What is the Breakdown of Human-Induced Yearly Methane Emissions?

This is a breakdown by source of yearly methane (CH₄) emissions from human activities and processes expressed as weight in teragrams. The sources of human methane emissions are

• Fossil fuels
• Livestock
• Rice cultivation
• Biomass
• Waste

Fossil fuels

Fossil fuel-related methane emissions are not from combustion, but are mostly emitted during the extraction, storage and transportation processes. For example, methane is deliberately ventilated from mines during the extraction of coal. Also, methane leaks occur during the handling of oil and gas during storage, transport, incomplete combustion and many more.

Methane is a primary part of “gas”, also called “natural gas” or “fossil gas”. Natural gas is used, for example, for heating and electricity generation, whereby it emits CO₂ during the combustion process.

Livestock

Livestock emits methane, which is produced in the digestive system of the animals. Most methane is emitted from the mouth during rumination. A much smaller amount of methane is emitted from the manure. Depending on how the manure is managed, i.e., wet or dry, more methane is emitted. Wet management leads to higher methane emissions than dry management. However, dry management also emits nitrous oxide (N₂O), which is another potent greenhouse gas.

Rice cultivation

Rice cultivation generates large amounts of methane during plant growth. These emissions are mostly from flooded paddies, which create the swamp-like environment of rice fields. There are agricultural techniques to reduce the emissions significantly, like periodic drainage and aeration. Rice is the main staple for about half the world’s population, and its emissions a significant part of total human methane emissions.

Waste

Waste from landfills and wastewater produces a lot of methane when biodegradable material breaks down without oxygen.

Biomass and biofuel

Biomass and biofuel emit methane when they are incompletely burned. Biomass from forests, savannahs and grasslands is burned for various reasons, often for agriculture. Biofuel in forms like wood, charcoal and dung is still used by a large part of the world’s population for domestic heating and cooking.

Further reading

Units and measures

The unit teragram describes the average weight of atmospheric methane per year.

Insights from this chart

Fossil fuel and livestock emissions are the largest contributors to human methane emissions, and their contributions are still rising. These are followed by landfill and waste water management, rice cultivation, and biomass and biofuel burning.

There is a very long delay in the data. This is because this data is produced periodically by a global research project where scientists contribute to a mutually agreed knowledge base. It takes a lot of time and effort to generate trustworthy data that we can be confident in.

About the data

The Global Carbon Project has a Global Methane Budget besides its Global Carbon Budget. It has calculated averages for the single year 2017 and for the decades 2000 to 2009 and 2008 to 2017, based on which we show yearly values.

They also calculate the budget using two approaches: top-down and bottom-up. We show the results from the bottom-up approach because this approach also contains a breakdown of the emissions. Feel free to also explore the Global Methane Budget from the top-down perspective in the following link.

Data sources

Global Carbon Project: Global Methane Budget 2020 Global Methane Budget 2020
Credits: Saunois, M. et al (2020) - full reference belowUpdate cycle: unknownDelay: unknownReference: Global Methane Budget 2000-2017: Saunois, M., Stavert, A. R., Poulter, B., Bousquet, P., Canadell, J. G., Jackson, R. B., Raymond, P. A., Dlugokencky, E. J., Houweling, S., Patra, P. K., Ciais, P., Arora, V. K., Bastviken, D., Bergamaschi, P., Blake, D. R., Brailsford, G., Bruhwiler, L., Carlson, K. M., Carrol, M., Castaldi, S., Chandra, N., Crevoisier, C., Crill, P. M., Covey, K., Curry, C. L., Etiope, G., Frankenberg, C., Gedney, N., Hegglin, M. I., Höglund-Isaksson, L., Hugelius, G., Ishizawa, M., Ito, A., Janssens-Maenhout, G., Jensen, K. M., Joos, F., Kleinen, T., Krummel, P. B., Langenfelds, R. L., Laruelle, G. G., Liu, L., Machida, T., Maksyutov, S., McDonald, K. C., McNorton, J., Miller, P. A., Melton, J. R., Morino, I., Müller, J., Murgia-Flores, F., Naik, V., Niwa, Y., Noce, S., O'Doherty, S., Parker, R. J., Peng, C., Peng, S., Peters, G. P., Prigent, C., Prinn, R., Ramonet, M., Regnier, P., Riley, W. J., Rosentreter, J. A., Segers, A., Simpson, I. J., Shi, H., Smith, S. J., Steele, L. P., Thornton, B. F., Tian, H., Tohjima, Y., Tubiello, F. N., Tsuruta, A., Viovy, N., Voulgarakis, A., Weber, T. S., van Weele, M., van der Werf, G. R., Weiss, R. F., Worthy, D., Wunch, D., Yin, Y., Yoshida, Y., Zhang, W., Zhang, Z., Zhao, Y., Zheng, B., Zhu, Q., Zhu, Q., and Zhuang, Q.: The Global Methane Budget 2000–2017, Earth Syst. Sci. Data Discuss., https://doi.org/10.5194/essd-2019-128, in review, 2019