Bauman Climate Bet Bleg
By Bryan Caplan
The Economist confirms that global warming has paused over the last 15 years:
Between 1998 and 2013, the Earth’s surface temperature rose at a rate of
0.04°C a decade, far slower than the 0.18°C increase in the 1990s.
Meanwhile, emissions of carbon dioxide (which would be expected to push
temperatures up) rose uninterruptedly. This pause in warming has raised
doubts in the public mind about climate change.
The rest of the piece discusses explanations for the pause:
A convincing explanation of the pause therefore matters both to a proper
understanding of the climate and to the credibility of climate
science–and papers published over the past few weeks do their best to
provide one. Indeed, they do almost too good a job. If all were correct,
the pause would now be explained twice over.
I’m not qualified to evaluate any of this research. As a matter of general epistemic policy, though, I put very little stock in after-the-fact explanations. And that seems to be all the latest research is.
Indeed, for a long time, most specialists just downplayed the facts:
As evidence piled up that temperatures were not rising much, some
scientists dismissed it as a blip. The temperature, they pointed out,
had fallen for much longer periods twice in the past century or so, in
1880-1910 and again in 1945-75 (see chart), even though the general
trend was up. Variability is part of the climate system and a 15-year
hiatus, they suggested, was not worth getting excited about.
Or disputed the facts:
An alternative way of looking at the pause’s significance was to say
that there had been a slowdown but not a big one. Most records,
including one of the best known (kept by Britain’s Meteorological
Office), do not include measurements from the Arctic, which has been
warming faster than anywhere else in the world. Using satellite data to
fill in the missing Arctic numbers, Kevin Cowtan of the University of
York, in Britain, and Robert Way of the University of Ottawa, in Canada,
put the overall rate of global warming at 0.12°C a decade between 1998
and 2012–not far from the 1990s rate. A study by NASA puts the “Arctic
effect” over the same period somewhat lower, at 0.07°C a decade, but
that is still not negligible.
Or moved the goalposts:
It is also worth remembering that average warming is not the only
measure of climate change. According to a study just published by Sonia
Seneviratne of the Institute for Atmospheric and Climate Science, in
Zurich, the number of hot days, the number of extremely hot days and the
length of warm periods all increased during the pause (1998-2012).
To repeat, I’m not qualified to debate these experts. But their reaction seems fishy to me, and I am more than qualified to bet against the consensus on the basis of that perceived fishiness. Of course, since the experts are claiming knowledge, and I’m claiming ignorance, the odds should be in my favor. Last week on Twitter, I publicly offered to bet at 2:1 odds that the global warming pause will continue for another 15 years.
Yoram Bauman has nobly accepted my offer. Indeed, he offers better terms than I requested: 3:1 odds, and I win if (according to according to ncdc.noaa.gov/cag/time-series) the average global annual land + ocean temperature increase between 2014 and 2028 inclusive is less than or equal to +.05 C.
My main question: Do Bauman’s terms raise any red flags? In particular, does anyone have any problem with his suggested data source?
Otherwise, I propose only cosmetic changes:
1. Since we already have some data from 2014, the bet should run from 2015 to 2029.
2. Yoram proposed Wheat and Chessboard stakes, but I prefer to simply bet my nominal $333.33 against his nominal $1000.
3. If ncdc.noaa.gov/cag/time-series stops publishing data during this period, we call the bet off. Alternately, Yoram can propose back-up data sources, and we only call the bet off if they all stop publishing data.
My main reservation is the past reluctance of global warming skeptics to bet. But after a 15-year pause that was not widely predicted in advance (also known as “predicted”), I’m ready to take my chances.
P.S. My Bettor’s Oath states: “When I lose a bet, I will admit defeat, pay promptly, and hold my tongue
– never protesting that I was “really right.” If I have caveats or reservations, I will declare them when I make the bet – not after I lose it.” So let me state one caveat here and now: I expect to lose this bet. I would not make it at even odds. I am betting because I think climate experts know less than they think, not because I know future climate with any confidence.