Book Review By Donald Rapp [ see for the post on Donald’s book – The Climate Debate]
Bob Tisdale has produced an extraordinary new book:
Who Turned on the Heat? – The Unsuspected Global Warming Culprit, El Niño-Southern Oscillation –The Unsuspected Global Warming Culprit, El Niño-Southern Oscillation is now on sale in pdf form for US$8.00 – Please click here to buy a copy.
This book is also subtitled “Everything you wanted to know about El Niño and La Niña” and that is quite accurate.
I didn’t realize how little I understood El Niño and La Niña phenomena until I read Bob Tisdale’s book. I learned a great deal from this book, which provides the reader with thorough but easily understandable explanations of El Niño and La Niña phenomena enhanced by many wonderful cartoon-like illustrations. The book provides lucid descriptions of the various indices used to characterize El Niño and La Niña phenomena. It also provides a wealth of graphical data on El Niño and La Niña occurrences. While the book deals predominantly with the last thirty years, it also deals with the entire 20th century.
Perhaps the three most important facts that I had not previously fully appreciated were:
(1) While incident sunlight can penetrate several to many meters into oceans, incident IR penetrates only up to a few mm.
(2) After an El Niño (particularly a strong one) a pool of warm surface water stretches across the Pacific that continues to warm the atmosphere even after El Niño conditions have subsided. (This seems to have been particularly important for the great 1998 El Niño).
(3) A La Niña is not the opposite of an El Niño, but rather is an amplified version of normal conditions in the Pacific Ocean.
In addition, Tisdale emphasizes the enormity of the Pacific Ocean (about 1/3 of the earth’s surface) and he also emphasizes the worldwide climatic effects of El Niños.
Tisdale uses Fact (1) to argue his view that the atmosphere, even if heated by greenhouse gases, does not warm oceans; rather sunlight warms oceans. On the contrary, he argues that warm ocean surface waters heat the atmosphere. So, he disagrees with climate modelers as to which is the dog and which is the tail that wags.
Tisdale uses Facts (2) and (3) to argue that the warming of the atmosphere that began around 1976 commensurate with the beginning of an era of El Niño preponderance was due to the warm surface waters during and after El Niños. He backs up this argument with extensive data.
Looking at the full extent of the 20th century, Tisdale shows that the century can be divided into three periods: 1900-1940; 1940-1976; and 1976-2006. The first and last periods were preponderantly El Niño while the middle period was slightly favored with La Niña. These period are also the periods during which global temperatures rose sharply, dipped slightly, and then rose again. This relationship has been noted previously by many climatologists (see Sec. 4.9 of my book: “The Climate Debate”). Tisdale shows (as my book does also) that the integral of an El Niño index looks amazingly like the global temperature curve for the entire 20th century.
Tisdale’s book is so excellent in so many ways that it is difficult to find anything to criticize. The only thing I can harp on is that Tisdale is perhaps too sure of himself. He seems certain that prevalent El Niños caused essentially 100% of the warming from 1976 to 2006 and greenhouse gases contributed nothing. He said:
“The SST and ocean heat content data for the past 30 years show that the global oceans have warmed. There is no evidence, however, that the warming was caused by anthropogenic greenhouse gases in part or in whole; that is, the warming can be explained by natural ocean-atmosphere processes, primarily ENSO” (emphasis added).
Other skeptics have suggested that El Niños provided 70% of warming over the past 50 years (McLean et al., 2009) while some alarmists have suggested 15-30% (Foster et al., 2010).
There is evidence that the 300-year period from say 1600 to 1900 was characterized by relatively low global temperatures (the little ice age) and we might surmise that El Niños were not preponderant during that period. Yet, something changed beginning shortly after 1900. There were two extended periods of preponderant El Niños commensurate with rising global temperatures. The change around 1976 was particularly noticeable and has been referred to in the literature (“sudden and decisive change in the circulation patterns and upwelling characteristics in the Pacific began around 1976”, “… the tendency for more El Niño and fewer La Niña events since the late 1970s is highly unusual and very likely to be accounted for solely by natural variability”, “Several studies have noted that the pattern of El Niño–Southern Oscillation (ENSO) variability changed in 1976, with warm (El Niño) events becoming more frequent and more intense”, “Particularly dramatic physical and biological excursions occurred during the 1976–77 change in the Pacific Decadal Oscillation”, “It is now widely accepted that a climatic regime shift transpired in the North Pacific Ocean in the winter of 1976–77. This regime shift has had far reaching consequences for the large marine ecosystems of the North Pacific” (references for these quote given in “The Climate Debate”). During the 20th century when earth temperatures were rising, the CO2 concentration was also rising. Several related questions are suggested. Can variability of preponderance of El Niños explain most, if not all of the 20th century warming? If it can, is there some underlying reason why El Niños emerged preponderant in the 20th century, or was it merely a statistical quirk? Is there any connection between rising CO2 and the advent of preponderant El Niños? Tisdale says there is no evidence for this.
As for me, in matters of climate, I am not sure of hardly anything.
Added info: for other posts by Donald, please see