Toward a More Reflective Planet

CAMBRIDGE – The last time the atmosphere held as much carbon dioxide as it does today was about three million years ago – a time when sea levels were 10-30 meters higher than they are now. Climate models have long struggled to duplicate those large fluctuations in sea levels – until now. Indeed, for the first time, a high-quality model of Antarctic ice and climate has been able to simulate these large swings. That is smart science, but it brings devastating news.

The new model shows that melting in Antarctica alone could increase global sea levels by as much as one meter (3.2 feet) by the end of this century – well above prior estimates. Worse, it suggests that even extraordinary success at cutting emissions would not save the West Antarctic Ice Sheet, locking in eventual sea-level increases of more than five meters. As little as one meter could put at risk entire cities, from Miami to Mumbai, and cause enormous economic disruption.

We need to turn down the heat – and fast. To this end, albedo modification – a kind of geoengineering intended to cool the planet by increasing the reflectivity of the earth’s atmosphere – holds tremendous promise.