heat of the earth is not that far away. But if we pump heat out what are the long term consiquences.

http://www.consumerenergycenter.org/home/heating_cooling/geothermal.html

consiquences....

Water Vapor is a top greenhouse gas! We need closed systems.

http://www.cosis.net/abstracts/EAE03/11488/EAE03-A-11488.pdf

Here is a great series of slides
http://geothermal.marin.org/GEOpresentation/sld116.htm