He advised that if humans continue to dirty the environment the ecosystem can be disrupted.

UNESCO: SIV Backchat participates in beach clean

At the same time, our environment is too dirty: Studies show that pollution (such as exhaust fumes) can trigger allergic flare-ups.

CNN: Why your allergies are bugging you

Coal is dirty, heavy, difficult to transport and terrible for the environment.

FORBES: Frack Gas Not Likely To Displace King Coal, Study Suggests

For those concerned about carbon emissions, that's half way to a good news story, as gas-burning is less dirty than coal, but it's still a long way short of good for the environment.

BBC: Energy bills, and loose change