Let me just repeat what the panel concluded: “The substantial uncertainties currently present in the quantitative assessment of large-scale surface temperature changes prior to about A.D. 1600 lower our confidence in this conclusion compared to the high level of confidence we place in the Little Ice Age cooling and 20th century warming.”

Beyond that, the central claim of the hockeystick - that of unprecedented warming for the past 1000 years - is reduced to the merely “plausible”.

> ‘not all of AGW science rests on the “hockey stickâ€?’

Clearly so, but we are talking here specifically about the infamous hockeystick, a device which has been the principle propaganda tool for supporters of the AGW theory for many years. Either its claim to demonstrate warming unprecedented in the last 1000 years is valid or it isn’t. As it turns out, it isn’t.

From now on, anyone who produces the hockeystick chart as supporting evidence for the AGW theory will simply be revealing their ignorance. That’s why the hockeystick is shattered.

> “more recent data is unambiguous about the most recent century, and they have no great doubt about the last 1000 years.”

You can only make this claim if you dispute the existence of the Medieval Warm Period (MWP); a period when temperatures were as warm or even warmer than today. I provided a link to a site which is collating studies demonstrating that this is the case. Given that this is absolutely key to your argument, did you check it out, or do you prefer to remain in denial?

So, again, the most you can honestly claim is that temperatures now are the warmest they have been since the recent Little Ice Age. Such a reduced claim is obviously not one that even remotely suggests anything awry with the climate, much less that drastic intervention on an unprecedented scale is demanded.

I’m still waiting (not!) for Mouldwimp to get back to us with a refutation of the rest of the palaeoclimatic data.

Did you go on to read the rest of that piece or are you content to allow statistical uncertainty confuse you? The “hockey stick” isn’t “gone” it is simply statistically uncertain where the handle is from the sparser proxies. No such problem exists in the last 100 years, of which the last 10 are the warmest, and no such problem exists in the ocean data for the last 100 years either…. not a topic of the NAS but important nonetheless.

You seem to confuse “less confidence” with refutation, and that is not what happened.

I suggest you step all the way in to page 109 of the report.

Based on the analyses presented in the original papers by Mann et al. and this newer supporting evidence, the committee finds it plausible that the Northern Hemisphere was warmer during the last few decades of the 20th century than during any comparable period over the preceding millennium.

Note also that Mann said “likely” , which is to say, a WEAK scientific assertion not better that 2/3 likelihood and well outside the realm of certainty you appear to demand, but the more recent data is unambiguous about thbe most recent century, and they have no great doubt about the last 1000 years.

Finally, not all of AGW science rests on the “hockey stick” and that tentative assertion of Mann. Even though it is likely a true representation globally. It rests on the work of literally thousands of scientists who NEVER get their names in the papers, because they are unanimously of the opinion that this is happening and we’re doing it to ourselves. The only people who get into the news are the ones who argue the point still, SOME who at least are using scientific methods but getting odd results (compared to everyone else) and MOST who are using scientific methods but getting odd bank deposits (compared to everyone else).

The deniers get the press. So I have to answer you.

What a world.

BJ

Nobody (and I mean nobody) is denying that climate change occurs. In fact, central to the skeptics’ case is the fact that the climate changes all the time quite naturally; and often very rapidly and significantly.

As a believer in the AGW theory, it is simply not enough for you to observe that the climate is changing: That much is a given. Rather, you have to demonstrate that recent climate change is unnatural. You also have to show that it is anthropogenic CO2 that is the primary cause and not any other anthropogenic effect such as land use change, aerosols/particles, pollution changing the earth’s albedo etc. And finally you have to prove that the effect is a harmful one on balance and that your proposed remedy meets cost/effectiveness criterion.

Sorry but sob stories about polar bears don’t cut it.

bjchip,

Who is being selective here? If you had continued with the quotation you would have come to the panel’s conclusions about the claims you quoted:-

‘The substantial uncertainties currently present in the quantitative assessment of large-scale surface temperature changes prior to about A.D. 1600 lower our confidence in this conclusion compared to the high level of confidence we place in the Little Ice Age cooling and 20th century warming. Even less confidence can be placed in the original conclusions by Mann et al.(1999) that ‘”the 1990s are likely the warmest decade, and 1998 the warmest year, in at least a millenium.”‘

In other words, the fundamental claim of Mann’s hockeystick - that we can say with reasonable certainty that the current temperature is unprecedented in 1000 years - has been firmly rejected.

