Global methane (CH₄) emissions are rising

November 4th, 2021

Global methane (CH₄) emissions are rising. But is this true for all regions? Are humans responsible for these increases or are natural processes driving this change? Is there a way to stop this rise? In a recent paper, Stavert and co-workers show that humans are responsible for recent increases but regional trends suggest that decreases are possible.

Increasing trends

Human sources are responsible for a ~10% increase in global emissions between 2000 and 2017 through agriculture, waste disposal and fossil fuels. Methane emissions have increased in almost all parts of the globe with some areas (China and the Middle East) increasing at more than double the global rate. Chinese coal alone accounts for ~15% of the global emissions increase.

Decreasing emissions

Excitingly, some regions show a decrease in CH4 emissions. European agricultural and waste disposal policies along with a decline in fossil fuel usage have driven a 10-20% reduction in CH4 emissions across Europe. In Japan, the increased adoption of renewable energy, a switch toward nuclear power and increases in energy efficiency have contributed to a ~10% emission reduction in the Japan & Korea region. These reductions provide hope that with the right combination of policy, economic and societal change CH4 emissions can be tamed.

Data used in this study was collected as part of the global methane budget. It consisted of a combination of the latest methane emission estimates, made using atmospheric observations, process-models and inventories. This regional analysis is featured in NASA’s recent visualisation.

See also:

NASA visualisation

Regional trends and drivers of the global methane budget Stavert et. al. (2021)

Global carbon project – Methane budget

Global totals of methane

Annual estimates of the global total CH₄ emissions global total. Inventory and process model-based estimates (blue) and atmospheric observation-based (red - surface sites only, magenta – surface sites and satellite data).

Annual estimates of the global total CH₄ emissions global total. Inventory and process model-based estimates (blue) and atmospheric observation-based (red – surface sites only, magenta – surface sites and satellite data). Both of these methods of estimating methane show a trend where global (CH₄) emissions are rising.

Annual estimates of total CH4 by land region

Annual estimates of total CH4 emissions for each land region, the ocean region and the global total. Inventory and process model-based estimates (blue) and atmospheric observation-based (red – surface sites only, magenta – surface sites and satellite data). Thick lines indicate the mean estimate while thin lines represent individual estimates. The lower right plot shows global methane (CH4) emissions are rising.

Sectorial methane budget for each region

The sectorial CH4 budget for each region for 2008-2017. Each panel shows methane emissions for the five key sectors, from left to right: wetlands, biomass burning & biofuels, fossil fuels, agriculture & waste and other natural (including inland waters). Atmospheric observation-based estimates are shown on the left as light-coloured boxes and inventory and process model-based estimates on the right as dark-coloured boxes. The box represents the 25th to 75th percentile range, “x” represents the outliers and the whiskers show the minimum and maximum values (outliers excluded).

Article by: Ann Stavert (GASLAB)