Summer marks a break from school, time with family and friends, exploring new places, and for our planet, the awakening of the ‘carbon cycle’. Warm summer temperatures and longer days are the key ingredients for photosynthesis. This removes huge amounts of carbon dioxide from the atmosphere and feeds an interconnected web of plant growth, soil health, animals, microbes, and our food system.

Forest, grassland, and wetland ecosystems have been capturing and storing carbon from the atmosphere for thousands of years. Those carbon stores are at increasing risk of being released back to the atmosphere, particularly during these hot summers, through fires or increased decomposition—both of which are intensifying. 

For example, larger forest fires convert stored carbon in trees to atmospheric carbon dioxide. Meanwhile, in the tropics, as wetlands grow warmer, wetter, and larger, more plant matter breaks down in oxygen-deprived soils, where the plant matter’s carbon is converted to methane—a particularly powerful climate pollutant. These additional ‘warming-induced emissions’ of carbon dioxide and methane add to direct emissions from human activity, such as the use of fossil fuels, deforestation, agriculture, and more.

Warming-induced emissions of all greenhouse gases are an increasingly important consideration as natural systems are altered by climate change. But the impact of adding even more methane—on top of our already high methane emissions—may be particularly important. Methane is already responsible for about 30% of today’s global warming, and is currently experiencing a rapid growth in our atmosphere.

‍Why Differences in Methane Concentrations versus Emissions Matter

Because methane contributes such a large portion of warming, if we truly want to understand what climate trajectory we are on and take all appropriate actions, we need to know just how much methane is being added to the atmosphere and where it comes from. There are two ways to try to answer that question. One estimates emissions ‘bottom-up’, by combining activity data (e.g., number of cows) with emission factors (e.g., methane emissions per cow). The other calculates emissions using ‘top-down’ measurements of atmospheric concentrations and models that trace the concentrations back to where the emissions occur. The results of these methods lead to different answers—and show a widening gap—that points to an important climate blind spot. 

First, it’s important to understand a bit about climate trajectories. The Intergovernmental Panel on Climate Change (IPCC), which represents the authoritative global scientific consensus on climate science, develops different scenarios that range from low-end (optimistic, characterized by highly ambitious global action to rapidly reduce emissions and limit temperature increases) to high-end (significant increases in global temperatures and severe impacts in terms of flooding, droughts, heatwaves, etc) with a number of scenarios in between. We would expect both a bottom-up and top-down accounting of methane to track with the same scenario. But do they?    

First, the bottom up. This past May, thanks to the efforts of dozens of scientists from around the world, the most comprehensive snapshot to date of estimated methane emissions was released: the Global Methane Budget: 2000-2020 (Saunois et al., 2025). This tallies up methane emissions from all sources: thermogenic (i.e., oil and gas activities), biogenic (i.e., agriculture, wetlands, and waste), and pyrogenic (fire) sources over a 20-year period.¹ The results follow a similar trajectory to what would be expected under a ‘middle of the road’ climate scenario (Figure 1).  

Second, the top-down. The National Oceanographic and Atmospheric Administration (NOAA) uses a network of air sampling sites to measure how much methane is actually in the atmosphere. Also in May, NOAA reported that methane concentrations in the atmosphere grew by ~9 ppb in 2024. More concerning than the level is the trend: over the past two decades, atmospheric methane concentrations have started growing faster. The measurements of methane concentration in the atmosphere are now following a higher-end scenario than the bottom-up emissions estimates.    

In other words, scientists are seeing significantly more methane in the atmosphere than we would expect based on how much methane we estimate is being emitted from human activity alone. Importantly, the gap appears to be widening. The two methods of methane accounting had historically led to similar results, however, starting in 2020 the gap between our estimated methane emissions and measured atmospheric methane levels began to widen. 

These two new figures from our colleague Glen Peters from CICERO illustrate the different trajectories:

‍Figure 1: Anthropogenic emissions of methane from the most recent Global Methane Budget from 2000 to 2020 (thick black line is ensemble mean and thin black lines are from individual inventories) and the emissions associated with the IPCC’s SSP database. Observed emissions track more closely SSP2. Figure from Glen Peters, CICERO. 

Figure 2: Observed concentrations of atmospheric methane provided by NOAA GML from 2000 to 2024 (black line) compared to the concentrations from the IPCC Shared Socioeconomic Pathways (SSP) database from the Sixth Assessment Report. The SSPs are identified by their radiative forcing and the associated temperature change (in parentheses). Observed concentrations follow more closely SSP4 while SSP2 concentrations decline. Figure from Glen Peters, CICERO.

Warming-Induced Emissions Blind Spot

These recent findings raise concerns that methane concentrations are rising faster than can be explained by anthropogenic emissions. Scientists are confident that this ‘blind spot’ is due to increasing biologically-driven emissions from agriculture and/or wetlands because of evidence related to the ‘source signature’ of the methane accumulating in the atmosphere. And what appears to be emerging is that in the tropics, wetlands are producing more methane as they warm, and in the Arctic and boreal regions, wetlands are emitting more methane as the growing season is extended.

In addition, the breakdown of methane in the atmosphere may be slowing due to complex chemical processes, and this remains an active area of research. However, observations from monitoring networks are sparse, and a more detailed understanding of these processes is required through developing and applying more sophisticated models in a coordinated way.

If what we are seeing is indeed increased methane emissions from natural systems, that would be alarming for several reasons. First, it could supercharge warming and make climate impacts, such as extreme heat, worse. 

Second, it would significantly eat into our remaining carbon budget, meaning we need to raise our mitigation ambitions even higher to maintain a safe climate.

Third, there are many other natural systems at risk of similar changes as the planet heats up, such as thawing permafrost and increased wildfires. 

‍Taking action

Several key actions can be taken today to prevent and mitigate the effects of warming-induced emissions on the climate. 

• The first is to minimize future additional climate damages by mitigating greenhouse gas emissions, including transitioning from fossil fuels to renewable energy sources, addressing emissions from agriculture, transportation, and industry, and scaling up carbon removals. 
• The second is to expand research and monitoring capacity to understand how greenhouse gas emissions and natural systems respond to warming. 
• The third is to integrate warming-induced emissions observations and projections into the remaining carbon budgets for 1.5°C or 2.0°C warming, and understand their implications for our climate trajectory and necessary action, including the possibility that net-negative emissions may be required to stabilize temperatures. 
• And finally, potential additional actions to protect the impacted natural systems and mitigate rising emissions from natural sources need to be thoroughly researched.

Warming-induced greenhouse gas emissions are no longer a hypothetical scenario existing in the distant future. Shining a spotlight on warming-induced emissions is critical for catalyzing research to reduce uncertainties, improving monitoring, and raising ambition for climate mitigation and action. 

‍Get More Information

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¹The Global Methane Budget compares bottom-up and top-down approaches to identify uncertainties and opportunities for future research.