Cherry Picking Climate Catastrophes: Response to Conor Clarke, Part II
Conor Clarke at The Atlantic blog, raised several issues with my study, “What to Do About Climate Change,” which Cato published last year.
One of Conor Clarke’s comments was that my analysis did not extend beyond the 21st century. He found this problematic because, as Conor put it, climate change would extend beyond 2100, and even if GDP is higher in 2100 with unfettered global warming than without, it’s not obvious that this GDP would continue to be higher “in the year 2200 or 2300 or 3758”. I addressed this portion of his argument in Part I of my response. Here I will address the second part of this argument, that “the possibility of ‘catastrophic’ climate change events — those with low probability but extremely high cost — becomes real after 2100.”
The examples of potentially catastrophic events that could be caused by anthropogenic greenhouse gas induced global warming (AGW) that have been offered to date (e.g., melting of the Greenland or West Antarctic Ice Sheets, or the shutdown of the thermohaline circulation) contain a few drops of plausibility submerged in oceans of speculation. There are no scientifically justified estimates of the probability of their occurrence by any given date. Nor are there scientifically justified estimates of the magnitude of damages such events might cause, not just in biophysical terms but also in socioeconomic terms. Therefore, to call these events “low probability” — as Mr. Clarke does — is a misnomer. They are more appropriately termed as plausible but highly speculative events.
Consider, for example, the potential collapse of the Greenland Ice Sheet (GIS). According to the IPCC’s WG I Summary for Policy Makers (p. 17), “If a negative surface mass balance were sustained for millennia, that would lead to virtually complete elimination of the Greenland Ice Sheet and a resulting contribution to sea level rise of about 7 m” (emphasis added). Presumably the same applies to the West Antarctic Ice Sheet.
But what is the probability that a negative surface mass balance can, in fact, be sustained for millennia, particularly after considering the amount of fossil fuels that can be economically extracted and the likelihood that other energy sources will not displace fossil fuels in the interim? [Remember we are told that peak oil is nigh, that renewables are almost competitive with fossil fuels, and that wind, solar and biofuels will soon pay for themselves.]
Second, for an event to be classified as a catastrophe, it should occur relatively quickly precluding efforts by man or nature to adapt or otherwise deal with it. But if it occurs over millennia, as the IPCC says, or even centuries, that gives humanity ample time to adjust, albeit at a socioeconomic cost. But it need not be prohibitively dangerous to life, limb or property if: (1) the total amount of sea level rise (SLR) and, perhaps more importantly, the rate of SLR can be predicted with some confidence, as seems likely in the next few decades considering the resources being expended on such research; (2) the rate of SLR is slow relative to how fast populations can strengthen coastal defenses and/or relocate; and (3) there are no insurmountable barriers to migration.
This would be true even had the so-called “tipping point” already been passed and ultimate disintegration of the ice sheet was inevitable, so long as it takes millennia for the disintegration to be realized. In other words, the issue isn’t just whether the tipping point is reached, rather it is how long does it actually take to tip over. Take, for example, if a hand grenade is tossed into a crowded room. Whether this results in tragedy — and the magnitude of that tragedy — depends upon how much time it takes for the grenade to go off, the reaction time of the occupants, and their ability to respond.
Filed under: Energy and Environment; International Economics and Development
Response to Conor Clarke, Part I
Last week Conor Clarke at The Atlantic blog , apparently as part of a running argument with Jim Manzi, raised four substantive issues with my study, “What to Do About Climate Change,” that Cato published last year. Mr. Clarke deserves a response, and I apologize for not getting to this sooner. Today, I’ll address the first part of his first comment. I’ll address the rest of his comments over the next few days.
Conor Clarke:
(1) Goklany’s analysis does not extend beyond the 21st century. This is a problem for two reasons. First, climate change has no plans to close shop in 2100. Even if you believe GDP will be higher in 2100 with unfettered global warming than without, it’s not obvious that GDP would be higher in the year 2200 or 2300 or 3758. (This depends crucially on the rate of technological progress, and as Goklany’s paper acknowledges, that’s difficult to model.) Second, the possibility of “catastrophic” climate change events — those with low probability but extremely high cost — becomes real after 2100.
Response: First, I wouldn’t put too much stock in analyses purporting to extend out to the end of the 21st century, let alone beyond that, for numerous reasons, some of which are laid out on pp. 2-3 of the Cato study. As noted there, according to a paper commissioned for the Stern Review, “changes in socioeconomic systems cannot be projected semi-realistically for more than 5–10 years at a time.”
Second, regarding Mr. Clarke’s statement that, “Even if you believe GDP will be higher in 2100 with unfettered global warming than without, it’s not obvious that GDP would be higher in the year 2200 or 2300 or 3758,” I should note that the conclusion that net welfare for 2100 (measured by net GDP per capita) is not based on a belief. It follows inexorably from Stern’s own analysis.
