Climate change influencing risk of crop slowdown in the next 20 years
The authors behind this study say that climate change has substantially increased the prospect that crop production will fail to keep up with rising demand in the next 20 years.
While the overall risk of a major production slowdown of wheat and corn is not very high, their study finds that it is about 20 times more significant than it would be without global warming. This they say, may require planning by organizations that are affected by international food availability and price. As global demand for crops rapidly increases and we experience more severe effects from climate change, the likelihood of such a slowdown increases.
In many discussions of climate change impacts in agriculture, the large magnitudes of expected impacts toward the end of the century are used to emphasize that most of the risks are to future generations. However, this perspective misses the important fact that demand growth for food is expected to be much slower after 2050 than before it, and that the next two decades represent the bulk of growth before 2050. Thus, impacts of smaller magnitude in the near-term can be as or more consequential for food prices or food security as larger magnitude impacts in the future. Here we estimate the risks that climate trends over the next 10 or 20 years could have large impacts on global yields of wheat and maize, with a focus on scenarios that would cut the expected rates of yield gains in half. We find that because of global warming, the chance of climate trends over a 20 year period causing a 10% yield loss has increased from a less than 1 in 200 chance arising from internal climate variability alone, to a 1 in 10 chance for maize and 1 in 20 chance for wheat. Estimated risks for maize are higher because of a greater geographic concentration than wheat, as well as a slightly more negative aggregate temperature sensitivity. Global warming has also greatly increased the chance of climate trends large enough to halve yield trends over a 10 year period, with a roughly 1 in 4 chance for maize and 1 in 6 chance for wheat. Estimated risks are slightly larger when using climate projections from a large ensemble of a single climate model that more fully explores internal climate variability, than a multi-model ensemble that more fully explores model uncertainty. Although scenarios of climate impacts large enough to halve yield growth rates are still fairly unlikely, they may warrant consideration by institutions potentially affected by associated changes in international food prices.
Lobell, D. B., Tebaldi. C., 2014, Getting caught with our plants down: the risks of a global crop yield slowdown from climate trends in the next two decades. Environmental Research Letters, 9 (7): 074003 DOI: 10.1088/1748-9326/9/7/074003
While some of the food system challenges facing humanity are local, in an interconnected world, adopting a global perspective is essential. Many environmental issues, such as climate change, need supranational commitments and action to be addressed effectively. Due to ever increasing global trade flows, prices of commodities are connected through space; a drought in Romania may thus increase the price of wheat in Zimbabwe.
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