Technology explainer
How Can Warming Cause More Greenhouse-Gas Emissions?
Warming can thaw frozen soils, intensify fires and accelerate methane production in wetlands and lakes. Those added gases trap more heat, but the feedback’s size still depends strongly on human emissions.
Climate change is not only a response to greenhouse gases released directly by people. Once the planet warms, forests, frozen ground, wetlands and water bodies can change in ways that release additional carbon dioxide or methane. Those gases trap more heat and create a positive climate feedback.
Where do the extra gases come from?
Permafrost stores organic material that has remained frozen for centuries or millennia. Thaw allows microbes to decompose it. Drier soils tend to release more carbon dioxide, while wet, oxygen-poor soils can produce methane. Because deep ground thaws slowly, emissions may continue after surface temperatures stabilize.
Wildfires transfer carbon from vegetation and soils into the atmosphere. A forest may absorb some of it again as it regrows, but more frequent or severe burning can reduce the average amount of carbon held on land. Fire can also remove the insulating vegetation above permafrost.
Wetlands naturally emit methane because their waterlogged soils contain little oxygen. Warming can speed microbial activity. Lakes, ponds, reservoirs and rivers can respond similarly, with methane escaping through diffusion or bubbles.
Does this create unstoppable warming?
Not automatically. A feedback amplifies a change, but it is not necessarily a tipping point or an irreversible runaway process. The amount of extra emissions depends on the amount and rate of human-caused warming, local moisture, ecosystem changes and many other conditions.
Reducing fossil-fuel, agricultural and waste emissions limits the initial temperature rise. That in turn reduces the stress placed on natural systems and the additional gases they release. Some delayed emissions may already be difficult to avoid, especially from slowly thawing permafrost, but their total scale is not fixed.
Why are estimates uncertain?
Global monitoring is sparse in places such as Siberia, tropical wetlands and the Congo Basin. Individual process models also make different assumptions about fire, soil moisture, methane production and ecosystem recovery. Climate researchers compare these models and test them against field and satellite observations before integrating the processes into larger Earth-system simulations.
Numbers for warming-induced emissions should therefore be read as scenario-dependent ranges, not forecasts with a single certain outcome. Their practical message is simpler: every fraction of avoided warming lowers both direct climate harm and the risk that natural systems add more greenhouse gases.
First appeared in
Nature’s Emissions Could Add Up to 0.4°C of Warming
