly. It is also good to note that the radiative forcing associated with a doubling of atmospheric carbon dioxide is about 4 W/m2, which is itself a small signal in the total radiative budget (with 1365 W/m2 of incoming sunlight at the top of the atmosphere, distributed over a day (divide by 4) and an albedo of about 0.3 you're talking in the neighborhood of a 225 W/m2 of sunlight being absorbed at the surface, and all of global warming comes down to 4W/m2 give or take!).
Okay so before I sign off, leaving you totally confused. I wanted to point out a couple of interesting things about ship tracks that aren't necessarily in the article. First of all, it is helpful to remember why ship tracks form. The ships are steaming ahead, burning fairly dirty fuel to get where they are going, and the exhaust goes right out into the atmosphere. This exhaust contains particulate matter as well as precursors for particles, so the ship is basically making a trail of particles behind it. These particles act as nucleation sites for water, forming small cloud droplets. Because the ships spew out so much stuff, there are enough nucleation sites available to grow lots of droplets and form these linear clouds. Why don't the clouds form anyway if there's that much water in the atmosphere already? Well, a couple of reasons. One is that the relative humidity isn't quite 100% in fair weather conditions, but even if it were, water doesn't like to condense unless there are surfaces (supplied by the particles). At a relative humidity of about 80%, there just aren't enough particles floating around the clean maritime boundary layer to let the water condense into clouds. The ships provide the extra nucleation sites necessary, and make it even easier by supplying the boundary layer with hygroscopic particles, meaning the particles effectively decrease the saturation specific humidity (http://en.wikipedia.org/wiki/Hygroscopic). That just means that the particles are very efficient at turning water vapor into liquid water. So a ship goes by, spews out water-loving particles, water condenses on those particles forming droplets, and a big collection of droplets is a cloud. Fine, what else?
So okay, the ships go by and make lines of clouds, but we now know (or strongly suspect) based on Schrier et al. that the global effect of these cloud is negligible and the local effect is also pretty small. Can we be done with it then? Not quite. These clouds are a great example of the Twomey effect, which is an old idea now and just says that by increasing the number of particles in the air, the size of cloud droplets gets smaller, and when clouds are made up of small droplets they are brighter (i.e., more reflective). Coakley et al. (1987) presented ship tracks as such an example, showing with satellite data that the reflectivity of ship tracks is higher than the surrounding low-level cloud cover. This is exactly what leads to the radiative forcing that has now been estimated by Schreier et al. The important thing to recognize here is that the Coakley et al. study is essentially a proof of concept, showing that pollution can impact atmospheric radiative transfer. They definitely did not say ships were impacting global climate.
There is a related effect, sometimes called the Albrecht effect, which takes into account the change in cloud fraction associated with changes in particles in the atmosphere. It is presented by Albrecht (1989), and is also a pretty simple idea. When extra particles are put into the atmospheric boundary layer, they form droplets and brighter clouds, as discussed above. Smaller droplets can also change the formation of raindrops, or more precisely in the case of shallow maritime clouds, drizzle drops. The change is to reduce the precipitation efficiency, which increases the liquid water in the cloud layer, and can lead to an increase in the fractional cloudiness. The important point here is that not only could increased particle concentration in the marine atmospheric boundary layer make brighter clouds, but could actually increase the overall cloudiness. This would amplify the effects discussed by Coakley et al. because there would now be a larger area covered by brighter clouds. The Albrecht study makes use of ship tracks only in the sense of the Coakley et al. study, and only suggests that changes in precipitation could account for the sustained difference in ship tracks from the stratiform cloud in which they are embedded. This is supported to some extent by aircraft observations.
And finally, since we're covering so many bases, there's another effect that should be mentioned. Pincus and Baker (1994) present a study that extends the Albrecht study in that it accounts for the change in the thickness of clouds in the presence of varying particle concentration. They use a model of a cloudy boundary layer and account for changes in absorption and precipitation with cloud thickness and droplet number, respectively. This effect is not quite as "obvious" as the other indirect effects, but the bottom line is that more droplets can make thicker clouds with a higher albedo, which is thus another facet of this negative feedback associated with changes in atmospheric aerosol (particles). They note, however, that you'd expect to see ship tracks extend higher than surrounding clouds, which at that time was not observed. I'm not sure where this effect really stands, but it is interesting to consider.
So these are the indirect effects of aerosol on climate. We came a long way in this post, from a recent study showing that the globally averaged radiative forcing due to ship tracks is small all the way through aerosol effects on cloud albedo, precipitation processes, and horizontal and vertical cloud distribution. Well done. There are a lot more details that could have been added, and tons more studies. These will be left for future posts, though. I've included some references below for those of you who want to follow up.
References
Schreier, Mathias; Mannstein, Hermann; Eyring, Veronika; Bovensmann, Heinrich
Global ship track distribution and radiative forcing from 1 year of AATSR data
Geophys. Res. Lett., Vol. 34, No. 17, L17814
10.1029/2007GL030664 (LINK)
JAMES A. COAKLEY JR., ROBERT L. BERNSTEIN, and PHILIP A. DURKEE
Effect of Ship-Stack Effluents on Cloud Reflectivity
Science 28 August 1987: Vol. 237. no. 4818, pp. 1020 - 1022 DOI: 10.1126/science.237.4818.1020
BRUCE A. ALBRECHT
Aerosols, Cloud Microphysics, and Fractional Cloudiness
Science 15 September 1989: Vol. 245. no. 4923, pp. 1227 - 1230 DOI: 10.1126/science.245.4923.1227
ROBERT PINCUS & MARCIA B. BAKER
Effect of precipitation on the albedo susceptibility of clouds in the marine boundary layer
Nature 372, 250 - 252 (17 November 2002); doi:10.1038/372250a0
Ship tracks are the contrails of the sea. Perhaps more accurately, ship tracks are to the marine atmospheric boundary layer what contrails are to the upper troposphere. They are lines of what we will call clouds that form behind a ship. They are the focus of a recent article that I found very interesting. A news summary can be found on the Science (LINK) web site, while the paper appears in GRL. For a good picture of ship tracks, NASA's MODIS is a good resource.
The idea in the paper is to establish the radiative forcing associated with ship tracks on the global scale. This hasn't been done before using observations because ship tracks are very low, very small clouds that cover a tiny amount of Earth's surface area. However, they are common, as the paper points out, in several regions, notably off the coast of Africa and in the North Pacific. These are, somewhat coincidentally (but not really), the same regions where we think about extensive stratocumulus decks.
Schreier et al. use one year of satellite imagery, from the ENVISAT-AATSR, and go through a straight forward but intensive process of identifying ship tracks and then estimating their radiative forcing. The bottom line is that in some regions the radiative impact of ship tracks, lets call it the local radiative effect, can be a non-trivial -0.05 W/m2, but on the global scale the effect is miniscule at -0.4 to -0.6 mW/m2 (plus or minus 40%). Note that the global value is in milliWatts, so is 100 time smaller than the largest regional radiative effect (-0.05 W/m2 = -50 mW/m2). The negative sign arises because ship tracks are very low clouds that are very white (i.e., reflective), so when they appear they provide a more reflective surface for sunlight to bounce off, which to first order reduces the amount of energy in the climate system (because most of the reflected light goes back out to space) and cools the climate. This is familiar if you've been exposed to cloud "feedback" ideas, in which more low cloud cover increases the albedo of Earth and cools it. In fact, this is a terrific example of that effect, but we'll come to that shortly. It is also good to note that the radiative forcing associated with a doubling of atmospheric carbon dioxide is about 4 W/m2, which is itself a small signal in the total radiative budget (with 1365 W/m2 of incoming sunlight at the top of the atmosphere, distributed over a day (divide by 4) and an albedo of about 0.3 you're talking in the neighborhood of a 225 W/m2 of sunlight being absorbed at the surface, and all of global warming comes down to 4W/m2 give or take!).
Okay so before I sign off, leaving you totally confused. I wanted to point out a couple of interesting things about ship tracks that aren't necessarily in the article. First of all, it is helpful to remember why ship tracks form. The ships are steaming ahead, burning fairly dirty fuel to get where they are going, and the exhaust goes right out into the atmosphere. This exhaust contains particulate matter as well as precursors for particles, so the ship is basically making a trail of particles behind it. These particles act as nucleation sites for water, forming small cloud droplets. Because the ships spew out so much stuff, there are enough nucleation sites available to grow lots of droplets and form these linear clouds. Why don't the clouds form anyway if there's that much water in the atmosphere already? Well, a couple of reasons. One is that the relative humidity isn't quite 100% in fair weather conditions, but even if it were, water doesn't like to condense unless there are surfaces (supplied by the particles). At a relative humidity of about 80%, there just aren't enough particles floating around the clean maritime boundary layer to let the water condense into clouds. The ships provide the extra nucleation sites necessary, and make it even easier by supplying the boundary layer with hygroscopic particles, meaning the particles effectively decrease the saturation specific humidity (http://en.wikipedia.org/wiki/Hygroscopic). That just means that the particles are very efficient at turning water vapor into liquid water. So a ship goes by, spews out water-loving particles, water condenses on those particles forming droplets, and a big collection of droplets is a cloud. Fine, what else?
