Sea Levels Reducing on East Coast?

[TheLurch]

As I have continually said, I'd like to see some kind of "if we do X, we are reasonably certain that Y will happen". Along with "at what price?"

Have i shared this with you at any point?
http://www.worldenergyoutlook.org/me...ClimateMap.pdf

This report "Sets out four specific measures for the energy sector that can be quickly and effectively implemented, at no net economic cost, to help keep the 2şC target alive while international negotiations continue." So, these things are getting done.

[Kbertsche]

That's funny - didn't realized you'd worked with Muller. What years were you at Berkeley? (I was there 89-95, but nowhere near physics).

I finished up in 1989.

Like i said, i have my own issues with some of the presentations in Gore's film, and it's clear that he chose to present some findings that were extremely preliminary, and haven't stood the test of more detailed research. But if you want to criticize, it's important to not go overboard in the other direction, finding fault where none exists, and Rich clearly has on one of these:

Source: R.A. Muller

In An Inconvenient Truth, Al Gore shows a plot with the cold weather extending back 1000 years, and he makes fun of those who claim there was a medieval warm period, but the plot he shows has now been discredited, in the National Academy review that I mentioned earlier. (pp. 252-253)

© Copyright Original Source

I read the National Academies review, and sat in on the press conference in which its authors talked about the work. The "plot" in question here is Mike Mann's original reconstruction of the climate of the last 1,500 years. The report in question found the paper's conclusions to be (in their words) "plausible", and made it clear that later, improved studies by both Mann and others have produced results largely in line with it. That's anything but discredited.

Like i said, nobody's immune from confirmation bias...

Your information seems to be in conflict with Rich's, and Rich was one of the referees on the report. Maybe you are working from a more recent report or more recent data? Here's more of what Rich says about this:

Source: R.A. Muller

The hockey stick figure appears five times in just the {IPCC} summary volume alone. It is one of the prominent plots that Vice President Gore shows in An Inconvenient Truth.
...
Then came a shock. Canadians Stephen McIntyre and Ross McKitrick uncovered a fundamental mathematical flaw in the computer program that had been used to produce Mann's hockey stick result. ...
...
The error was very embarrassing for people who had publicized the hockey stick as the smoking gun of global warming. Congress requested that the National Research Council of the US National Academy of Sciences conduct a review. I was asked to be a referee on the review. After considerable work, the report concluded that the strongest statement that could be made was that the present years were the warmest in the last 400 years, not 1000 as Mann had said. Of course, that fact wasn't news. It was known even back in 1990, when the IPCC issued its first report. The council also concluded that Mann's analysis showing the absence of the medieval warm period was not correct (despite Al Gore's sarcasm). It's report stated that Mann had underestimated his errors... In the end, there was nothing new left in Mann's papers that the National Academy supported, other than that the idea of using principal component analysis was, in principle, a good one. (pp. 292-295)

© Copyright Original Source

[Cow Poke]

Have i shared this with you at any point?
http://www.worldenergyoutlook.org/me...ClimateMap.pdf

This report "Sets out four specific measures for the energy sector that can be quickly and effectively implemented, at no net economic cost, to help keep the 2şC target alive while international negotiations continue." So, these things are getting done.

I'll give that a look this evening.

[TheLurch]

Your information seems to be in conflict with Rich's, and Rich was one of the referees on the report. Maybe you are working from a more recent report or more recent data?

I'm pretty sure there's been only one NAS report on the topic. And all i can say is that the authors who presented the report to the public would not agree with his characterization (believe me, some of the reporters present asked similar things).

[Juvenal]

Your information seems to be in conflict with Rich's, and Rich was one of the referees on the report. Maybe you are working from a more recent report or more recent data? Here's more of what Rich says about this:

I'd imagine you two are speaking about Surface Temperature Reconstructions for the Last 2,000 Years (2006) referenced in a June 22, 2006, NAP press release. Here's the relevant passage.

The basic conclusion of Mann et al. (1998, 1999) was that the late 20th century warmth in the Northern Hemisphere was unprecedented during at least the last 1,000 years. This conclusion has subsequently been supported by an array of evidence that includes both additional large-scale surface temperature reconstructions and pronounced changes in a variety of local proxy indicators, such as melting on ice caps and the retreat of glaciers around the world, which in many cases appear to be unprecedented during at least the last 2,000 years. Not all individual proxy records indicate that the recent warmth is unprecedented, although a larger fraction of geographically diverse sites experienced exceptional warmth during the late 20th century than during any other extended period from A.D. 900 onward.

