Global Warming and Grain Yields: Eve of Destruction?

As discussed a few weeks ago on this blog, a recent study in Nature Climate Change concludes that global warming “is already slowing yield gains at a majority of wheat-growing locations,” and forecasts absolute reductions in yields (tons per hectare) under +2ºC and +4ºC warming scenarios. I noted that despite the overall warming trend of the past half century and more, global average wheat yield increased every decade and during the past five years.

Specifically, compared to the preceding decade, average yield increased by 33% in the 1970s, 27% in the 1980s, 20% in the 1990s, 9% in the 2000s, and 10% during 2010-2014. Average yield was 149% higher in 2010-2014 than in the 1960s (my calculation based on USDA data).

Another relevant source I should have consulted is the UN Food and Agriculture Organization. An FAO analysis published in November forecast that world cereal production in 2014 would “surpass the record in 2013.” Two record-breaking years in a row. Clearly, we’re on the eve of destruction!

Among other cheery information, FAO reports that “Global wheat production is currently forecast at 725 million tonnes, up 7.6 million tonnes (1.1 percent) from the 2013 record level and 2.3 million tonnes more than reported in November.”