Climate action taken by the world today wouldn’t be noticed for decades to come, according to researchers who say warming on Earth won’t start to slow down for at least 20 years.

And that’s probably an optimistic scenario.

A study published Tuesday in Nature Communications illustrates how the rewards for aggressive action would come much later. If global carbon dioxide emissions began falling tomorrow by at least 5% every year, the rate at which the Earth is warming wouldn’t begin to change —at least in a detectable way —until after the year 2040 or so.

Currently, worldwide emissions are still rising.

The situation is similar, in some ways, to a “very large ship, which is at high speed,” said Marianne Lund, a…