Several billion years ago, on a mass of rock floating around the Sun, little bundles of organic molecules somehow came together and, in a process scientists still don’t fully understand, shuddered into life.
When these first lifeforms were busy coalescing in the primordial soup, the Earth’s atmosphere was mixed very differently, a breathless mass of mostly nitrogen and carbon dioxide (CO2). Some of the earliest microbes that evolved on Earth, therefore, digested organic matter in low or no-oxygen conditions. They produced waste gases including methane and CO2.
Today, these critters, known as methanogens, are still among us, festering in waste heaps and piles of manure, in sewage plants, and at the bottom of stagnant water bodies, happily munching decaying matter and processing it into gases, including a boatload of methane.
That’s a problem, because methane is a greenhouse gas, and it’s around 27 times more potent at heating the planet than CO2. World leaders agreed to slash methane emissions by 30% by 2030 at COP26 last year, though Australia notably refused to commit.