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. 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 millennium” because the uncertainties inherent in temperature reconstructions for individual years and decades are larger than those for longer time periods and because not all of the available proxies record temperature information on such short timescales.

Source: R.A. Muller

The hockey stick figure appears five times in just the {IPCC} summary volume alone. It is one of the prominent plots that Vice President Gore shows in An Inconvenient Truth.
...
Then came a shock. Canadians Stephen McIntyre and Ross McKitrick uncovered a fundamental mathematical flaw in the computer program that had been used to produce Mann's hockey stick result. ...
...

© Copyright Original Source

This led to Mann's acknowledgment in a July 2004 corrigendum.

It has been drawn to our attention (S. McIntyre and R. McKitrick) that the listing of the ‘proxy’ data set in the Supplementary Information published with this Article contained several errors. In Table 1 we provide a list of the records that were either mistakenly included in the Supplementary Information, or mistakenly left out. A small number of other corrections of the original listing include (see Table 1) corrections of the citations originally provided, or corrections of the start years for certain series.

The full, corrected listing of the data is supplied as Supplementary Information to this corrigendum. Also provided as Supplementary Information are a documented archive of the complete data (instrumental and ‘proxy’ climate series) used in our original study, and an expanded description of the methodological details of our original study.

None of these errors affect our previously published results(1).

_____

1. Mann, M. E., Bradley, R. S. & Hughes, M. K. Global-scale temperature patterns and climate forcing
over the past six centuries. Nature 392, 779–787 (1998).

Independent of the merits of their criticism of Mann's data sets, there's no question that the revised reconstruction in S. McIntyre and R. McKitrick's CORRECTIONS TO THE MANN et. al. (1998) PROXY DATA BASE AND NORTHERN HEMISPHERIC AVERAGE TEMPERATURE SERIES has not held up.

Source: R.A. Muller

The error was very embarrassing for people who had publicized the hockey stick as the smoking gun of global warming. Congress requested that the National Research Council of the US National Academy of Sciences conduct a review. I was asked to be a referee on the review. After considerable work, the report concluded that the strongest statement that could be made was that the present years were the warmest in the last 400 years, not 1000 as Mann had said. Of course, that fact wasn't news. It was known even back in 1990, when the IPCC issued its first report. The council also concluded that Mann's analysis showing the absence of the medieval warm period was not correct (despite Al Gore's sarcasm). It's report stated that Mann had underestimated his errors... In the end, there was nothing new left in Mann's papers that the National Academy supported, other than that the idea of using principal component analysis was, in principle, a good one. (pp. 292-295)

© Copyright Original Source

Muller is an interesting guy, if for no other reason than because of the contrasts that can be drawn between him and others less credibly identified as AGW skeptics. Muller is, or was, the real deal.

The Conversion of a Climate-Change Skeptic

CALL me a converted skeptic. Three years ago I identified problems in previous climate studies that, in my mind, threw doubt on the very existence of global warming. Last year, following an intensive research effort involving a dozen scientists, I concluded that global warming was real and that the prior estimates of the rate of warming were correct. I’m now going a step further: Humans are almost entirely the cause.

My total turnaround, in such a short time, is the result of careful and objective analysis by the Berkeley Earth Surface Temperature project, which I founded with my daughter Elizabeth. Our results show that the average temperature of the earth’s land has risen by two and a half degrees Fahrenheit over the past 250 years, including an increase of one and a half degrees over the most recent 50 years. Moreover, it appears likely that essentially all of this increase results from the human emission of greenhouse gases.

Some of his criticisms didn't pan out, and some were overstated. It would be interesting to see how he sees his earlier criticism from the time when he refereed the review. It might even be a good question to pose to him on Quora.

[Kbertsche]

I'd imagine you two are speaking about Surface Temperature Reconstructions for the Last 2,000 Years (2006) referenced in a June 22, 2006, NAP press release. Here's the relevant passage.

The basic conclusion of Mann et al. (1998, 1999) was that the late 20th century warmth in the Northern Hemisphere was unprecedented during at least the last 1,000 years. This conclusion has subsequently been supported by an array of evidence that includes both additional large-scale surface temperature reconstructions and pronounced changes in a variety of local proxy indicators, such as melting on ice caps and the retreat of glaciers around the world, which in many cases appear to be unprecedented during at least the last 2,000 years. Not all individual proxy records indicate that the recent warmth is unprecedented, although a larger fraction of geographically diverse sites experienced exceptional warmth during the late 20th century than during any other extended period from A.D. 900 onward.

