re: #308 freetoken

You need to update your talking points, as even Lindzen, the proponent of “iris” effect and those nasty clouds is giving up on it.

On the catastrophe part, you skip over the entire paleoclimate record. During the previous interglacial periods, the Eemian roughly 100,000 years ago, and the previous interglacial before that, temperatures were just a bit warmer than today and yet sea levels were several feet higher. In other words, there is reason to believe that even modest temperature rises over today will lead to significant sea level rise.

As for the sensitivity of the climate to CO2 doubling, you are of course unwilling to admit to anything more than the purely radiative balance (which is near 1.2C), though again all the paleoclimatology data would indicate the sensitivity has to be more than that.

Finally, the models area hind-cast to the entire 20th century record and unlike your assertion, those were observations, and indeed the models do reproduce the 20th century fairly well. The three generations of models have shown progress on this matter, and the third generation handles the major changes as well as the volcanic influences very well.

Your right, the science is more nuance than your current grasp.

They’re not “talking points.” And I don’t pay particular attention to Lindzen although I am familiar with his Iris effect theory. I was actually referring to Dr. Spencer’s research into cloud cover changes. Dr. Spencer is (supposedly) a creationist and therefore his research is not valid here per Charles IIRC, despite the inclusion of his work in the IPCC and the fact that he is part of the team to create the first satellite measurements of climate (UAH). His research is what I was referring to.

Moving on to the substance of your post, I’ve never seen that connection made between past interglacial sea levels and temperatures. I know that sea levels were higher during past interglacials, but I’ve yet to see a correlation between temperatures and sea levels in a study that applies to the modern climate. Can you post the material that you’re referring to? I’m able to read most journals so no worries if it’s subscriber only. I’m not infallible, so I’m perfectly willing to grant that there is some correlation that I am unaware of. I just have never read it nor seen it referenced in the IPCC, so I am a bit confused as to what you are talking about. I’d need to read what studies you’re referring to before responding.

On your second point, I’m not unwilling to believe that positive feedbacks exist. Some, such as alterations in albedo, are logical and falsifiable. I’m just not convinced that our current modeling of the feedbacks is accurate. To put it another way, if we understood the climate system perfectly (not just feedbacks, but things like ENSO & solar flares), it stands to reason that our climate models would be incredibly accurate. They are not, thus far. Therefore, there’s a lack of information somewhere in the chain.

On your final point, I’m aware that climate models go backwards to make sure they replicate past climate changes. That doesn’t necessarily mean that they are able to forecast. Ask any financial modeler that. And I would recommend that you look closely at the predictions of the 15 GCMs that the IPCC utilizes. There is an incredibly wide range in their predictions. For the lay person, it’d be like going to 15 doctors and 3 saying you’re going to be 7’2 and 3 saying you’re going to be 5’11 and the other 9 somewhere in between. The fact that the mean is 6’6 kind of hides the fact that there is an incredibly wide variance in the predictions.