A couple of recent studies (see here and here) have highlighted the impacts of global climate change in a very real way. It seems that we are having more extreme weather than natural cycles might explain, and that our warmer climate is having a primarily negative impact on global food crop production. These studies are as important for what they say directly, as they are for the picture they paint of climate change impacts.
In science, it is impossible to prove something right and, in practice, scientists very rarely deal in the absolutes of right and wrong. What is far more typical of scientific research is exploring probabilities — being able to say that an outcome is likely or very likely to be the case given other trends and information. I’ve often thought that much of the public skepticism about climate change in the US is because we’re so used to thinking in absolutes that we have a hard time accepting as “truth” a hypothesis that isn’t presented as indisputable fact but rather as a very statistically significant probability.
The two studies here are great examples. They don’t analyze one particularly bad storm, or discuss horrible crop yields in a single location. (Indeed it would be virtually impossible to attribute the cause of so specific an event to global climate change.) Instead, these studies take in huge quantities of data regarding heavy rainfall events and relative crop yields over a long period of time. Then, using computer models and statistical analysis, they seek trends not otherwise accounted for by natural cycles, changes in technology or bad weather.
These studies have found that over the last 30 to 40 years, extreme precipitation events and harvests with relatively low crop yields have increased in frequency. And man-made climate change is very likely to cause of those increased events. They aren’t explained by anything else. Is that an absolute “truth” we can all believe in? I don’t know. But I do know that these trends will make it harder to keep people housed and fed around the globe, and that is very troubling indeed.
The evidence for man-made global warming is sound. We are beginning to see stronger and increasingly clear evidence of the impacts of that warming. The question we now must ask ourselves is, when are we going to start doing something serious about this? Now, when we still have a chance to stem the tide, or later, when our only option will be to try to adapt to a radically different planet?