By Carolyn Opium
Livestock Policy Officer of the FAO Subregional Office for Mesoamerica
The study points out that this gas accounts for about half of the net 1.0 degree Celsius increase in mean global temperature since the pre-industrial era. Atmospheric CH4 has increased since 2007, reaching 262 percent of pre-industrial levels in 2020 due to booming emissions from anthropogenic sources.
Although China, South Asia and North America stand out as the main emitters, the levels observed in all regions of the world are significant.
METHANE AND CLIMATE DISCOURSE
Methane is the second largest contributor to global warming after CO2 and is at least 84 times more potent than carbon dioxide over a 20-year period.
It is also a precursor to ozone: chemical reactions in the atmosphere involving methane produce ozone, a pollutant that poses significant health risks.
Therefore, due to methane’s short residence time in the atmosphere, significantly reducing its emissions may give the world a little more time to continue working to reduce other greenhouse gases, such as carbon dioxide and nitrous oxide. .
CH4 has the ability to strongly heat the atmosphere for about 12 years, but then it dissipates and its heating power decreases.
This means that at a constant rate of methane emissions, the amount of CH4 emitted today will replace the methane that is gone and its atmospheric concentration will remain stable. For this reason, methane is critical as it is essentially a flow resource, going in and out of the atmosphere.
In this sense, it is imperative to control methane emissions, which can reduce the exchange rate in the short term.
Lower CH4 emissions would offset some of the significant costs associated with rapidly reducing CO2 emissions. In addition, it will be possible to ensure the adaptability of ecosystems, food systems and the economy and to make the achievement of the goals of the Paris climate agreement more likely. However, reducing methane emissions does not replace the need to reduce CO2 emissions as the gases are not truly “equivalent”. Substituting efforts to reduce one gas with another will not produce the same result.
The relative permanence of CO2 and the cumulative effects of its continued emission imply that we are “committed” to future warming even if all sources of methane were removed today.
Carbon dioxide is largely a reserve resource. Every time we produce carbon dioxide, it accumulates in the atmosphere and adds to the previously emitted CO2.
It takes hundreds and even thousands of years for carbon dioxide added to the atmosphere to dissipate in the oceans or turn into inert forms like coal or oil.
This means that if we continue to burn fossil fuels at the current rate, the planet will continue to warm. Even if we reduce our use of fossil fuels, the planet will continue to warm as the supply of CO2 in the atmosphere continues to increase.
METHANE SOURCES
Methane is produced naturally in the environment, by animals and as a result of human activities.
Today, about 60 percent of the methane in the atmosphere is man-made, while the rest comes from sources that existed before humans began affecting the carbon cycle.
According to the Global Methane Assessment 2021 report, anthropogenic methane emissions come from three sectors: fossil fuels (35 percent), waste (20 percent), and agriculture (40 percent).
It should be noted that in agriculture, methane emissions from manure and enteric fermentation – chemical reactions in the stomachs of cows and other grazing animals during crop degradation – account for about 32 percent and rice cultivation for 8.0 percent of global anthropogenic emissions.
Ruminants are one of the main contributors to methane emissions. In fact, about 70 percent of methane in agriculture comes from enteric fermentation.
In regions with a significant ruminant presence, such as Latin America and the Caribbean, livestock contribute about 60 percent of total regional methane emissions.
If we want to find innovative climate solutions, we have to think outside the box. In addition to climate, there are ethical, nutritional, sociocultural and livelihood arguments that need to be analyzed to understand the benefits and costs associated with ruminant production.
The debate on ruminants and climate change needs to move beyond methane, including a full explanation of the role played by ruminant systems in different contexts.
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