Slashdot Mirror

"The largest of these debates centers around whether or not Global Warming is manmade" - Yes it is now the "largest [public] debate", maily because of people like Barton and the recent G8 pronouncement by Bush. The scientists Barton is attacking have no doubt and are now debating the magnitude of it's effects.

Er, the paragraph I quoted in turn contained a quote from a Republican congressman.

The main point, though, is to read this before jumping to any conclusions.

Since you responded within two minutes I am reasonably confident you didn't.

Here, let me save you a step. How would you like to be minding your own business (in Mann's case, in the process of moving to a new university in a different state) and suddenly from out of the blue receive a letter like one of these?

Read the scienists official responses to Barton. The hockey stick has not been discredited and it is not claimed to be "the difinitive proof". It is generally acknowledged that the IPCC report is "the" standard body of Global warming knowledge, undermining the IPCC report is the real target of Barton.

Read the scienists official responses to Barton. The hockey stick has not been discredited and it is not claimed to be "the difinitive proof". It is generally acknowledged that the IPCC report is "the" standard body of Global warming knowledge, undermining the IPCC report is the real target of Barton.

For another perspective, see http://www.realclimate.org/index.php?p=172 and the individual responses by: Michael Mann http://www.realclimate.org/Mann_response_to_Barton .pdf,
Ray Bradley http://www.realclimate.org/Bradley_response_to_Bar ton.pdf and Malcolm Hughes http://www.realclimate.org/Hughes_response_to_Bart on.pdf.

Though the NSF does not require the disclosure of code, the procedures used have been available for years, as well as the FORTRAN codes.

For another perspective, see http://www.realclimate.org/index.php?p=172 and the individual responses by: Michael Mann http://www.realclimate.org/Mann_response_to_Barton .pdf,
Ray Bradley http://www.realclimate.org/Bradley_response_to_Bar ton.pdf and Malcolm Hughes http://www.realclimate.org/Hughes_response_to_Bart on.pdf.

Though the NSF does not require the disclosure of code, the procedures used have been available for years, as well as the FORTRAN codes.

For another perspective, see http://www.realclimate.org/index.php?p=172 and the individual responses by: Michael Mann http://www.realclimate.org/Mann_response_to_Barton .pdf,
Ray Bradley http://www.realclimate.org/Bradley_response_to_Bar ton.pdf and Malcolm Hughes http://www.realclimate.org/Hughes_response_to_Bart on.pdf.

Though the NSF does not require the disclosure of code, the procedures used have been available for years, as well as the FORTRAN codes.

For another perspective, see http://www.realclimate.org/index.php?p=172 and the individual responses by: Michael Mann http://www.realclimate.org/Mann_response_to_Barton .pdf,
Ray Bradley http://www.realclimate.org/Bradley_response_to_Bar ton.pdf and Malcolm Hughes http://www.realclimate.org/Hughes_response_to_Bart on.pdf.

Though the NSF does not require the disclosure of code, the procedures used have been available for years, as well as the FORTRAN codes.

You are absolutely wrong. The real question is; Is the research outcome correct or not?

You think that the right way to figure this out is to ask where the money is coming from? So what if the research is paid for by the Sierra Club, or George Soros, or the Democratic National Committee? Do you think this will change the answers? Make the statistics less true? The only reason one would ask for this kind of financial detail is if you have decided that the research is deliberately falsified and you want to track the evidence of deliberate manipulation.

There are many mays to figure out whether research conclusions are true or not. In the case of research published in 1998 and 1999 you can check the subsequent papers which cite the original works and see where the consensus is. This is easy. You can do it yourself, most of this stuff is online. You will discover that the scientific community finds little to complain about, subsequent work has upheld and repeated the conclusions quite independently. To that end I find Dr Mann's response to Barton's request very interesting reading, you can check it out here:
http://www.realclimate.org/Mann_response_to_Barton .pdf

This request by Joe Barton is clearly meant purely as intimidation. If Barton really wanted to understand the science I am quite sure that most responsible climate scientists would actually be delighted to spend some serious time with him going over the science and helping him comprehend how we come to conclusions like this. The fact that Barton attempted no such contact shows clearly his bias in this matter.

