France, Nov. 26 -- While some climate activists have been throwing food at famous paintings, a French group has been shutting down roads. Their acts of civil disobedience have drawn anger and criticism, but they say it is the only way to get people to pay attention to what they see as an existential threat.

Every few days, a handful of activists walk onto a highway or busy street somewhere in France and sit down, blocking traffic, facing insults from the angry drivers being held up.

Videos show drivers yelling and gesturing aggressively, sometimes physically picking up some of the activists and dragging them, while police try to clear the roads.

"The only way that we everyday people have left to put pressure on the government is to lit...