Dan,

Perhaps you should read posts at Deltoid, and John Quiggin, about this:
http://scienceblogs.com/deltoid/2006/09/matthew_warren_continues_where.php#more
http://johnquiggin.com/index.php/archives/2006/09/04/the-oz-blows-it-again-on-global-warming/

The Australian (and its coal industry PR flack) are playing games with the tightening of confidence limits. You really shouldn't fall for this.

If the worst-case scenario goes from 5.8 degrees celsius to 4.5 degrees celsius, isn't that a roughly 25-percent improvement rather than a 50-percent improvement?

And a 4.5 degree increase instead of a 5.8 degree increase isn't going to make any one less "inconvenienced". We're still incredibly screwed with these numbers.

My word, I just read the Quiggin and Deltoid posts. Dan, you really should be ashamed of pushing this drivel.

Realclimate has also posted on the subject.

I'm no statistician but a tightening of the range from "1.4 - 5.8" to "2 - 4.5" means that the worst case scenario improved by around 25%. However, it also means that the best case scenario deteriorated by around 40%.

I don't know what the highest probability model projects, but the median of those two ranges improved by around 10% (from 3.6 to 3.25)

I agree that an improvement is always welcome but, to quote Pulp Fiction, "Let's not start sucking each others d***s just yet."

I notice that everyone who posts this story ignores the fact that the best case scenario is now less rosy than before (2 degree C rather than 1.4).

The latest published studies on the Greenland Ice cap confirm that it is melting faster than expected. There are also several other reports that have just been published that have some rather depressing data. All of these studies are too recent to be included in the latest IPCC report. Expect further revisions

It makes no sense to talk about percentage improvements when using an arbitrary measurement scale, like Celsius or Fahrenheit.
4C is not "twice as hot" as 2C.

Bernard,
Actually, a 4 degree C change IS twice that of a 2 degree C change. It doesn't matter which arbitrary system (K, F, C, Rankine) is used. Now of course, we should make clear that it is an x% improvement/deterioration in the rate of change, not of absolute values. But most talk of global climate is looking at global climate change, so the rates are the numbers people care about the most.

The latest published studies on the Greenland Ice cap confirm that it is melting faster than expected.

Which part? Last I heard, some areas were thinning, others were thickening, and the net change was within normal variation.

If you have information to the contrary (scientific only, not popular media), please respond with a link.

Dan -- Andrew R is pretty much right, and I'll just be more specific; all that's going on here is the margin of error on the projection is going down. The bottom line is that the three celsius that has been talked about as the most likely outcome for some time still seems to be the most likely outcome, but now they're simply predicting it with more confidence. The Aussie press can spin it all they want, but all we're seeing here is more data tightening the standard error within the previous predictions. Three celsius is a mighty big change and one that will be highly destructive. It's far cheaper in the long run and far more ethical to start making plans now (not to mention that costs incurred on reducing emission are offset by savings in energy use).

Doesn't it bother anyone that a dramatic change in a 100 year prediction occurred not because of real physical changes in the globe, nor because of a real change in time (5 years), but because the model changed? If the model was that unreliable 5 years ago, what makes you think this model is necessarily more reliable? I'm pretty agnostic about global warming (though I'm not convinced 'we're screwed' is terribly accurate), but if the modelling is in this much flux right now, frankly, such modelling flux suggests an ill-developed science.

Steve

Take a hop over to "Making Light" to read a story about a conference in Oz that had as its topic how to attack such people who are concerned about global warming. Always be very aware of "Astroturf".

Shane,

Yeah. I know. It was a careless and dumb coment. Thanks for being polite about it.

You know, DD, This post and Steve's comment brought that exact post to mind.

I doubt this will have any effect at all on Gore, who's been trying to spook us with doomsday scenarios that go far beyond anything the IPCC has ever predicted. The people who might have issues with it are the scientific skeptics, people like Lindzen and Michaels; as I recall, the modest warming they've been forecasting falls within the bounds of the old IPCC range but not the new one.

