Nov 30 2023
Eating Methane
Methane is the forgotten greenhouse gas (sort of). Often, when discussing how best to reduce anthropogenic climate change, we talk about decarbonizing our electrical and transport sectors, and carbon removal. But methane is also a greenhouse gas, contributing to global warming, and we cannot afford to ignore it. As I discussed recently, methane traps more heat than CO2 but survives for a shorter amount of time in the atmosphere (about 12 years vs hundreds for CO2). Over 20 years it is 80 times worse than CO2, over 100 years it is 28 times worse.
The world releases 580 million tons of methane each year, compared to 37 billion tons for CO2 (about two orders of magnitude more). That means over a 20 year timespan, methane has the equivalent greenhouse gas effect as 46 billion tons of CO2 (570 million x 80). In the short term methane is driving global warming a little more than CO2. Perhaps this is an opportunity. CO2 release is essentially the unavoidable consequence of burning fossil fuel. We can mitigate it with carbon capture, but this so far is minimally effective. I only real option is to reduce and then stop the burning of fossil fuel. We are in a race to do this, but it will take decades because the world is dependent on fossil fuel as an energy source.
Methane leaking into the atmosphere, however, is not a completely unavoidable consequence of industry. The largest source of methane emissions is natural, from wetlands (195 million tons). Next is agriculture (142 million) followed closely by the energy sector (135 million). Waste is another 73 million tons, followed by another 45 million from everything else (mostly natural). How can we mitigate this?