09.3.2018
The Great Debate Part D – Summary
here) we discussed Dr. David Karoly’s and Dr. William Happer’s arguments regarding how unusual recent global warming is and how we know the recent observed increase in CO2 is due to human activities. In Part B we examined their thoughts on the amount of warming caused by greenhouse gas emissions and the accuracy of the calculation. In Part C we discussed the dangers of global warming, the calculation of the vital value of ECS (the equilibrium climate sensitivity to a doubling of CO2), and discuss the need to do something about climate change. In this final part of the series I will summarize the debate and provide my thoughts. Summary Karoly summarizes as follows:
“Science has established that it is virtually certain that increases of atmospheric CO2 due to burning of fossil fuels will cause climate change that will have substantial adverse impacts on humanity and on natural systems. Therefore, immediate stringent measures to suppress the burning of fossil fuels are both justified and necessary.”Happer’s key point is:
“Climate models don’t work. They have predicted several times more warming from greenhouse gas increases than has been observed.”In a nut shell, both agree the world is warming, and CO2 and other greenhouse gases have contributed to the warming. Karoly and Tamblyn think the recent warming is unusual, but Happer and the historical record suggest it isn’t, or if it is, there is certainly no evidence it is unusual. Rapid rises of more than one-degree are common in ice core records, three geologically recent examples that occur at about the same time in Greenland and Antarctica are shown in Table 1.
Table 1. Examples of one degree increases in temperature in 100 years or less, in these examples increases occurred in both Greenland and Antarctic ice cores at about the same time. Source: (May 2018). Year BP means years before 1950.
“There is no scientific basis for the claim that increases in atmospheric CO2 due to burning of fossil fuels will cause climate change that will have substantial adverse impacts on humanity and natural systems.”This can be considered true. Because all the proposed hazards of CO2 hinge on a poorly estimated value, the climate sensitivity (CS) to CO2. Low values of CS are no problem. High values may be a problem, but no one knows what the correct value is. The last part of Happer’s initial statement is:
“Any resulting climate change will be moderate, and there will be very major benefits to agriculture and other plant life.”Because the CS is so poorly understood, the first part of this statement is stated too firmly. Given what we read in the debate materials and the references, I think we can safely say any human-caused climate change will probably be moderate. The last part of the statement is fine, we can be certain that there will be major benefits to agriculture and other plant life, that is already happening. Generally, the debate was very informative and interesting. The organization of the documents is poor, and they are quite long and repetitive. I’ve tried to fix these problems here. The material will not be new to many readers, but Karoly and Happer are well-known, credible experts and that gives weight to their remarks and opinions. Tamblyn’s arguments are weaker than those of the other two and are mostly conjecture, using unstated and unrealistic assumed temperature increases with little foundation. Happer describes them well in his final reply:
“Mr. Tamblyn has produced not so much a response to my Statement, as a primer on global-warming alarmism, a whole list of scary talking points and computer-generated graphs, with occasional asides to deplore how obtuse I am for not understanding the gravity of this supposedly existential threat to the planet or how ignorant I am of basic physics.”That last bit had me chuckling, Professor Happer is probably the most accomplished and brilliant physicist alive today. Tamblyn did not pick up where Karoly left off and chose to begin a new debate by listing a lot of very speculative claims of the dangers of warming. Most of these “dangers” involved warming rates and amounts that are completely unrealistic. Unfortunately for us, what he adds is mostly irrelevant to the original discussion between Happer and Karoly. Thus, Happer had to defend his views in two separate debates, but he soldiered on and did quite well in both. It is a shame that Karoly backed out in the middle of the debate, had he stayed, the result would have been better. As it is we gained something, we found out it is all about how much and how fast it is warming. In my opinion, Happer won the debate, both of them.