Rising Methane Emissions: A Growing Concern

Methane concentrations in Earth's atmosphere have soared at an unprecedented pace over the last five years. Human activities now account for at least two-thirds of annual methane emissions, including fossil fuel extraction, agriculture, landfills, and waste management.

Currently, global methane emissions continue to climb, reports Science Daily. Despite over 150 nations committing to reduce emissions by 30% in this decade through a global methane pact, new research indicates that emissions have risen significantly more than in previous years.

Researchers state that this trajectory "cannot continue if we are to maintain a habitable climate," highlighting severe concerns. Their observations feature in a Sept. 10 perspective article published in Environmental Research Letters, released with data in Earth System Science Data by the Global Carbon Project, chaired by Stanford scientist Rob Jackson.

Current Trends in Methane Emissions

Methane levels are now more than 2.6 times higher than pre-industrial levels, reaching their highest point in at least 800,000 years. Emission rates are escalating along the most extreme paths outlined by leading climate scientists, suggesting dangerous global warming trends.

Currently, this path threatens to push global temperatures over 3 degrees Celsius (5 degrees Fahrenheit) by the century's end. As Jackson, the Michelle and Kevin Douglas Provostial Professor in the Stanford Doerr School of Sustainability, emphasized, the goals of the Global Methane Pledge feel distant.

Sources of Methane Emissions

Methane is a potent greenhouse gas. It originates from natural sources like wetlands and from human-driven sources including agriculture, fossil fuel extraction, and landfills. Over the first two decades after release, methane heats the atmosphere nearly 90 times faster than carbon dioxide, emphasizing its importance in near-term global warming strategies.

Despite increased focus on methane policy, annual emissions have surged by 61 million tons, or 20%, in the last two decades. The primary drivers include emissions from coal mining, oil and gas industries, cattle and sheep farming, and decomposing waste in landfills.

According to Marielle Saunois of the Université Paris-Saclay, only the European Union and possibly Australia have managed to reduce emissions from human activities during this period. The largest increases have occurred in China and southeastern Asia.

Impact of the COVID-19 Pandemic

In 2020, nearly 400 million tons, or 65% of global methane emissions, originated directly from human activities. Agriculture and waste sectors produced about two tons of methane for each ton attributed to fossil fuel industries. Notably, human-induced emissions continued rising through at least 2023.

During 2020, the atmosphere accumulated nearly 42 million tons of methane. This amount represented double the average annual increase in the 2010s and more than six times that of the earlier decade.

Pandemic lockdowns led to reduced transport-related nitrogen oxides (NOx) emissions, typically detrimental to air quality but capable of slowing atmospheric methane buildup. The decline in NOx pollution accounted for half of the increase in methane concentrations that year, highlighting the intricate relationship between air quality and climate change.

Human Influence on Methane Emissions

The Global Carbon Project scientists recently revised their accounting of global methane sources and sinks, integrating forests and soils that absorb methane. Previously, emissions from wetlands and aquatic regions were labeled as natural. The new classifications make the first attempt to calculate human-impacted emissions from these sources.

For instance, reservoirs generated by human activity are estimated to emit around 30 million tons of methane yearly due to decomposing organic matter. Jackson states that such emissions are direct human contributions, akin to those from livestock or fossil fuel fields.

It's estimated that a third of methane emissions from wetlands and freshwater in recent years relate to human activity, including impacts from reservoirs, agricultural runoff, wastewater, land use, and rising temperatures.

Impact of Rising Temperatures

Amid severe weather patterns and intense heat waves, the authors assert that "the world has reached the threshold of 1.5C increases in global average surface temperature, and is only beginning to experience the full consequences."

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