Friday, August 06, 2010

Engaging climate contrarians on the science - An experiment

This post - and project - is an exploration into taking a different, "nitty gritty science" path, looking into the science cited as supporting some contrarian climate science claims. The purpose is to see what we find on the journey, and to compare the efficiency & the outcome of two approaches: the "look at the [purported] science" approach, and the "CEO using science" one.

People don't all prefer to use the same tools for thought. When different people use different ways of learning about and understanding the world - particularly if one way has more pitfalls than another - they may come to different - and not equally good - understandings of what the science is saying about climate change.

The "CEO" approach:
My own preferred way is the lazy (aka "CEO", aka most bang for the buck, aka highest return on investment of my time&attention) way: because I have confidence in the scientific endeavor (in that it's the best way we have of knowing, largely because it's self-correcting, since the way you make a name for yourself in science is by picking holes in the other guy's work and coming up with something better), I just assess scientific claims based on the rank of the claimant (or of the person/institution whose views he/she is conveying, if they're being conveyed accurately) on the (excellent) scientific credibility spectrum.

The "Assembling scientific evidence" approach:
But some individuals - including most/all contrarians - distrust this high-level approach; they prefer to do it themselves, to grasp the science by building their own "edifice of evidence" (sometimes with advice/input from some working climate scientists.)

Since they're unconvinced by "CEO-level" evidence, any efforts we make to use that kind of evidence to reach them will fail.

And alas, I have done exactly that, more times than I care to remember.

The Experiment:
So as an experiment, it's worth trying to reach the "assemble your own evidence" folks on their own epistemological turf - and it's worth taking a look at the evidence ourselves, as a check on our own ways of knowing - and it's worth showing you, dear reader, how we can go about looking into the scientific claims we might hear around town, and what we may find in our investigation.

So I'm starting an experiment - I'm coming as a tourist to visit these others' home "nitty gritty science" turf, to look at the climate issue from that perspective. And you're invited along for the ride.

I want to look at two contrarian views:

Contrarian View I - it's not us causing the warming, it's Galactic Cosmic Rays
This contrarian view holds that the climate change episode we've experienced so far (the last 100 years) hasn't even been caused by human activities - that the cause is a change in galactic cosmic rays (GCR) - and so therefore, any projections into the future are pointless if they're based on understanding the warming's cause to be increased CO2 (plus other greenhouse gases).

As support for the "cosmic-rays-as-cause of our current warming" idea, some people reference this graph - which does show a GCR-temperature correlation.
But it often pays to look at a graph's timescale, and when you do so here, you'll see that the graph's GCR-temperature correlation is over the distant, 99.9% nonhuman, 600-million-year past era - which tells us nothing about whether GCR changes are causing our current warming. To use a metaphor,
"We’re [now] sawing away at the tree limb we’re sitting on, and some people are telling us not to worry because of all the times in the past when branches we weren’t sitting on broke without the aid of our saw." (link)
So I've asked an adherent of this contrarian view to provide evidence that is relevant to the cause of our current warming:
"Do you have a graph that's more relevant to the current warming, just showing, say, the last 100-200 years? Because what we're concerned with is the *current* warming, not paleohistorical-type warming."
I'm still hoping to get a [substantive] reply.

p.s. If you-the-CEO wanted to check out the "GCR" contrarian view, you could go to the excellent SkepticalScience , search for "cosmic rays", and find&skim the excellent Could cosmic rays be causing global warming?
In short -
"What the science says: While the link between cosmic rays and cloud cover is yet to be confirmed, more importantly, there has been no correlation between cosmic rays and global temperatures over the last 30 years of global warming."

Contrarian View II - it's us, but it won't be so bad
This second contrarian view is that climate change is real, that it seems to be human caused, but that the likely future temperature change prospects aren't as dire as projected.

There's a standard metric for judging the likely severity of future climate change - namely, how much higher the world temperature will go if we allow the amount of CO2 in our atmosphere to double, known as the "CO2 doubling sensitivity". This contrarian view holds that its likely value (which we can't know for sure, ahead of time) lies somewhere in the range between 1.5 and 3 degrees Centigrade; and therefore, that the "scorched earth" 3C value wouldn't be too likely, since it's way over at the fringe of the "most likely" range.
...Whereas my understanding, from my reading in the science-aligned climate blogging community (link), is that the scientific evidence indicates that the likely "sensitivity" range extends considerably higher than 3C - that it's 1.5 to 4.5C - and that multiple lines of evidence indicate the most likely sensitivity is somewhere around 3 degrees C, the aforementioned "scorched earth" value.

(Since this project is about how to approach science, & not about rational climate policy, I won't slip into policy & explain why climate action would *still* be the only sane response even if the science did support this "not so high" sensitivity - but if you want to know more, you can see the degree-by-degree chapters in the book "6 degrees - our future on a hotter planet" (blog) - and also consider that the parameters are necessarily underestimates - that the future extends beyond 2100, and that dumping CO2 into the air won't magically stop when there's twice as much of it up there.)

So to look into the science for this "low sensitivity" climate view, I've asked an adherent to point me to the evidence we'd need (if we were delving into the "sensitivity" science ourselves and not, say, delegating this task to the excellent SkepticalScience "sensitivity" page) in order to see 1.5-3C as the most likely range:
"A request for sources bearing on the "1.5-3C likely range" conclusion:
In short [could you point me to]:
A) strong
(est) papers supporting [the 1.5-3C range], (3 or fewer, please)
B) strong
(est) scientists supporting, (3 or fewer, please)
C) (if possible) strong
(est) lines of evidence supporting,
D) strong
(est) data or arguments *opposing* A and/or C, & why they're unconvincing.

These are the 4 things I'd need in order to evaluate the 1.5-3C estimate, right? If I've missed any, please let me know."
When I get any of this information, I'll report & analyze it.


Anna Haynes said...

Here's an update on the "climate sensitivity" part of this experiment.

Anna Haynes said...

...and an update on the "Galactic Cosmic Rays"/"It's the sun" part - this contrarian declined to participate further, most likely because:

"There is no trend in GCR [to correspond with the increasing-temperature trend]. It's really that simple. - gavin"

Anna Haynes said...

(to clarify a bit, the above "no trend in GCRs" quote is from a real climate scientist, not from the local contrarian)

Anna Haynes said...