Joe Bartons 2006 campaign funding.

Scientists funding history is detailed in thier individual responses to Barton. (not to mention 'Nature' requires this info before publication).

Some main points that don't seem to have come out so far in the Slashdot discussion so far are that

• the congressman is parroting criticisms from a certain Canadian gadfly who has been proven on several occasions not to be well educated on matters of physical climatology.
• these criticisms have been picked up by the Wall Street Journal (in an editorial piece that was severely flawed in other ways as well), but carry no weight in the scientific community, and any serious investigation would show this to be the case.
• The letter was accusatory in tone and onerous in its demands. It wasn;t the request for clarification that is at stake, it is the punishment for results that are out of line with what the congressman wants
• The individual result is illustrative of the seriousness of the situation, so it has received a lot of attention, including from the IPCC. Opponents of the scientific consensus, being political rather than scientific, decided this was an opportunity. They are attempting to tar the entire field with the brush of this purportedly bad article
• It's not clear why the authors took so ling to release the code. However, if this means that conservative elements in congress are going to support a mandate for a purely open source tool chain in non-military science, that will certainly be a silver lining!

Anyway, follow the link and read what the main scientific institutions think of this episode before you come to your own conclusions please.

Also, if you don't mind signing in, see the recent editorial in the New York Times. It includes the following:

Sherwood Boehlert of New York - a fellow Republican who is chairman of the House Science Committee and an enlightened moderate on environmental issues - seemed much closer to the truth when he described Mr. Barton's inquisition as "an effort to intimidate scientists rather than learn from them, and to substitute Congressional political review for scientific peer review."

Actually, part of the interest by Congress is in results from federally funded studies, so part of the interest is from its own funding.

• The Congressional letters are available in PDF format.
• The replies from some people are available.
• The scientists explained some things, but it seems odd that the source code does not match the data, so the program can not simply be run as is.
• Although the program calculated R2 statistics they were not published along with an explanation of why they were not important so others would learn from their wisdom.
• The Barton questions about statistics were not answered.

The scientists responses. They gave him all he wanted and then some. I don't think he was expecting the answer he got and probably wishes he hadn't asked it now.

The resopnses to Barton can be found here. The site is apolitical, thier editoral on the matter ends with these very sane words...

"The real question we are faced with is not whether humans are changing climate. The science on this is clear, and decades of research have culminated in a scientific consensus on this point. The real question now is what we need to do about it. A Congressional committee concerned with energy could be - and indeed should be - a key player in exploring policy options to deal with the global warming threat. We hope that after studying the responses by the scientists, they will make a start."

This BBC artice quotes one of Barton's cronnies as saying "it's about time the science was put on trial". WTF - To be "science" means it is permanently "on trial" but this moron wants to "settle it in a court of law".

"If you move the date of "industrialization" from 1700 to 1500, suddenly, temperatures have cooled since the start of industrialization."

Your post is nothing but a work of mind-numbing fiction, the facts about medieval warming are specifically selected and twisted so that you can bury your head in the sand and feel comfortable in your fantasy world. I can only assume your home is not built on permafrost and is well above sea-level.

"Let me put it this way, when global warming becomes a problem, we'll build a machine to fix it."

Climate change and environmental degredation are already the biggest problems that humanity MUST confront in order to progress, so where is this magic machine that can undo the "sixth great extinction" and refreeze the North Pole?

"Kyoto has been blamed for missing the point by focussing on CO2 (instead of ie. nitrogen-based emmisions and heavy metals)."

Kyoto does not claim to tackle "pollution" in general, it's sole aim is to reduce the rate of growth in GHG emmisions (in particular CO2).

"But sure, even in the area of greenhouse gasses, cow farts are probably a worse threat than all the rest combined"

Sharp as a billiard ball I'd say. - some science for your edification.

http://www.realclimate.org/index.php?p=169.

Science doesn't take sides.

