Their actions and attitudes did not reflect the sort of behavior you would expect from people who truly believe that the planet is in peril. The high-profile global-warming partisans focused on ridiculing nonbelievers, rather than persuading them. They hopped onto private planes to be seen at confabs, where nothing real got done. Biggies like Gore would refuse to debate -- even as they argued that Mother Earth's condition was near critical.
The worst part is that these loudmouths have drowned out the voices of scientists -- including those who believe global warming is largely caused by man -- who have been ready to engage in the complexities of climate science. In their hubris, they decided that they, and only they, would save the planet.
But their egos got in the way.