Climate Change

[Zeta-Flux]

Originally Posted by garo

I think Zeta does not "get" the fact that Science doesn't mind being surprised and scientists are always on the lookout for fresh evidence to prove or disprove their theories.

Not at all. In fact, what I wrote implies quite the opposite!

If they find contradictory evidence they have no problem changing their theory. In this case, even though the finding was a surprise it does not negate the climate change hypothesis.

Of course. (Meaning and pun intended.)

-----------

Originally Posted by axn

I think he is confusing the obviousness of the general principle -- "Even when average temperatures are clearly rising regionally or globally, what happens in any given location depends on the exact dynamics of that place" -- which Cheesehead asserted, with the "surprise" of this particular instance.

axn, that is pretty close (minus the confusion). What I was saying is that the scope of the "general principle", when understood in the context of the article, is not obvious.

I imagine that is it trivially true that the exact dynamics of a place decide what happens in that place. Definitionally, even. But is that was the person quoted was trying to say? Or was he trying to say something more, about how major global conditions do not always rule the day, even over long periods of time?

[ewmayer]

Originally Posted by garo

I think Zeta does not "get" the fact that Science doesn't mind being surprised and scientists are always on the lookout for fresh evidence to prove or disprove their theories. If they find contradictory evidence they have no problem changing their theory. In this case, even though the finding was a surprise it does not negate the climate change hypothesis.

I fear you give scientists rather too much credit for open-mindedness, especially with regard to theories in which they have invested much or most of their careers. Look at the (gradually dwindling) number of scientists who still think the K-T impact was (co)incidental to the mass extinction of the dinosaurs - perhaps the leader of that bunch being Princeton`s Gerta Keller, whose main objection is based on the fact that in many places the layers of K-T-associated glass spherules and Iridium-enriched clay appear to be stratigraphically separated by what would amount to several hundred thousand years. The problem being that numerous such objections (e.g. planktonic foraminifera appearing to persist beyond the impact layer) have already been explained by other means (e.g. later shaking-up/settling/etc of the sediments), the "time window" for all the stratigraphic changes keeps getting relentlessly narrowed as more science is done, and there are simply no viable competing hypotheses for that particular mass extinction for which there is any significant evidence. Keller will undoubtedly go to her grave railing against the impactor theory.

Now, some of you might point out that my skepticism vis-a-vis AGW sounds very similar ... but note that I do not question that there is a large (and growing) body of evidence which supports it - I mainly dislike scientifically premature proclamations of "overwhelming consensus" of the kind made by the IPCC several years ago. Of course their aims are as much political as scientific, and scientific nuance/ambiguity is something dangerous to supply politicians with - but I've made clear my objections are strictly on scientific-standards-of-proof grounds, which means as long as there is a significant body of apparently-contradictory evidence, it's premature to claim consensus.

On to the "evidence" front: Interesting recent study in Science, which appears to correctly account for orbital changes and does not over-rely on computer models:

Arctic Temperatures Highest in 2,000 Years

Sept. 3, 2009 -- The Arctic is warmer than it's been in 2,000 years, even though it should be cooling because of changes in the Earth's orbit that cause the region to get less direct sunlight.

Indeed, the Arctic had been cooling for nearly two millennia before reversing course in the last century and starting to warm as human activities added greenhouse gases to the atmosphere.

"If it hadn't been for the increase in human-produced greenhouse gases, summer temperatures in the Arctic should have cooled gradually over the last century," said Bette Otto-Bliesner, a National Center for Atmospheric Research scientist and co-author of a study of Arctic temperatures published in Friday's edition of the journal Science.

The most recent 10-year interval, 1999-2008, was the warmest of the last 2,000 years in the Arctic, according to the researchers led by Darrell S. Kaufman, a professor of geology and environmental science at Northern Arizona University.

Summer temperatures in the Arctic averaged 2.5 degrees Fahrenheit (1.4 degrees Celsius) warmer than would have been expected if the cooling had continued, the researchers said.

The finding adds fuel to the debate over a House-passed climate bill now pending in the Senate. The administration-backed measure would impose the first limits on greenhouse gases and eventually would lead to an 80 percent reduction by putting a price on each ton of climate-altering pollution.

It is the latest in a drumbeat of reports on warming conditions in the Arctic, including:

* A marine scientist reports that Alaskan waters are turning acidic from absorbing greenhouse gases faster than tropical waters, potentially endangering the state's $4.6 billion fishing industry.

* NASA satellite measurements show that sea ice in the Arctic is more than just shrinking in area, it is dramatically thinning. The volume of older crucial sea ice in the Arctic has shrunk by 57 percent from the winter of 2004 to 2008.

