The weather has gotten even weirder in 2012 and may lead to even bigger increases in food costs this year. The European cold snap is likely to reduce the continent's soft wheat crop by about 5%. Officials in Texas cut off irrigation water to rice farmers downstream of reservoirs depleted by the worst one-year drought in Texas history. It is the first time in its seventy-eight year history that the Lower Colorado River Authority has cut off water to farmers. In California, only 50 percent of the water requested from the State Water Project is expected to be delivered to nearly one million acres of irrigated farmland due to the lack of snow this winter.
So the question becomes, are the spate of floods and droughts just a fluke, or is extreme weather going to get worse? According to a couple of theories, the droughts and flooding are being caused by aspects of global climate change.
1) research by Jennifer Francis and Steve Vavrus suggests that warming in the Arctic is causing weather patterns in mid-latitudes to become more persistent. This persistence can lead to conditions like heat waves, cold spells, drought, flooding, and heavy snows. The researchers found that as temperatures in the Arctic warm and become closer to temperatures in lower latitudes, the waves of the jet stream tend to spread out, and west-to-east winds slow down in the upper level of the atmosphere (where storm tracks form). Both of these effects tend to slow the progression of weather patterns, which means that a weather pattern, whether hot or cold, is more likely to stick around.
If the above theories are correct, then it seems likely that the balance of 2012 will continue to feature extreme weather events. An increase in droughts and flooding would lead to further agricultural losses. And the increase in weird weather may be a long term problem. If extreme weather leads to food shortages in future years, big increases in the cost of food could become a serious problem. Thus, it seems appropriate to worry about extreme weather inflating the cost of buying food.2) A 4% increase in atmospheric moisture has been observed and is consistent with a warming climate.7 The increased moisture in the atmosphere is driving the shift to heavier but less frequent rains — “when it rains, it pours.” While an atmosphere that holds more moisture has greater potential to produce heavier precipitation, precipitation events also become less frequent and shorter, as it takes longer to recharge the atmosphere with moisture.9 By analogy, a larger bucket holds and dumps more water, but takes longer to refill.