Study Finds Climate Feedback Loops Could Worsen Global Warming by 30%

Rising global temperatures caused by burning fossil fuels are transforming landscapes, the study says. Permafrost in high latitudes is thawing. Fiercer wildfires are burning through drying forests. Wetlands and lakes are warming. These changes are releasing methane and carbon dioxide that had been locked in trees and soils, worsening the climate crisis.

Scientists have long known about feedback loops that amplify the impact of direct pollution from coal, oil and gas. But emissions from natural sources are largely unaccounted for in climate projections, the paper states. The researchers found this additional heating is significant. Emissions from natural sources are set to amplify global heating by 20 percent to 30 percent by the end of this century.

The study estimates that this would add 0.2C to 0.4C to global average temperature by that time. Under the most optimistic climate scenario, in which emissions are cut quickly, natural sources will add 0.2C of warming. Under a worse case with higher emissions, 0.4C will likely be added.

Current policies put in place by governments are likely to see global temperature rise to 2.6C above pre-industrial times, according to Climate Action Tracker. That outcome would likely cause severe disruption and hardship for billions of people through sea level rise, crop losses and other consequences.

'This hidden multiplier is missing from the models guiding climate policy, so those models are likely underestimating how much warming is coming -- and overestimating how much carbon we can still afford to emit,' Abernethy said. Abernethy led the research published in Environmental Research Letters.

Rob Jackson, a Stanford University scientist and study co-author, said the disruption of the world's carbon cycles is now being seen in 'real time.' 'The results are a wake-up call, and it's imperative that they be included in the next generation of climate policies,' Jackson said. 'Failure to do so will make meeting the world's climate goals less and less likely.'

The paper makes clear that action by countries to cut fossil fuel pollution will still lessen the amount of additional emissions that come from landscapes, according to the report. The study's authors say these feedback effects need to be included in future climate policy as governments weigh emissions cuts.

Editor's Summary A new study in Environmental Research Letters finds that natural emissions from thawing permafrost, wildfires and warming wetlands could add 0.2C to 0.4C to global average temperatures by 2100, or 20% to 30% of additional heating. The researchers say current climate models largely omit these feedback loops, and they warn that failure to include them in future policy will make global climate goals harder to meet.