There’s a strange circularity to writing about climate change. Every few months or so, a new report comes out from an esteemed scientific body; each time, the conclusions are grim: the planet continues to warm steadily; each time, there are more severe observed effects at lower levels of warming than scientists had previously predicted. Every time one of the well-meaning scientists who wrote the report says something like “the final tick box is political will.” Another says something like “it’s a line in the sand and what it says to our species is that this is the moment and we must act now.” Every time we don’t. Instead everyone freaks out for a few days, and then something else happens that everyone freaks out about instead (myself included). Meanwhile, the cliff grows closer and closer.

Yesterday was one of those days: a new United Nations Intergovernmental Panel on Climate Change (IPCC) report — the gold standard of climate research, produced by an international body of scientists aggregating thousands of scientific studies — estimated that by 2040 the earth will have warmed 1.5º C (2.7º F) from the “pre-industrial levels,” with world-changing effects.

A 1.5º rise is typically considered the threshold of caution, and 2º the threshold of safety, though even that is increasingly in doubt: many of the effects scientists once thought would only kick in at 2º or higher now look likely to begin much sooner. The oceans will get more acidic and coral will die. Hundreds of millions of poor people will get poorer. Millions of people will be forced to leave their homes and migrate in search of new ones. There’s still time to keep warming to 2º, or even 1.5º — but it will take major action on a very short timescale. The news was bad but familiar.