I just sat down to have a quick look at some of the (too many) RSS feeds I subscribe to, and I clicked on ClimateArk.org, which is essentially an environmental news aggregator. Five headlines appeared in my Google Reader screen. They highlight one of the directions that seems more and more relevant to climate science and policy: regional impacts of climate change. As the entire planet warms slightly, there will be substantial, life-altering changes to some regions, while others will be largely unaffected. Well, at least not as directly affected as some. Understanding these regional variations and predicting where they will occur and estimating the impact of changes in the physical system to ecosystems and populations is an emerging science. Even with relatively well-understood effects, like decreasing snow cover and melting permafrost in the far north, have unknown consequences (like understanding how much methane will be released when the permafrost melts).
The articles that came up on ClimateArk.org show some additional examples. First, form the Senate Foreign Relations Committee held hearings about how climate change will impact national security. Essentially, this is an example of how regional climate change will amplify unstable political situations around the world by stressing food and water supplies, changing coastlines, and shifting weather patterns. Second, a study coming out of the University of Colorado and CIRES assesses the water supply in the Colorado River Basin, and the authors suggest that persistent drought associated with climate change could lead to severe water shortages in the basin, which supplies water to some 30,000,000 people. This article reminded me of Brian Fagan’s interesting book “The Great Warming,” which looked at the so-called Medieval Warm Period and the rise and fall of societies around the world. One of the take-home messages of that book was that a little warming isn’t too bad for a lot of societies, but persistent drought destroys them. The third news item that was sitting on the top of the ClimateArk.org feed was covered by two articles, and is about crops in California’s central valley. A UC Davis study finds there has been a decrease in the “chilling hours” that cropland experiences, and several important crops rely on this cold winter weather. I would venture to guess that this regional effect is partly due to land use change and partly due to global warming, but that is just a guess. The important thing is that this becomes a serious concern to the food supply for the whole country, and many other countries, not to mention that California’s economy had long depended on agriculture. If crops start to falter in California, it really could have a destabilizing effect on the national economy and will impact jobs (agriculture, packing, shipping) and food supply and prices.
It’s also worth noting that two of the above articles contain sentences that say something like, “climate change isn’t just about polar bears, it’s about security.” In the first it is national security and in the last food security.