And without sides, you have no conflict. And without conflict, you have no story, and you sell no papers, get no nielsons. It used to be known as "Yellow", now it is just SOP.

PS, if you can handle it, try this www.realclimate.org

Watch out though, it's like really boring, buncha eggheads, going on and on about stuff, with their studies and references and all that muck...

...(not to mention that burning (e.g. oxydizing) hydrogen creates water vapor, which is a far more efficient greenhouse gas than CO2)...

http://www.realclimate.org/index.php?p=142

Water vapour: feedback or forcing?

Whenever three or more contrarians are gathered together, one will inevitably claim that water vapour is being unjustly neglected by 'IPCC' scientists. "Why isn't water vapour acknowledged as a greenhouse gas?", "Why does anyone even care about the other greenhouse gases since water vapour is 98% of the effect?", "Why isn't water vapour included in climate models?", "Why isn't included on the forcings bar charts?" etc. Any mainstream scientist present will trot out the standard response that water vapour is indeed an important greenhouse gas, it is included in all climate models, but it is a feedback and not a forcing. From personal experience, I am aware that these distinctions are not clear to many, and so here is a more in-depth response...

...
While water vapour is indeed the most important greenhouse gas, the issue that makes it a feedback (rather than a forcing) is the relatively short residence time for water in the atmosphere (around 10 days).


http://mustelid.blogspot.com/2005/01/water-vapour- is-not-dominant.html
...
Water vapour is a "reactive" GHG with a short atmospheric lifetime of about 1 week. If you pump out a whole load of extra water vapour it won't stay in the atmosphere; it would condense as rain/snow and we'd be back to where we started. If you sucked the atmosphere dry of moisture, more would evaporate from the oceans. The balance is dynamic of course: humidity of the air varies by place and time, but its a stable balance.

In contrast, CO2 has a long lifetime (actually calculating a single "lifetime" for it doesn't work; but a given CO2 pulse such as we're supplying now will hang around for.. ohh... a century or more). It doesn't rain out (amusing factoid: the surface temperature of the deep interior Antarctica in winter can be colder than the freezing point of CO2; but this doesn't lead to CO2 snow (sadly, it would be fun) because the freezing point is lower because of the lower pressure because its higher up). So if you put in extra CO2 the climate warms a bit; because of this move WV evaporates (it doesn't have to, but just about all models show that the relative humidity tends to be about constant; so if you heat the atmos that means that the absolute humidity will increase). This in turn warms the atmosphere warms up a bit more; so more water gets evaporates. This is a positive feedback but a limited one: the increments (if you think of it that way) get smaller not larger so there is no runaway GH effect.

So: adding CO2 to the atmosphere warms it a bit and ends up with more WV. Adding WV does nothing much and the atmos returns to equilibrium. This is why WV is not the *dominant* GHG; its more like a submissive GHG :-)

"We don't even know for certain if we are causing global warming"

This is a common misconception also alluded to by the GP post. Check somewhere where the climate scientists hang out rather than listening to the politically skewed crap on TV and in the newspapers. There are a remarkable number of peer reviewed studies that have predicted a change that has later been confirmed by observation. That does not mean they have all the answers but they are telling us that the planet is definitely warming (even though soot may be slowing it down somewhat).

However I do agree that the idea of building a "sapce ring" is stupid and wastefull in the extreme. In my mind is just giving ammo to the politicians and corporations who claim change is too hard and will bring financial ruin apon us all.

This also neglects the issue of "How much carbon does mankind produce" vs. "How much carbon does nature produce." (It may turn out that natural production of CO2, including volcanos, dwarf any human contribution).

The research in that area ends up reporting different results depending on who is paying the scientist's bills. (And its easy to find criticism about scientific climate models and data collection methods.)

If global warming is due to CO2, there is the question of how much it costs to reduce CO2 emissions, and if that money could be better spent on other environmental causes.

Due to the above, I'm rather skeptical about most proposals to limit global warming. The data isn't there to justify the expenditures, especially considering that (1) sooner or later, climate change will happen naturally sooner or later and (2) if global warming will happen, it will probably have a net benefit on many countries' economies.

