Hi Alan, this is an interesting article:

http://www.ostp.gov/html/ucs.html

There are so many scientists debating global warming (still). It surprises me at times. However, I'm with you on this one now. Especially after no guaranteed compelling argument can be presented against it, better safe than sorry:

Union of Concerned Scientists site:

http://www.ucsusa.org/

EPA's site:
http://www.epa.gov/climatechange/

A perspective from 1992:

http://www.cato.org/pubs/regulation/regv15n2/reg15n2g.html

GWIC:

http://www.globalwarming.net/

NRDC:

http://www.globalwarming.net/

And then there are those skeptics:

http://en.wikipedia.org/wiki/Global_warming_skeptic
http://www.ucsusa.org/global_warming/science/skeptic-organizations.html
http://www.skepticism.net/faq/environment/global_warming/index.html