So okay, the ships go by and make lines of clouds, but we now know (or strongly suspect) based on Schrier et al. that the global effect of these cloud is negligible and the local effect is also pretty small. Can we be done with it then? Not quite. These clouds are a great example of the Twomey effect, which is an old idea now and just says that by increasing the number of particles in the air, the size of cloud droplets gets smaller, and when clouds are made up of small droplets they are brighter (i.e., more reflective). Coakley et al. (1987) presented ship tracks as such an example, showing with satellite data that the reflectivity of ship tracks is higher than the surrounding low-level cloud cover. This is exactly what leads to the radiative forcing that has now been estimated by Schreier et al. The important thing to recognize here is that the Coakley et al. study is essentially a proof of concept, showing that pollution can impact atmospheric radiative transfer. They definitely did not say ships were impacting global climate.
There is a related effect, sometimes called the Albrecht effect, which takes into account the change in cloud fraction associated with changes in particles in the atmosphere. It is presented by Albrecht (1989), and is also a pretty simple idea. When extra particles are put into the atmospheric boundary layer, they form droplets and brighter clouds, as discussed above. Smaller droplets can also change the formation of raindrops, or more precisely in the case of shallow maritime clouds, drizzle drops. The change is to reduce the precipitation efficiency, which increases the liquid water in the cloud layer, and can lead to an increase in the fractional cloudiness. The important point here is that not only could increased particle concentration in the marine atmospheric boundary layer make brighter clouds, but could actually increase the overall cloudiness. This would amplify the effects discussed by Coakley et al. because there would now be a larger area covered by brighter clouds. The Albrecht study makes use of ship tracks only in the sense of the Coakley et al. study, and only suggests that changes in precipitation could account for the sustained difference in ship tracks from the stratiform cloud in which they are embedded. This is supported to some extent by aircraft observations.
And finally, since we're covering so many bases, there's another effect that should be mentioned. Pincus and Baker (1994) present a study that extends the Albrecht study in that it accounts for the change in the thickness of clouds in the presence of varying particle concentration. They use a model of a cloudy boundary layer and account for changes in absorption and precipitation with cloud thickness and droplet number, respectively. This effect is not quite as "obvious" as the other indirect effects, but the bottom line is that more droplets can make thicker clouds with a higher albedo, which is thus another facet of this negative feedback associated with changes in atmospheric aerosol (particles). They note, however, that you'd expect to see ship tracks extend higher than surrounding clouds, which at that time was not observed. I'm not sure where this effect really stands, but it is interesting to consider.
So these are the indirect effects of aerosol on climate. We came a long way in this post, from a recent study showing that the globally averaged radiative forcing due to ship tracks is small all the way through aerosol effects on cloud albedo, precipitation processes, and horizontal and vertical cloud distribution. Well done. There are a lot more details that could have been added, and tons more studies. These will be left for future posts, though. I've included some references below for those of you who want to follow up.
References
Schreier, Mathias; Mannstein, Hermann; Eyring, Veronika; Bovensmann, Heinrich
Global ship track distribution and radiative forcing from 1 year of AATSR data
Geophys. Res. Lett., Vol. 34, No. 17, L17814
10.1029/2007GL030664 (LINK)
JAMES A. COAKLEY JR., ROBERT L. BERNSTEIN, and PHILIP A. DURKEE
Effect of Ship-Stack Effluents on Cloud Reflectivity
Science 28 August 1987: Vol. 237. no. 4818, pp. 1020 - 1022 DOI: 10.1126/science.237.4818.1020
BRUCE A. ALBRECHT
Aerosols, Cloud Microphysics, and Fractional Cloudiness
Science 15 September 1989: Vol. 245. no. 4923, pp. 1227 - 1230 DOI: 10.1126/science.245.4923.1227
ROBERT PINCUS & MARCIA B. BAKER
Effect of precipitation on the albedo susceptibility of clouds in the marine boundary layer
Nature 372, 250 - 252 (17 November 2002); doi:10.1038/372250a0
2007-09-11
The Arctic and its role in the climate change discourse
I spend most of my time thinking about clouds in the tropics and subtropics, but lately there's been a lot of mainstream coverage of the Arctic and how it relates to climate chage. I've posted about Arctic issues before, of course, but today I not only want to highlight a little of the coverage that I've noticed lately, but also warn you, gentle reader, that this is really just going to be one of myriad posts, articles, stories, and sundry coverage of the Arctic over the coming 2-3 years (and probably beyond). Why? Because of the "International Polar Year," which is a big enough deal to have its own domain: ipy.org. It is, as the name implies, an international effort to better understand the Earth system near the poles, from their web site:
Don't fool yourself either, this is not a group of environmental activists who are out trying prove something; this is a concentrated period of study of the Arctic and Antarctic by the people who do that work anyway. It should lead to some great collaborations and synthesis of datasets that haven't been able to be compared or incorporated in meaningful ways before.
So that is the future, what is going on now?
Well, just over the past few days I've read a few interesting tidbits about the Arctic, which people seem to enjoy discussing more than the Antarctic (but more on that later). One of the poster children for climate change awareness is the polar bear, which relies on big pieces of sea-ice floating around near other pieces of sea-ice. The bears hang out on the ice, get hungry, dive in after fish or seals, and come up onto more ice. Apparently they aren't so well adapted to feeding on land, plus there isn't as much food available on land for them. Anyway, a quick article from the BBC, which came to be via ClimateArk, reports on a study that suggests two-thirds (2/3) of the polar bear population will be gone by the middle of the century [LINK]. That's 30-50 years from now, if you're keeping score at home. Why are the bears going to disappear? Because the ice is going away. So what does that mean for a species that relies on ice rafts as hunting platforms? It means that the bears are going to starve and drown. That is a fact. There is already evidence that some populations of polar bears are losing weight, and it probably isn't in preparation for beach season (Regehr et al 2006, also Roberson 2005 (news), Obbard et al. 2006).
This leads directly into our topic number two: sea-ice. This is one of the reasons it's more interesting to talk about the Arctic than the Antarctic, actually. Think about the globe, and picture the poles; the south pole is covered by a landmass (Antarctica) which is actually pretty large, extending far from the pole before giving way to the Southern Ocean. The fact that it is land, combined with the fact that it is surrounded by a continuous ring of ocean, makes climate change near the pole more difficult to understand: the ice in the middle of Antarctica isn't melting. And the sea-ice is much more seasonal (for the most part, though don't forget the Larson B ice shelf!) than in the Arctic (we're painting with a broad brush here). The Arctic is just an ocean, really, which provides easy passage among North America, Europe, and Asia, you remember the Northwest Passage [news], except that it has historically been blocked up by sea-ice. Lately this isn't so true [news, Randy Boswell].
The opening of the Northwest Passage is due to summertime melting of sea-ice, as discussed in Randy Boswell's very nice piece above. There has always been a lot of seasonal sea-ice around the Arctic. During the winter there is little to no sunshine available to deliver energy to warm the surface or melt ice, so as temperatures drop, ice forms, and it stays there until summer when the sun comes out. So that happens every year, and is perfectly normal and expected. However, what has happened over the past few years is a tremendous summertime melting, and just about every year now we hear about how sea-ice extent and sea-ice area are reaching record lows. One of the problems with this is that there is a potential feedback, since the "permanent" sea-ice (that ice that does not melt during the summer) is being reduced each year, so during the winter the ice that grows is thin, leading to quick melting in the summer, which exposes more permanent sea-ice to warm water and sunshine, leading to more loss and a diminished base amount of ice going into the winter. This most recent report suggests that the speed of this cycle might have been underestimated, and now some experts (yes, they are experts in Arctic sea-ice) say that an ice-free Arctic (in the late summer) could exist by 2030 (Serreze et al 2007a,b), which is right around the corner. This bodes ill for the polar bears.
Finally on this subject, it is interesting to note the relationship between the absurd observed sea-ice melt in the last few years compared with our best comprehensive climate models (Serreze et al. 2007b, Overland & Wang 2007). Some of the current-generation models do sort of okay, while basically all of them show a strong trend in the Arctic, but none of the models accurately predict the magnitude of the observed trend. Let me reiterate that these models don't know anything about the observations; they are physical models of climate system forced by atmospheric composition (carbon dioxide) and sunshine, so this isn't a matter of poor data assimilation or statistical techniques or a poor model (in the sense of statistical modeling). This is a dramatic underestimation of the impact of climate change on a region of the world known to be prone to positive feedbacks. What this means is that our "uncertainty" about the future of climate change goes in both directions. Climate change deniers like to point out problems with the models that they think lead to unlikely warming, but here we have a beautiful example of the models underestimating what is actually happening. Perhaps the models are too conservative? Not really, I just wanted to be provocative for a moment. My interpretation is that we need to improve the physics in the models, and probably spend more effort in doing atmosphere-ocean-ice interactions much better than this round of climate models. That is a rant I'll save for later though, as this post is stretching the average blog reader's patience.
Some references:
Regehr, E.V., Amstrup, S.C., and Stirling, Ian, 2006, Polar bear population status in the southern Beaufort Sea: U.S.
Geological Survey Open-File Report 2006-1337, 20 p. [PDF]
Obbard, Martyn E., Marc R.L. Cattet, Tim Moody, Lyle R. Walton, Derek Potter, Jeremy Inglis, and Christopher Chenier, 2006, Temporal Trends in the Body Condition of
Southern Hudson Bay Polar Bears. Climate Change Research Information Note, Issue 3. Ministry of Natural Resources, Ontario, Canada, 8 p. [PDF, see also MNR SIT]
Serreze, M. C., M. M. Holland, and J. Stroeve. 2007. Perspectives on the Arctic's shrinking sea-ice cover. Science 315(5818): 1533-1536, doi:10.1126/science.1139426. [pdf]
Stroeve, J., M. M. Holland, W. Meier, T. Scambos, and M. Serreze. 2007. Arctic sea ice decline: Faster than forecast. Geophysical Research Letters 34, L09501, doi:10.1029/2007GL029703.