If the model was that unreliable 5 years ago, what makes you think this model is necessarily more reliable?

How many digits do you have to have on one particular number before you can dismiss it because it comply with your desires?

So maybe then those who say we can't do anything and shouldn't even try are being undermined.

Um, why should we care wht the IPCC says in any event.

That same outfit brought us, in their last report, the infamous hockey stick graph, which has since been completely debunked. I expect that this iteration of their report will be just just as reliable as the last iteration.

I don't really have much to add to the comments above, except to say that The Australian is taking a justifiable hammering for this dishonest piece, and you really ought to post a correction/retraction, rather than implicitly sticking by them.

As if they know. I don't know, you don't know, none of the commenters here knows and sure as hell Al Gore doesn't know.

But this seems to be developing into a Chicken Little situation.

Dan, if the critical comments haven't convinced you that you have the wrong end of the stick on this one, surely the supportive comments must do so.

As if they know. I don't know, you don't know, none of the commenters here knows and sure as hell Al Gore doesn't know.

Of course they *know*. They know now just like they knew the hockey stick five years ago. The fact that certain "facts" change, or like the hockey stick, get completely debunked, doesn't phase the faith-based community of true believers in anthropogenic global warming. Hell, the faith-based will tell you *today* that the hockey stick was never debunked! It's an article of faith, you see - belief in the infallibility of the IPCC has replaced belief in the infallibility of God.

All we can be reasonably certain of is that temperatures have been rising since the end of the Little Ice Age 400 years ago. The extent to which - and even whether - such change is caused by humans is a matter of faith, not science.

"The fact that certain "facts" change, or like the hockey stick, get completely debunked, doesn't phase the faith-based community of true believers in anthropogenic global warming"

Yeh, but they're not as bad as the faith-based community of true believers who insist there is no global warming going on. I do not believe any of the more apocalyptic scenarios, but nor do I believe the head-in-the-sand there's no global warming going on, but even if there were, its nothing to do with us blah, blah blah, we can't be absolutely sure blah, blah blah

And the NRC largely backed the hockey stick graph. But never mind that, cling to your delusions abotu it being "totally debunked"

Yeh, but they're not as bad as the faith-based community of true believers who insist there is no global warming going on.

Erg, very very few people deny that the climate has changed in the past, is changing in the present, and will continue to change in the future.

What people do disagree on is the magnitude of the effect that human activity will have on the changes in the future, if the projected changes would be a net benefit, and if the costs of dealing with whatever changes will occur will be more or less than trying to prevent the change in the first place.

Considering that the system that results in the changes is still a very long way from being well understood (the effects of atmospheric water vapor is the big one, IIRC), these are all valid arguments for which there is no satisfactory answer at present. These are issues on which reasonable people can disagree with each other in good faith.

No one except a very very few luddites are saying we should stop studying the issue. Quite a few people are saying that the science is not yet to a point where we should be basing policy decisions on it- including the policy makers. Despite the rhetoric, what they're actually doing is damn little, which should tell you something.

Now, I am not a climate scientist- my background is information technology. But you don't need to be a hardcore computer geek to understand this: when you take the data up to, say, 1950, and project the next 50 years, the output has very little relation to the observed historical record.

What I want to know is why should I take what the model predicts for 50 or 100 years from now seriously, when they don't 'predict' the past?

By all means, keep studying the problem- it's an important matter that would be good to understand. But please keep in mind that it is a long way from being a 'mature' science with well understood basic principles, and it wasn't very long ago that the climatologists were predicting an ice age, not a heat wave.

I've noticed that the hockey stick graph has a significant margin of error prior to 1600 AD (see here, margin of error in grey). I've also noticed that climatologists can't agree on temperature estimates prior to 1900 AD.

Now about the future...has anyone tested the accuracy of climatologists' forecasting models? How well have they predicted temperature changes in the past? Did this year's drop in sea surface temperatures throw off any estimates?

In early 2005, hurricane expert Chris Landsea resigned from the Fourth Assesment Report of the IPCC because its head prostituted his expert findings in order to pimp for man-made climate change.

