Mark Bahner recently wrote an article on his blog challenging me to a
series of bets relating to GHG emissions and climate change. Rather
than blogging back-and-forth, I think it is more sensible to discuss
the offers on an open forum. So here is my reply. His full original can
be seen at:
My comments are interleaved:
> Proposed bets for James Annan, regarding IPCC TARThere's your first mistake, because I have previously pointed directly
> I have been having a discussion with James Annan about betting on
> Here are my responses:
> a) Don't you mean, "septics?" (See your comment on William Connolley's
> b) You seem to know-or think you know-what the IPCC "consensus" is. (As
(at least twice) to the obviously relevant sentence in the TAR Summary:
"anthropogenic warming is likely to lie in the range of 0.1 to 0.2°C
[Reference to this is on my blog at
> c) If I was personally trying to figure out what the "consensus" was inTo put it bluntly, that is your problem, not mine, and this is your
> the farce known as the IPCC TAR, I'd go to Wigley and Raper's 2001
> article in Science
> I'm willing to bet against that "consensus," based on satelliteLower troposphere? Surely you cannot be unaware of the fact that all of
> measurements of the temperature in the lower troposphere in 1990 versus
> in 2030.
the projections, model results and predictions are provided in terms of
_surface_ air temperature, (conventionally 2m). Strike three...but I'll
>The measurements should be based on a three-year averageWhich satellite measuremments? There are at least 4 interpretations,
> centered around those years (i.e., satellite measurements for 1989,
> 1990, 1991 versus satellite measurements for 2029, 2030, and 2031).
which give historic trends ranging from 0.09 to 0.24/decade. That is,
Spencer and Christy, Mears et al, Vinnikov and Grady, Fu et al.
No doubt you will demand to use whichever analysis gives the coldest
I've already suggested using the _surface_ air temperature analysis
> IfHuh? That bet is centred on 0.62C warming in 4 decades. That's more
> the temperature increase in the lower troposphere is more than 0.75
> degrees Celsius, I will pay you $100. If the temperature increase is
> between 0.62 and 0.75 degrees Celsius, I will pay you $50. If the
> temperature increase is between 0.48 and 0.62 degrees Celsius, you will
> pay me $50. If the temperature increase is less than 0.48 degrees
> Celsius, you will pay me $100.
(just) than the IPCC forecast! How is this contradicting the consensus?
Why would I want to bet on that? The bet has negative value to anyone
who takes the IPCC summmary at face value.
So I reckon that makes 5 mistakes. I'm afraid that is only worth a
If you could predict what _you_ think the temperature change will be by
I do, however, wonder if many of the critics of the IPCC report have
> However, I also challenge you to bet on methane atmosphericWell, these are primarily issues of politics, population growth,
> concentrations, and CO2 emissions and atmospheric concentrations.
economics and technology, none of which is my field, and the IPCC makes
no forecasts on these matters. In fact it quite explicitly states that
the scenarios do not form any sort of probabilistic prediction. So
basically, I have little interest in your challenges here.
> CO2 concentrations: The CO2 atmospheric concentration in 1990 wasThis sounds sufficiently attractive that I will take you up on it, even
> approximately 354 ppm. The IPCC TAR projects a 50 percent chance that
> the CO2 atmospheric concentration will be more than 438 ppm in 2030. If
> the CO2 atmospheric concentration is more than 438 ppm in 2030, I will
> give you $25. If the CO2 atmospheric concentration is less than 438 ppm
> in 2030, you give me $1. Again, I'm offering you 25-to-1 odds on
> something that, if the IPCC TAR was correct, should be even money.
though I am not primarily interested in predicting CO2 emissions and
the IPCC explicitly avoids making such a forecast.
To make it worthwhile, I suggest upping the stakes a bit - how about my
Better confirm that you will aceept Mauna Loa measurements, and won't
Look forward to hearing your further commments,
You must Sign in before you can post messages.
To post a message you must first join this group.
Please update your nickname on the subscription settings page before posting.
You do not have the permission required to post.