Monday, October 16, 2006

The puzzle analogy

I recently heard a good analogy about climate science from Bill Chameides, chief scientist for Environmental Defense.

The state of science of climate change today is like a partially completed jigsaw puzzle. There are lots of pieces in place --- things we know quite well (like the water vapor feedback) --- and lots of areas where there are no pieces --- things we don't know particularly well (like cloud feedbacks). The point here is that you don't have to have every piece in place in order to know what the picture looks like. Consider the image above. While many pieces are missing, one can easily observe that it's an image of fruit.

Climate science is like that. While there's a lot we don't know, the big picture is still clear. We know the climate is warming, humans are contributing, and there's a risk of significant warming over the next century. The missing pieces don't change any of that.

The "uncertainty" argument would have you believe that, if even one piece is not in place, that we have no idea what the big picture is. That's simply not true.


Dano said...

Excellent analogy sir.

Many folk argue from this perspective, yet many different puzzles in societies have pieces missing. And we make policy every day based on our view of what picture the puzzles depict.

Medicine is the best 'puzzle' analogy here, altho climate is still good. That is: if we were to argue like the denialists do, we wouldn't have a pHrma industry, because we don't know enough to predict to the denialist's ever-changing standard what a body might do in response to a drug/dose.



D. B. Paul said...

I can't agree that Medicine is the best puzzle analogy here. Medicines are tested under FDA guidelines using time-tested techniques with verifiable and repeatable results. Yes, errors can be made, but the point is that in Medicine, something is tested on a control group or under tightly controlled conditions before it is released into the general population. If we could do that with the climate, it would be nice, but we can't. Certainly computer climate models are an attempt at that, but they don't suffice. Would you take a Medicine that had never been tested on a living organism, but only run through computer simulations to demonstrate that it is safe and effective?

Dano said...


The point being the variability of the dose/response across the human spectra - with confounding factors of multiple medications and environmental effects - makes the reliability of dose-response curve sufficiently complex to use the same argument for inaction as the denialists*. IOW, there's a lotta tinkerin' of doses by doctors 'til they done git it right.

That is: "gee, it's hard. Let's not do it" isn't a good argument. See, the argument falls flat because other things are hard yet we make policy for them (viz. your FDA guidelines).



* Golly, I hope that sentence isn't used to argue associating climate denial with another type of denial, thus Silencing Debate (TM).

Mark UK said...

There is an interesting article on decision making in the face of future uncertainty by Jay Brown here:

"If the results from this experiment can be generalized,
they would imply that people who feel that the consequences
of their actions are unpredictable are less likely to make decisions driven by long-term consequences
(prudent decisions). Further, if this feeling of uncertainty
can be reduced (through feedback) by increasing awareness
of the contingencies which operate in the world, then
prudent decision-making should increase. This seems to
be particularly true when the future is uncertain (it might
be argued that the creation of Future-Uncertainty in the
present experiment is confounded with average payoff
for prudent decision-making)."

And the real point I want to stress here:

"Anything we can do to show people that though the world
is uncertain, it is definitely not unpredictable ought to increase
their prudent behaviors (or decrease imprudent behaviors
as the case may be)"

Anonymous said...

Sort of playing devil's advocate here ... If we don't need to complete the puzzle to get the general picture, why should we continue to spend a large chunk of change on climate modeling? Shouldn't that money be shifted to programs to slow down emission rates and mitigate the impacts instead? After all, the problem is identified - why spend money on diminishing returns from any modeling efforts.

Andrew Dessler said...


Your question is really one of policy. If you think that we know enough and that future research will not be of value, then sure, let's stop funding. My take on this, however, is that 1) we know enough now to begin to take action, but 2) uncertainties remain, and there is value in reducing them in the future, so funding should continue.


Bill Chameides said...

Andy, Thanx for spreading the word on the jigsaw puzzle analogy - I have found it quite helpful.

Of course the flip side of the jigsaw puzzle is the "house of cards" sleight of hand.

