Climate’s Troubling Trends for Crops

The good news: If you’ve been looking at those calorie restriction diets, this could help.

CNN:

Of the many impacts of the fossil fuel-driven climate crisis, damage to the global food system is one of the most terrifying. But the overall impact of climate change on crops — and how much it can be offset by farmers’ adaptations — has been hard to establish and hotly debated.

The new analysis, eight years in the making, is “the first attempt to really tackle both of those problems,” said Solomon Hsiang, a study author and professor of global environmental policy at the Stanford Doerr School of Sustainability.

The scientists analyzed six crops — maize, soybeans, rice, wheat, cassava and sorghum — in more than 12,000 regions across 54 countries. Together, these crops provide more than two thirds of humanity’s calories.

They also measured how real-world farmers are adapting to climate change, from changing crop varieties to adjusting irrigation, to calculate the overall impact of global warming.

Their findings are stark. Every 1 degree Celsius the world warms above pre-industrial levels will drag down global food production by an average of 120 calories per person per day, according to the study, published Wednesday in Nature.

This will push up prices and make it harder for people to access food, Hsiang said.

“If the climate warms by 3 degrees, that’s basically like everyone on the planet giving up breakfast,” he said. The world is currently on track for around 3 degrees Celsius of warming by the end of the century.

Wheat, soy and maize — high value crops for a lot of the world — will be especially badly affected, the study found.

If humans keep burning large amounts of fossil fuels, maize production could fall by 40% in the grain belt of the US, eastern China, central Asia, southern Africa and the Middle East; wheat production could fall by 40% in the US, China, Russia and Canada; and soybean yields could fall 50% in the US.

Project Drawdown:

Food and agriculture account for around one-quarter of global greenhouse gas emissions, primarily due to land use. Meanwhile, millions of people around the world live without enough to eat. To feed the planet without destroying it will require remarkable efficiency – growing as much food as possible on as little land as possible. Unfortunately, as the planet warms, global food systems seem to be getting less efficient.

“Agricultural efficiency is the invisible lever that determines how much land we need to feed the world,” says University of Minnesota research scientist Jessica Till, Ph.D., who co-led the study.  “Our study shows that improvements in agricultural efficiency can be a powerful buffer against cropland expansion. But climate change is eroding that buffer, partially reversing the progress that made modern agriculture more sustainable.”

Across the 110 countries analyzed for the study, the researchers found that croplands have expanded by 3.9% over the last three decades. Absent climate change, however, total croplands could have actually shrunk by roughly 2% while maintaining current production levels, as improved farming practices led to greater efficiency. 

This reduced land use and increased efficiency would have spared 88 million hectares – twice the size of California – from being cleared for agriculture worldwide. It would have also prevented 22 gigatons of CO₂ from entering the atmosphere, enough to offset the annual emissions from more than five billion fossil-fueled cars. 

“When climate change slows productivity gains, it pushes more land into cultivation, often at the expense of forests and carbon-rich ecosystems,” says study author and University of Minnesota Associate Professor Zhenong Jin, Ph.D. “Clearing land for cultivation changes the local temperature and rainfall patterns, and also releases carbon, which worsens climate change, creating a runaway feedback loop.” 

Nature – Impacts of Climate Change on Global Agriculture Accounting for Adaptation:

In contrast to analyses of other outcomes that project the greatest damages to the global poor^10,11, we find that global impacts are dominated by losses to modern-day breadbaskets with favourable climates and limited present adaptation, although losses in low-income regions losses are also substantial. These results indicate a scale of innovation, cropland expansion or further adaptation that might be necessary to ensure food security in a changing climate.