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Sreven Guilbeault is neither a scientist or an economist. The more pain he inflicts the better. Canadians are the sacrificial lambs in his pointless climate crusade.
The Social Cost of Carbon game
Estimates of the SCC championed by Guilbeault are not science
Environment Minister Steven Guilbeault recently announced that the Social Cost of Carbon (SCC), or the dollar value of supposed damages associated with each tonne of carbon dioxide emissions, is about $247, nearly five times higher than the old estimate of $54. He made it sound like a discovery, as if a bunch of experts had finally been able to measure something they previously only guessed at. Like when scientists were finally able to measure the mass of an electron or the age of the Earth, now finally we can measure the SCC.
But in reality there has been no breakthrough in economics comparable to those physics breakthroughs. Countless SCC estimates already exist ranging from small negative amounts (i.e. carbon dioxide emissions are beneficial) to many thousands of dollars per tonne. Every such estimate is like a complex "if-then" statement: if the following assumptions hold, then the SCC is $X. Yale economist William Nordhaus won the 2018 Nobel Memorial Prize in economics for developing some of the first methods for combining all the "if" statements into systems called Integrated Assessment Models or IAMs. And using conventional economic and climate modelling methods, he tended to get pretty low SCC values over the years, which has long been a sore point among climate activists and the politicians who share their agenda.
But economists are on the case. The $247 figure referenced by Guilbeault comes from a new report from the Biden administration that tossed out all the previous models, including Nordhaus's, and instead cobbled together a set of new models that when run together yield much higher SCC values.
In many ways the new models are just like the old ones. For example they persist in using an Equilibrium Climate Sensitivity of 3 degrees C. This refers to the warming expected from doubling the amount of CO2 in the atmosphere. The authors cite the Sixth Assessment Report of the Intergovernmental Panel on Climate Change as the basis for this decision, apparently unaware that that estimate has already been shown in the climate literature to be flawed. Using the IPCC's own method on updated data yields a sensitivity estimate of about 2.2 C or less, and as I have shown in a recent publication this is enough to cause the SCC estimate in a standard model to drop to nearly zero.
The biggest boosts to the new SCC figure hailed by Guilbeault come from revisions to agricultural productivity impacts and mortality costs from climate warming. The evidence for large negative agricultural impacts comes from a 2017 article by Frances Moore and co-authors that looked at the combined effects of CO2 fertilization and warming, concluding the net effect would harm global agriculture. Oddly, they used the same data as a 2014 study by Andrew Challinor and co-authors who had found the opposite: the combination of increased CO2 and warming would have much more benign, and in some cases even beneficial, results.
How did Moore et al. get different results from the same data? They used a different statistical model but unfortunately didn't provide evidence showing it is better than the one Challinor used, so it's unclear whose results are stronger. But we know whose are more popular. The Biden administration team referred only to the Moore study and left out any mention of the Challinor one, and it is a safe assumption that the reviewers didn't notice the omission. See how the game is played?
Regarding the mortality effect, the report relies on evidence in a new study that apparently shows that warming will mean fewer deaths from cold and more from heat, and the combined effect globally is a much larger overall death toll than previously thought. The study is by an impressive team led by economist Tamma Carleton and 15 co-authors. In their preface they thank 17 research assistants, four project managers, 13 reviewers and seminar participants at 20 prestigious academic institutions around the world. It's a high-quality piece of work, but like tens of thousands of other splashy climate impacts studies it relies for its headline conclusions on the discredited RCP8.5 emissions scenario. How did all those prestigious researchers and reviewers miss this flaw?
The authors compiled mortality data from selected countries around the world and matched them to temperature records, then built a statistical model to extrapolate over the entire world. They used some clever economic modelling to estimate the beneficial effects of adaptive behaviour (like installing air conditioning) as well as the costs. Then they estimated a "mortality function" that spits out the number of additional deaths between now and the year 2300 attributable to each additional tonne of emissions, both from warming itself and the costs of adaptation. To compute this number the authors needed emissions and income projections out to 2300.
For this they used two scenarios: the extreme, coal-blackened Dickensian fiction called RCP8.5, and a mid-range emissions projection called RCP4.5. In my 2020 JSW column I discussed the efforts of climate analysts to convince their colleagues to stop using the RCP8.5 scenario because of its unrealistic assumptions. Interestingly the Biden administration report moves away from both RCP scenarios and focuses on a new one from Resources for the Future (RFF) which, through most of the rest of this century, projects emissions even below RCP4.5.
https://financialpost.com/opinion/junk-science-week-social-cost-of-carbon-game?fbclid=IwAR3t0VXvTpZcU0MieH0BcBh4No_XOmkd5g0v1U9Q7z_mQ0VzLhMLkwJ5e7k">https://financialpost.com/opinion/junk- ... hMLkwJ5e7k">https://financialpost.com/opinion/junk-science-week-social-cost-of-carbon-game?fbclid=IwAR3t0VXvTpZcU0MieH0BcBh4No_XOmkd5g0v1U9Q7z_mQ0VzLhMLkwJ5e7k
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