Science skeptics often try to undercut established science (be it global warming or something else) by portraying the knowledge-base as a house of cards. They hope by identifying one weak link, they can bring the whole house down (i.e., create the illusion of uncertainty in the entire subject.)
In fact, most science is like a jigsaw - lots of interlocking pieces based on multiple, independent lines of inquiry. Even if you take away one piece, the picture is still apparent.

As scientists we will be forever working on those indidual puzzle pieces - for policy formation and action often all that is needed is the basic picture.

Bill Chameides

Dano said...

If we don't need to complete the puzzle to get the general picture, why should we continue to spend a large chunk of change on climate modeling?

To extend Andrew's answer, this is a good question. It is one of policy - of adaptive management policy.

When managing systems, you always get to your milestones, gather your data, and see where you are. You need modeling to then take your data, make adjustments, and see what is the new trajectory.



D. B. Paul said...

The puzzle analogy is nice, but it depends on reaching agreement on what the picture being painted actually is. So, what is the picture? What is a "denialist" (I dislike that term because it is pejoritive, but we can use it here anyway). The actual contetns of the picture and the definition of a "denialist" go hand-in-hand, and I have yet anyone who uses the term "denialist" tell me a what a "denialist" is. Is a "denialist":

A. One who denies the earth is warming at all?
B. One who believes the earth is warming, but man has little to do with it?
C. One who believes earth is warming and man is near 100% reponsible, but we shouldn't do anything about it?
D. Anyone who deviates from the idea that the earth is warming rapidly and at a historically unprecedented rate, man is 100% reponsible and if we don't take drastic action now, we are all doomed?

A differs greatly from D and paint two radically different pictures.

Andrew Dessler said...

I agree that denialist is a loaded term and that it's probably best to try to find an alternative phrasing. That said, I would define a "denialist" as someone who contradicts the following conclusions of the IPCC:

1) the climate is warming
2) humans are contributing, and are likely responsible for most of the recent warming (the caveats on this statement are important; see this blog entry)
3) there is a significant risk of serious future warming

Note that these are quite different from the options you provided. e.g., you provide a choice of "humans are not contributing" and "humans are contributing 100%" to the warming, neither of which is scientifically acceptable.

Also, I don't define a denialist in terms of their preferred policy. If you accept the science but don't want to do anything about it, then you're certainly not a denialist. (although, speaking as a citizen, I disagree with that position)


EliRabett said...

Sorry Andrew, I have to disagree with you on this one. The reason that the denialists don't want to be called denialists is precisely because the term is accurate and powerful. Human driven climate change has been scientifically established and the balance of the discussion has shifted to the policy response arena.

As you, yourself have pointed out the denialists have always tried to poison the debate by any means possible on any issue (climate, tobacco, CFCs, et.). As manipulators of words and opinions they understand that for them to be labelled denialists is a significant problem.

Confusing the issue by dragging in the Holocaust is by another diversionary tactic that plays on your openness. By engaging at anything other than the level of simply saying that you will use the terms you wish you grant their premise legitimacy.

Dano said...

D.B. doesn't give the proper range of choices to choose from.

A denialist is, simply, one who denies current scientific knowledge.

This can affect public policy when enough folk call their Congresscritter ("Senator X, stem cell research would prevent that embryo from becoming a snowflake!!!!! *heart*"), or it can just be limited to a single personal life ("I'll burn in h-e-double-hockey-sticks if I say a bad word").

A denialist can appear in many topics: DDT, climate change, stem-cell research, immigration, war effects justification, etc. IMHO, denial is not just a river in Egypt, but a part of the human coping mechanism.

Thus, denial should be acknowledged as it is part of life. Whether we call it denialism, denial, or denial-o-rama matters not as it isn't a pejorative, just as calling someone depressive or depression-prone isn't a pejorative (although some use 'pejorative' as a tactic, as in ad hom.



Nexus 6 said...

An analogy I like to use is that of the 'casino'.

The second there is a cold winter somewhere, a less-than-average hurricane season or some other phenomenon that appears to contradict global warming theory, denialists jump on it as though AGW is automatically disproved.