Overland, J. E., and M. Wang (2007), Future regional Arctic sea ice declines, Geophys. Res. Lett., 34, L17705, doi:10.1029/2007GL030808. [pdf]
IPY, organized through the International Council for Science (ICSU) and the World Meteorological Organization (WMO), is actually the fourth polar year, following those in 1882-3, 1932-3, and 1957-8. In order to have full and equal coverage of both the Arctic and the Antarctic, IPY 2007-8 covers two full annual cycles from March 2007 to March 2009 and will involve over 200 projects, with thousands of scientists from over 60 nations examining a wide range of physical, biological and social research topics. It is also an unprecedented opportunity to demonstrate, follow, and get involved with, cutting edge science in real-time.
Don't fool yourself either, this is not a group of environmental activists who are out trying prove something; this is a concentrated period of study of the Arctic and Antarctic by the people who do that work anyway. It should lead to some great collaborations and synthesis of datasets that haven't been able to be compared or incorporated in meaningful ways before.
So that is the future, what is going on now?
Well, just over the past few days I've read a few interesting tidbits about the Arctic, which people seem to enjoy discussing more than the Antarctic (but more on that later). One of the poster children for climate change awareness is the polar bear, which relies on big pieces of sea-ice floating around near other pieces of sea-ice. The bears hang out on the ice, get hungry, dive in after fish or seals, and come up onto more ice. Apparently they aren't so well adapted to feeding on land, plus there isn't as much food available on land for them. Anyway, a quick article from the BBC, which came to be via ClimateArk, reports on a study that suggests two-thirds (2/3) of the polar bear population will be gone by the middle of the century [LINK]. That's 30-50 years from now, if you're keeping score at home. Why are the bears going to disappear? Because the ice is going away. So what does that mean for a species that relies on ice rafts as hunting platforms? It means that the bears are going to starve and drown. That is a fact. There is already evidence that some populations of polar bears are losing weight, and it probably isn't in preparation for beach season (Regehr et al 2006, also Roberson 2005 (news), Obbard et al. 2006).
This leads directly into our topic number two: sea-ice. This is one of the reasons it's more interesting to talk about the Arctic than the Antarctic, actually. Think about the globe, and picture the poles; the south pole is covered by a landmass (Antarctica) which is actually pretty large, extending far from the pole before giving way to the Southern Ocean. The fact that it is land, combined with the fact that it is surrounded by a continuous ring of ocean, makes climate change near the pole more difficult to understand: the ice in the middle of Antarctica isn't melting. And the sea-ice is much more seasonal (for the most part, though don't forget the Larson B ice shelf!) than in the Arctic (we're painting with a broad brush here). The Arctic is just an ocean, really, which provides easy passage among North America, Europe, and Asia, you remember the Northwest Passage [news], except that it has historically been blocked up by sea-ice. Lately this isn't so true [news, Randy Boswell].
The opening of the Northwest Passage is due to summertime melting of sea-ice, as discussed in Randy Boswell's very nice piece above. There has always been a lot of seasonal sea-ice around the Arctic. During the winter there is little to no sunshine available to deliver energy to warm the surface or melt ice, so as temperatures drop, ice forms, and it stays there until summer when the sun comes out. So that happens every year, and is perfectly normal and expected. However, what has happened over the past few years is a tremendous summertime melting, and just about every year now we hear about how sea-ice extent and sea-ice area are reaching record lows. One of the problems with this is that there is a potential feedback, since the "permanent" sea-ice (that ice that does not melt during the summer) is being reduced each year, so during the winter the ice that grows is thin, leading to quick melting in the summer, which exposes more permanent sea-ice to warm water and sunshine, leading to more loss and a diminished base amount of ice going into the winter. This most recent report suggests that the speed of this cycle might have been underestimated, and now some experts (yes, they are experts in Arctic sea-ice) say that an ice-free Arctic (in the late summer) could exist by 2030 (Serreze et al 2007a,b), which is right around the corner. This bodes ill for the polar bears.
Finally on this subject, it is interesting to note the relationship between the absurd observed sea-ice melt in the last few years compared with our best comprehensive climate models (Serreze et al. 2007b, Overland & Wang 2007). Some of the current-generation models do sort of okay, while basically all of them show a strong trend in the Arctic, but none of the models accurately predict the magnitude of the observed trend. Let me reiterate that these models don't know anything about the observations; they are physical models of climate system forced by atmospheric composition (carbon dioxide) and sunshine, so this isn't a matter of poor data assimilation or statistical techniques or a poor model (in the sense of statistical modeling). This is a dramatic underestimation of the impact of climate change on a region of the world known to be prone to positive feedbacks. What this means is that our "uncertainty" about the future of climate change goes in both directions. Climate change deniers like to point out problems with the models that they think lead to unlikely warming, but here we have a beautiful example of the models underestimating what is actually happening. Perhaps the models are too conservative? Not really, I just wanted to be provocative for a moment. My interpretation is that we need to improve the physics in the models, and probably spend more effort in doing atmosphere-ocean-ice interactions much better than this round of climate models. That is a rant I'll save for later though, as this post is stretching the average blog reader's patience.
Some references:
Regehr, E.V., Amstrup, S.C., and Stirling, Ian, 2006, Polar bear population status in the southern Beaufort Sea: U.S.
Geological Survey Open-File Report 2006-1337, 20 p. [PDF]
Obbard, Martyn E., Marc R.L. Cattet, Tim Moody, Lyle R. Walton, Derek Potter, Jeremy Inglis, and Christopher Chenier, 2006, Temporal Trends in the Body Condition of
Southern Hudson Bay Polar Bears. Climate Change Research Information Note, Issue 3. Ministry of Natural Resources, Ontario, Canada, 8 p. [PDF, see also MNR SIT]
Serreze, M. C., M. M. Holland, and J. Stroeve. 2007. Perspectives on the Arctic's shrinking sea-ice cover. Science 315(5818): 1533-1536, doi:10.1126/science.1139426. [pdf]
Stroeve, J., M. M. Holland, W. Meier, T. Scambos, and M. Serreze. 2007. Arctic sea ice decline: Faster than forecast. Geophysical Research Letters 34, L09501, doi:10.1029/2007GL029703.
Overland, J. E., and M. Wang (2007), Future regional Arctic sea ice declines, Geophys. Res. Lett., 34, L17705, doi:10.1029/2007GL030808. [pdf]
2007-09-04
hurricanes again
It has been far too long since my last post... the casual blogger's constant lament. In my own defense, a lot has happened in the past few months, not the least of which is that I finished my PhD program and moved to Fort Collins, Colorado as a postdoc. I am now affiliated with both UCLA and CSU via the CMMAP project. Of course, anything I say on this blog has nothing to do with those institutions, and could still be wrong even though I am now officially an "expert."
Now to what I was going to write....
After a rather slow start, the Atlantic hurricane season is really getting going now. Early this morning Hurricane Felix came ashore along the Mosquito Coast in central America as a powerful category 5 hurricane. This is the second category 5 storm to make landfall in the past 3 weeks (following Dean), and apparently is the first time two category 5 storms have made landfall in the same season. It is also worth noting that only about 31 category 5 storms have been recorded in the Atlantic since 1928. Of course, reliable observations were not available until the 1960s; there have been 18 category 5 storms since 1966. Eight of those have occured over the past five years [2003,2007]!
The big storms are not the only story though. There is a lot of tropical activity already, including three tropical storms (Barry, Chantal, and Erin) and numerous disturbances that haven't developed. There is currently an area off the Florida coast that is probably going to develop into a tropical storm over the next few days (although there is significant wind shear). There's also a region out in the central Atlantic that could still develop, basically following the same path as Dean and Felix. These all originate as "easterly waves" coming off the west coast of Africa, and it is starting to look like it's going to be a very active season; don't be surprised to see another category 5 by the end of the month. If that does happen, it will only be the second year with more than two category 5 storms in the Atlantic.
By the way, yes there are tropical cyclones in the Pacific too! Henriette is the third East Pacific hurricane of the year (Cosme, Flossie), and although it is only a category 1 right now (possibly 2 by landfall), it is bringing substantial rain to the west coast of Mexico. In the western Pacific there have already been 7 typhoons this season and 2 tropical storms.
Now to what I was going to write....
After a rather slow start, the Atlantic hurricane season is really getting going now. Early this morning Hurricane Felix came ashore along the Mosquito Coast in central America as a powerful category 5 hurricane. This is the second category 5 storm to make landfall in the past 3 weeks (following Dean), and apparently is the first time two category 5 storms have made landfall in the same season. It is also worth noting that only about 31 category 5 storms have been recorded in the Atlantic since 1928. Of course, reliable observations were not available until the 1960s; there have been 18 category 5 storms since 1966. Eight of those have occured over the past five years [2003,2007]!
The big storms are not the only story though. There is a lot of tropical activity already, including three tropical storms (Barry, Chantal, and Erin) and numerous disturbances that haven't developed. There is currently an area off the Florida coast that is probably going to develop into a tropical storm over the next few days (although there is significant wind shear). There's also a region out in the central Atlantic that could still develop, basically following the same path as Dean and Felix. These all originate as "easterly waves" coming off the west coast of Africa, and it is starting to look like it's going to be a very active season; don't be surprised to see another category 5 by the end of the month. If that does happen, it will only be the second year with more than two category 5 storms in the Atlantic.
