27 feedback loops could permanently shift Earth’s climate

27 feedback loops could permanently shift Earth’s climate

An international collaboration of scientists has identified 27 climate feedback loops, that is, factors that trigger processes that intensify global warming and aggravate the consequences of climate change.

However, what is worrying about this situation is that the study, prepared mainly by Oregon State University (United States), warns that some of the threats are not contemplated by current climate models.

Emissions and limit future warming

In view of this finding, the study, whose conclusions are published this Friday in the One Earth magazine, underlines the urgency of responding to the climate crisis and acting “both in research and in policy” to reduce “immediately and massively ” emissions and limit future warming.

An example of a loop would be the warming of the Arctic, which causes sea ice to melt, which in turn increases warming, as seawater absorbs radiation instead of reflecting it.

The map shows example locations where select positive feedback loops are likely operating. Source: cell.com

In this sense, the authors point out that certain processes are especially worrisome, such as permafrost, drying of wetlands and forest retreat. And since these are not yet fully incorporated into current climate models, plans to reduce greenhouse gas emissions may not limit future warming.

In climatology, climate feedback loops are processes that can amplify or decrease the effects of greenhouse gas emissions, starting a chain reaction that repeats itself over and over again.

Some of these loops, the authors point out, are particularly worrying, such as the permafrost loop, in which rising temperatures cause permafrost to thaw, which translates into more carbon dioxide and methane emissions, with the consequent increase of the warm-up

Other potentially dangerous feedbacks are the drying up or smouldering of peatlands and the retreat of forests.

And since these loops may not yet be fully incorporated into climate models, current emission reduction plans may not adequately limit future warming, the study warns.

Take the ice of the Arctic, for example. Warmer temperatures cause sea ice to melt, revealing the dark ocean water below. As dark surfaces absorb more heat than reflective surfaces like ice, the ocean warms and more ice melts.

What are Climate Feedback Loops?

Climate feedback loops are a process in which an external factor, such as the release of heat-trapping greenhouse gases or the injection of aerosols into the atmosphere, causes a change in a part of the climate system that feeds back and is amplifies.

Earth’s climate is constantly changing due to such feedback loops. These loops can be positive or negative. Positive feedback loops increase the rate of change in a particular system. While negative feedback loops slow down or reverse changes caused by external factors.

An immediate and massive reduction of emissions

The study calls for an “immediate and massive reduction in emissions” to minimize short-term warming and reduce climate disasters that are already occurring such as wildfires, coastal flooding, permafrost thaw, and other extreme events.

Furthermore, it calls for mitigating the possible threats of climate tipping points, ever closer due to numerous amplifying feedback loops (a tipping point is a threshold beyond which a change in a component of the climate system becomes self-perpetuating).

According to the researchers, even relatively moderate warming would increase the likelihood that the earth would cross several tipping points, triggering big changes in the planet’s climate system and potentially reinforcing and amplifying feedback.

“It’s too late to completely avoid the pain of climate change, but if we take meaningful action soon and prioritize basic human needs and social justice, it may still be possible to limit the damage,” said William Ripple, OSU researcher and director of the study.

The study also regrets that, despite several decades of scientific warnings, emissions have increased substantially in the last century.

Rising atmospheric

Scientists believe that interactions between feedback loops could cause a permanent change from Earth’s current climate state to one that threatens the survival of many humans and other life forms.

“In the worst case, if the amplifying feedbacks are strong enough, the result is likely to be tragic climate change that humans could not control,” Ripple says.

In addition to the 27 amplifying loops identified in the study, the team has found seven “buffers” (which act to stabilize the climate system) such as carbon dioxide fertilization, in which rising atmospheric CO2 concentrations cause an increase of carbon uptake by vegetation.

The study also identifies seven other reactions whose effects are unknown, such as increasing atmospheric dust and reducing the stability of the oceans.


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