It's hard to fight groupthink. There are many reasons among greens to try and convince others of their argument and they are slowly winning in the media, government, and academics despite contrary evidence.
There is one motive though...... power.
The power of socialism where the elite tell the masses what they can and cannot do. The same elite who live in huge mansions, fly private jets, and have vacation homes. The global warming scientist and academics are the apparatchik.
Welcome to the U.S.S.R. comrade.
Another reason is that the "greens" have made a religion of environmentalism.
As I've said to some "greenies", they are the biggest proselytizers on the planet.
Environmentalism has become the Morality in Schools, the Eschatology of Belief, and the Purpose for Living among these Believers.
Michael Crichton made an excellent speech on this topic several years ago.