I always figured a green streak had to run through vampire culture.

They know they don't get to punch their ticket at 75/80/90 and miss the worst of climate collapse. They've likely learned an instinctive "we can't overgrow our environment" relationship from experience (story premise: a vampire who oversires and creates social upheaval as his hunting ground goes barren and his childer starve).

And gosh, turning into a cloud of bats to travel is much less CO2-intensive than a private jet.