Reducing methane emissions may be the most effective measure to slow global warming (and one that is possible)

When it comes to global warming, carbon dioxide (CO2) emissions are often in the headlines. But methane (CH4), another greenhouse gas, also contributes to global warming.

According to estimates by the Intergovernmental Panel on Climate Change (IPCC), the impact of methane on the environment could be as much as 84 times greater than that of CO2 over a 20-year period. Methane emissions released into the atmosphere have increased by 9% between 2000 and 2017, according to a study by the Global Carbon Project released in July 2020.

Although methane is currently responsible for about 30% of global warming, it has the advantageous property of decomposing in the atmosphere after about ten years, which is much faster than CO2 (which takes about 100 years to decompose). Furthermore, there are simple and inexpensive strategies to scale back its emissions, according to a new report by the United Nations environmental program Climate & Clean Air Coalition.

Mainly known as the pollution linked to cattle breeding (and thus to the meat we eat), methane represents the second source of global warming. But this greenhouse gas is also linked to waste management (especially open dumps that emit methane into the atmosphere), as well as the exploitation of fossil fuels.

Identifying and repairing methane leaks from fossil fuel extraction more effectively, ameliorating biogas capture from organic waste, and changing the diet of livestock cows for example, by switching from corn or soybeans to flaxseed or alfalfa are among the strategies that can be implemented to help reduce methane emissions.

Of course, the nature and extent of the strategies to be implemented vary by country. "For example, whereas the largest potential in Europe and India is in the waste sector, in China it is from coal production and livestock, while in Africa it is from livestock followed by oil and gas," the study indicates.