Nearly a quarter of methane emissions can be attributed to agriculture, much of which is from raising livestock.
The latest report by the Intergovernmental Panel on Climate Change (IPCC) identified greenhouse gases as one of the primary drivers of climatic changes on the planet that may soon become irreversible. Among these greenhouse gases, methane could be the worst with nearly 60 per cent being generated by human sources alone.
Researchers are now saying that if methane emissions decline,ld its atmospheric concentration cou be reduced in just ten years. This could have a major impact on climate change and keep the global temperature change below 2 degrees celsius. The IPCC also stated that sustained methane mitigation could reduce surface temperatures in the long term.
According to a recent study by Nasa, nearly a quarter of methane emissions can be attributed to agriculture, much of which is from raising livestock. Amid other sources, the burning of fossil fuels and decomposition in landfills also drive the methane concentration in the atmosphere, raising global temperatures.
The IPCC findings
The panel has been identifying methane as one of the villains in the study of climate change for decades. In the 2007 assessment, the body had called it an unequivocal contributor to global warming.
“It is unequivocal that the increase of CO2, methane (CH4) and nitrous oxide (N2O) in the atmosphere over the industrial era is the result of human activities and that human influence is the principal driver of many changes observed across the atmosphere, ocean, cryosphere and biosphere.”
The 2021 IPCC report stated sustained methane mitigation could help in reducing global surface temperatures in the long term. “Sustained methane mitigation reduces global surface ozone, contributing to air quality improvements and also reduces the surface temperature in the longer term, but only sustained CO2 emission reductions allow long-term climate stabilisation,” the report said.
Sources of Methane emission
While human sources are at the core of methane emissions, there are other factors at play. “The greatest natural source of methane is wetlands, which contribute 30 per cent of global methane emissions. Other natural sources of methane emissions include the oceans, termites, permafrost, vegetation and wildfires,” Nasa said.
One of the biggest human sources of methane production are cattle that produce the chemical gas as a by-product of digestion. In 2018, the food system contributed 33 per cent of all greenhouse gases and the atmospheric concentration of methane has more than doubled in just 200 years.
The only positive news came from Europe and the Arctic where the methane emissions decreased between 2000 and 2018 while peaking everywhere else.
The greenhouse effect
Energy from the Sun is absorbed by Earth’s surface, though some of this energy is reflected in the atmosphere. The greenhouse gases trap this solar energy radiated from Earth, acting as a thermal blanket. The energy is then re-emitted, however, only some escape into space and the rest is trapped in the atmosphere by greenhouse gases. This continuous process of trapping heat over time leads to the warming of the planet.
The increase in atmospheric methane concentrations slowed during the 20th century, however, it started peaking up again after 2006 “as a result of rising emissions from raising livestock, renewed reliance on natural gas and, in recent years, wetlands and global warming.”
Methane is the second-largest contributor to global warming after carbon dioxide and is known for trapping heat more effectively than carbon dioxide. Researchers say that the lifetime of a molecule of methane is shorter than a molecule of carbon dioxide because of natural chemical processes and therefore if methane emissions were to decline and the natural chemical scrubbing of methane maintained, atmospheric methane could decrease in just ten years.