2016 was a milestone year in the continued warming of the planet. From unstable agriculture to the drought in California to melting ice sheets to extreme weather events and heat waves, climate change has disrupted virtually every corner of the world.
It’s impossible to exhaustively list all the ways in which climate change was felt in 2016, but here’s a guide to understanding the year that was for the planet:
A carbon dioxide milestone
“In the centuries to come, history books will likely look back on September 2016 as a major milestone for the world’s climate,” Brian Kahn of Climate Central wrote earlier this year.
That’s because, during September, a month in which atmospheric carbon dioxide — a heat-trapping greenhouse gas —is usually at its lowest, the monthly value failed to drop below 400 parts per million. The 400 ppm mark has sad significance in the climate community, as it has long been considered a point of no return for the atmosphere by scientists.