By the way, yes there are tropical cyclones in the Pacific too! Henriette is the third East Pacific hurricane of the year (Cosme, Flossie), and although it is only a category 1 right now (possibly 2 by landfall), it is bringing substantial rain to the west coast of Mexico. In the western Pacific there have already been 7 typhoons this season and 2 tropical storms.
2007-04-30
ye olde iron fertilizing effect
So apparently people now think they can make money by throwing iron into the ocean... YES, throwing iron into the ocean.
Here's the, actually very good, story on NYTimes.com: [The Energy Challenge: Recruiting Plankton to Fight Global Warming]
The basic idea is that plankton reproduce like mad when the conditions are right, and in large swaths of the ocean the conditions are right. Except there isn't enough iron. So, when you dump some iron on those areas, plankton bloom, creating regions of increased biological activity. The upside to this, according to some, is that the plankton use carbon from the ocean to make their little calcium carbonate exoskeletons, which when the critters die, can sink to the bottom of the ocean. This means that carbon is removed from the atmosphere-ocean system... it is sequestered, like an OJ juror. So now at least two companies, so cleverly named Planktos and Climos, think they can get governments (or companies working under cap and trade systems) to pay them to go throw some iron into the ocean.
I do not reject this idea outright. There are clearly some good ideas here, but we have to be careful. Here are a couple of my primary concerns.
First, I'm worried that these plankton species will produce a lot of methane waste, possibly negating any decrease in atmospheric CO2 that they might be responsible for. There is similar concern with nitrous oxide, apparently.
Second, the amount of carbon actually deposited might be less than has been thought recently. This is actually in this week's Science [LINK].
Third, as these operations scale up, will they account for their own carbon emissions. Boats are notoriously bad for emissions, and there's going to have to be a lot of boating involved. Also, where is this iron coming from, and how much energy (i.e., carbon) is going into collecting and transporting it?
Finally, there are possible feedbacks that could negate any good this will do. Including the old DMS-cloud condensation nuclei, in which more biology produces more aerosol (in the form of dimethylsulfide, DMS) which acts as nucleation sites for cloud droplets, making more cloud. The effect could be to shade the surface, reduce SST, and thus reduce biological productivity, leaving a rusty sea surface instead of a nice, healthy green one. I don't know if this is feasible, but things like this always seem to come up.
Also consider the amount of carbon dioxide that needs to be removed from the atmosphere. I've just come from a talk that reminded me of this. Carbon dioxide, when frozen, has about the same density as water. That means that a ton of CO2 is about one cubic meter (size of a coffee table). You're now talking about removing billions of tons of carbon dioxide annually, which is an enormous mass, many cubic kilometers of frozen CO2. The ocean is a big place, but we've got to be careful about how and where such deposits are made, or they'd just be mixed back up to the atmosphere. There's just so many potential pitfalls that it is hard to imagine a successful implementation. But as I said at the beginning, I'm willing to keep an open mind on the subject, and would be happy to see a successful strategy.
Here's the, actually very good, story on NYTimes.com: [The Energy Challenge: Recruiting Plankton to Fight Global Warming]
The basic idea is that plankton reproduce like mad when the conditions are right, and in large swaths of the ocean the conditions are right. Except there isn't enough iron. So, when you dump some iron on those areas, plankton bloom, creating regions of increased biological activity. The upside to this, according to some, is that the plankton use carbon from the ocean to make their little calcium carbonate exoskeletons, which when the critters die, can sink to the bottom of the ocean. This means that carbon is removed from the atmosphere-ocean system... it is sequestered, like an OJ juror. So now at least two companies, so cleverly named Planktos and Climos, think they can get governments (or companies working under cap and trade systems) to pay them to go throw some iron into the ocean.
I do not reject this idea outright. There are clearly some good ideas here, but we have to be careful. Here are a couple of my primary concerns.
First, I'm worried that these plankton species will produce a lot of methane waste, possibly negating any decrease in atmospheric CO2 that they might be responsible for. There is similar concern with nitrous oxide, apparently.
Second, the amount of carbon actually deposited might be less than has been thought recently. This is actually in this week's Science [LINK].
Third, as these operations scale up, will they account for their own carbon emissions. Boats are notoriously bad for emissions, and there's going to have to be a lot of boating involved. Also, where is this iron coming from, and how much energy (i.e., carbon) is going into collecting and transporting it?
Finally, there are possible feedbacks that could negate any good this will do. Including the old DMS-cloud condensation nuclei, in which more biology produces more aerosol (in the form of dimethylsulfide, DMS) which acts as nucleation sites for cloud droplets, making more cloud. The effect could be to shade the surface, reduce SST, and thus reduce biological productivity, leaving a rusty sea surface instead of a nice, healthy green one. I don't know if this is feasible, but things like this always seem to come up.
Also consider the amount of carbon dioxide that needs to be removed from the atmosphere. I've just come from a talk that reminded me of this. Carbon dioxide, when frozen, has about the same density as water. That means that a ton of CO2 is about one cubic meter (size of a coffee table). You're now talking about removing billions of tons of carbon dioxide annually, which is an enormous mass, many cubic kilometers of frozen CO2. The ocean is a big place, but we've got to be careful about how and where such deposits are made, or they'd just be mixed back up to the atmosphere. There's just so many potential pitfalls that it is hard to imagine a successful implementation. But as I said at the beginning, I'm willing to keep an open mind on the subject, and would be happy to see a successful strategy.
2007-04-27
US Army getting into supercomputers
Here's a quick story that seems like it is important. I will refrain from any interpretation of speculation here.
Army funds supercomputing center [LINK]
Army funds supercomputing center [LINK]
2007-03-21
Ex-Bush Aide Challenged on Climate Reports - New York Times
For lack of time and energy to blog, please go read an update about our friend Phil Cooney:
Ex-Bush Aide Challenged on Climate Reports - New York Times
Ex-Bush Aide Challenged on Climate Reports - New York Times
2007-02-04
IPCC AR4 - Summary for Policymakers
So you by now know, I hope, that the Intergovernmental Panel on Climate Change has issued it's Fourth Assessment Report of working group I (i.e. the "physical scientists). Okay, actually, it has only released an abstraction of the AR4 called the Summary for Policymakers. The full report will be available in a couple months. For now, get the summary from the UCAR site [PDF].
There are a lot of issues about this report and the IPCC in general that I'm tempted to start spouting. Instead, I'm going to let those thoughts roll around a little more, and perhaps wait for the full report. For today, I just want to point out some key points, about the summary, along with some cautionary words.
The report is written by climate scientists (so is the summary). All the writers, both lead authors and contributing authors, work on a voluntary basis. I think the idea, at least for the north American and European scientists, is that the IPCC is an important way for scientists to interface with the policymakers and general public, and that working on the report is an important outreach activity. The IPCC as an entity is organized under the auspices of the World Meteorological Organization (WMO) and the United Nations Nations Environment Programme (UNEP), and as such it is open to members of those organizations. That means that a lot of scientists are eligible to contribute to the report, but it also means that there are a lot of governments that have vested interests in what the report ultimately says.
Do governments influence the content of the report? Well, from what I've heard ('round the proverbial water cooler), there is very little direct interaction with world governments. Drafts of the reports are sent out to tons and tons of people, including governments, so there are notes sent back. Those notes have to be addressed individually, but I'm sure that most of them are insignificant and are basically ignored. The indirect influence is probably more important. The scientists writing the report are aware of the political/societal implications, and try to protect themselves by explicitly avoiding making prescriptive suggestions; they don't say what to do about climate change, they just evaluate the scientific evidence to evaluate the extent of climate change and projections of future change. The indirect influence of governments and economics makes the authors, in my opinion, even more conservative in their language than scientists normally are. I think the report generally does not embrace more extreme projections and predictions, which is to their credit, but is a caveat when reading the report or the summary. That is, some of the key points are probably more conservative than individual scientists would suggest.
Of course, there is also pressure to put new and important results into the report. This pressure comes less from external sources and more from the drive to show how much we've learned since the last report. There are a few points in the summary that I was surprised to see, not because they aren't important, but because I think there have to be many, many caveats. The two examples that stick out are (1) that tropical cyclones are getting more intense with global warming and (2) that patterns of precipitation will change in the future, with specific patterns emerging as robust. I'll blog more about both of these in the future, but here I'll just say that I look forward to reading the specifics in the full report. I generally believe the first claim, while the second one seems extremely poorly constrained by climate models.
Even with these opposing pressures, the results of the summary are largely unsurprising and in line with the Third Assessment Report (2001). The lower range of climate sensitivity has inched up a bit from 1.5C to 2.0 C. That basically has had to move up as we've seen more and more warming over the past decade. They are also making the upper range of possible sensitivity more hazy by mentioning some projections of greater than 5C or so, even though they don't necessarily incorporate those very sensitive projections in the non-analysis that goes into writing the report. (I'll also talk about what I mean by non-analysis in a future post.)
So, yes, global warming is happening. Oh, and yes, it is because of humans emitting carbon dioxide into the atmosphere.
There are a lot of issues about this report and the IPCC in general that I'm tempted to start spouting. Instead, I'm going to let those thoughts roll around a little more, and perhaps wait for the full report. For today, I just want to point out some key points, about the summary, along with some cautionary words.