I'd rather see the money spent on tasks with a more tangable benefit. We know what will happen if we spend $1M to set aside a wildlife area. We don't know what will happen if we spend $1M to put X units of CO2 under the sea floor.

Right now, we have a lot of different computer programs that claim to show us the future. Not one of them can start with the known conditions of fifty years ago and end up with today.

I've heard, recently, that there's so much forrest, agraculture and so-on in the USA that it's taking carbon dioxide out of the atmosphere faster than it's putting it in, but I don't have a cite for it.

Review Part One
Review Part Two

The posts on that site are well worth it - at least, you'll learn more than you would in arguing with slashdot trolls.

Review Part One
Review Part Two

The posts on that site are well worth it - at least, you'll learn more than you would in arguing with slashdot trolls.

Review Part One
Review Part Two

The posts on that site are well worth it - at least, you'll learn more than you would in arguing with slashdot trolls.

"We cant even predict the weather without real-time pictures, to say nothing of climate prediction."

This is by far the most common fallacy when climate change is being discussed, I can't be bothered explaining, look it up for yourself using peer-reviewed sources.

As for sunspots, accurate records were not available until well after the invention of the telescope, so claims regarding unusual sunspot activity before the 17th century are anecdotal at best. To then go on and claim that the non-existant records are correlated with climate fluctuations is pure bullshit. I do know of any peer-reviewed study that has been published linking sunspots to major climate change but there are a plethora of industry shrills and whaco's who spout this crap to anyone who is still willing listen.

""the best-predicting climate models" ... um suck."

I don't understand the pathological aversion to climate models by so called scientifically minded people. I don't hear anyone refuting physists, chemists, etc, with such well thought out arguments as "um suck". Science is the art of building and refining models. If you can't, (or don't want to), understand that fundemental point then I suggest you might find more solice in religion or witchcraft.

We've all seen the talking points from the PR firms of the chemical and oil industries... your regurgitation of them adds nothing new.

If you're a "concerned citizen" who is reciting them and NOT getting paid, you're an idiot as well as a troll. Go check out Techcentralstation for how to get on the gravy train.

For real information from actual scientists working in the field, the rest of slashdot can check out:
http://www.realclimate.org/
http://www.altenergyaction.org/

So far nobody has been able to verify M&M's claims either. I can see why you are perfectly happy with that.

I really can't comment on the reliability of unnamed authors with unnamed publications providing similar results that I can't check. You may very well be right but without any documentation, your comment is worthless in a scientific debate on reliability.

Dummies guide to the latest "Hockey Stick" controversy

8) So does this all matter?

No. If you use the MM05 convention and include all the significant PCs, you get the same answer. If you don't use any PCA at all, you get the same answer. If you use a completely different methodology (i.e. Rutherford et al, 2005), you get basically the same answer. Only if you remove significant portions of the data do you get a different (and worse) answer.

9) Was MBH98 the final word on the climate of last millennium?

Not at all. There has been significant progress on many aspects of climate reconstructions since MBH98. Firstly, there are more and better quality proxy data available. There are new methodologies such as described in Rutherford et al (2005) or Moberg et al (2005) that address recognised problems with incomplete data series and the challenge of incorporating lower resolution data into the mix. Progress is likely to continue on all these fronts. As of now, all of the 'Hockey Team' reconstructions (shown left) agree that the late 20th century is anomalous in the context of last millennium, and possibly the last two millennia.

So far nobody has been able to verify M&M's claims either. I can see why you are perfectly happy with that.

I really can't comment on the reliability of unnamed authors with unnamed publications providing similar results that I can't check. You may very well be right but without any documentation, your comment is worthless in a scientific debate on reliability.

Dummies guide to the latest "Hockey Stick" controversy

8) So does this all matter?

No. If you use the MM05 convention and include all the significant PCs, you get the same answer. If you don't use any PCA at all, you get the same answer. If you use a completely different methodology (i.e. Rutherford et al, 2005), you get basically the same answer. Only if you remove significant portions of the data do you get a different (and worse) answer.

