Subjectivist wrote:dissident wrote:
I have made the point several times on this board before: comparing the climate sensitivity to CO2 increases today and 5.3 million years ago is not appropriate. We slipped into an ice age because the Panama channel closed and due to ocean currents around Indonesia about 5 million years ago and not because the CO2 was removed by some unknown process. So 450 ppmv CO2 today will have a different impact than it did 5 or 10 million years ago. From the paleclimate record there will be a smaller temperature response with today's sensitivity.
Really? How much smaller do you believe the response will be? So far from the effects we see in the Arctic the amplification has been higher than what the climate models were predicting, not smaller.
This smells of trolling. Which climate models? Please provide some references.
Everyone and his dog knows that climate GCM land and sea ice schemes are very primitive (glorified ice cube models). They also only started using coupled ocean-atmosphere models very recently (not for the previous IPCC round) due to lack of computer power. I have not seen the diagnostics of these coupled models. If they have realistic sea ice schemes (e.g. ones where the sea ice is transported by the ocean circulation as affected by the atmospheric circulation), then they should do a much better job of capturing the albedo loss we have seen during the last 10 years.
You show the basic problem with climate science: everyone thinks he's an expert. Do you have a gut feeling about the ocean circulation under different land mass arrangements? Do you also have a gut feeling about CO2 flux at the ocean surface due to different circulation regimes?