Courtesy of Texas state climatologist John Nielsen-Gammon, a very nice graphical demonstration of why “warming” hasn’t stopped in the last decade (or two). Nielsen-Gammon took the GISS global temperature series, classified years as El Niño dominated, neutral, or La Niña, excluded the influence of the Pinatubo-cooled years in the early 90s, and then calculated the trends for each set. The graph really says it all, but his blog post provides all the analysis. The next El Niño looks as though it’s going to be interesting…
JNG’s graph has been doing the rounds a bit! In many ways I reckon it’s more straightforward than Foster and Rahmstorf, and says the same thing. It’s well worth seeing the other charts on the post…
Yes, I had already read the original. However, monday evening on Stratos I caught the tail end of an interview with a Prof Davies, Auckland uni, the guy who found cloud heights had lowered about 20 metres during the recent past which he described as displaying little or no warming. He supposed a negative cloud feedback was in operation (a favourite of denialists) although he acknowledged no knowledge as to the cause of the lowering. What I heard of the interview was straight denialist memes, uncertainty so need more research, lots of time apparently, the precautionary principle gets a shrug. I thought the interviewer was displaying more knowledge of climate science than he was, yet he has quite a few papers to his credit. He is described as a climate physicist. I wondered if he was hanging on to the (little or no warming) meme in the hope the cloud lowering represents a significant negative feedback. If so John Nielsen-Gammon has shown that is a weak hope. Davies did acknowledge that if, over some more years, the clouds climb back up again there will be nothing in it. If not he is onto something.
Note: If I ever get the chance, when I hear someone push out the uncertainty meme I will ask them to be very specific – they usually are vague.Clouds are a rather vague area but whatever they do it is not enough to dislodge the effect of GHGs.
Noel
Noel, I wrote an SkS post about the cloud height trend here: Falling Cloud Height In the Last Decade: Is It Just ENSO?
Figure 6 is needs to be plotted inversely to better communicate that low cloud height overall, since the early 80’s, has increased, and appears to follow the warming/cooling anomaly trends.
We can be fairly certain that a strong negative cloud feedback does not exist, otherwise the dramatic climatic changes throughout Earth’s history would not have happened.
If the governer gets to hear about this he will have to have another prayer in.