9) Was MBH98 the final word on the climate of last millennium?

Not at all. There has been significant progress on many aspects of climate reconstructions since MBH98. Firstly, there are more and better quality proxy data available. There are new methodologies such as described in Rutherford et al (2005) or Moberg et al (2005) that address recognised problems with incomplete data series and the challenge of incorporating lower resolution data into the mix. Progress is likely to continue on all these fronts. As of now, all of the 'Hockey Team' reconstructions (shown left) agree that the late 20th century is anomalous in the context of last millennium, and possibly the last two millennia.

So far nobody has been able to verify M&M's claims either. I can see why you are perfectly happy with that.

I really can't comment on the reliability of unnamed authors with unnamed publications providing similar results that I can't check. You may very well be right but without any documentation, your comment is worthless in a scientific debate on reliability.

Dummies guide to the latest "Hockey Stick" controversy

8) So does this all matter?

No. If you use the MM05 convention and include all the significant PCs, you get the same answer. If you don't use any PCA at all, you get the same answer. If you use a completely different methodology (i.e. Rutherford et al, 2005), you get basically the same answer. Only if you remove significant portions of the data do you get a different (and worse) answer.

9) Was MBH98 the final word on the climate of last millennium?

Not at all. There has been significant progress on many aspects of climate reconstructions since MBH98. Firstly, there are more and better quality proxy data available. There are new methodologies such as described in Rutherford et al (2005) or Moberg et al (2005) that address recognised problems with incomplete data series and the challenge of incorporating lower resolution data into the mix. Progress is likely to continue on all these fronts. As of now, all of the 'Hockey Team' reconstructions (shown left) agree that the late 20th century is anomalous in the context of last millennium, and possibly the last two millennia.

If you have the patience for a little bit of careful exposition, see this article on realclimate.org.

As discussed above, MM incorrectly truncated the PC basis set at only 2 PC series based on a failure to apply standard selection rules to determine the number of PC series that should be retained in the analysis. Five, rather than two PC series, are indicated by application of standard selection rules if using the MM, rather than MBH98, centering convention to represent the North American ITRDB data. If these five series are retained as predictors, essentially the same temperature reconstruction as MBH98 is recovered (Figure 2).

...

We further show that the entire issue raised by MM regarding the centering convention used in PCA is spurious by demonstrating that similar results are produced whether or not proxy networks are represented using PCA at all

So let's assume for argument's sake that Mann, Bradley and Hughes made some terrible mistake in their statistical analysis, so we need to discard their results altogether. This wouldn't change our picture of the last millennium (or anything else) very much: independent groups, with different analysis methods, have arrived at similar results for the last millennium. The details differ (mostly within the uncertainty bounds given by Mann et al, so the difference is not significant), but all published reconstructions share the same basic features: they show relatively warm medieval times, a cooling by a few tenths of a degree Celsius after that, and a rapid warming since the 19th Century. Even without Mann et al, we'd still be stuck with a "hockey stick" type of curve - quite boring.

As discussed above, MM incorrectly truncated the PC basis set at only 2 PC series based on a failure to apply standard selection rules to determine the number of PC series that should be retained in the analysis. Five, rather than two PC series, are indicated by application of standard selection rules if using the MM, rather than MBH98, centering convention to represent the North American ITRDB data. If these five series are retained as predictors, essentially the same temperature reconstruction as MBH98 is recovered (Figure 2).

...

We further show that the entire issue raised by MM regarding the centering convention used in PCA is spurious by demonstrating that similar results are produced whether or not proxy networks are represented using PCA at all

So let's assume for argument's sake that Mann, Bradley and Hughes made some terrible mistake in their statistical analysis, so we need to discard their results altogether. This wouldn't change our picture of the last millennium (or anything else) very much: independent groups, with different analysis methods, have arrived at similar results for the last millennium. The details differ (mostly within the uncertainty bounds given by Mann et al, so the difference is not significant), but all published reconstructions share the same basic features: they show relatively warm medieval times, a cooling by a few tenths of a degree Celsius after that, and a rapid warming since the 19th Century. Even without Mann et al, we'd still be stuck with a "hockey stick" type of curve - quite boring.