The report is written by climate scientists (so is the summary). All the writers, both lead authors and contributing authors, work on a voluntary basis. I think the idea, at least for the north American and European scientists, is that the IPCC is an important way for scientists to interface with the policymakers and general public, and that working on the report is an important outreach activity. The IPCC as an entity is organized under the auspices of the World Meteorological Organization (WMO) and the United Nations Nations Environment Programme (UNEP), and as such it is open to members of those organizations. That means that a lot of scientists are eligible to contribute to the report, but it also means that there are a lot of governments that have vested interests in what the report ultimately says.
Do governments influence the content of the report? Well, from what I've heard ('round the proverbial water cooler), there is very little direct interaction with world governments. Drafts of the reports are sent out to tons and tons of people, including governments, so there are notes sent back. Those notes have to be addressed individually, but I'm sure that most of them are insignificant and are basically ignored. The indirect influence is probably more important. The scientists writing the report are aware of the political/societal implications, and try to protect themselves by explicitly avoiding making prescriptive suggestions; they don't say what to do about climate change, they just evaluate the scientific evidence to evaluate the extent of climate change and projections of future change. The indirect influence of governments and economics makes the authors, in my opinion, even more conservative in their language than scientists normally are. I think the report generally does not embrace more extreme projections and predictions, which is to their credit, but is a caveat when reading the report or the summary. That is, some of the key points are probably more conservative than individual scientists would suggest.
Of course, there is also pressure to put new and important results into the report. This pressure comes less from external sources and more from the drive to show how much we've learned since the last report. There are a few points in the summary that I was surprised to see, not because they aren't important, but because I think there have to be many, many caveats. The two examples that stick out are (1) that tropical cyclones are getting more intense with global warming and (2) that patterns of precipitation will change in the future, with specific patterns emerging as robust. I'll blog more about both of these in the future, but here I'll just say that I look forward to reading the specifics in the full report. I generally believe the first claim, while the second one seems extremely poorly constrained by climate models.
Even with these opposing pressures, the results of the summary are largely unsurprising and in line with the Third Assessment Report (2001). The lower range of climate sensitivity has inched up a bit from 1.5C to 2.0 C. That basically has had to move up as we've seen more and more warming over the past decade. They are also making the upper range of possible sensitivity more hazy by mentioning some projections of greater than 5C or so, even though they don't necessarily incorporate those very sensitive projections in the non-analysis that goes into writing the report. (I'll also talk about what I mean by non-analysis in a future post.)
So, yes, global warming is happening. Oh, and yes, it is because of humans emitting carbon dioxide into the atmosphere.
2007-01-09
Newsflash? No.
Well, according to NOAA's National Climatic Data Center, 2006 was even warmer than 2005. That means, if you haven't been keeping score, that 2006 was the warmest year on record (for the USA). I didn't find an actual ranking for the global mean temperature, but I think we can safely assume 2006 was in the top 5 (if not the top 2). The press release blames (rightly, for a change) ENSO (which is El Nino) for the getting 2006 into the top seat. It turns out December was really hot, mostly because there weren't very many storms crossing the country. My suspicion is that this El Nino will continue to make this winter much warmer than average, and 2007 will beat 1998 and 2006 as the warmest year in the past 1000+ years.
LINK TO NCDC
LINK TO NCDC
2006-12-12
meltdown
I don't have time to really think too hard about this story, but it is making the rounds, so I'll at least acknowledge it. Some NCAR simulations now predict essentially no late-summer ice in the Arctic by 2040. See the story at BBC [LINK] or at Nature [LINK]. The actual paper is in Geophysical Research Letters [doi:10.1029/2006GL028024].
What does this mean? Well, I haven't had a chance to look closely at the paper, but I have some first impressions. I did get a sneak-peek of these results this summer, and at the same time was introduced to some of the details of the sea-ice model used in CCSM (NCAR's climate model), so maybe I'll be able to say something halfway meaningful. The paper itself does not predict an ice-free Arctic in 2040, so let's just get that out of the way. This paper is really about the possibility of abrupt decreases in sea-ice in a changing climate, and the current generation of climate models suggest a real possibility of large reductions in perennial ice coverage in the first half of the 21st century. The main focus is a set of CCSM simulations using one of the emissions scenarios from IPCC. They also take a look at some of the results from other IPCC models. The CCSM always has what the authors call "abrupt reductions" in Arctic ice, and several of the other models also show large reductions.
I am willing to accept these results, but I think some skepticism has to be exercised still. First off, this is a GRL paper, which is a journal of short, usually preliminary, work focusing on "sexy" results. The peer-review process for GRL is sometimes thought to be a little lax, and sometimes the quality of the work is questionable. That does not seem to be an issue for this paper; the CCSM is a respected climate model, the authors are top-notch climate scientists, and this work is presented well. That said, this is not the last word on this project; I'm sure that the authors are doing more detailed work and are planning a longer, more careful analysis for another journal (e.g., Journal of Climate, Climate Dynamics). The best thing that could do would be to better quantify what "abrupt changes" really are, and the physical processes that trigger them, which is a big open question in this paper. They say the abrupt changes are driven by thermodynamics, but don't really present evidence of this; I assume they mean that wind patterns/ocean currents are changing to just move ice out of the Arctic, but it is not explained. The other thing to keep in mind is that even in the current generation climate models, the sea-ice models are fairly crude. I don't mean that in a bad way, the people working on these models are doing the best they can. Ice processes are quite complicated, and to properly model sea-ice, much like "properly" modeling clouds, the simulations need to be run in much higher resolutions. That kind of resolution is too expensive right now, and even if the resources were there, it would be a tough sell to dedicate it to the sea-ice component rather than better atmospheric and oceanic components. This particular climate model is known to be fairly sensitive, and when it gets knocked out of equilibrium, the sea-ice is one of the things known to respond fairly erradically. So while I think the CCSM, and several other high-end climate models, can get a lot of important changes correct, we still can't trust the details of these fully coupled simulations. My interpretation is then something like this: in the near future (50 years), it is likely that rapid reductions in perennial Arctic sea-ice will be observed, associated with (but not well-correlated with) increasing atmospheric greenhouse gases.
What does this mean? Well, I haven't had a chance to look closely at the paper, but I have some first impressions. I did get a sneak-peek of these results this summer, and at the same time was introduced to some of the details of the sea-ice model used in CCSM (NCAR's climate model), so maybe I'll be able to say something halfway meaningful. The paper itself does not predict an ice-free Arctic in 2040, so let's just get that out of the way. This paper is really about the possibility of abrupt decreases in sea-ice in a changing climate, and the current generation of climate models suggest a real possibility of large reductions in perennial ice coverage in the first half of the 21st century. The main focus is a set of CCSM simulations using one of the emissions scenarios from IPCC. They also take a look at some of the results from other IPCC models. The CCSM always has what the authors call "abrupt reductions" in Arctic ice, and several of the other models also show large reductions.
I am willing to accept these results, but I think some skepticism has to be exercised still. First off, this is a GRL paper, which is a journal of short, usually preliminary, work focusing on "sexy" results. The peer-review process for GRL is sometimes thought to be a little lax, and sometimes the quality of the work is questionable. That does not seem to be an issue for this paper; the CCSM is a respected climate model, the authors are top-notch climate scientists, and this work is presented well. That said, this is not the last word on this project; I'm sure that the authors are doing more detailed work and are planning a longer, more careful analysis for another journal (e.g., Journal of Climate, Climate Dynamics). The best thing that could do would be to better quantify what "abrupt changes" really are, and the physical processes that trigger them, which is a big open question in this paper. They say the abrupt changes are driven by thermodynamics, but don't really present evidence of this; I assume they mean that wind patterns/ocean currents are changing to just move ice out of the Arctic, but it is not explained. The other thing to keep in mind is that even in the current generation climate models, the sea-ice models are fairly crude. I don't mean that in a bad way, the people working on these models are doing the best they can. Ice processes are quite complicated, and to properly model sea-ice, much like "properly" modeling clouds, the simulations need to be run in much higher resolutions. That kind of resolution is too expensive right now, and even if the resources were there, it would be a tough sell to dedicate it to the sea-ice component rather than better atmospheric and oceanic components. This particular climate model is known to be fairly sensitive, and when it gets knocked out of equilibrium, the sea-ice is one of the things known to respond fairly erradically. So while I think the CCSM, and several other high-end climate models, can get a lot of important changes correct, we still can't trust the details of these fully coupled simulations. My interpretation is then something like this: in the near future (50 years), it is likely that rapid reductions in perennial Arctic sea-ice will be observed, associated with (but not well-correlated with) increasing atmospheric greenhouse gases.
2006-12-07
Would I qualify?
A small story, ultimately of no consequence, suggesting the "need" for a Nobel Prize for the Environment: LINK.
Funny as it may sound, I don't think it would be a very good idea to add such a prize. I would like to see more earth scientists honored for their contributions to understanding physics, chemistry, and dynamical system, but the Nobel prizes are so high profile, and climate change such a charged issue, I think such a prize would be politicized immediately. That would sully the award, because there would always be questions about why people get the prize. Not only that, but it would be difficult to separate scientific achievment in understanding the environment from conservation of the environment, which is more social science or economics or political or who knows what. If conservation groups tended to be awarded the prize, then earth scientists would be even less likely to be honored, since they wouldn't get the environment prize and they'd usually be excluded from the physics or chemistry prizes.
