Meeting the global food demand of roughly 10 billion people by the middle of the 21st century will become increasingly challenging as the Earth’s climate continues to warm. Earlier studies suggest that once the optimum growing temperature is exceeded, mean crop yields decline and the variability of yield increases even if interannual climate variability remains unchanged. Here, we use global datasets of maize production and climate variability combined with future temperature projections to quantify how yield variability will change in the world’s major maize-producing and -exporting countries under 2 °C and 4 °C of global warming. We find that as the global mean temperature increases, absent changes in temperature variability or breeding gains in heat tolerance, the coefficient of variation (CV) of maize yields increases almost everywhere to values much larger than present-day values. This higher CV is due both to an increase in the SD of yields and a decrease in mean yields. For the top four maize-exporting countries, which account for 87% of global maize exports, the probability that they have simultaneous production losses greater than 10% in any given year is presently virtually zero, but it increases to 7% under 2 °C warming and 86% under 4 °C warming. Our results portend rising instability in global grain trade and international grain prices, affecting especially the ∼800 million people living in extreme poverty who are most vulnerable to food price spikes. They also underscore the urgency of investments in breeding for heat tolerance.
|Original language||English (US)|
|Number of pages||6|
|Journal||Proceedings of the National Academy of Sciences of the United States of America|
|State||Published - Jun 26 2018|
Bibliographical noteFunding Information:
ACKNOWLEDGMENTS. We thank Walter Falcon and Matthew Reynolds for comments and Matthew Higgins for data assistance. D.S.B. and M.T. were funded by a grant from the Tamaki Foundation. R.L.N. was funded by her William Wrigley Chair (Stanford University).
© 2018 National Academy of Sciences. All Rights Reserved.
- Climate change
- Food security
- Price volatility
PubMed: MeSH publication types
- Journal Article
- Research Support, Non-U.S. Gov't