Here, however, we choose to focus on some curious additional related assertions made by MM holding that (1) use of non-centered PCA (as by MBH98) is somehow not statistically valid, and (2) that "Hockey Stick" patterns arise naturally from application of non-centered PCA to purely random "red noise". Both claims, which are of course false, were made in a comment on MBH98 by MM that was rejected by Nature , and subsequently parroted by astronomer Richard Muller in a non peer-reviewed setting--see e.g. this nice discussion by science journalist David Appell of Muller's uncritical repetition of these false claims. These claims were discredited in the response provided by Mann and coworkers to the Nature editor and reviewers, which presumably formed the primary basis for the rejection of the MM comment.

...

Lets turn, now, to MM's claim that the "Hockey Stick" arises simply from the application of non-centered PCA to red noise. Given a large enough "fishing expedition" analysis, it is of course possible to find "Hockey-Stick like" PC series out of red noise. But this is a meaningless exercise. Given a large enough number of analyses, one can of course produce a series that is arbitrarily close to just about any chosen reference series via application of PCA to random red noise. The more meaningful statistical question, however is this one: Given the "null hypothesis" of red noise with the same statistical attributes (i.e., variance and lag-one autocorrelation coefficients) as the actual North American ITRDB series, and applying the MBH98 (non-centered) PCA convention, how likely is one to produce the "Hockey Stick" pattern from chance alone.

And, to top it off, Mann's equation always produces hockey-stick graphs, even with randomly distributed data.

The above remark appears seriously dubious. See http://www.realclimate.org/index.php?p=98.

You do know that Mann writes this website, right? You do realize that the source of your argument (http://www.realclimate.org/) is a shill for Mann and his cronies?

You do know that Mann writes this website, right? You do realize that the source of your argument (http://www.realclimate.org/) is a shill for Mann and his cronies?

Second of all, there was a flaw in the original algorithm that was pointed out by McIntyre and McKitrick before they even got to the bad data being put into the equation.

And, to top it off, Mann's equation always produces hockey-stick graphs, even with randomly distributed data.

Don't point at Mann's own site as a defense of Mann.

I think the important conlusion of this guide is that if you take all of the original Mann, Bradley and Hughes data and run it using the same fully open-source algorithms of McKitrick & McIntyre, you get the same results.

Which is reasonable since MM's argument is about source data and not methodology (as per this guide).

So a team of real scientists (that is, by folks who work in climate science, not reporters or pundits) wrote a Dummies Guide to the latest controversy. Click on the link for a nice question-by-question breakdown, but I'll spoil the conclusion for you:

(MBH98 is the old paper with "closed" source, MM05 is the new "open source") paper)

7) Basically then the MM05 criticism is simply about whether selected N. American tree rings should have been included, not that there was a mathematical flaw?

Yes. Their argument since the beginning has essentially not been about methodological issues at all, but about 'source data' issues. Particular concerns with the "bristlecone pine" data were addressed in the followup paper MBH99 but the fact remains that including these data improves the statistical validation over the 19th Century period and they therefore should be included.

8) So does this all matter?

No. If you use the MM05 convention and include all the significant PCs, you get the same answer. If you don't use any PCA at all, you get the same answer. If you use a completely different methodology (i.e. Rutherford et al, 2005), you get basically the same answer. Only if you remove significant portions of the data do you get a different (and worse) answer.

9) Was MBH98 the final word on the climate of last millennium?

Not at all. There has been significant progress on many aspects of climate reconstructions since MBH98. Firstly, there are more and better quality proxy data available. There are new methodologies such as described in Rutherford et al (2005) or Moberg et al (2005) that address recognised problems with incomplete data series and the challenge of incorporating lower resolution data into the mix. Progress is likely to continue on all these fronts. As of now, all of the 'Hockey Team' reconstructions (shown left) agree that the late 20th century is anomalous in the context of last millennium, and possibly the last two millennia.

