Scientists struggling to understand the threat of sea level rise on a warming Earth found Wednesday that amid lingering uncertainty, this much is clear: Meeting the goals of the Paris climate agreement remain humanity’s best hope for preserving current coastlines in the 21st century.
At the same time, they diverged over the risks posed by the biggest wild card, the Antarctic ice sheet, which contains by far the most ice on the planet and holds the potential to unleash tens of feet of sea level rise.
Ice losses from Antarctica have been accelerating in recent years, and research suggests that in warm periods in the Earth’s past (similar to the one that humanity is now fueling), the ice sheet shed a great deal of its mass. But a central issue is how fast that could occur this time around and whether today’s computer simulations can adequately capture what will really happen, especially during the lifetimes of people currently living.