Nick - The skeptics point to those three things because those things correctly expose the serious problems AGW has - a lack of evidence for CO2 as a cause for warming.
>> 1) there has been warming ...and cooling. And warming. Etc. (I figured you meant currently since human CO2 contribution, but I'm pointing to the larger picture here.) and... >> 2) that CO2 has increased in parallel with that warming Indeed that's the case. And it follows warming as if driven by it, not as a driver of it. Easy to understand this, and already a staple of the tipping point folks. But they see CO2 as a driver, so they claim large accelerating feedback. Problems: there's no evidence it's a driver, so the alleged feeback loop is broken. And for confirmation, no historical evidence of runaway when CO2 was much higher. >> 3) that CO2 should contribute to future warming. And it "should" because that's the greenhouse *theory*, not the observation. CO2 might be expected to *coincide* with warming, because that's been a fairly reliable historical trend. But apparently we don't have all the information we need about this one because although our carefully crafted models can be coaxed to display outcomes conforming to the theory, nature seems to have other ideas. (psst...again, want to bet it's the sun?) - Rick