So a team of real scientists (that is, by folks who work in climate science, not reporters or pundits) wrote a Dummies Guide to the latest controversy. Click on the link for a nice question-by-question breakdown, but I'll spoil the conclusion for you:

(MBH98 is the old paper with "closed" source, MM05 is the new "open source") paper)

7) Basically then the MM05 criticism is simply about whether selected N. American tree rings should have been included, not that there was a mathematical flaw?

Yes. Their argument since the beginning has essentially not been about methodological issues at all, but about 'source data' issues. Particular concerns with the "bristlecone pine" data were addressed in the followup paper MBH99 but the fact remains that including these data improves the statistical validation over the 19th Century period and they therefore should be included.

8) So does this all matter?

No. If you use the MM05 convention and include all the significant PCs, you get the same answer. If you don't use any PCA at all, you get the same answer. If you use a completely different methodology (i.e. Rutherford et al, 2005), you get basically the same answer. Only if you remove significant portions of the data do you get a different (and worse) answer.

9) Was MBH98 the final word on the climate of last millennium?

Not at all. There has been significant progress on many aspects of climate reconstructions since MBH98. Firstly, there are more and better quality proxy data available. There are new methodologies such as described in Rutherford et al (2005) or Moberg et al (2005) that address recognised problems with incomplete data series and the challenge of incorporating lower resolution data into the mix. Progress is likely to continue on all these fronts. As of now, all of the 'Hockey Team' reconstructions (shown left) agree that the late 20th century is anomalous in the context of last millennium, and possibly the last two millennia.

So a team of real scientists (that is, by folks who work in climate science, not reporters or pundits) wrote a Dummies Guide to the latest controversy. Click on the link for a nice question-by-question breakdown, but I'll spoil the conclusion for you:

(MBH98 is the old paper with "closed" source, MM05 is the new "open source") paper)

7) Basically then the MM05 criticism is simply about whether selected N. American tree rings should have been included, not that there was a mathematical flaw?

Yes. Their argument since the beginning has essentially not been about methodological issues at all, but about 'source data' issues. Particular concerns with the "bristlecone pine" data were addressed in the followup paper MBH99 but the fact remains that including these data improves the statistical validation over the 19th Century period and they therefore should be included.

8) So does this all matter?

No. If you use the MM05 convention and include all the significant PCs, you get the same answer. If you don't use any PCA at all, you get the same answer. If you use a completely different methodology (i.e. Rutherford et al, 2005), you get basically the same answer. Only if you remove significant portions of the data do you get a different (and worse) answer.

9) Was MBH98 the final word on the climate of last millennium?

Not at all. There has been significant progress on many aspects of climate reconstructions since MBH98. Firstly, there are more and better quality proxy data available. There are new methodologies such as described in Rutherford et al (2005) or Moberg et al (2005) that address recognised problems with incomplete data series and the challenge of incorporating lower resolution data into the mix. Progress is likely to continue on all these fronts. As of now, all of the 'Hockey Team' reconstructions (shown left) agree that the late 20th century is anomalous in the context of last millennium, and possibly the last two millennia.

So a team of real scientists (that is, by folks who work in climate science, not reporters or pundits) wrote a Dummies Guide to the latest controversy. Click on the link for a nice question-by-question breakdown, but I'll spoil the conclusion for you:

(MBH98 is the old paper with "closed" source, MM05 is the new "open source") paper)

7) Basically then the MM05 criticism is simply about whether selected N. American tree rings should have been included, not that there was a mathematical flaw?

Yes. Their argument since the beginning has essentially not been about methodological issues at all, but about 'source data' issues. Particular concerns with the "bristlecone pine" data were addressed in the followup paper MBH99 but the fact remains that including these data improves the statistical validation over the 19th Century period and they therefore should be included.

8) So does this all matter?

No. If you use the MM05 convention and include all the significant PCs, you get the same answer. If you don't use any PCA at all, you get the same answer. If you use a completely different methodology (i.e. Rutherford et al, 2005), you get basically the same answer. Only if you remove significant portions of the data do you get a different (and worse) answer.

