If the world’s largest carbon polluters don’t cut emissions more aggressively, Antarctic ice melt could speed up dramatically around the middle of this century, triggering “rapid and unstoppable” sea-level rise for hundreds of years to come, a new modeling study has found.

Nearly 200 nations have submitted emissions reductions targets, called Nationally Determined Contributions, under the Paris Agreement. But while the global climate accord calls for limiting warming to 3.6 degrees Fahrenheit (2 degrees Celsius), the initial Paris Agreement pledges place the world on track for at least 5.4 degrees Fahrenheit (3 degrees Celsius) of warming this century. Last month, President Joe Biden and several other world leaders increased their nations’ emissions reduction