New research from Future Earth Global Research Network Global Carbon Project finds that methane emissions caused by human activity are rising faster than ever – by more than 20% in the past two decades. This is despite pledges from more than 150 nations to slash methane by more than 30% this decade. Methane is a greenhouse gas more potent than carbon dioxide. 

The new “Global Methane Budget” report finds that agriculture contributes 40% of global methane emissions, followed by the fossil fuel sector, solid waste and wastewater, and biomass and biofuel burning. Pep Canadell, Executive Director of the Global Carbon Project, says, “For net-zero emission pathways consistent with the Paris Agreement, which is stabilizing temperatures below 2°C from pre-industrial levels, anthropogenic methane emissions need to decline by 45 per cent by 2050, relative to 2019 levels.”

We spoke with Rob Jackson, a climate scientist at Stanford University and Chair of the Global Carbon Project about the new research and what comes next. Jackson is also author of a new book on methane and climate solutions: Into the Clear Blue Sky

Future Earth: This is your 4th update. What is the most significant finding in this latest Methane Budget?

Rob Jackson: Methane’s a climate menace that the world’s ignoring. Emissions from all sources— cows, fossil fuels, landfills—keep rising, as do atmospheric methane concentrations. In fact, human activities now drive at least two-thirds of global methane emissions (four years ago we estimated that 60% of global methane emissions were anthropogenic). Moreover, methane concentrations in the atmosphere rose faster in the last five years (2019-2023) than at any time in the instrument record.

What’s the value of calculating a global methane budget separately to other greenhouse gases?

We have to understand sources and sinks of each greenhouse gas individually to be able to track policy progress and, ultimately, reduce emissions. We study greenhouse gases separately and together. Of course, all greenhouse gases drive climate change together.

What are the main challenges in calculating the methane budget?

Our biggest challenge with the global methane budget is to estimate the rates at which methane is destroyed in the air (how fast methane leaves the air, or its atmospheric lifetime), as compared to measuring the rate that methane enters the air through measurements of emissions. For emissions, we have trouble telling some sources apart from looking solely at the atmosphere. For instance, chemical isotopes make it fairly easy for us to tell fossil methane (methane derived from oil, gas, and coal use) from biological sources of methane. However, we have trouble distinguishing microbial sources from human systems (cows and landfills) from natural sources such as wetlands and freshwater systems such as lakes. We’re also starting to see increased emissions from natural systems, such as tropical wetlands, which is troubling.

Can you talk about the team behind the methane budget and your process?

Scientists from 66 institutions around the world contributed to our newest methane budget. We assemble top-down atmospheric data as well as bottom-up data from greenhouse gas inventories and other sources. The atmosphere is the truth—telling us how much methane is increasing and where. The bottom-up inventory gives us information about where, how much, and which sources are most important for the increases we observe.

What sort of impact do you hope to achieve as an outcome of this work?

Better information on methane sources gives policymakers power to reduce methane emissions. Unfortunately, methane emissions and atmospheric concentrations continue to track scenarios that assume no or minimal climate policies (SSP5 and SSP3). Emissions are tracking 3 °C scenarios fairly closely, and are inconsistent with both 1.5 and 2 °C scenarios. Most importantly, the Global Methane Pledge has yet to decrease global methane emissions detectably.

What’s next?

We’re developing new closer-to-real-time estimates of methane emissions to quicken the pace of our reports. We’re also developing a new global hydrogen (H2) budget. Emissions of hydrogen lengthen the lifetime of methane in the air by consuming atmospheric detergents such as hydroxyl radicals that would otherwise destroy methane.