By David L. Brown
Note: This item is cross-posted from Ag Dead End (www.agdeadend.com).
Drought is already rearing its head in many parts of the world, most recently in north China, Australia, and Russia and the Ukraine. Experts say we can expect more in the coming years. Here’s a snippet from an article from Reuters posted on the Scientific American website:
Increasing drought has long been forecast as a consequence of climate change, but a new study from the U.S. National Center for Atmospheric Research projects serious impact by the 2030s. Impacts by century’s end could go beyond anything in the historical record, the study suggests.
The study warns that by 2100 unprecedented drought can be expected in some of the world’s most populous areas, including southern Europe, northern Africa, the western U.S. and much of Latin America. Some areas, including much of Canada and Russia may see increased rainfall — which isn’t necessarily a good thing since rain in excess can be as damaging to farm production as drought. Just this year heavy rains significantly reduced crop yields in Canada, and last year’s harvest in the eastern Corn Belt was plagued with wet conditions.
How serious can things get in those regions threatened with serious drought in the coming years? The article explains:
To get an idea of how severe the drought might get, scientists use a measure called the Palmer Drought Severity Index, or PDSI. A positive score is wet, a negative score is dry and a score of zero is neither overly wet nor dry.
As an example, the most severe drought in recent history, in the Sahel region of western Africa in the 1970s, had a PDSI of -3 or -4.
By contrast, the new study indicates some areas with high populations could see drought in the -15 or -20 range by the end of the century.
We don’t have any concept of how serious drought of that severity would be, since it is beyond our experience. The only thing we can conclude is that it will not be good.
Climate change is a serious threat because our civilization has been built (and in fact has over-built) upon conditions as they have been in recent centuries. Significant change in climate patterns, something that is probably already taking place, has the potential to gravely impact human society. The most important message is that those changes might be taking place faster than expected, and with the possibility of tipping points the picture could change even more quickly. Drought, excess rainfall, more serious storms, hotter temperatures—all these will undermine the ability of farmers to produce enough food to feed an increasingly hungry world.