Despite global efforts to curb emissions, there has been a 20 per cent increase in human-produced methane sources over the last two decades.
ADVERTISEMENTGlobal methane emissions are soaring to record highs driven largely by human activity - and it’s putting climate goals at risk.
The Global Methane Budget 2024, published in the journal Earth System Science Data, is a comprehensive analysis of methane trends and their implications for climate change. It was produced by the Global Carbon Project, an international coalition of scientists.
The report reveals that human activities are now responsible for at least two-thirds of global methane emissions. Despite global efforts to curb emissions, there has been a 20 per cent increase in human-produced methane sources over the last two decades, according to new estimates.
Atmospheric concentrations of the gas reached 1,923 parts per billion in 2023. This is a level 2.6 times higher than in pre-industrial times and the highest concentration in at least 800,000 years.
This trend “cannot continue if we are to maintain a habitable climate”, the researchers write in a separate article published alongside the report. The current trajectory, they found, would put the Paris Agreement’s 1.5C global warming limit at risk.
Why are methane emissions a problem?
Methane is a highly potent greenhouse gas that is short-lived in the atmosphere. It comes from natural sources like wetlands or human-caused (anthropogenic) sources such as agriculture and the fossil fuel industry.
In the first 20 years after its release, this gas heats the atmosphere nearly 90 times faster than carbon dioxide.
Addressing methane emissions is crucial for achieving climate goals as there are currently no technologies capable of directly removing this gas from the atmosphere.
Where are human-caused methane emissions coming from?
The world’s five biggest methane emitters are China (16 per cent), India (9 per cent), the US (7 per cent), Brazil (6 per cent) and Russia (5 per cent).
The report finds that agriculture, including livestock and rice paddies, is still the biggest source accounting for 40 per cent of global anthropogenic methane emissions. Fossil fuel activity contributes 34 per cent, waste handling 19 per cent and biomass burning 7 per cent.
Emissions have grown in these sectors due to increased activity in developing regions and the intensified exploitation of fossil fuels.
But researchers made an important change in their most recent assessment of methane sources. Previously they had categorised all emissions from wetlands, lakes, ponds and rivers as natural. The newest edition of the report makes an attempt to quantify the influence human activity is having on the growing emissions from these sources.
Reservoirs built by people, for example, lead to an estimated 30 million tonnes of methane emitted per year, because newly submerged organic matter releases methane as it decomposes.
The scientists estimate that roughly a third of wetland and freshwater methane emissions in recent years were influenced by human-caused factors including reservoirs and emissions increased by fertiliser runoff, wastewater, land use and rising temperatures.
Is the world on track to meet methane reduction goals?
There are significant international commitments to reduce methane emissions including the Global Methane Pledge signed by 150 countries, which aims for a 30 per cent reduction by 2030.
ADVERTISEMENTThe goals of this pledge now “seem as distant as a desert oasis” according to Stanford University scientist Rob Jackson, chair of the Global Carbon Project.
Global Carbon Project researchers found little evidence that the world is making progress on pledges to cut methane emissions.
Between 2020 and 2023, satellite data shows that methane emissions grew an additional 5 per cent. The biggest increases were seen in China, southern Asia and the Middle East. Emissions from coal mining in China and oil and gas extraction in the Middle East were major contributors.
“Only the European Union and possibly Australia appear to have decreased methane emissions from human activities over the past two decades,” says Marielle Saunois of the Université Paris-Saclay in France, lead author of the Earth System Science Data paper.
ADVERTISEMENTIf current trends continue, the report warns that we are unlikely to meet the targets set in the Global Methane Pledge.
The growth in emissions they observed follows the Intergovernmental Panel on Climate Change’s most pessimistic greenhouse gas scenarios. This could mean a global temperature increase of more than 3C above pre-industrial times by the end of the century.
