IS GLOBAL WARMING CAUSED BY HUMANS?

CO2 isn't a "contaminant", much else on the ice core is. This isn't directly related, just loved the pic:


From the latest National Geographic: http://environment.nationalgeographic.com/staticfiles/NGS/Shared/StaticFiles/Environment/Images/Global_Warming/polar-bear-jumping-1052295-ga.jpg
http://environment.nationalgeographic.com/environment/photos/arctic-climate-change/polar-bear-arctic.html

I was talking about CO2 in tree rings and I never called it a contaminant, I said that OTHER contaminants were measurable in tree rings.

Neat pic.

Sorry; glad you love the pic. I wonder how National Geographic makes money - taking that one pic must have cost them an entire expedition escorting the photographer for months.

Even National Geographic is hurting from a huge drop in the subscription of their magazines. They're offering subscriptions on the cheap - just about pays for the postage.