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. 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 millennium” because the uncertainties inherent in temperature reconstructions for individual years and decades are larger than those for longer time periods and because not all of the available proxies record temperature information on such short timescales.

Yes, this seems to be the report in question. But the two paragraphs above seem to contradict one another. As the first paragraph says, Mann claimed that "the late 20th century warmth in the Northern Hemisphere was unprecedented during at least the last 1,000 years". It then says that "This conclusion has subsequently been supported by an array of evidence ...", but this seems to contradict the second paragraph. (Where did you get these paragraphs, BTW? Were they from the report itself? I don't see them in the press release.)

The second paragraph agrees with the NAP press release that you linked to above. Here are some excerpts:

Source: NAP press release

'High Confidence' That Planet Is Warmest in 400 Years;
Less Confidence in Temperature Reconstructions Prior to 1600

The Research Council committee found the Mann team's conclusion that warming in the last few decades of the 20th century was unprecedented over the last thousand years to be plausible, but it had less confidence that the warming was unprecedented prior to 1600; fewer proxies -- in fewer locations -- provide temperatures for periods before then.

© Copyright Original Source

The press release says nothing about the medieval warm period. But it seems to agree with Rich's other major claims:

Source: R.A. Muller

After considerable work, the report concluded that the strongest statement that could be made was that the present years were the warmest in the last 400 years, not 1000 as Mann had said. ... Its report stated that Mann had underestimated his errors ...

© Copyright Original Source

[TheLurch]

The second paragraph agrees with the NAP press release that you linked to above. Here are some excerpts:

Source: NAP press release

'High Confidence' That Planet Is Warmest in 400 Years;
Less Confidence in Temperature Reconstructions Prior to 1600

The Research Council committee found the Mann team's conclusion that warming in the last few decades of the 20th century was unprecedented over the last thousand years to be plausible, but it had less confidence that the warming was unprecedented prior to 1600; fewer proxies -- in fewer locations -- provide temperatures for periods before then.

© Copyright Original Source

The press release says nothing about the medieval warm period. But it seems to agree with Rich's other major claims:

Source: R.A. Muller

After considerable work, the report concluded that the strongest statement that could be made was that the present years were the warmest in the last 400 years, not 1000 as Mann had said. ... Its report stated that Mann had underestimated his errors ...

© Copyright Original Source

So, there are multiple things going on here. I'll try as best i can to untangle them.

"The strongest statement that could be made" claim by Muller about 400 years is accurate - that is what the report concluded. Mann did NOT, however, say that the strongest statement was 1,000 years. Mann had concluded that it was likely the warmest in the last 400 years, which in the terminology used in the field means 2/3 probability. The committee termed that conclusion plausible, which means a reasonable chance that it's right, but they don't feel that Mann, at the time, really had all the data he needed to come to a strong conclusion.

So, there's some careful use of language by Mann and the NAS, and i think Muller imputed something that wasn't there into it.

SEPARATELY, the NAS report basically concluded that it's stupid to focus on Mann's original report back in 2006 or whenever the report was released. Mann's paper was a solid first attempt at doing a global reconstruction from proxies, but it was just that: a first attempt, done in the 1990s. By 2006, other work had used more extensive data and improved methods to produce other reconstructions (as is typical). And these give us much more confidence in the overall conclusions reached by Mann. So, the report overall makes stronger claims about past climates than its authors felt were justified at the time Mann produced his paper.

This might be helpful as further reading in regards to some of this:
http://www.realclimate.org/index.php...thesis-report/


Bringing this full circle: Gore's film was released the same year as the NAS report. So, Gore was apparently correct about the state of the science regarding the Medieval warm period at the time the film was released. Was that because he had assimilated the same knowledge that the NAS report's authors had, or did he just get lucky? You'd have to ask him.

In any case, it's now 2016, and it's even more pointless to be overanalyzing a 20 year old paper. :)

[TheLurch]

Ugh, sorry - made a goof.

"Mann had concluded that it was likely the warmest in the last 400 years, which in the terminology used in the field means 2/3 probability."
That should read 1,000, not 400.