* Global warming effects in Alaska also include shrinking glaciers, coastal erosion and the march north of destructive forest beetles formerly held in check by cold winters.

And with the melting of land-based ice, such as the massive Greenland ice cap, sea levels could rise across the world, threatening millions who live in coastal cities.

The new report is based on a decade-by-decade reconstruction of temperatures over the past 2,000 years developed using information from ancient lake sediments, ice cores, tree rings and other samples. The findings were then compared with complex computer climate model simulations created at the National Center for Atmospheric Research in Boulder, Colo.

"This study provides us with a long-term record that reveals how greenhouse gases from human activities are overwhelming the Arctic's natural climate system," commented NCAR scientist David Schneider, a co-author on the study.

Added Jonathan T. Overpeck, a University of Arizona professor of geosciences: "The Arctic should be very sensitive to human-caused climate change, and our results suggest that indeed it is."

In addition, he pointed out, as the Arctic warms there is less snow and ice to reflect solar energy back into space and the newly exposed dark soil and dark ocean surfaces absorb solar energy and warm further, accelerating the warming process.

The Arctic cooling had been the result of a 21,000-year cycle in the Earth's movement that caused the far north to get progressively less summertime energy from the sun for the last 8,000 years. That process won't reverse for another several thousand years.

p.s.: My Firefox spell-checker is alas woefully scientifically illiterate ... I had to manually override a half-dozen words (even leaving aside the proper names) in the above text.

[ewmayer]

Forgot to add the key point I intended to make with the "give scientists too much credit" theme above, namely that while *individual* scientists have the same kinds of biases, blind spots, prejudices, personal grudges etc that all humans are subject to - leaving aside the question of whether scientific training makes one less prone to such subjective biases - the whole point is that science as a collective endeavor works remarkably well in terms of self-correction. Individual biases - especially among influential individual scientists or folks controlling funding purse strings - may delay progress in certain fields but eventually "the truth" will come out. The medieval church and science provide a good illustration of this, one in which the delays were alas on the of centuries.

[cheesehead]

(Edit: As I do the final edit on this posting, I now see that Ernst has preceded me. )

Scientists have the same human frailties as everyone else. There are indeed closed-minded scientists, just as there are closed-minded people in any other field.

The process of science has been constructed to compensate for such failings.

[Zeta-Flux]

[begin-nitpicking]
ewmayer: ...but eventually "the truth" will come out.

cheesehead: The process of science has been constructed to compensate for such failings.

Me: The process of science has been constructed to attempt to compensate for many human failings, and often is (eventually) successful so that "the truth" comes out.
[end-nitpicking]

[cheesehead]

Originally Posted by Zeta-Flux

[begin-nitpicking]
ewmayer: ...but eventually "the truth" will come out.

cheesehead: The process of science has been constructed to compensate for such failings.

Me: The process of science has been constructed to attempt to compensate for many human failings, and often is (eventually) successful so that "the truth" comes out.
[end-nitpicking]

[begin-counternitpicking]

Compensation is not the same as abolition, negation or neutralization. "Attempt" was not a necessary modifier in my sentence.

[end-counternitpicking]

[Zeta-Flux]

cheesehead, are you sure? Looking at all of the definitions at dictionary.com, and looking at the thesaurus entry (which I've included below), it does seem to imply those things.

---------------
Main Entry: compensate
Part of Speech: verb
Definition: offset, make up for
Synonyms:
abrogate, annul, atone for, balance, better, cancel out, counteract, counterbalance, counterpoise, countervail, fix, improve, invalidate, make amends, negate, negative, neutralize, nullify, outweigh, redress, repair, set off

[cheesehead]

Originally Posted by Zeta-Flux

cheesehead, are you sure?

No, I'm never sure, but sometimes I'm lazy.

[garo]

From Gerta Keller's wiki page - Is she for real? Wow!

[cheesehead]

Originally Posted by garo

From Gerta Keller's wiki page

Link?

Is she for real? Wow!

Based on http://en.wikipedia.org/wiki/Gerta_Keller and http://scienceblogs.com/gregladen/20...ter_impact.php it looks to me like she's doing good science investigating a possible alternative to or modification of the Alvarez hypothesis (http://en.wikipedia.org/wiki/Alvarez_hypothesis), but perhaps you're referring to something else?

[cheesehead]

Ernst,

Are you as unconvinced about the causal connection between atmospheric CO₂ and ocean acidification as you are of the connection between the CO₂ and global mean temperature?

At what point might you consider the deleterious effects of ocean acidification to be sufficient reason for taking action to curb anthropogenic CO₂ emissions?