A farmer’s son in Oklahoma during the Dust Bowl era. Image: By Arthur Rothstein, for the Farm Security Administration/Public domain, via Wikimedia Commons
When the US Great Plains are hit again by sustained drought, the world’s food stocks will feel the heat.
The next time the fertile soils of North America turn to dust, the consequences will hit food stocks worldwide.
Within four years of a climate crisis of the kind that fired John Steinbeck’s 1939 masterpiece The Grapes of Wrath, the US would have consumed almost all its grain reserves.
And the ripple effects would be felt in all those countries to which America normally exports grain. That is because America feeds much of the world: in a good year, the US exports wheat with an energy value of more than 90 trillion kilocalories. The collapse of farmland into wasteland on the scale that inspired John Steinbeck could reduce this over a four-year period to around 50 trillion kcal.
Worldwide, global wheat reserves would fall by 31% in the first year, and four years on somewhere between 36 and 52 countries would have consumed three-fourths of their own reserves. Food prices would rise around the planet.
“In today’s system of global food trade, disruptions are not bound by borders. Shocks to production are expected to affect trade partners who depend on imports for their domestic food supply,” said Alison Heslin, a climate scientist at Columbia University in the US.
“Accessing food reserves can, for a time, buffer populations from trade-induced supply shortages, but as reserves deplete, people are at risk of food shortages”
“Our results remind us that mitigating climate risks requires accounting not only for the direct effects of climate change, like local extreme weather events, but also the climate impacts which travel through our interconnected system of global trade.”
By some time in the mid-century, most of the US will be between 1.5°C to 2°C warmer. Researchers have already warned that the border between the arid western states and the more fertile mid-western plains has shifted to the east.
There have been repeated warnings that as global average temperatures rise, in response to ever greater use of fossil fuels, the US will become increasingly vulnerable to climate extremes, including megadroughts. Drought is already becoming the “new normal” for Californians, and the fertility of the Great Plains is in any case vulnerable to human changes to a natural landscape.
A succession of droughts of the kind that turned the farmland of Kansas and Oklahoma into a devastated landscape, and turned thousands of Americans into climate refugees, would not necessarily now mean the onset of regional famine.
Dr Heslin and her colleagues report in the journal Frontiers in Sustainable Food Systems that they contemplated the likelihood of a four-year drought of the kind that created the notorious 1930s Dust Bowl, and then examined the possible impact on world trade systems.
Yields and nutrition affected
Just one such climate event could hit hard those nations that rely on food imports, but even the other great grain-producing countries – among them China, India, Iran, Canada, Russia, Morocco, Australia and Egypt – would see their reserves fall.
The climate crisis is in any case a threat to the world’s supper tables. There has been repeated evidence that food output will inevitably be at risk in a warming world. With higher temperatures, yields will be reduced and with higher atmospheric levels of carbon dioxide that warm the planet, nutrition levels of many staples are expected to fall.
The researchers factored in none of these things. They supposed that a climate catastrophe that paralleled the Dust Bowl era would occur only in the US, and found that, despite strain, the world’s markets could probably cope.
But other studies have repeatedly found that the potential for climate catastrophe and massive crop failure to strike in more than one region at any one time are increasing, with ominous consequences for world food security.
“In the context of food security, we show that accessing food reserves can, for a time, buffer populations from trade-induced supply shortages,” said Dr Heslin, “but as reserves deplete, people are at risk of food shortages.” – Climate News Network
About the Author
Tim Radford is a freelance journalist. He worked for The Guardian for 32 years, becoming (among other things) letters editor, arts editor, literary editor and science editor. He won the Association of British Science Writers award for science writer of the year four times. He served on the UK committee for the International Decade for Natural Disaster Reduction. He has lectured about science and the media in dozens of British and foreign cities.
Book by this Author:
Science that Changed the World: The untold story of the other 1960s revolution
by Tim Radford.