In a recent Watts Up With That (WUWT) post Bib Tisdale claims that Skeptical Science still misunderstands, or misrepresents, the El Ninño Southern Oscillation. In this post Bob makes the following “challenge”
If you believe that manmade greenhouse gases are responsible for the recent bout of global warming, please provide links to the climate model-based, peer-reviewed papers that explain:
1. How and why the lower troposphere temperature anomalies of the mid-latitudes of the Northern Hemisphere show upward shifts in response to strong El Niño events—without proportional cooling during the trailing La Niñas. That is, the RSS lower troposphere temperature anomalies for the latitudes of 20N-90N do not cool proportionally during the La Niña event of 1988/89, Figure 1, but they did warm in response to the 1986/87/88 El Niño, which caused a major portion of the long-term warming trend.
Maybe this has been prompted by one of my earlier posts in which I have a couple of basic questions for Bob Tisdale. He still hasn’t answered my questions, but I’ll take him up on his challenge, anyway, and attempt to respond to his question.
His question, in some sense, is precisely the point. ENSO cycles cannot generate energy. They can simply move energy around. There is no dispute (as far as I’m aware) that an El Niño can heat the land and atmosphere to produce the observed jump in surface temperatures. However – as I attempted to illustrate in this a post a few days ago – in the absence of any enhanced greenhouse effect, this excess energy should be radiated back into space in a few days or maybe a month. In the absence of any enhanced greenhouse effect (due to increased CO2 levels in the atmosphere) we would expect the land and atmosphere to cool proportionally. That it doesn’t happen is evidence for greenhouse warming, not evidence against greenhouse warming.
As far as I understand things, the lack of proportional cooling during La Niña is what one would expect if greenhouse warming was taking place (i.e., the planet’s surface is still below the equilibrium temperature even though the El Niño has just dumped a lot of energy into the land and atmosphere). What I would really like to know is how Bob Tisdale can explain this lack of proportional cooling because it would seem to be a real problem for his theory, while being quite consistent with anthropogenic global warming.