As described in my last post, I am a “lukewarmer”. That means I acknowledge the scientific principles underlying the theory of AGW. I have little difficulty with the general findings of the IPCC and that anthropogenic sources are responsible for most of the heating observed since 1951. But I also believe that based on the trend of the most recent literature, climate sensitivity will eventually be determined to be at the bottom end of the range reported in the IPCC Working Group I Report. Funny thing though, for the “crime” of expressing this opinion, I have been called a “denier” by the purveyors of the political “consensus” that dominates the on-line discourse in the field.
So I gave in and used the magic word: “consensus”. Up until now I have been talking about the actual scientific consensus. To be clear here, when I talk about the scientific consensus, I am talking about what the IPCC reports and actual climate scientists actually say, not the “consensus” trumpeted in the media by social, political and environmental activists. Why do I distinguish between the two? Well the answer is pretty simple, this thing the activists call the “consensus” has little in common with the actual scientific consensus in the field, as defined by what the IPCC has actually presented in black ink on the pages of its reports. The “consensus” is a political construct created by a band of environmental NGOs and activist organizations. These organizations are made up of well-meaning but essentially scientifically blind [see my previous definition of the term] political activists, social scientists and lay people most of whom are deep in a Dunning-Kruger haze of their own good intentions. Many have read at least some portion of the IPCC Summary for Policymakers. But as those familiar with the process can explain, the Summary document, while initially produced by the scientists, is only approved line-by-line by votes which means that it is a political and not a scientific document. A few of these activists may have read the Working Group I (Physical Science Basis) Summary for Policymakers and virtually none have read (or frankly have the expertise to understand) the actual chapter reports prepared so carefully by the scientific professionals.
The reason this is important is that the actual technical chapters highlight the limitations of the global climate models and highlight why decision-makers should be cautious. One issue I do have with the IPCC reports is that we are presented with levels of confidence which are actually nothing of the sort. For those of us used to seeing error bars; levels of significance based on testing and repetition; and qualifiers in reports much of the field of climate science is frustrating to say the least. The IPCC confidence levels are unsupported by statistical rigour and while they may be correct, are not in the least reproducible. I will acknowledge that they do, at least, represent the best guesses from the author group that prepared the reports. This essentially self-selected group has expertise I cannot match but that being said, they were limited by the information that was used to write their chapters. In the case of climate sensitivity they did not have the most recent technical papers, since the cut-off for inclusion in the Working Group I report was March 2013. The balance of the newer papers have added to the weight of evidence at the lower end of the IPCC range.
Based on the trend of the most recent literature, I expect that the science will settle in the 1.5 oC – 2.5 oC range. So what does that mean? It means that in order to avoid serious consequences in the future we need to identify a path to decarbonizing our power and transport systems. But what else does it mean? Well, if the models predicting low sensitivity (i.e. less than 2 oC per doubling) are correct then the atmosphere can tolerate substantially higher carbon dioxide concentrations than if the sensitivity is higher (say 6oC). In the lower case maybe mitigation can be used to reduce societal/ecological stress while we work our way towards a goal of stable atmospheric carbon dioxide concentrations (where emissions essentially equal deposition). If it turns out to be 6 oC plus per doubling, then not only had we better ban all coal plants tomorrow, it is unlikely that we can avoid serious ecological damage/cataclysms as we deal with a + 6oC – +10oC world, because even if everything goes perfectly in Lima we are on a path to a doubling plus before we can get this thing in hand.
As I said, were I confident that this alarmist “consensus” was reliable I would argue that immediate responses were necessary and damn the expense. However, I believe that the lower end of the scientific consensus will win out and that means it is time to consider the Precautionary Principal. Wait there is another of those magic terms. I don’t mean the “Precautionary Principal” used by activists to ban all development and scientific advances. I mean the real Precautionary Principal as expressed as Principal 15 in the Rio Declaration which states:
“In order to protect the environment, the precautionary approach shall be widely applied by States according to their capabilities. Where there are threats of serious or irreversible damage, lack of full scientific certainty shall not be used as a reason for postponing cost-effective measures to prevent environmental degradation.”
Yes, you read that right; the actual Precautionary Principal includes a qualifier for cost-effectiveness. The activists pretend that line is not there as they look to mandate massively intrusive and completely unworkable ideas on an unwilling populace without demonstrating their effectiveness or addressing major concerns. Consider the first few rounds of this game: the Chicago carbon exchange went belly up, tradable carbon credits ended up being scammed world-wide, ethanol requirements for fuel have taken much needed calories out of the global food chain and activists are talking about preventing developing countries from getting the energy needed to pull their populaces out of poverty. I don’t have time for all this now but I suggest you read up on “environmental Kuznet curves” to get a feel for where I am going. That being said, I want to invest heavily in renewables and I happen to live in BC where our carbon tax has slowed down the production of CO2. Given that history, I think it might be a good next step still we need to get societal buy-in to get the right combination of ideally low carbon power for each region and that means a debate as to what represents “right” for each region, but that is a topic for a future post.
I appreciate your drawing attention to the fact that the original Rio Declaration said the “precautionary principle” considered that “cost effective measures” were a criteria for moving forward. Many, perhaps even most, of the policy responses around the world claiming climate change as justification have promoted non-cost effective measures.
In considering the overall impacts of CO2 on people and the biosphere, CO2 fertilization effects deserve consideration. CO2 fertilization has definitely enhanced agricultural productivity, although this benefits is completely ignored in the AR5 Summary for Policymakers.
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