>You can point at an asteroid and say "That thing. It's going to melt half the planet."
How do you get people to believe it up until the day it gets close enough to make out with the human eye that it's approaching the planet? It's too late at that point. How many people have a telescope with that type of resolution, cameras that can pull out something likely low magnitude? We present scientific evidence to the public on Climate Change and many just don't care enough to actually do anything, why wouldn't the same happen with an Asteroid?
Because enough people will believe it when they see an asteroid looming towards them on CNN, Fox, whatever. There are plenty of people that deny climate change because it's convenient, either politically or economically. There are considerably fewer people that think the moon landing was faked, or the earth is flat, or pluto and mars and jupiter are actually jewels hanging from threads in a crystal sphere.
An asteroid is a sufficiently "concrete" science that the average person would believe if they see it. You can't "see" climate change, which is part of the issue.
How do you get people to believe it up until the day it gets close enough to make out with the human eye that it's approaching the planet? It's too late at that point. How many people have a telescope with that type of resolution, cameras that can pull out something likely low magnitude? We present scientific evidence to the public on Climate Change and many just don't care enough to actually do anything, why wouldn't the same happen with an Asteroid?