The escalating concerns about methane emissions are driving significant attention toward their major sources of methane. A new methane-monitoring satellite has recently been deployed to observe rogue emissions, particularly from the oil and gas sectors, indicating a step forward in tracking this potent greenhouse gas. However, the complexity of methane’s impact on climate extends far beyond fossil fuel industries. Agriculture stands out as the largest anthropogenic source of methane, closely followed by leaks from oil and gas fields.
Methane is responsible for 20-30% of the current global warming, and it has a warming potential more than 80 times greater than CO2 over a 20-year period. Despite its shorter atmospheric lifespan compared to CO2, the urgency to understand and mitigate methane emissions is critical. Among the natural sources of methane, permafrost and wetlands are significant contributors. These are thawing and becoming more waterlogged due to rising temperatures, which accelerates methane release into the atmosphere.
Noteworthy among the sources of methane are the mysterious giant craters in Russia’s Yamal and Gyda peninsulas, where elevated methane levels have been detected. These craters appear as the permafrost thaws, possibly releasing methane trapped beneath the ice for millennia. This phenomenon highlights the large-scale environmental changes occurring in the Arctic, potentially turning it into a major methane emission hotspot as global temperatures continue to rise.
Another surprising source revealed involves glaciers, which are melting and releasing previously trapped methane into the atmosphere. A study by the University of Copenhagen found that methane concentrations in the meltwater of glaciers in Canada’s Yukon territory were significantly higher than anticipated, suggesting that glacial melt could be a more extensive emitter of methane than previously understood.
Human-made reservoirs, such as those from hydroelectric dams, also rank high among sources of methane. These reservoirs release methane produced by the decomposition of organic material at the bottom when water flows through turbines. Innovative efforts by companies like Bluemethane aim to capture these emissions for use as biogas, illustrating the potential for technological solutions to mitigate such emissions.
Freshwater ecosystems, encompassing rivers and lakes, contribute nearly half of the global methane emissions. Studies in regions like Hong Kong’s New Territories have shown that these bodies of water can become heavily saturated with methane due to pollution and nutrient runoff. Additionally, agriculture remains a dominant sector for methane emissions, particularly from livestock such as cattle, which are significant producers of methane through enteric fermentation.
The challenges in addressing methane emissions from agriculture are complex, involving socio-economic and policy dimensions that make mitigation efforts difficult. Wetlands, another substantial natural emitter, have seen an increase in methane release, exacerbated by climate change-induced temperature rises and changing rainfall patterns.
Waste management is another critical area, with organic decay in landfills producing substantial methane emissions. Efforts to divert organic waste to composting operations could significantly reduce these emissions. Finally, wildfires have become a notable source, with the intensity and frequency of these events contributing increasingly to methane and other greenhouse gases in the atmosphere.
Understanding and controlling these diverse sources of methane is crucial for global climate strategies, highlighting the need for comprehensive monitoring and aggressive emission reduction tactics to mitigate the impacts of this powerful greenhouse gas.
https://www.bbc.com/future/article/20240402-the-surprising-sources-of-methane