There is also the issue of the maturity of the fields of meteorology, oceanography, climate dynamics, environmental sciences, and such. While those of us in the field could come up with a list of deserving people, it would be difficult after a few years to say with confidence that a person(s) have made a lasting positive contribution. This comes up in the other science prizes when people complain that awardees get the award decades after the work, but the defense is that it takes that long to figure out what work needs to be honored. We don't really have very many decades of work to choose from (of course, excluding the early pioneers like Bjerknes, Charney, Richardson, Ekman, von Neuman, and many other dead folks).
Funny as it may sound, I don't think it would be a very good idea to add such a prize. I would like to see more earth scientists honored for their contributions to understanding physics, chemistry, and dynamical system, but the Nobel prizes are so high profile, and climate change such a charged issue, I think such a prize would be politicized immediately. That would sully the award, because there would always be questions about why people get the prize. Not only that, but it would be difficult to separate scientific achievment in understanding the environment from conservation of the environment, which is more social science or economics or political or who knows what. If conservation groups tended to be awarded the prize, then earth scientists would be even less likely to be honored, since they wouldn't get the environment prize and they'd usually be excluded from the physics or chemistry prizes.
There is also the issue of the maturity of the fields of meteorology, oceanography, climate dynamics, environmental sciences, and such. While those of us in the field could come up with a list of deserving people, it would be difficult after a few years to say with confidence that a person(s) have made a lasting positive contribution. This comes up in the other science prizes when people complain that awardees get the award decades after the work, but the defense is that it takes that long to figure out what work needs to be honored. We don't really have very many decades of work to choose from (of course, excluding the early pioneers like Bjerknes, Charney, Richardson, Ekman, von Neuman, and many other dead folks).
2006-12-05
Down under, where the carbon is.
Today's little tidbit is a short news story about a Journal of Climate paper [LINK]. The paper is about a climate simulation that includes an ocean (and presumably a carbon cycle model). The bottom line is that they think they have a credible southern hemisphere atmospheric circulation, with then drives a realistic Antarctic circumpolar current. If you have never done so, go get a globe and look at it from the "bottom," so you are looking right at the south pole; notice that there is a ring of water around Antarctica. That's the only place where that happens, and it makes a big difference to the world's climate. Anyway, they say that as the winds around Antarctica move south, they change the uptake of carbon dioxide into the ocean, which partially offsets the climate change associated with the anthropogenic greenhouse effect. That's good! Unfortunately, it also accelerates sea level rise (by pumping heat into the ocean, raising the temperature faster) and ocean acidification (which might feed back onto the carbon cycle if critters start dying off). So there you go. Maybe I'll try to tap Nikki for more nuianced insight, since this is closely related to her work.
2006-11-17
mid-term updates
The dearth of posts here for the last month should be taken as an indication of progress and stress here at the home base. It is difficult to save the world one simulated cloud at a time, but it will be worth it. The blog will likely continue to suffer in coming months, but I will try to put up interesting tidbits on a weekly-ish basis.
Today's tidbit is about supercomputers. What do I know about supercomputers? Not too much, but sometimes I use them. Okay, sometimes I use small little chunks of them (anywhere from 8 to 128 processors right now, maybe more in the near future). However, people who do know about high-performance computing are abuzz about the new rankings of the top 500 supercomputers [LINK]. The IBM machine at the Lawrence Livermore National Lab is destroying its competition, running at an impressive 280.6 teraflops. That is 280.6 trillion operations per second, where an operation is basically adding or multiplying some numbers. A nice desktop computer can usually crank out about one billion operations per second (1 gigaflops), which is 280,600 times less than the BlueGene/L at LLNL. The next closest speed to the BlueGene/L is at Sandia National Lab, which runs a Cray (called "red storm") that gets 101.4 teraflops. That seems like nothing in comparison, but it is only the second system to break the 100 TFLOPS barrier.
For comparison, the Earth-Simulator in Japan (made from NEC parts, 5120 processors) is now ranked 14th at about 35 TFLOPS. That facility is still considered an amazing feat, and the atmospheric simulations coming from them are still astounding people in the atmospheric sciences [EXAMPLE]. NCAR's newest machine (one I definitely do not have access to) is "blueice," an IBM machine running 1696 processors at 10.5 TFLOPS.... I think this machine is getting expanded very soon, too. They also have a BlueGene to play with that is ranked 144, using 2048 processors, and IBM machines (1600, 608 processors) at numers 193 and 213.
Why does any of this matter? Well, for one thing, we are inching closer and closer to the ultimate goal. Also, we are on the brink of "peta-scale" computing, which is probably going to change the way computational science gets done. We'll be able to do simulations much faster with much finer resolutions, which will produce incredible amounts of data. It will be a challenge over the next few years to develop ways to deal with all that data. It will require different software approaches as well as new hardware. With standard desktop technology of today, the file I/O (that is, just reading the data from the hard disk) is far too slow to deal with the amount of information that we're going to be dealing with. Crunching the numbers and then visualizing the model output is going to be tremendously difficult without an incredible amount of support from computer-savvy folks who can help the scientists. The technology is coming, money is already being spent, projects are being planned, so now is the time to start thinking about how to deal with the output.
Today's tidbit is about supercomputers. What do I know about supercomputers? Not too much, but sometimes I use them. Okay, sometimes I use small little chunks of them (anywhere from 8 to 128 processors right now, maybe more in the near future). However, people who do know about high-performance computing are abuzz about the new rankings of the top 500 supercomputers [LINK]. The IBM machine at the Lawrence Livermore National Lab is destroying its competition, running at an impressive 280.6 teraflops. That is 280.6 trillion operations per second, where an operation is basically adding or multiplying some numbers. A nice desktop computer can usually crank out about one billion operations per second (1 gigaflops), which is 280,600 times less than the BlueGene/L at LLNL. The next closest speed to the BlueGene/L is at Sandia National Lab, which runs a Cray (called "red storm") that gets 101.4 teraflops. That seems like nothing in comparison, but it is only the second system to break the 100 TFLOPS barrier.
For comparison, the Earth-Simulator in Japan (made from NEC parts, 5120 processors) is now ranked 14th at about 35 TFLOPS. That facility is still considered an amazing feat, and the atmospheric simulations coming from them are still astounding people in the atmospheric sciences [EXAMPLE]. NCAR's newest machine (one I definitely do not have access to) is "blueice," an IBM machine running 1696 processors at 10.5 TFLOPS.... I think this machine is getting expanded very soon, too. They also have a BlueGene to play with that is ranked 144, using 2048 processors, and IBM machines (1600, 608 processors) at numers 193 and 213.
Why does any of this matter? Well, for one thing, we are inching closer and closer to the ultimate goal. Also, we are on the brink of "peta-scale" computing, which is probably going to change the way computational science gets done. We'll be able to do simulations much faster with much finer resolutions, which will produce incredible amounts of data. It will be a challenge over the next few years to develop ways to deal with all that data. It will require different software approaches as well as new hardware. With standard desktop technology of today, the file I/O (that is, just reading the data from the hard disk) is far too slow to deal with the amount of information that we're going to be dealing with. Crunching the numbers and then visualizing the model output is going to be tremendously difficult without an incredible amount of support from computer-savvy folks who can help the scientists. The technology is coming, money is already being spent, projects are being planned, so now is the time to start thinking about how to deal with the output.
2006-10-03
The Ozone Hole is confusing
I've been seeing small news items over the past week or two saying that this year's Antarctic ozone hole has matched the previous record, and that the amount of ozone is the lowest ever [e.g., LINK]. While this is interesting and important news, I'm wondering if it might confuse people. Afterall, a lot, way more than you think, of people think there is a direct link between anthropogenic global warming and the ozone hole. Not just laypeople on the street either, smart and usually-informed people think this. Climate scientists everywhere are constantly being forced to correct people at cocktail parties and other social events. "No, the ozone hole is due to chemicals called CFCs in the upper atmosphere; global warming has to do with burning fossil fuels."
After the gigantic ozone hole of 2000, the size has actually decreased, leading most to believe that the Montreal Protocol of 1987 was a smashing success, and that the hole would disappear in 50 years or so. Actually, that is still what most people in the know are thinking.
So what's with the new big ozone hole? Well, it may have something to do with global warming. Sigh.
Basically, every winter (in Antarctica the winter is during June-July-August) it gets really, really, really cold around and over Antarctica. Because of the geography of the southern hemisphere, there are incredibly strong winds that essentially circle around the continent of Antarctica. Cold air basically gets trapped inside this huge votex, and has nothing better to do than get even colder, all winter. During this deep freeze, polar stratospheric clouds (PSCs) can form, in which molecular chlorine can form (Cl2), and the stronger the vortex, the larger the PSCs and the more Cl2 can form.
When the spring comes, sunlight is added to the equation. Sunlight easily breaks the molecular chlorine into atmoic chlorine. The atomic chlorine (Cl) quickly reacts in a chain of events that destroys ozone; it's a catalytic reaction; a single chlorine atom can tear apart many ozone molecules. This is why the ozone hole appears suddenly in September, when the sun finally shines on the pole.
