Nearly 30 dangerous feedback loops could permanently alter Earth’s climate, scientists say

(CNN) Dangerous climate feedback loops are increasing global warming and risk causing a permanent shift away from Earth’s current climate, according to a new study.

Climate feedback loops are cyclical chain reactions that occur when one change triggers further changes, in a process that continues to repeat itself. Some of these feedback loops reduce warming, but others amplify it.

Take arctic ice for example. Warm temperatures cause the sea ice to melt, revealing the dark ocean water beneath. As dark surfaces absorb more heat than reflective surfaces such as ice, the ocean warms and more ice melts.

A group of international researchers from institutions including Oregon State University, Exeter University and the Potsdam Institute for Climate Impact Research in Germany reviewed the climate literature to identify 41 climate feedback loops.

Of these, they found that 27 are driving up global temperatures, according to the study published Friday in the scientific journal One Earth, while only seven are helping to slow the pace of the climate crisis.

William Ripple, a professor of ecology at Oregon State University and lead author of the study, told CNN that forest death, smoldering peatlands and thawing permafrost were of particular concern.

“These feedbacks can be large and are difficult to quantify accurately,” Ripple told CNN.

The researchers were surprised by the large number of reinforcing climate feedback loops they found, he added.

“To our knowledge, this is the most comprehensive list available of climate feedback loops, and not all of them are fully considered in climate models,” Christopher Wolf, a postdoctoral fellow at Oregon State University and the study’s second lead author, said in a statement.

Climate feedback loops can also indirectly affect each other, according to the study, creating a complex web of interconnected changes that could accelerate the effects of the climate crisis.

For example, planet-warming pollution released by thawing permafrost—the frozen layer of soil that covers the Arctic and other parts of the planet’s far north—increases global temperatures, which in turn helps create the warmer, drier conditions that cause wildfires to spread faster and burn more intense. Forest fires release pollution from the planet, increasing the temperature further, and so on.

These interconnections “make it challenging to predict the precise impacts of climate change,” Ripple said.

There is a risk that some of these feedback loops could trigger climate tipping points. For example, feedback loops that accelerate the melting of Arctic ice could eventually lead to the collapse of the Greenland ice sheet.

“In the worst case scenario, if amplifying feedbacks are strong enough, the result is likely to be tragic climate change that has moved beyond anything humans can control,” Ripple said in a statement.

The study also found seven “damping” feedback loops, which help to stabilize the climate system. These included the ability of land and oceans to absorb carbon emissions from the planet.

It’s important to “try to get at the strength of all these feedbacks,” Tim Lenton, head of climate change and earth system science at the University of Exeter and one of the co-authors, told CNN, to better understand how they work within the complex climate system.

“We, already at 1.5 (degrees Celsius), are likely to cross several tipping points, causing feedback loops that will make our options for a safe climate future even fewer,” Johan Rockström, director of the Potsdam Institute and co-author of the study, told CNN .

The authors called for “immediate and massive” reductions in global warming pollution, as well as increased research into climate feedback loops.

“It is too late to completely prevent the pain of climate change, but if we take meaningful steps soon while prioritizing basic human needs and social justice, it may still be possible to limit the damage,” Ripple said.

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