Where do you get that natural cycles aren't accounted for in GW? These models take supercomputers months to run. That implies a hell of a lot of things are accounted for in these models.

It is weak to say that because large scale cycles occur that have been in balance for thousands of years a rise that can be accounted by man's documented emmisions is somehow not caused by man's documented emmissions. Another case of overlooking obvious linkages for any hand waving excuse that can be found. If the natural cycles had not been in balance recently, Earth's climate would not have been stable recently. That's an obvious no brainer. When something happened to change the natural balance in the past (supervolcanoes, continental drift casued changes in albedo, etc) Earth's climate changed. The only reasonable alternative proposed for recent changes is fluctuations in solar activity, but the data for that has no where near the accuracy or the linkage that the CO2 data has. Again why should you ignore a clear linkage in favor of a questionable one except that it is convenient to do so?

Past changes in climate do not negate a clear correspondance between industrial CO2 emmissions and recent temperature rises from relatively stable levels over a much longer period. Clear graphs on this data were presented in the last big round of GW debate with absolutely 0 response from the GW doubters. No one claims CO2 emmisions are the only thing that can change climate, but rather they are what is changing climate now.

The fact that climate has changed in the past also does not negate concern for its impact now. We did not have a huge population dependent on fixed agriculture and massive populations in low lying coastal areas until a few hundred years ago. The huge economic damage potential to these interests is certainly worth considering as a trade off to a small baseline increase in costs to deal with the issue.

Regards,
Mark