Following a plateau in the early 2000s, global concentrations of the powerful greenhouse gas methane have hit new highs in recent years. Chemical fingerprint tests seem to rule out a major role for fossil fuels. With more than half a dozen possible natural and human sources, how will scientists figure out where it's coming from?
As of 2021, the warming effect of long-lived greenhouse gases in Earth's atmosphere had increased by 49% compared to 1990. Relative to pre-industrial times, today's atmosphere absorbs more than 3 extra Watts of energy per square meter.