The most that can be now claimed (from Mann’s work, at least) is that the temperature now is (thankfully) warmer than it was during the recent Little Ice Age (which is, to be sure, a statement of the bleedin’ obvious.)

The hockeystick chart has been fundamental to the whole AGW scare and it has now been discredited. The only question is are you willing and able to update your worldview in the light of this informtation?

Note also that, in order to exaggerate recent climate change, the hockeystick team effectively whitewashed the Medieval Warm Period and Little Ice Age from history, thus falsely depicting an eerily stable climate prior to the warming of the last 150 years. The glossary at realclimate does its best to dismiss the LIA
(www.realclimate.org/index.php?p=32). Yet the NAS panel concludes that in fact we have a “high level of confidence in the LIA cooling.” So, again, the hockeystick team got it profoundly wrong.

In addition, there is plenty of evidence to suggest that the Medieval Warm Period was as warm if not warmer than now (http://www.co2science.org/scripts/CO2ScienceB2C/data/mwp/mwpp.jsp).

So the *evidence* is that temperatures now are about the same as they were a few hundred years ago. That being the case, an honest person must conclude that it is simply not possible to assert that recent climate change is in any way unnatural.

The letter is at http://listener.co.nz/issue/3451/letters/6394.html

They published my letter refuting the claims made for Golden Rice several weeks ago, but I’ll have a go anyway.

respectfully
BJ

Did anyone see the Panorama programme “The World Uncovered”
Sunday and Monday (1-2 July) on BBC (Channel 55 on Sky TV)?

It dealt with the current Republican Administration in the White House “editing” reports (including the major “Arctic Climate Report”) either by changing the wording or by removing whole sections (depending on what they could get away with) to change or at least minimise the impact at the behest of the “energy industry” etc.

(Apparently Texas, where Bush’s backing comes from, “if it were a country, would be the sixth greatest polluter of the atmosphere in the World.”)

The documentary showed the plight of Inuit people having to leave their homelands of 4000+ years (minimum) as the ice melts and the sea levels rise … They have been moving their houses year by year to higher ground, but their entire lands are now going under water.

So much for the “scientific” protesters who say that our climate /sea level records only go back about 100 years … “far to short a time for anything but anecdotal evidence”. (No prizes for spotting the chauvanism/racism in this.)

Locally, the NZ Listener (1-7 July, P6) gave its “Letter of the Week” award to John Blundell for a well written “there are very reasonable scientific grounds for adopting a view that the jury is still out” … letter on GLOBAL WARMING.

(Read it to get the flavour and I hope some will write your replies NOW! … less than 300 words to letters@listener.co.nz with name and postal address included)

Methinks we ALL need to discuss this topic (adeptly) in a much wider arena than “frogblog” …

eredwen

It may have drifted out of your short attention span, but I did exactly that a couple of weeks ago in this post :

http://blog.greens.org.nz/index.php/2006/05/29/agenda-video-online/#co mment-15678

That post linked to this eminently uncontroversial site :
http://www.ncdc.noaa.gov/paleo/globalwarming/howdo.html
(your comment at the time : “I’m not going to do a complete review of that reference at this point in time”. You’ve got a second chance now…)

It summarises numerous paeleoclimatological studies using a great variety of different proxies. (Straw)Mann’s work is one among many. Even if his work were to be debunked (and I do not concede that it has, since I have debunked the only debunking you have linked), you’ve got a lot of work to do on the others…

Yes, temperatures have varied widely over the ages, and the causes are pretty well-understood. Oddly enough, all of the proxy studies break down in explaining temperatures when applied to the past few decades, unless you figure in the contribution from greenhouse gases.

The science is conclusive. The flat-earthers will continue to deny it, because they have an ideological vested interest.

Happy reading!

Not an endorsement, just making the best of it.