I always add, no body said every single winter will be warmer than the last, every hurricane season worse than the last etc. It's just that the odds of that happening increase each year. If you go to a casino and play games of chance like roulette, the odds are that you will loose money. But that doesn't mean you will loose money every time you go there. Same with climate change and its impacts. We're stacking the odds against ourselves, but every now and then we'll get lucky (Hopefully, that'll occur in Australia with the breaking of the terrible drought we're having here)

D. B. Paul said...

nexus 6 - Of course what you say is true about a quiet hurricane season not proving or disproving anything about AGW. However, conversely, one-time events like Hurricane Katrina, a mild winter somewhere, a heat wave in New York or glaciers sliding off Antarctica into the sea (as though that doesn't happen anyway) don't automatically prove AGW either. I believe both sides of this debate have their "poster child" events to prove their points and these claims cannot be scientifically validated, and like I said in the thread about the difference in weather and climate, I cringe when people point to these events as if they prove something.

BobKC said...

Dr. Dessler,

I like the idea of using an incomplete jigsaw puzzle as an analogy for the current state of climate science, but I think a few improvements are in order.

- The ratio of missing pieces to pieces in place seems close, but I would take away a few more. Plus, a lot of the missing pieces are still in the box (and the box has no picture;).

- Several pieces should be forced in the wrong place (they almost fit there, but not quite).

- The puzzle should be irregularly shaped, with most of one side missing (you're not sure the problem is bounded yet).

- The picture you are using is too simplistic. You could have less than half the pieces placed and know what it was about. I think the climate (science) is a bit more sophisticated. I would suggest oh, maybe [url=] this[/url] triptych better represents the complexity of climate science, with most of the left panel pieces missing :)

Anonymous said...

Indeed, from the picture you could assume its some delicious pieces of fruit - yum yum! On the other hand, the pieces missing from the far right-hand apple, the apple at bottom centre and the water melon, could be the ones that would have shown you that the fruit is in fact rotten. You wouldn't know that from the picture as it stands though would you?

Over-reliance on models with regard to something as complex as planetary climate is somewhat risky, in my humble opinion.

Nexus 6 said...

Point taken, d.b. paul. I do agree that individual events, such as Katrina or the current Australian drought, can never be solely attributed to AGW. However, if climate theory predicts these kinds of events will become more common or severe, and they do in fact become more common or severe, then it would certainly be good supporting evidence for AGW. After all, a viable mechanism and a correlation have been demonstrated. In reality, 100 % iron-clad proofs exist in mathematics only.

D. B. Paul said...

nexus 6 - And I will agree with you that if it can be shown that extreme weather events do become more common over time, a period of many years, it would be evidence that climate change is having the predicted effects, regardless of the cause. My problem is always with highlighting a single event. Hurricane Katrina is a great example. Since it hit New Orleans so hard (although one could argue it did little direct damage to New Orleans - levees which should not have failed caused most of the damage), it became a poster child for those promoting AGW at any cost. If it had hit an unpopulated part of South Texas, no one would have said much at all about it since it would not have been in the public's eye. I believe we could have a statistically signficant increase in cat 4 & 5 hurricanes, enough to point to GW as the reason, but as long as they don't hit populated areas, they will never gain traction in the public's mind or popular media. It takes the one big one like Katrina to get that attention, warranted or not. I think it speaks more to the mathematical and scientific ignorance in our country.

Anonymous said...

Hmmm. My link didn't work above. In case you can't see it all, the URL is; 9799/bosch8mc.jpg (delete the space)

eduardo zorita said...

I think there exist here a confusion between climate science and climate policy.

Climate policy should weight the evidence available and reach some decisions based on this evidence and previous values (of society, environment, etc). Climate policy could accept eventual contradictions between observations and predictions of the theory and put them under the umbrella of "still existing uncertainties".

This is not the case for climate science and science in general. A theory must explain each and everyone of the observed facts, without the slight contradiction or inconsistency, and it should not be allowd to resort to claiming "kown unkowns".

Many theories in the past broke down because they could not explain the last 1% of the observations (e.g. Newton's gravitation).

If the theory of AGW is not complete, then it is not satisfactory for a scientist, albeit it may be ussful for a policy maker. The conflict arises when scientist try to play the role of policy makers. I think they are incompatible.