In 2016, nearly 200 world leaders pledged to do everything possible to limit global warming to 1.5 degrees Celsius. Since then, policymakers across the globe have designed countless laws around the assumption that warming would never cross that threshold.

Reductions in air pollution have helped warm the planet by cutting down on reflective particles in the atmosphere – but researchers still disagree on the size of this effect

The rapid meltdown of polar ice could shut down a key ocean current by 2050, triggering catastrophic surges of sea level rise along the U.S. East Coast and dangerous climate shifts in northwestern Europe.