Since 2006, the amount of heat-trapping methane in Earth's atmosphere has been rising fast and, unlike the rise in carbon dioxide (CO₂), methane's recent increase seems to be driven by biological emissions, not the burning of fossil fuels.

In the past few million years, Earth's climate has flipped repeatedly between long, cold glacial periods, with ice sheets covering northern Europe and Canada, and shorter warm inter-glacials.

When each ice age ended, Earth's surface warmed by as much as several degrees centigrade over a few millennia. Recorded in air bubbles in ice cores, sharply rising methane concentrations are the bellwethers of these great climate-warming events.

Highlights

• For example, around 131,000 years ago during Termination II, the British climate suddenly flipped from glaciers in the Cotswolds to hippopotami wallowing in what is now Trafalgar Square.

• Full terminations take several thousands of years to complete, but many include a creeping onset of warming, then a very abrupt phase of extremely rapid climate change that can take a century or less, followed by a longer, slower period during which the great ice caps finally melt.

• There's much to be done that could hastily stop methane's rise: plugging leaks in the oil and gas industry, covering landfills with soil, reducing crop-waste burning. Shooting the methane messenger won't stop climate change, which is primarily driven by CO₂ emissions, but it will help.

See full article