How is this related to global warming? Well, the same course of events happens year in and year out, but there is variability, of course. Because of the international agreement to eliminate the use of CFCs, every year the amount of CFCs decreases. As a side note, CFCs get absorbed by the upper ocean, and are used as a great passive tracer to study ocean motion. Even with the decrease, the coldness of the winter is still quite variable. The colder the winter, the stronger the polar vortex, the more PSCs can form and condition the stratosphere for ozone depletion. It is possible that the large-scale circulation pattern of the southern hemisphere could adjust to make the polar night colder even as the global surface temperature rises. A paper from 2000 explores some of these issues of synergy between stratospheric ozone depletion and greenhouse gas warming (Hartmann et al, 2000, PNAS). This is ongoing research, as the question of how the circulation will adjust to a warmer world is hard to answer, but my feeling is that more and more people seem to think that the change might favor these extremely cold winters with a strong polar vortex and favorable conditions for ozone depletion.
By the way, Cambridge has a nice ozone hole web site: LINK
After the gigantic ozone hole of 2000, the size has actually decreased, leading most to believe that the Montreal Protocol of 1987 was a smashing success, and that the hole would disappear in 50 years or so. Actually, that is still what most people in the know are thinking.
So what's with the new big ozone hole? Well, it may have something to do with global warming. Sigh.
Basically, every winter (in Antarctica the winter is during June-July-August) it gets really, really, really cold around and over Antarctica. Because of the geography of the southern hemisphere, there are incredibly strong winds that essentially circle around the continent of Antarctica. Cold air basically gets trapped inside this huge votex, and has nothing better to do than get even colder, all winter. During this deep freeze, polar stratospheric clouds (PSCs) can form, in which molecular chlorine can form (Cl2), and the stronger the vortex, the larger the PSCs and the more Cl2 can form.
When the spring comes, sunlight is added to the equation. Sunlight easily breaks the molecular chlorine into atmoic chlorine. The atomic chlorine (Cl) quickly reacts in a chain of events that destroys ozone; it's a catalytic reaction; a single chlorine atom can tear apart many ozone molecules. This is why the ozone hole appears suddenly in September, when the sun finally shines on the pole.
How is this related to global warming? Well, the same course of events happens year in and year out, but there is variability, of course. Because of the international agreement to eliminate the use of CFCs, every year the amount of CFCs decreases. As a side note, CFCs get absorbed by the upper ocean, and are used as a great passive tracer to study ocean motion. Even with the decrease, the coldness of the winter is still quite variable. The colder the winter, the stronger the polar vortex, the more PSCs can form and condition the stratosphere for ozone depletion. It is possible that the large-scale circulation pattern of the southern hemisphere could adjust to make the polar night colder even as the global surface temperature rises. A paper from 2000 explores some of these issues of synergy between stratospheric ozone depletion and greenhouse gas warming (Hartmann et al, 2000, PNAS). This is ongoing research, as the question of how the circulation will adjust to a warmer world is hard to answer, but my feeling is that more and more people seem to think that the change might favor these extremely cold winters with a strong polar vortex and favorable conditions for ozone depletion.
By the way, Cambridge has a nice ozone hole web site: LINK
2006-09-25
Slate misunderstands wine AND global warming
Last friday, Slate.com posted an article by Joel Waldfogel called "Go North, Young Grapes: The effect of global warming on the world's vineyards." I was excited to see it, since I'm really interested in both global warming and wine. However, after reading it, I find several major deficiencies, some of which are obvious errors in understanding what global warming is and how plants, specifically grape vines, work.
The article reports on something called a "working paper" by Orley Ashenfelter and Karl Storchmann, who I think are economists. The paper is called "Using a Hedonic Model of Solar Radiation to Assess the Economic Effect of Climate Change: The Case of Mosel Valley Vineyards," written for the National Bureau of Economic Research, Inc., whatever that is. I have looked at this paper, which you can find through the RePEc (Research Papers in Economics) web site [LINK,pdf], and so I will let Joel Waldfogel off the hook for a time while we discuss the paper itself.
Section 2B of the paper states, "it is apparent that
total solar radiation is highly dependent on the amount, kind and density of clouds, and varies
with time and place. For the sake of simplicity engineers often calculate the so-called
extraterrestrial radiation, that is, the radiation that would be available if there were no
atmosphere (Duffie and Beckman, 1991)." What this means to me is that they don't want to account for variations in the atmosphere (weather and such, you know, that's not important), so they are going to use what I would call solar insolation. However, that varies only with latitude and time of year, and they are calculating it at the ground, so they ignore the atmosphere but take into account the slope of the ground. Okay, well, I'll tell you why that is a poor assumption shortly.
Let me now quote from section 2D:
"D. Other Factors that Affect Vineyard Sites Gladstones (1992) provides a detailed analysis of several other factors that make specific geographic sites more or less suitable for the production of high quality grapes. Important factors include those that reduce diurnal (night-day) temperature differences. Nearness to a body of water and, especially, soil type are important determinants of diurnal fluctuations..."
Hold on to this for our discussion below.
Before going on to the analysis, the authors discuss the data for vineyard prices, and how they take into account non-south-facing slopes, altitude, and soil characteristics. There are gross assumptions built into these choices, which I will ignore here. However, let's just say that vineyards don't necessarily suffer from being farther away from bodies of water, despite the authors' assumption. One aspect that might be worth mentioning here is that the authors state that they think vineyards far from large bodies of water will be hurt because they don't have smaller diurnal temperature fluctuations; as I understand it, grapes do extremely well in conditions where there is large diurnal variation.... the hot days and cool nights of California's Napa, Sonoma, and Mendocino counties come to mind.
So how do they do global warming without an atmosphere? Well, they don't. They do a very simple energy flux calculation using blackbody radiation, albedo (reflectivity) and an "emissivity." Fair, except that instead of actually considering something resembling an emissivity, the authors choose to assume that the energy emitted from the surface is half of that emitted from the atmosphere. Crude to say the least, especially when it would have been easy to do much better. So they are sort of taking account of the greenhouse effect, since they'll get temperatures that are way too cold if they don't. They then plug in a temperature change associated with global warming, and get the amount of "radiation energy" that must be associated with that change, and they continue to assert this is "solar radiation" (actually in their figure they say "positive net radiation" which is correct).
Here's the thing. They set up their model using solar insolation, or atmosphere-free radiative flux at the surface, but then they try to apply a climate change that relies on a crude assumption about the atmosphere. This is inconsistent. They could have done better, but let us accept it. A greater problem is that they are making a model based on how agriculture should use incident solar radiation, which is visible light. Yes, there is a connection between sunshine and temperature, but plants are highly dependent on the actual sunshine for photosynthesis, not temperature alone. This is a complex biological relationship the authors fail to take into account.
They mention that there are other factors that affect vineyards, as quoted above. A critical one is the night-day temperature variation. The model punishes vineyards for having a large/larger diurnal variation, including an assumption that higher altitude vineyards are farther from water, must have larger day-night temperature variations, and therefore suffer more from "global warming." I'm just not sure why they do that, as I've learned that wine grapes are better with large diurnal cycles, and also wines made from mountainside vineyards are among the most prized/collected wines in the world. This is actually going to be important too, because in global warming scenarios, the diurnal variation is often affected more than the actual maximum temperature. That is because the effect is in the infrared, not the visible light, so after the sun goes down the surface can't cool as efficiently because the atmosphere is warmed. That means minimum temperatures get higher, and they change more than daytime maximum temperatures, which reduces the diurnal variation. The authors ignore this fact.
The major deficiency of the paper is the assumption that plants will thrive under warmer conditions based on energy input arguments. While it is true that there will be a larger energy flux into the surface under global warming, this energy will be in the infrared, which does not necessarily benefit plants. In marginal growing areas where occasional freezing conditions damage crops during the growing season, increases in daily minimum temperatures might reduce the occurence of these freezes, but the increased energy flux will not increase photosynthetic activity. Vineyards will not benefit directly from global warming by absorbing more radiant energy.
A more appropriate hypothesis to test is whether the changes in growing season length might affect vineyards. Since "spring" will start earlier, plants might respond by starting their growth cycle earlier. Autumn-like temperatures will come slightly later, so the growing season my be extended further. In the case of vineyards, this might allow grapes to ripen more, which increases the sugar content of the berries and increases the alcohol content of the wine. More importantly, different grape varieties might benefit by a longer growing season, so areas that only grow grapes with a short "hang time" now might be able to expand to other longer "hang time" varieties. Regions that don't have a long enough growing season to properly ripen grapes might get a boost and obtain growing seasons long enough to produce them (thinking especially of regions of Oregon and Washington).
Existing vineyards are unlikely to be affected by global warming, especially in established regions with strong control on growing practices (e.g., Bordeaux, Burgundy). It is possible that the nature of the wine will change, as warmer days and nights might change the sugar levels of grapes, or various other aspects of the fruit. It is also possible that changes in rainfall patterns will significantly alter the agricultural practices, and the possibility of severe droughts and floods putting more vintages in jeopardy in the future is a distinct threat.
The article reports on something called a "working paper" by Orley Ashenfelter and Karl Storchmann, who I think are economists. The paper is called "Using a Hedonic Model of Solar Radiation to Assess the Economic Effect of Climate Change: The Case of Mosel Valley Vineyards," written for the National Bureau of Economic Research, Inc., whatever that is. I have looked at this paper, which you can find through the RePEc (Research Papers in Economics) web site [LINK,pdf], and so I will let Joel Waldfogel off the hook for a time while we discuss the paper itself.
