Climate Conversation Group

Barry Brill points out the warmists don’t seem pleased at the recent good news about climate sensitivity (a new paper says it’s not going to warm catastrophically). Could it be because the warmists cry only crocodile tears about the forecast disaster and they’re actually looking forward to it? (It lets them control us.) – Richard Treadgold

– by Barry Brill, Chairman of the New Zealand Climate Science Coalition

Whether the future level of Anthropogenic Global Warming is dangerous or catastrophic or merely interesting turns entirely on how “sensitive” the climate is to carbon dioxide emissions.

The key sensitivity measure is the increase in temperature resulting from a doubling of the CO2 atmospheric concentration of 280ppm that is said to have existed in pre-industrial times.

Laboratory experiments have shown that sensitivity should be about 1°C before feedbacks – but the net impact of positive and negative feedbacks is the subject of incessant debate. Sceptics generally say negatives (especially clouds) are dominant so that the final outcome falls back to about 0.4°C. The majority view is that positives (especially water vapour) drive the outcome up to 3-4°C, while some catastrophists see runaway warming up to 6°C or above.

There is no consensus.

The science is not settled. The debate is not over. Read more… »

Spencer claims that climate sensitivity has been “grossly overestimated” because of confusion over cause and effect between cloud cover and temperature. All the computer models now wrongly treat cloud cover as a positive feedback, amplifying warming. But some clouds directly cause warming (a forcing) and are not the result of warming (a feedback). He gives details and says they’re having to fight to get it published. more…