Methane bombs
Methane leaks are a growing environmental concern, particularly because of their significant impact on climate change. New satellites have made it possible to detect and record methane leaks around the world. Stopping these methane emissions is an important lever for mitigating the effects of climate change.
What is Methane and why is it important?
Methane, CH4, is the second most important contributor to the greenhouse gases that contribute to climate change, after carbon dioxide. The main human activities responsible for methane emissions are :
Animal husbandry Enteric fermentation in cattle stomachs emits methane. To put it simply, cows' burps (not farts) emit methane.
Rice growing methane is produced by the lack of oxygenation in constantly submerged soils.
Waste decomposition of organic waste in landfills produces methane.
Fossils In gas and oil production sites and coal mines.
Unlike carbon dioxide, methane is much less abundant in the atmosphere. In 2020, methane accounted for less than 20% of global greenhouse gas emissions while CO2 accounted for almost 75%. So why is it so important to focus on methane emissions?
Although it is less present than CO2, its capacity to trap heat is much greater: its global warming potential is estimated to be 28 times greater than that of CO2 over a period of 100 years! This means that emitting 1 tonne of methane into the atmosphere will have the same impact on temperature rise over a century as emitting 28 tonnes of CO2.
This figure triple when we consider the impact that the emission of one tonne of methane will have over the first 20 years following its release. And with good reason: unlike CO2, which has an average lifespan of several centuries, a molecule of methane has a lifespan of several decades. an average lifespan of 12 years. This means that it is during the first few years after a methane molecule is emitted that it contributes most to global warming. But it also means that a rapid reduction in methane emissions can mitigate the effects of climate change in just a few years.
Methane super-emitters
To reduce our methane emissions, we need to know who is emitting methane, how and how much. If we analyze the distribution of methane emissions worldwide, it becomes clear that a small but influential fraction of projects, dubbed "super-emitters", are responsible for a large proportion of these emissions. These large-scale emissions mainly come from oil and gas production, urban landfill sites and coal mines. However, they are not always well recorded in national emissions inventories, as they often result from one-off malfunctions, such as gas flare malfunctions.
For this reason, a team of researchers has developed tools to automatically detect these methane super-emissions from satellite images. In 2021, these researchers listed nearly 3,000 projects worldwide, mainly in Asia and North America.
Source mapping of methane super-emitters in 2021 by emission source
A recent study highlights a promising prospect for reducing methane emissions: the adoption of existing technologies could significantly reduce them. These technologies, which are not only effective but also economically viable, thus represent a major opportunity for environmental policies and companies in the sector.
Morocco in all this?
In Morocco, the majority of emissions come from landfills located on the outskirts of Casablanca, notably near the towns of Médiouna and Nouaceur. In addition to environmental issues, the poor management of these urban landfills raises major public health concerns. Indeed, landfills can be the cause of respiratory diseases and disorders affecting local residents, notably through open-air waste incineration. By looking at the socio-economic profile of the people who breathe this polluted air, questions of environmental inequality can emerge. In the United States, the first study on environmental justice showed in 1979 that the majority of landfills were expressly located near predominantly black and Hispanic communities.
Distribution of methane emission sources in Casablanca province. The size of the dots corresponds to the quantity of methane emitted by each source.
Conclusion
Rapid, effective action is therefore needed to reduce methane emissions and limit their impact on climate change. These actions are accompanied by numerous co-benefits: improved air quality, which helps prevent hundreds of thousands of deaths every year, securing food supplies by limiting crop lossesThis will help to increase productivity by limiting the number of working hours lost due to extreme heat, as well as helping to achieve a number of Sustainable Development Goals.
Article by Mehdi Mikou