Study: Crop Failure Risk is Underestimated in Climate Models

Risks of reduced crop yields occurring across major crop-producing regions are vastly underestimated in climate and crop model projections, a new study finds.

Why it matters: As climate change continues to impact food insecurity worldwide, we need to be able to anticipate climate shocks in order to build resilience into our food systems.

Driving the news: Scientists analyzed observational and climate model data between 1960 and 2014 and for future projections between 2045 and 2099 for a study published Tuesday in Nature Communications.

  • They found that climate models substantially underestimate the magnitude of heat extremes associated with specific jet stream patterns — which means the predicted impacts on crops are also underestimated.

Zoom in: Jet streams are fast-flowing air currents that travel through the Earth’s atmosphere and keep weather systems moving across the planet’s surface.

  • Some climate scientists think that over time, climate change is affecting the jet stream in ways that make contortions more likely to occur — mainly long-lasting, stronger areas of high pressure, or heat domes, writes Axios’ Andrew Freedman.

Zoom out: Under current conditions, low crop yields during persistent jet patterns are expected to spread during the Northern Hemisphere summer, including Eastern Asia, North America, and Eastern Europe, according to the new paper.

What they’re saying: Kai Kornhuber, an adjunct research scientist at Columbia University who led the paper, says that by underestimating the negative effects of such circulation patterns on crop yields, the predictions of how climate change will impact food security are likely conservative estimates.

  • “Whenever we talk about food security risks in the future, and provide estimates, we should assume that these are really the lower boundary of what to expect,” says Kornhuber, who researches weather extremes.

The intrigue: The paper focuses on projections under a high emissions scenario — though there’s an ongoing debate in the climate science community over how likely that is.

  • While Kornhuber says they intentionally “cranked up the dial” to see if changes could be expected under very extreme conditions, he notes that their conclusions are “not at all dependent” on one emissions scenario.

The big picture: “We need better models of food systems that can be used for decision-making, and that includes better assessments of production failures,” food security and climate researcher Zia Mehrabi, who is unaffiliated with the study, tells Axios in an email.

  • “But perhaps more important than this is a need for more co-ordinated governance of these risks by the different nations of the world. And when it comes to production risks from climate change, governments need to wake up to this reality, and fast,” says Mehrabi.

Andrew’s thought bubble: A number of extreme events in recent years have involved persistent summertime jet stream events, and have hurt grain yields in Russia, the U.S. and other countries.

  • This study shows a key consequence of the connection between climate change, the jet stream and shifting odds of extreme heat and precipitation events. It’s still an emerging scientific area, however.

Source : AXIOS


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