The world is facing a critical challenge in tackling methane emissions, a major contributor to climate change. Despite the commitment of over 150 countries to reduce methane emissions by 30% in the coming decade, recent research indicates that global methane emissions have been increasing at an unprecedented rate.
Current atmospheric methane levels are more than 2.6 times higher than pre-industrial levels, reaching the highest point in at least 800,000 years. The alarming rise in methane emissions is following the most extreme emission scenario outlined by leading climate scientists, which could result in a global temperature increase of over 3 degrees Celsius or 5 degrees Fahrenheit by the end of this century.
“Right now, the goals of the Global Methane Pledge seem as distant as a desert oasis,” said Jackson, Michelle, and Kevin Douglas, Provostial Professor in the Stanford Doerr School of Sustainability and lead author of the Environmental Research Letters paper. “We all hope they aren’t a mirage.”
Methane, a potent greenhouse gas, is released from natural and human sources such as agriculture, fossil fuels, and landfills. Over the first 20 years after release, methane heats the atmosphere almost 90 times faster than carbon dioxide, making it crucial to limit global warming.
Despite increased policy attention on methane, recent estimates show a 20% rise in annual emissions, driven by coal mining, oil and gas production, cattle and sheep ranching, and organic waste in landfills. Addressing these sources is essential to curbing global methane emissions.
“Only the European Union and possibly Australia appear to have decreased methane emissions from human activities over the past two decades,” said Marielle Saunois of the Université Paris-Saclay in France and lead author of the Earth System Science Data paper. “The largest regional increases have come from China and southeast Asia.”
In 2020, human activities were responsible for nearly 65% of global methane emissions, totaling almost 400 million tons. Agriculture and waste contribute about two tons of methane for every ton from the fossil fuel industry. Despite pandemic lockdowns reducing transport-related emissions of nitrogen oxides, human-caused methane emissions continued to increase through at least 2023.
The atmosphere accumulated almost 42 million tons of methane in 2020, which is double the average annual increase seen during the 2010s and more than six times the rise observed during the first decade of the 2000s. The decline in NOx pollution due to pandemic lockdowns accounted for roughly half of the increase in atmospheric methane concentrations that year, highlighting the intricate connections between air quality and climate change.
“We’re still trying to understand the full effects of COVID lockdowns on the global methane budget,” said Jackson. “COVID changed nearly everything – from fossil fuel use to emissions of other gases that alter the lifetime of methane in the atmosphere.”
The Global Carbon Project scientists have recently revised their assessment of global methane sources and sinks. In their latest analysis, they have made a groundbreaking effort to estimate the increasing emissions of methane from human-influenced sources such as wetlands, lakes, ponds, and rivers.
For example, it is now estimated that reservoirs built by humans lead to approximately 30 million tons of methane emitted annually due to the release of methane from decomposing organic matter. This new approach provides a more comprehensive understanding of human impacts on methane emissions.
“Emissions from reservoirs behind dams are as much a direct human source as methane emissions from a cow or an oil and gas field,” said Jackson.
The impact of human activities on wetland and freshwater methane emissions is significant, with scientists estimating that approximately one-third of recent emissions are influenced by factors such as reservoirs, fertilizer runoff, wastewater, land use changes, and rising temperatures. With severe weather and heat waves becoming more frequent, we are already witnessing the predicted extremes of climate change.
The world has reached the critical threshold of a 1.5°C increase in global average surface temperature, and we are just starting to experience the full consequences.
