Rising global temperatures driven by fossil fuel combustion are triggering natural feedback mechanisms in forests, wetlands, tundra, and other ecosystems, which could increase global warming by up to 30%, according to a new study published in Environmental Research Letters. The research highlights that as permafrost thaws, wildfires intensify, and lakes warm, vast quantities of methane and carbon dioxide stored in soils and vegetation are being released, reinforcing the climate crisis.
Scientists have long acknowledged these “feedback loops” that amplify the effects of anthropogenic greenhouse gas emissions, but the study points out that current climate models largely omit emissions from these natural sources. The researchers estimate that such emissions could contribute an additional 0.2°C to 0.4°C of warming by the end of the century, depending on the extent of global efforts to reduce fossil fuel pollution.
The four key natural sources analyzed in the study are thawing permafrost, drying forests vulnerable to wildfires, wetlands, and freshwater bodies. Methane and carbon dioxide emissions from these regions, which have historically acted as carbon sinks, are turning into net sources of greenhouse gases, exacerbating warming trends. Such temperature increases, even in modest fractions of a degree, can substantially elevate the risks of extreme heatwaves, floods, droughts, and other severe weather events worldwide.
The findings coincide with recent warnings from the United Nations that the international target of limiting warming to 1.5°C above pre-industrial levels may be exceeded within the next few years. The UN has underscored that climate-related impacts are arriving sooner, becoming more intense, and enduring longer. The new study suggests that this trajectory could worsen beyond current official projections, which do not fully account for natural feedback emissions.
Sam Abernethy, lead author and scientist at Sprk Climate Solutions, emphasized that these additional emissions represent a “hidden multiplier” absent from many climate policy models, potentially leading to an underestimation of future warming and an overestimation of the remaining carbon budget available to humanity. Co-author Rob Jackson of Stanford University described the release of these natural greenhouse gases as a “wake-up call” requiring integration into future climate strategies to avoid undermining global emissions targets.
This study adds to ongoing concerns about crossing critical tipping points in the Earth’s climate system. Earlier research has warned that melting ice sheets in Greenland and Antarctica, disruptions to ocean currents, and large-scale biome shifts such as the conversion of the Amazon rainforest into savannah could trigger runaway warming beyond human control.
Despite the heightened risks, the researchers note that rapid decarbonization efforts can mitigate some of the feedback emissions. Under the most optimistic emissions scenarios involving swift fossil fuel reductions, natural sources might contribute only 0.2°C to future warming. In contrast, delayed action and continued high emissions could push this figure closer to 0.4°C.
Current climate policies, however, are projected to lead to approximately 2.6°C of warming by 2100, according to independent assessments such as the Climate Action Tracker. Such an outcome would likely result in significant global disruption, including sea level rise, agricultural losses, and widespread socioeconomic challenges.
Ecologist Bill Ripple of Oregon State University, who was not involved in the study but has previously researched the potential for runaway climate change, highlighted the danger posed by these feedback loops, noting that warming-induced emissions could perpetuate a cycle of escalating temperature increases. The study underscores the urgency of integrating natural feedback emissions into climate modeling and policy frameworks to better anticipate and address future climate risks.