Daniela Goyheix
Pablo Brassiolo
Methane is the second most important greenhouse gas (GHG) in terms of emissions after carbon dioxide (CO2), both globally and in Latin America and the Caribbean. In the region, methane emissions have increased over the last fifty years, both in absolute terms and relative to other gases, to represent 23% of total emissions in 2019.
Although methane has a short atmospheric lifetime, its impact on global warming is considerable, being some 27-30 times greater than that of CO2 over 100 years. Furthermore, methane is a precursor of tropospheric ozone, which is toxic to both humans and plants (RED, 2023). This means that methane emissions affect air quality and crop yields through air pollution. Therefore, reducing emissions of this gas is a key strategy that would allow relatively rapid reductions in global warming rates and at the same time bring benefits for public health and agricultural productivity.
Sixty percent of methane emissions are the result of human activities, while the other 40% come from natural sources, such as freshwater bodies (wetlands, lakes and rivers), geological releases, wild animals, termites and permafrost (RED, 2023).
What are the main human activities that release methane into the atmosphere in Latin America and the Caribbean? As shown in the figure below, 55% of anthropogenic methane emissions in the region come from livestock, while other agricultural practices such as rice cultivation, manure management and biomass burning together account for a further 5%. Industrial waste management accounts for 26% of methane emissions, while fugitive oil and gas emissions from the energy supply sector account for another 11%.
Given the greater importance of the agricultural sector in the region's production structure, this sectoral composition of emissions explains why methane emissions have a greater weight than in more developed countries, where they accounted for just 13% of total emissions in 2019. In turn, the top five methane emitters in Latin America and the Caribbean are Brazil, Mexico, Argentina, Colombia and Venezuela.
Latin America and the Caribbean's continued commitment to reducing methane emissions has been reaffirmed through support for initiatives such as the Global Methane Pledge. Participants agree to take voluntary actions to contribute to a collective effort to reduce global methane emissions by at least 30% of 2020 levels by 2030. The latter could eliminate more than 0.2°C of global warming by 2050 (GMP, 2023). Overall, however, the region faces the need for more robust resources, technologies and policies to achieve its methane emission reduction targets.
Technological solutions currently exist that would allow methane emissions of anthropogenic origin to be halved within a decade and at relatively low costs (Ocko et al., 2021). These include, for example, changes in agricultural practices, reducing fugitive emissions in the oil and gas industries, or capturing methane emissions from landfills. The use of these technologies could help to control the increase in temperatures in the coming years, moderating the need for ecosystems and people to adapt to climate change.
Within agriculture, there are techniques with methane mitigation potential and possible positive externalities in both productivity and environmental protection. The quality and composition of feed given to animals, particularly those that increase energy utilization in metabolism, have significant effects on methane emissions. Adding lipids to their diet increases the energy they obtain from the feed and reduces the amount of methane they emit when digesting it. As for manure management, changing the way manure is stored can help reduce methane emissions. Storing it in cool, open places, capturing the methane and burning it, or composting the manure are effective practices. However, despite being cost-effective, the adoption of these techniques has been limited by problems of access to credit, uncertainty and lack of information (RED, 2023). Thus, the policies that could be implemented to promote these actions in the agricultural sector are mainly financing, information and education.
