MIT Prof. Richard Lindzen (retired) has published (19 May 2020) a very interesting new paper in The European Physical Journal Plus (Springer) titled “An oversimplified picture of the climate behavior based on a single process can lead to distorted conclusions“. The full article is paywalled (a shockingly high 45€ for 10 pages!), but it is easy to find an accessible version by googling.
The article is written in very easy terms, at least concerning the first 3 chapters and the conclusion in chapter 5. I read it carefully several times and will try to summarize as best I can.
- Introduction
In the introduction Lindzen recall’s that greenhouse warming is a recent element in climate literature, and even if known and mentioned, played a minor role in climate science before 1980. He also repeats a mostly ignored argument, i.e. that even if there is some global warming now (from whatever causes) the claim that this must be catastrophic should be seen with suspicion.
2. Chapter 2
Chapter 2 is titled “The climate system” and on these less than 1.5 pages Lindzen excels in clarity. He writes nothing that could be controversial, but many of these facts are constantly ignored in the media: the uneven solar heating between the equator and the poles drives the motions of heat in the air and the oceans; in the latter there are changes in timescales ranging from years (e.g. El-Nino, PDO and AMO) to millenia, and these changes are present even if the composition of the atmosphere would be unchanging.
The surface of the oceans is never in equilibrium with space, and the complicated air flow over geographic landscapes causes regional variations in climate (not well described by climate models). Not CO2, but water vapor and clouds are the two most important greenhouse substances; doubling the atmospheric CO2 content would increase the energy budget by less than 2%.
He writes that the political/scientific consensus is that changes in global radiative forcing are the unique cause of changes of global temperatures, and these changes are predominantly caused by increasing CO2 emissions. This simplified picture of one global cause (global radiative forcing) and one global effect (global temperature) to describe the climate is mistaken.
It is water vapor that essentially blocks outgoing IR radiation which causes the surface and adjacent air to warm and so triggers convection. Convection and radiative processes result in temperature decreasing with height, up to level where there is so little water vapor left that radiation escapes unhindered to space. It is at this altitude where the radiative equilibrium between incoming solar energy and outgoing IR energy happens, and the temperature there is 255 K. As the temperature has decreased with height, level zero (i.e. the surface) must be warmer. Adding other greenhouse gases (like CO2) increases the equilibrium height, and as a consequence the temperature of the surface. The radiative budget is constantly changed by other factors, as varying cloud cover and height, snow, ocean circulations etc. These changes have an effect that is comparable to that of doubling the CO2 content of the atmosphere. And most important, even if the solar forcing (i.e. the engine driving the climate) would be constant, the climate would still vary, as the system has autonomous variability!
The problem of the “consensus” climatology (IPCC and politics) is that they ignore the many variables at work and simplify the perturbation of energy budget of a complex system to the perturbing effect of a single variable (CO2).
3. History
In this short chapter Lindzen enumerates the many scientists that disagreed up into the eighties with the consensus view. But between 1988 and 1994, climate funding in the USA for example increased by a factor of 15! And all the “new” climate scientists understood very well that the reason for this extraordinary increase in funding was the global warming alarm, which became a self-fulfilling cause.
Let me here repeat as an aside what the German physicist Dr. Gerd Weber wrote 1992 in his book “Der Treibhauseffekt”:
4. Chapter 4
This is the longest chapter in Lindzen’s paper, also one that demands a few lectures to understand it correctly. Lindzen wants to show that the thermal difference between equatorial and polar region has an influence on global temperature, and that this difference is independent from the CO2 content of the atmosphere. He recalls the Milankovitch cycles and the important messages that variations in arctic (summer) insolation cause the fluctuations in ice cover. The arctic inversion (i.e. temperature increasing with height) makes the surface difference between equator and polar temperatures greater than they are at the polar tropopause ( 6 km). So one does not have to introduce a mysterious “polar amplification” (as does the IPCC) for this temperature differential.
Lindzen establishes a very simple formula which gives the change in global temperature as the sum of the changes of the tropical temperature (mostly caused by greenhouse radiative forcing) and that of the changes of the equator-to-pole temperature difference (which is independent of the greenhouse effect). This means that even in the absence of greenhouse gas forcings (what is the aim of the actual climate policies) there will be changes in global temperature.
5. Conclusion
The conclusion is that the basic premise of the conventional (consensus or not) climate picture that all changes in global (mean) temperature are due to radiative forcing is mistaken.
My personal remarks:
Will this paper by one of the most important atmospheric scientists be read by the people deciding on extremely costly and radical climate policies? Will it be mentioned in the media?
I doubt it. The climate train like the “Snowpiercer” in the Netflix series is launched full steam ahead, and political decisions become more and more the result of quasi religious emotions than that of scientific reasoning. But reality and physics are stubborn… and so as the Snowpiercer is vulnerable to avalanches and rockfall, the actual simplistic climate view could well change during the next decades, long before the predicted climate catastrophe in 2100 will occur.