Abandoned Cropland Helps Make Europe Cooler

(CN) – Nature is not concerned with human crops and will reclaim land when it is abandoned. The process has a benefit: Croplands that are no longer tended help cool the planet.

It turns out the best remedy for the planet is to leave it alone.

Authors have speculated in both works of fiction and nonfiction how Earth will reclaim itself after humans are gone.

Farmland in the German state of Bavaria. (William Dotinga / CNS)

It’s an interesting thought experiment on a post-civilization world and in a paper published Wednesday in the journal Nature Communications, a group of researchers looked at over 20 years of satellite data and climate models to study the effects of abandoned cropland.

From 1992 to 2015, approximately 61 million acres of cropland in Europe were abandoned according to the study authors. During the same time about 49 million acres were turned into cropland, leaving a difference of about 12 million acres that were deserted – roughly the size of Switzerland.

Senior study author Francesco Cherubini from the Norwegian University of Science and Technology says the results show widespread seasonal cooling in western Europe due to the land cover changes.

“We can couple the global challenge of mitigation with the local need for climate adaption if we choose the right combination of land uses,” Cherubini said in a statement.

A study released last year showed stabilizing climate temperatures can shift based on reducing grazing land and increasing forest sprawl. More trees mean more carbon dioxide is taken out of the atmosphere.

In Wednesday’s study, researchers looked at how sunlight is absorbed by managed land and how that can influence humidity levels and the movement of water from the ground to the air and back down to the soil.

Carbon dioxide is simply one factor in the climate equation, says Cherubini.

“By having policies that only focus on carbon, you completely overlook these other effects, which are important from a regional climate perspective,” he said.

During the time period covered by the study, forested areas in Europe increased by nearly 57 million acres, a net gain of about 17 million acres as abandoned cropland became forests. A variation of forest sprawl occurred, including trees sprouting in wetlands and peatlands that dried out over time due to warm summers and less rain.

Data showed that cropland abandonment in the west was associated with regional cooling of roughly 1.8 degrees Fahrenheit in the spring and summer and less cooling during the rest of the year.

Eastern Europe saw a warming trend of up to 1.8 degrees in some areas during the spring and summer, which could be explained by the loss of wetlands. Drier parts of Europe and vegetation in that region respond differently to cropland loss because they don’t have as much soil water.

While east and west Europe showed different results, Scandinavia remained relatively untouched and so there were little changes in the climate.

Researchers say policymakers could utilize this type of information to stave the loss of wetlands and incentivize open land which would provide a cooling benefit for the global climate.

“The message is quite clear,” Cherubini said. “Abandoned cropland – or land cover change more generally – and its role in regional climate can help to us adapt and mitigate the effects of climate change. And by improving agricultural systems, we can free up land for multiple uses.”

An email to the study authors for comment on the study’s findings was not immediately answered by press time.

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