Moreover, as in
Committee on Surface Temperature Reconstructions for the Last 2,000 Years, National Research Council, Surface Temperature Reconstructions for the Last 2,000 Years, ISBN 0-309-66264-8, 196 pages, National Academies Press, 2006.
the temperature in year 2006 was essentially exactly the same as in the year 1000 before any role for CO2.
Moreover, also from that report, the increases from the 100 years before 2006 were essentially exactly the same as in the 100 years before year 1000. So, the increases in the last 100 years or so are not unusual and not necessarily from CO2 -- there can be other causes. Nearly year 1000, there really were other causes.
Moreover, we've been pulling out of the Little Ice Age since the late 1800s or so. We were deep into the Little Ice Age when Washington crossed the Delaware and when Napoleon returned from Moscow, and NOT from lower CO2.
The real hockey stick curves were from climate models that made predictions of hockey stick increases that have all been proven wildly wrong by now -- only a tiny fraction of the models made accurate predictions, that temperature would stay essentially the same. The graphs are at, say,
http://www.energyadvocate.com/gc1.jpg
Again, yet again, once again, over again, one more time, in the whole 800,000 years of the Antarctic ice core studies, there were lots of significant temperature changes but not once was significantly lower temperature closely preceded by significantly lower CO2, and the case for higher temperatures is nearly the same.
So, there are other causes -- CO2 can't be the only cause.
Moreover, the evidence that CO2 is increasing temperature now is junk -- temperature hasn't changed significantly in about 20 years while CO2 concentrations have increased.
Again, It's not getting warmer now. It's not particularly warm now and was significantly warmer often enough in the past. CO2 is from not a cause at all or at most only a minor one -- the main causes are elsewhere. For the last 800,000 years, the good evidence is sun spot activity -- good luck trying to stop or change that!