9) Was MBH98 the final word on the climate of last millennium?

Not at all. There has been significant progress on many aspects of climate reconstructions since MBH98. Firstly, there are more and better quality proxy data available. There are new methodologies such as described in Rutherford et al (2005) or Moberg et al (2005) that address recognised problems with incomplete data series and the challenge of incorporating lower resolution data into the mix. Progress is likely to continue on all these fronts. As of now, all of the 'Hockey Team' reconstructions (shown left) agree that the late 20th century is anomalous in the context of last millennium, and possibly the last two millennia.

The debate is well-documented (by the Mann team, at least) here, here, here.

The debate is well-documented (by the Mann team, at least) here, here, here.

The debate is well-documented (by the Mann team, at least) here, here, here.

Too bad, that the "Little Ice Age" was a relatively local phenomene restricted to parts of the northern hemisphere, and that in the last 50 years there was no raise in solar activity, whereas the global temperature was not.

Too bad, that the "Little Ice Age" was a relatively local phenomene restricted to parts of the northern hemisphere, and that in the last 50 years there was no raise in solar activity, whereas the global temperature was not.

Have fun. They are nice folks.

The folks at http://www.climate2003.com and http://www.climateaudit.org/ debunk the crackpots at http://www.realclimate.org/.

The folks at http://www.realclimate.org/ debunk the crackpots at http://www.climate2003.com/ and http://www.climateaudit.org/.

This is as it should be in science.

The graph used in the New Scientist article about the Bush Whitehouse accepting humans as the cause of global warming, here http://www.newscientist.com/article.ns?id=dn6334, has been debunked as bad science here:
http://www.climateaudit.org/. Mann's own bad science puts any reports that use it in doubt. This is how science works.

How did they debunk it? They used the scientific method of attempting to duplicate Mann's study using Mann's data. They couldn't. They found flaws. They found buggy software - the math was simply wrong! It always produces a hockey stick even with random data with a flat trend! They reported those flaws. Unfortunately for Mann his science was junk.

Scientific understanding progresses as a result. Now we know more.

As for the Time Online report at the top of this thread (http://www.timesonline.co.uk/article/0,,3-1489955 ,00.html. Where's the data? Where's the software? Where's the actual report/paper?

Open source the science otherwise it's all disconnected conclusions and might as well be mind poo (a technical term ;--). Mann et al kept their data secret (as you can read at the links above that debunk him). That's not science. That's closed science of the elite or the schiesters.

Open source science is science that can be audited by anyone. Otherwise how can you really judge it's value? If a scientist with the stature of Mann can be debunked and have his result crushed like a bug how can anyone trust the reputation of any scientist? The answer is that you can't ofcourse otherwise you're bringing a belief into your resoning: a belief that you trust a particular scientist. That's not science, that's potentially religion, or at least faith based science (due to the trust factor).

Open science is the only way to go to be able to have supportable conclusions. The Times Online article is just a fluff peice with no hard data to back it up. It's just a summary of items to peak interest. Where's the beef? Where's the data? I want the software. Let's audit the software for bugs. That's what was partly wrong with Mann's analysis, a software bug.

Earth is too important to us to have the wrong conclusions, no matter which way they are headed. It's better to know reality accurately than believe in a fantasy as far as Global Warming is concerned.

Which would you rather be: faith based or science based? If your are science based then you must be prepared to have your views shaken now and then as a result of more accurate and up to date science. If you are faith based then go to church and leave us rational humans be.

Oh, as a final point, it's the responsibility of a scientist to be skeptical. To hold the neurtal gound even when faced with conclusive data. To keep asking the questions time and time again. To ask questions that underly the conclusions. To question the conclusions. Remember that consensus isn't science, it's mob rule, science works by multiple scientists auditing the data, methods and process of the analysis and conclusions.

Unfortunately for Mann his famous hockey stick hasn't passed this close scutinty process. Now he has to fight for his reputation and career. It seems harsh, but that's what happens with junk science.

I remain an open minded skeptic.

Pet