Section 2B of the paper states, "it is apparent that
total solar radiation is highly dependent on the amount, kind and density of clouds, and varies
with time and place. For the sake of simplicity engineers often calculate the so-called
extraterrestrial radiation, that is, the radiation that would be available if there were no
atmosphere (Duffie and Beckman, 1991)." What this means to me is that they don't want to account for variations in the atmosphere (weather and such, you know, that's not important), so they are going to use what I would call solar insolation. However, that varies only with latitude and time of year, and they are calculating it at the ground, so they ignore the atmosphere but take into account the slope of the ground. Okay, well, I'll tell you why that is a poor assumption shortly.
Let me now quote from section 2D:
"D. Other Factors that Affect Vineyard Sites Gladstones (1992) provides a detailed analysis of several other factors that make specific geographic sites more or less suitable for the production of high quality grapes. Important factors include those that reduce diurnal (night-day) temperature differences. Nearness to a body of water and, especially, soil type are important determinants of diurnal fluctuations..."
Hold on to this for our discussion below.
Before going on to the analysis, the authors discuss the data for vineyard prices, and how they take into account non-south-facing slopes, altitude, and soil characteristics. There are gross assumptions built into these choices, which I will ignore here. However, let's just say that vineyards don't necessarily suffer from being farther away from bodies of water, despite the authors' assumption. One aspect that might be worth mentioning here is that the authors state that they think vineyards far from large bodies of water will be hurt because they don't have smaller diurnal temperature fluctuations; as I understand it, grapes do extremely well in conditions where there is large diurnal variation.... the hot days and cool nights of California's Napa, Sonoma, and Mendocino counties come to mind.
So how do they do global warming without an atmosphere? Well, they don't. They do a very simple energy flux calculation using blackbody radiation, albedo (reflectivity) and an "emissivity." Fair, except that instead of actually considering something resembling an emissivity, the authors choose to assume that the energy emitted from the surface is half of that emitted from the atmosphere. Crude to say the least, especially when it would have been easy to do much better. So they are sort of taking account of the greenhouse effect, since they'll get temperatures that are way too cold if they don't. They then plug in a temperature change associated with global warming, and get the amount of "radiation energy" that must be associated with that change, and they continue to assert this is "solar radiation" (actually in their figure they say "positive net radiation" which is correct).
Here's the thing. They set up their model using solar insolation, or atmosphere-free radiative flux at the surface, but then they try to apply a climate change that relies on a crude assumption about the atmosphere. This is inconsistent. They could have done better, but let us accept it. A greater problem is that they are making a model based on how agriculture should use incident solar radiation, which is visible light. Yes, there is a connection between sunshine and temperature, but plants are highly dependent on the actual sunshine for photosynthesis, not temperature alone. This is a complex biological relationship the authors fail to take into account.
They mention that there are other factors that affect vineyards, as quoted above. A critical one is the night-day temperature variation. The model punishes vineyards for having a large/larger diurnal variation, including an assumption that higher altitude vineyards are farther from water, must have larger day-night temperature variations, and therefore suffer more from "global warming." I'm just not sure why they do that, as I've learned that wine grapes are better with large diurnal cycles, and also wines made from mountainside vineyards are among the most prized/collected wines in the world. This is actually going to be important too, because in global warming scenarios, the diurnal variation is often affected more than the actual maximum temperature. That is because the effect is in the infrared, not the visible light, so after the sun goes down the surface can't cool as efficiently because the atmosphere is warmed. That means minimum temperatures get higher, and they change more than daytime maximum temperatures, which reduces the diurnal variation. The authors ignore this fact.
The major deficiency of the paper is the assumption that plants will thrive under warmer conditions based on energy input arguments. While it is true that there will be a larger energy flux into the surface under global warming, this energy will be in the infrared, which does not necessarily benefit plants. In marginal growing areas where occasional freezing conditions damage crops during the growing season, increases in daily minimum temperatures might reduce the occurence of these freezes, but the increased energy flux will not increase photosynthetic activity. Vineyards will not benefit directly from global warming by absorbing more radiant energy.
A more appropriate hypothesis to test is whether the changes in growing season length might affect vineyards. Since "spring" will start earlier, plants might respond by starting their growth cycle earlier. Autumn-like temperatures will come slightly later, so the growing season my be extended further. In the case of vineyards, this might allow grapes to ripen more, which increases the sugar content of the berries and increases the alcohol content of the wine. More importantly, different grape varieties might benefit by a longer growing season, so areas that only grow grapes with a short "hang time" now might be able to expand to other longer "hang time" varieties. Regions that don't have a long enough growing season to properly ripen grapes might get a boost and obtain growing seasons long enough to produce them (thinking especially of regions of Oregon and Washington).
Existing vineyards are unlikely to be affected by global warming, especially in established regions with strong control on growing practices (e.g., Bordeaux, Burgundy). It is possible that the nature of the wine will change, as warmer days and nights might change the sugar levels of grapes, or various other aspects of the fruit. It is also possible that changes in rainfall patterns will significantly alter the agricultural practices, and the possibility of severe droughts and floods putting more vintages in jeopardy in the future is a distinct threat.
2006-09-15
Sun spots only predict hemlines
This week's Nature has a short review article about the effect of variations in the Sun's luminosity on Earth's climate. In fact, most of the article is about trying to understand the Sun's luminosity and the solar physics at work. In the end, I think the important thing to glean is that there is a well-known 11-year sunspot cycle, and sunspots are cooler than the solar surface. However, when there are lots of sunspots, the sun is actually a bit brighter than normal because of faculae and the "magnetic network" of bright thermal "leaks," that let more energy escape the solar surface. All the evidence points to variations is luminosity (brightness or energy flux) being due almost entirely to magnetic field variations. Not so surprising perhaps. More surprising is that as hard as people try to find secular variability in the luminosity, it doesn't seem to change much. Even less surprising is that the variations that are observed, and inferred from proxies, should have a minimal influence on Earth's climate. This, despite global warming denialists always talking about "solar variability" as if it were a well-known, well understood phenomenon.
Here's something that hardly ever gets said out loud: climate scientists know at least as much about climate as solar physicists know about the sun. There, I said it. The two fields are covered in very different ways in popular press, though. Why? My little theory goes like this: People (general public, policymakers, media) can associate solar physics with astrophysics, which is like physics, which they (usually) didn't understand when they took it in high school/college compared; climate science, on the other hand, is not like physics (to them), and maybe it is more like meteorology, which is like the weather report, which is always wrong (right? Actually, no, but that is the perception.) So there is this tendency to not believe the "climate scientists" or "climatologists" (an even worse term) when they publish a new result, and this skepticism is amplified because there are so often controversial policy consequences/implications that bring out more vocal opposition and "fair and balanced" sort of treatment in the media. Contrast that with findings about the sun or stars or astronomy in general, which is mostly covered as amazing and important new scientific facts (unless it has to do with defining planets!). So that sort of sums up my pet theory.
Here's something that hardly ever gets said out loud: climate scientists know at least as much about climate as solar physicists know about the sun. There, I said it. The two fields are covered in very different ways in popular press, though. Why? My little theory goes like this: People (general public, policymakers, media) can associate solar physics with astrophysics, which is like physics, which they (usually) didn't understand when they took it in high school/college compared; climate science, on the other hand, is not like physics (to them), and maybe it is more like meteorology, which is like the weather report, which is always wrong (right? Actually, no, but that is the perception.) So there is this tendency to not believe the "climate scientists" or "climatologists" (an even worse term) when they publish a new result, and this skepticism is amplified because there are so often controversial policy consequences/implications that bring out more vocal opposition and "fair and balanced" sort of treatment in the media. Contrast that with findings about the sun or stars or astronomy in general, which is mostly covered as amazing and important new scientific facts (unless it has to do with defining planets!). So that sort of sums up my pet theory.
2006-08-31
Most Important Science Story of the Month
The observational confirmation of dark matter. [LINK] Far and away the most important science story for the month, and will definitely be in the top 10 for the year.
This is a great example of how science works. A set of physical rules seemed to make sense, but something didn't fit. Physicists thought they understood how gravity worked (at large scales), but galaxies and clusters of galaxies didn't seem to obey it. It was as if there were more mass that could be measured. A lot of explanations were presented, but one called dark matter seemed to come to the fore. The idea is that there is matter that interacts gravitationally, but we can't actually see it. This conjecture seems to be proved now with observations.
Guess what, science works!
Someone tell Congress.
This is a great example of how science works. A set of physical rules seemed to make sense, but something didn't fit. Physicists thought they understood how gravity worked (at large scales), but galaxies and clusters of galaxies didn't seem to obey it. It was as if there were more mass that could be measured. A lot of explanations were presented, but one called dark matter seemed to come to the fore. The idea is that there is matter that interacts gravitationally, but we can't actually see it. This conjecture seems to be proved now with observations.
Guess what, science works!
Someone tell Congress.
2006-08-30
Deniers try to misrepresent science.
A nice blog entry has been posted over on Deltoid, of ScienceBlogs [LINK]. It shows Hansen's 1988 climate model predictions of global warming along with observed global temperature. Despite how crude climate models were in 1988, Hansen's predictions are pretty much spot on. It is especially interesting to look at 1993, where the observations take a nosedive because of Mt. Pinatubo. They "recover" in about 2 years. Note that the credit on the figure is to the GISS page [LINK], but neither the blue line nor the extension of the red line (both observations) from 1998 to 2005 is on that page, and I don't know where that data come from. I tend to believe it though. If I find a better reference, I'll post it.
UPDATE: The red line (observations) actually isn't extended. Instead another dataset (blue) is just overlaid.
UPDATE: The red line (observations) actually isn't extended. Instead another dataset (blue) is just overlaid.
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