President Trump’s decision on Monday to begin the formal process of withdrawing from the Paris climate agreement prompted outrage from the Democratic presidential candidates, who may try to use the existential threat of climate change to motivate voters.

Politically, fighting climate change is particularly important to young voters, who will live to see its worst effects and are a key part of the Democratic base.

Senator Bernie Sanders of Vermont has been especially vocal, pivoting from his signature economic message to emphasize climate change in the final sprint to the Iowa caucuses in February.