This late July, Edward Wegman (GMU stats prof, and chair of the NAS applied stats section), concluded in a pro bono report to Congress that several Hockey Stick conclusions, including that the 1990s was the hottest decade on record, could not be verified. Michael Mann (et al) and his Hockey Stick" shaped temperature graph became the poster child for anthropogenic climate warming with the IPCC's TAR in 2001.

Also in July before Congress, NCAR's Tom Karl pimped for climate modeling as robust and reliable science, while John Christy could find no evidence in California’s 150 years of rural and mountain data for any statistically significant temperature warming. As for “erg” stating “the NRC largely backed the hockey stick graph,” that’s not true of the internals of the report, where chapters 8 and 10 trash it as methodology and back the Canadian amateurs Steve McIntyre and Ross McKitrick.

Now, since there has been no observed planetary warming since 1998, as measured by satellites, and the prior three decades have witnessed only minimal warming – who wants to argue against the IPCC news Dan Drezner posts as other than “necessary concessions” to reality?

In early 2005, hurricane expert Chris Landsea resigned from the Fourth Assesment Report of the IPCC because its head prostituted his expert findings in order to pimp for man-made climate change.

This late July, Edward Wegman (GMU stats prof, and chair of the NAS applied stats section), concluded in a pro bono report to Congress that several Hockey Stick conclusions, including that the 1990s was the hottest decade on record, could not be verified. Michael Mann (et al) and his Hockey Stick" shaped temperature graph became the poster child for anthropogenic climate warming with the IPCC's TAR in 2001.

Also in July before Congress, NCAR's Tom Karl pimped for climate modeling as robust and reliable science, while John Christy could find no evidence in California’s 150 years of rural and mountain data for any statistically significant temperature warming. As for “erg” stating “the NRC largely backed the hockey stick graph,” that’s not true of the internals of the report, where chapters 8 and 10 trash it as methodology and back the Canadian amateurs Steve McIntyre and Ross McKitrick.

Now, since there has been no observed planetary warming since 1998, as measured by satellites, and the prior three decades have witnessed only minimal warming – who wants to argue against the IPCC news Dan Drezner posts as other than “necessary concessions” to reality?

I repeat my comment above. Dan, if the critical comments haven't convinced you that you have the wrong end of the stick on this one, surely the supportive comments must do so.

You must know, for example, that 1998 was a spike in which the warming trend combined with El Nino to produce the hottest year on record (until 2005). At the time denialists were only too happy to point out the exceptional nature of that year, and claim that it should be ignored. Now you get them claiming, as with Orson Olson "no warming since 1998". The rest of the claims made above are similarly bogus.

Do you really want to throw your lot in with these guys?

"This late July, Edward Wegman (GMU stats prof, and chair of the NAS applied stats section), concluded in a pro bono report to Congress that several Hockey Stick conclusions,"

Wrong - the report was requested by a notably anti-science member of Congress.
And Wegman's work was a crock of sh*t. He either doesn't understand scientific networks, or chose to be dishonest. He played some remarkably dishonest games with graphs and the 'noise' sample he generated.

All in all, a GMU snow job.

Let me stress again that the statement Dan makes in his post is untrue. The IPCC worst case estimate has not been reduced. The story in the Australian is wrong. I hope that Dan will correct his post.

On Wegman, you might want to look at this critique. The study was as Barry says, a GMU snow job.

> if the critical comments haven't convinced you that you have the wrong end of the stick on this one, surely the supportive comments must do so.

Yeah, who could possibly agree with those GW-denier rubes?

Ad hominem attacks are just so incredibly convincing as a form of argument. Ass.

Ad hominem attacks are just so incredibly convincing as a form of argument. Ass.

Are you a self-parody ?

As for “erg” stating “the NRC largely backed the hockey stick graph,” that’s not true of the internals of the report, where chapters 8 and 10 trash it as methodology and back the Canadian amateurs Steve McIntyre and Ross McKitrick.

Let me repeat once again -- the NRC largely backed the report. You are forced to lies to claim otherwise.