"Those of us who try to monitor the torrent of climate change studies frequently come across various projections that just seem like a total waste of their researchers' time. The impacts of future climate change on crop productivity nearly a century hence is one such area. This particular blog post is provoked by a new study in Nature Climate Change purporting to predict that wheat yields will fall by 4.1 to 6.4 percent for every 1℃ increase in global average temperature. Some of the same researchers estimated in a 2014 study in the same journal that global wheat production will fall by 6 percent for each degree Celsius of further temperature increase. Other researchers projected that higher temperatures will also significantly lower corn yields in France, the U.S., Brazil, and Tanzania by "4.5, 6.0, 7.8 and 7.1% per °C at the four sites, respectively." While these projections claim to take into account efforts to adapt, the researchers all seem to be technological pessimists who more or less assume that farmers and crop breeders will be stuck using techniques and crop varieties not much different from the ones they have now.
Actually, crop breeders in the United Kingdom are already working to create a "super wheat" genetically modified with enhanced photosynthesis. In greenhouses, this boosts yields by 15 to 20 percent and the researchers are planning on field trials next year. In addition, the GMO wheat is even more productive when carbon dioxide levels are higher. In South Australia, researchers are figuring out how to add beneficial microbes (endophytes) that boost wheat yields by 10 percent. American researchers detail in a November 16 article in Science how they are working on another technique to boost photosynthesis that could increase yields by 15 to 20 percent.According to the Intergovernmental Panel on Climate Change the world has warmed at a rate of 0.12 degrees Celsius per decade since 1951 which implies that global average temperature has increased by nearly 0.8 degrees Celsius. Even as the world warmed, the World Bank reports that per hectare yields of coarse grains (including wheat and corn) have increased from an average of 1,400 kilograms per hectare in 1961 to 3,900 kilograms per hectare in 2014, an increase of 280 percent.
It bears noting that world grain production (including wheat) reached a record high this year, which has been declared by the World Meteorological Organization to be the warmest year ever in the instrumental temperature record."
Wednesday, November 30, 2016
Climate model projections of wheat yields are just stupid
See Record Temperatures and Record Grain Yields by Ronald Bailey, a science correspondent at Reason magazine.