Several leading climate scientists have warned that warming-induced emissions – greenhouse gas emissions from natural sources driven by rising temperatures – could amplify global warming by approximately 20–30%.

This would add an estimated 0.2–0.4°C of warming this century on top of anthropogenic warming under different scenarios.

The team added the concern remains that these major additional drivers of warming are largely unaccounted for in current climate projections and policies.

Scientists have long anticipated that rising temperatures could trigger more emissions from natural sources, which in turn would lead to even more warming. Examples include thawing permafrost causing ancient frozen organic matter to decompose, warmer wetlands and lakes releasing more methane (especially in the tropics), and drier conditions fuelling bigger wildfires that burn through carbon stored in forests.

The paper, Projected Amplification of Global Warming by Warming-Induced Greenhouse Gas Emissions represents the largest effort to date to quantify the combined impact of four major feedbacks (for both carbon dioxide and methane) from permafrost thaw, wildfires, wetlands, and inland waters. The authors of the paper include leading researchers from institutions including Stanford University, Spark Climate Solutions, Environmental Defence Fund, and Woodwell Climate Research Centre.

“What surprised us was the size of the feedback: we found that natural systems could amplify global warming by 20 to 30 percent. 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. To close that gap, we need to understand these processes better and build them into the models we rely on.” – Spark Climate Solutions research scientist Dr. Sam Abernethy, the paper’s lead author.

The research added even once emissions from human activities reach net-zero, greenhouse gas feedbacks could still add an estimated 0.2°C (1 standard deviation: +/- 0.2°C) of warming by 2100 under a stronger climate action scenario (SSP1-2.6). Under a scenario with higher emissions (SSP4-6.0), they could add an estimated 0.4°C (1 standard deviation: +/- 0.2°C) by 2100.

Critically, these warming-induced emissions remain largely absent from most Earth system models used to estimate the response of temperature to anthropogenic emissions. This means that current climate projections likely underestimate future warming. Scientists from around the world are convening to fill this gap by comparing different models of warming-induced emissions and advocating that these emissions be reflected in key policy and planning processes like IPCC assessments.

“Permafrost scientists have long warned that thawing soils would become a significant emissions source as the planet warms. This paper shows that permafrost thaw accounts for half of the anticipated warming-induced emissions. Warming-induced emissions are already in motion, and they scale with every fraction of a degree. Every little bit of warming we can avert today matters for what the climate looks like in the long term,” added  Dr. Christina Schädel, senior research scientist at the Woodwell Climate Research Centre and a co-author of the paper.

The good news is, it’s not too late to avert the worst impacts. The amount of warming that comes from these natural systems is directly related to the amount of warming from human-caused direct emissions—meaning if direct emissions decline, so too do these warming-induced emissions.

“This research makes clear that the earth and climate system doesn’t stand still while we debate policy,” explained Dr. Brian Buma, senior climate scientist at Environmental Defence Fund and a co-author of the paper. “Emissions from permafrost, wetlands, and wildfire could meaningfully erode our remaining time to warming thresholds – and they are unaccounted for in most scenarios. This means rapid fossil fuel emissions reductions are even more urgent than current projections suggest. The good news is that it’s in our hands—lower emissions now limit how severe these feedbacks become.”