Third, despite my skepticism of long term estimates, I have, for the sake of argument, extended the calculation to 2200. See here. Once again, I used the Stern Review’s estimates, not because I think they are particularly credible (see below), but for the sake of argument. Specifically, I assumed that losses in welfare due to climate change under the IPCC’s warmest scenario would, per the Stern Review’s 95th percentile estimate, be equivalent to 35.2 percent of GDP in 2200. [Recall that Stern’s estimates account for losses due to market impacts, non-market (i.e., environmental and public health) impacts and the risk of catastrophe, so one can’t argue that only market impacts were considered.]
The results, summarized in the following figure, indicate that even if one uses the Stern Review’s inflated impact estimates under the warmest IPCC scenario, net GDP in 2200 ought to be higher in the warmest world than in cooler worlds for both developing and industrialized countries.
Source: Indur M. Goklany, “Discounting the Future,” Regulation 32: 36-40 (Spring 2009).
The costs of climate change used to develop the above figure are, most likely, overestimated because they do not properly account for increases in future adaptive capacity consistent with the level of net economic development resulting from Stern’s own estimates (as shown in the above figure). This figure shows that even after accounting for losses in GDP per capita due to climate change – and inflating these losses — net GDP per capita in 2200 would be between 16 and 85 times higher in 2200 that it was in the baseline year (1990). No less important, Stern’s estimate of the costs of climate change neglect secular technological change that ought to occur during the 210-year period extending from the base year (1990) to 2200. In fact, as shown here, empirical data show that for most environmental indicators that have a critical effect on human well-being, technology has, over decades-long time frames reduced impacts by one or more orders of magnitude.
As a gedanken experiment, compare technology (and civilization’s adaptive capacity) in 1799 versus 2009. How credible would a projection for 2009 have been if it didn’t account for technological change from 1799 to 2009?
I should note that some people tend to dismiss the above estimates of GDP on the grounds that it is unlikely that economic development, particularly in today’s developing countries, will be as high as indicated in the figure. My response to this is that they are based on the very assumptions that drive the IPCC and the Stern Review’s emissions and climate change scenarios. So if one disbelieves the above GDP estimates, then one should also disbelieve the IPCC and the Stern Review’s projection for the future.
Fourth, even if analysis that appropriately accounted for increases in adaptive capacity had shown that in 2200 people would be worse off in the richest-but-warmest world than in cooler worlds, I wouldn’t get too excited just yet. Even assuming a 100-year lag time between the initiation of emission reductions and a reduction in global temperature because of a combination of the inertia of the climate system and the turnover time for the energy infrastructure, we don’t need to do anything drastic till after 2100 (=2200 minus 100 years), unless monitoring shows before then that matters are actually becoming worse (as opposing merely changing), in which case we should certainly mobilize our responses. [Note that change doesn’t necessarily equate to worsening. One has to show that a change would be for the worse. Unfortunately, much of the climate change literature skips this crucial step.]
In fact, waiting-and-preparing-while-we-watch (AKA watch-and-wait) makes most sense, just as it does for many problems (e.g., some cancers) where the cost of action is currently high relative to its benefit, benefits are uncertain, and technological change could relatively rapidly improve the cost-benefit ratio of controls. Within the next few decades, we should have a much better understanding of climate change and its impacts, and the cost of controls ought to decline in the future, particularly if we invest in research and development for mitigation. In the meantime we should spend our resources on solving today’s first order problems – and climate change simply doesn’t make that list, as shown by the only exercises that have ever bothered to compare the importance of climate change relative to other global problems. See here and here. As is shown in the Cato paper (and elsewhere), this also ought to reduce vulnerability and increase resiliency to climate change.
In the next installment, I’ll address the second point in Mr. Clarke’s first point, namely, the fear that “the possibility of ‘catastrophic’ climate change events — those with low probability but extremely high cost — becomes real after 2100.”
The President’s New Cars
I had an op-ed yesterday in USA Today about President Obama’s proposed new fuel-economy standards. Don’t like ‘em. Unfortunately, an editing snafu over at the newspaper inadvertently left out the fact that there are four models at present that meet the proposed new standard — the 2010 Honda Insight (41 mpg) and the 2010 Ford Fusion Hybrid (39 mpg) were left off the list.
Space prohibited me from making an additional point. Even if there is no rebound effect, my colleague Pat Michaels finds that global temperatures will only be reduced by 0.005 degrees Celsius by 2050 and 0.0078 degrees Celsius by 2100 once you plug those emissions reductions into the computer models used by the IPCC. Of course, proponents contend that U.S. action on fuel efficiency will lead to like action abroad. Well, good luck with that. But even if all of the signatories to the Kyoto Protocol adopted Obama’s proposed fuel-economy standards, global temperatures would be reduced by only 0.038 degrees Celsius by 2050 and 0.071 degrees Celsius by 2100. If you tried to monetarize those benefits, you would be hard pressed to come up with an defensible number of consequence.
So what should be done instead? Nothing. At the risk of sounding politically irrelevant, there is no good case for the government to reduce U.S. gasoline consumption via fuel economy standards or fuel taxes; an argument I made at length in a study I co-authored almost two years ago with my colleague Peter Van Doren.
[Cross-posted at The Corner]
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