Professor Richard Lindzen (http://www-eaps.mit.edu/faculty/lindzen.htm)
is a prominent sceptic who claims that the anthropogenic influence on
our climate is close to negligible and that in fact cooling is about as
likely as warming over the next 20 years. Now, although there is
certainly some non-zero chance of cooling on this time scale (due to the
natural variability of the climate, and the possibility of large
volcanic eruptions), this opinion certainly seems to be well to one
extreme of what most climate scientists think.

Recently, my attention was drawn to some comments attributed to Lindzen
in http://www.reason.com/rb/rb111004.shtml: "Richard Lindzen says he's
willing to take bets that global average temperatures in 20 years will
in fact be lower than they are now." (thanks to William Connolley for
the tip). Given his widely-promulgated views, I took this quote at face
value and contacted him to arrange a wager. A payoff at retirement age
would be a nice top-up to my pension.

Now here's the kicker. Richard Lindzen will indeed accept a bet - but
only if offered odds of 50:1 in his favour! He actually started out
quoting 100:1 - but came down to 50:1 in what he described as a special
favour to me. If the temperatures went down, I was to hand over $10,000,
but in the event of a rise, I'd get a whopping $200. That's worth around
$8 per year on my pension. Whoop-de-doo.

That's not really quite what I had in mind. In fact, not only is it a
waste of time for me, but I think that his side of the bet is actually
substantially more attractive than mine. Note that I certainly do not
consider myself to be a sceptic, but on the contrary am just a bit-part
player in climate research who thinks that the IPCC report has (broadly
speaking) got it right. Yet here is one of the most prominent sceptics
who is apparently substantially less confident about the chances of
medium-term cooling than I am myself! As a ballpark estimate, I reckon
something in the region of 10:1 or 5:1 odds on the bet would probably be
fair on the 20 year time scale - I haven't tried to pin it down with any
great precision, as I had assumed at the outset that there was such a
gulf between my viewpoint and Richard Lindzen's that it would be easy to
find a mutually agreeable wager in the region of 2:1 or 3:1 odds. As I
explained to him, 3:1 would be a reasonable middle ground between an
honest sceptic - Mr 50-50, who believes cooling is as likely as warming
and would therefore expect to win $1 on average from a $3 v $1 bet - and
a (mythical?) "true believer" who believes that a rise in temperatures
is certain and would therefore also expect the same bet to be worth $1
to _him_. I'm not claiming here that 3:1 is the _correct_ odds to
arrange a bet - but it certainly provides a meaningful and realistic
starting point for negotiations, in contrast to Lindzen's absurd
proposition. I hadn't reckoned that the gulf in opinions was that _he_
was more insistent on warming taking place, and less confident about the
prospects of cooling, than _I_ was!

Richard Lindzen's words say that there is about a 50% chance of cooling.
His wallet thinks it is a 2% shot. Which do you believe? He says he was
misrepresented in the quote on the reason.com site - can we expect to
see a correction, and headlines in the sceptic press along the lines of
"Richard Lindzen thinks there is at least a 2% chance of global
cooling"? I'd probably take bets against that happening, too - and 50:1
against seems fair in this case :-) If any other sceptics put more faith
in Lindzen's predictions than he does himself, I'd be very interested in
hearing from you. There isn't much money in climate science, and I'm
still looking for that gold watch at retirement.

James