Some do because they believe in being good stewards of the earth God gave them. Others really don't care because they are hardcore believers in Armogeddon and thus are just waiting for that to happen or them to die so they can see Jesus. To them the planet and environment are temporary anyway and don't matter.

For too many, this life is insignificant.

when you put power in heaven instead of on the earth, you don't care too much about the earth..and the "heavenly" power then becomes the realm of the earthly powerful..

Yes!
The rapture is too carry them away to the promised heaven and land!

Like everyone else on the planet, they do not understand that no one gets out of here alive!

That is really sad. In general about 25% of the people on this planet really care about Earth at some level. That just shows some christains are mentally ill.