The reductio ad absurdum of climate change skepticism

Because the vast majority of scientists on the planet agree that climate change is happening, and because this consensus view is shared even among most members of the public — although that consensus is eroding — the curious result is that most of the discussion about global warming is now happening at the ideological fringes of the debate. 

Notably, on sites that question or flatly deny the reality of climate change, such as the extremely popular Watts Up with That

Good thing? Bad thing? Not sure, but it's a fact. And some scientists, trying to make this exceedingly complex subject understandable, have resorted to going into the virtual lion's den to answer questions for this self-selected crowd of skeptics, deniers, and independent thinkers. 

This past week, Dr. Walt Meier of the National Snow and Ice Data Center picked up a gauntlet thrown down by Willis Eschenbach on "Watts Up…" Eschenbach challenged scientists to answer some skeptical questions about the science of climate change. 

Meier_walt  To yours truly, a lot of the problem here is the nature of scientific language, which often translates poorly into English, but Meier does bring real depth to some of his answers, even if they still don't fall gently off the tongue like Shakespeare, or even newspaper prose. 

Here's his answer to a logical and frequent complaint from skeptics — that is, if you can't predict the weather more than ten days out, how on earth do you think you can predict the climate decades into the future? 

How can a more complex situation be modeled more easily and
accurately than a simpler situation? Let me answer that with a couple
more questions:

1. You are given the opportunity to bet on a coin flip. Heads you win
a million dollars. Tails you die. You are assured that it is a
completely fair and unbiased coin. Would you take the bet? I certainly
wouldn’t, as much as it’d be nice to have a million dollars.

2. You are given the opportunity to bet on 10000 coin flips. If heads
comes up between 4000 and 6000 times, you win a million dollars. If
heads comes up less than 4000 or more than 6000 times, you die. Again,
you are assured that the coin is completely fair and unbiased. Would you
take this bet? I think I would.

But wait a minute? How is this possible? A single coin flip is far
simpler than 10000 coin flips. The answer of course is that what is
complex and very uncertain on the small scale can actually be
predictable within fairly narrow uncertainty bounds at larger scales. To
try to predict the outcome of a single coin flip beyond 50%
uncertainty, you would need to model: the initial force of the flip,
the precise air conditions (density, etc.), along with a host of other
things far too complex to do reasonably because, like the weather, there
are many factors and their interactions are too complex. However, none
of this information is really needed for the 10000 toss case because the
influence of these factors tend to cancel each other out over the 10000
tosses and you’re left with a probabilistic question that is relatively
easy to model. In truth, many physical systems are nearly impossible to
model on small-scales, but become predictable to acceptable levels at
larger scales.

Now of course, weather and climate are different than tossing a coin.
Whereas coin flips are governed largely by statistical laws, weather
and climate are mostly governed by physical laws. And climate models, as
I mentioned above, are far from perfect. The relevant question is
whether climate can be predicted at a high enough confidence level to be
useful. As mentioned in NH2
[null hypothesis two — scientific language, sorry], we find that climate has largely varied
predictably in response to past changes in forcing. This is clearly seen
in ice core records that indicate a regular response to the change in
solar forcing due to changes in the earth’s orbit (i.e., Milankovitch
cycles). If climate were not generally predictable, we would expect the
earth’s climate to go off into completely different states with each
orbital change. But that doesn’t happen – the earth’s climate responds
quite regularly to these cycles. Not perfectly of course – it is a
complex system – but close enough that the uncertainties are low enough
for us to make reasonable predictions.

It is worth mentioning here that while the general response of
climate to forcing is steady and predictable, there is evidence for
sudden shifts in climate from one regime to another. This doesn’t
invalidate NH2, it merely suggests that there may be thresholds in the
climate system that can be crossed where the climate transitions quickly
into a new equilibrium. When exactly such a transition may occur is
still not well known, which adds uncertainty suggest that impacts could
come sooner and be more extreme than models suggest.

This makes sense, but doesn't appear to have impressed the crowd at Watts Up, which includes some deniers of astonishing density. 

Here's my favorite excessive response to Meier's thoughtfulness, from "NewEyes": 

Ok, that’s where I get out of the boat because I do not believe that “step one” in science, OBSERVATION, is accurate.
I have come to believe that the reporting of observations is false and that the observations themselves are twisted.

Can we measure temperature?

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