Global warming, who cares. We’re only talking about a few degrees so what’s the big deal? The availability of food is the big deal.
Starch based foods, such as; corn, rice and wheat are members of the grass family and the life blood for most people on Earth. Not only do we eat starch-plants but our livestock is primarily fed corn and similar grassy vegetation. In addition, close to 70% of all items found on grocery stores shelves in developed countries have some type of corn byproduct in them (an unintended consequence of subsidized farming). The world depends on starchy grasses so we must have large land masses in climate zones suitable for growing these plants.
Global warming of a few degrees may not seem like much but when compared to temperature ranges required to grow our food, the small change isn’t so little.
For the purposes of this short article we’ll talk about corn. The ideal temperature range for growing corn is 68F to 73F degrees and having an abundant amount of weather in this range is needed to keep food prices affordable and available. The ideal growing range is only 5F degrees (73 – 68 = 5) so a climate shift of 2 or 3 degrees will consume 50% of corn’s growing range budget and that is significant. The average growing season temperature for America’s bread basket region (Nebraska, Iowa, Illinois…) is about 72F degrees so an upward shift of just a few degrees takes us out of the ideal condition. This is bad news for high yields.
Global warming also has another, more damaging, side effect; prolonged extreme temperature variation. This is what we are now experiencing in the Midwest and it’s having a devastating impact on crops. In past years, it was normal to have a handful of super-hot days but climate change is producing consecutive weeks of scorching heat. More bad news for crop yields. Corn can survive in a range of 50F to 95F degrees for a period of time but will not yield well above 80F or below 60F. Corn can even tolerate extreme temperatures (32F to 110F degrees) but only for a few days. When we have weeks of heat over 100F degrees, as we have seen this year, crops fail.
2012 may become a year to remember. It will be a year of climate records in both high temperatures and protracted heat days. It will be a year of failed crops.
A few degrees does make a difference.