Saturday, November 24, 2012

Why I think corn yields...  

Will be really, really hard to predict. From about 130 Iowa scientists, led by climatologist Gene Takle and signed by Elwynn Taylor, to name a couple familiar to farmers:

1. Globally over the past 30 years, there is clear statistical evidence that extreme high temperatures are occurring disproportionately more than extreme low temperatures. The climate likely will continue to warm due to increasing global emissions and accumulation of greenhouse gases.
2. In a warmer climate, wet years get wetter and dry years get dryer. And dry years get hotter that is precisely what happened in Iowa this year. We can expect Iowa to experience higher temperatures when dry weather patterns predominate. The latest science, based on overwhelming lines of physical evidence, indicates we can expect dry periods to be more frequent as soon as the 2020s.
3. Iowa also has experienced an increasing frequency of intense rains over the past 50 years (Iowa Climate Change Impacts 2010,, likely due to a higher surface evaporation in a warmer world. Because of these extremes in precipitation (drought and flood), Iowans will increasingly need infrastructure investments to adapt to climate fluctuations while developing and implementing mitigation. 

I have been trying to guess what one more strange production year would do in the ag economist community. My understanding is much of our belief in future yields rests on an assumption of weather being a factor whose average doesn't change very fast or much, so assuming past averages should work. Furthermore, as we saw last year, this assumption allows "outlier" years to be discounted as rare anomalies.

But how many 2012's will it take to start the hard work of generating a different weather assumption and its impact on national yields?

Meanwhile, the drought outlook doesn't seem optimistic.


And watching The Dust Bowl certainly doesn't reassure either.

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