Global Methane Budget 2000-2020: Latest Research and Findings

Strategic Insights -

Research into the global methane (CH4) budget has made significant progress in understanding and quantifying the global CH4 budget, crucial for assessing realistic pathways to mitigate climate change. A consortium of multidisciplinary scientists has established a consortium under the umbrella of the Global Carbon Project to improve, synthesize, and update the global CH(4) budget regularly and stimulate new research on the methane cycle.

Understanding the global CH4 budget is vital for assessing the efficacy of mitigation strategies. Methane is the second most important human-influenced greenhouse gas in terms of climate forcing after carbon dioxide (CO2), and both emissions and atmospheric concentrations of CH4 have continued to increase since 2007 after a temporary pause.

Fundamental to the study is the recognition of the complexity of methane emissions and the challenges in quantifying these emissions due to diverse, geographically overlapping sources and uncertain destruction of CH4 by short-lived and highly variable hydroxyl radicals (OH).

Key Takeaways:

  • The global methane budget has increased since 2007, with a higher increase in the 2010-2019 decade compared to the 2000-2009 decade.
  • Anthropogenic sources, dominated by direct emissions from the fossil, agriculture, and waste sectors, account for approximately 65% of global methane emissions.
  • The top-down budget estimates suggest that global methane emissions were 575 Tg CH4 yr^-1 (range 553-586) for the 2010-2019 decade.
  • The bottom-up budget reveals a discrepancy of 16% (94 Tg CH4 yr^-1) between the top-down and bottom-up budgets for the 2010-2019 period.
  • The major priorities for improving the CH4 budget include producing a high-resolution map of water-saturated soils and inundated areas emitting methanane, developing process-based models for inland-water emissions, and improvements in transport models and the representation of photochemical sinks.
  • The methane budget is influenced by climate change, eutrophication, and land use, which perturb natural fluxes.
  • For the 2010-2019 decade, agriculture and waste contributed an estimated 228 [213-242] Tg CH4 yr^-1 in the top-down budget and 211 [195-231] Tg CH4 yr^-1 in the bottom-up budget.
  • Fossil fuel emissions contributed 115 [100-124] Tg CH4 yr^-1 in the top-down budget and 120 [117-125] Tg CH4 yr^-1 in the bottom-up budget.
  • Biomass and biofuel burning contributed 27 [26-27] Tg CH4 yr^-1 in the top-down budget and 28 [21-39] Tg CH4 yr^-1 in the bottom-up budget.

Statistics:

  • Global methane emissions for the 2010-2019 decade were estimated to be 575 Tg CH4 yr^-1 (range 553-586) by top-down budget estimates.
  • The bottom-up budget suggests that global methane emissions were 669 Tg CH4 yr^-1 (range 512-849) for the 2010-2019 period, which is 16% (94 Tg CH4 yr^-1) higher than the top-down estimates.
  • The tropospheric loss of methane was estimated at 563 [510-663] Tg CH4 yr^-1 based on chemistry-climate models.
  • The total sink of methane is estimated to be 633 [507-796] Tg CH4 yr^-1 by the bottom-up approaches and 554 [550-567] Tg CH4 yr^-1 by top-down approaches.
  • The 2020 emission rate of methane reached 608 Tg CH4 yr^-1 (range 581-627), which is 12% higher than the average emissions in the 2000s.
  • The global methane budget has increased since 2007, with a higher increase in the 2010-2019 decade compared to the 2000-2009 decade.

Sources:

  • Martinez et al. (2024). Global Methane Budget 2000-2020. Earth System Science Data, 2025;17(5):1873-1958.
  • Copernicus Publications (2025). Earth System Science Data.
  • NewsRx. Findings from University of Paris Saclay Provides New Data on Climate Change (Global Methane Budget 2000-2020). Global Warming Focus. June 9, 2025; p 944.