From space, daily snapshot of CO2 levels and the feedback role of water vapor

We have blogged a bit about the techniques and precision of atmospheric CO2 measurements (see here).  Now a new space-based instrument, the Atmospheric Infrared Sounder (AIRS), is enhancing our ability to measure CO2 concentration and to forecast it’s implications, including the feedback associated with increasing water vapor.

TEXAS A&M—Researchers studying climate now have a new tool at their disposal that yields daily global measurements of carbon dioxide and water vapor in a key part of Earth’s atmosphere.

The data are courtesy of the Atmospheric Infrared Sounder (AIRS) instrument on NASA’s Aqua spacecraft and confirm the mainstream scientific view that large changes in the climate are likely over the next century.

Moustafa Chahine, the instrument’s science team leader at NASA’s Jet Propulsion Laboratory in Pasadena, unveiled the new measurements at a briefing on recent breakthroughs in greenhouse gas, weather, and climate research from AIRS at the recent American Geophysical Union meeting in San Francisco.

The new data have been extensively validated against both aircraft and ground-based observations. They give users daily and monthly measurements of the concentration and distribution of carbon dioxide in the mid-troposphere—the region of the atmosphere located between 5 and 12 kilometers, or 3 to 7 miles, above Earth’s surface and track its global transport.

Users can also access historical AIRS carbon dioxide data spanning the mission’s entire seven-plus years in orbit. The product represents the first-ever release of global daily carbon dioxide data that are based solely on observations.

One interesting findings and value of the AIRS data is that it is helping atmospheric scientists better understand (or confirm) the feedbacks between CO2, temperature and water vapor.

From John Cook @ SkepticalScience:  Water vapour is the most dominant greenhouse gas. Water vapour is also the dominant positive feedback in our climate system and amplifies any warming caused by changes in atmospheric CO2. This positive feedback is why climate is so sensitive to CO2 warming.

As water vapour is directly related to temperature, it’s also a positive feedback – in fact, the largest positive feedback in the climate system (Soden 2005). As temperature rises, evaporation increases and more water vapour accumulates in the atmosphere. As a greenhouse gas, the water absorbs more heat, further warming the air and causing more evaporation.

How does water vapour fit in with CO2 emissions? When CO2 is added to the atmosphere, as a greenhouse gas it has a warming effect. This causes more water to evaporate and warm the air more to a higher (more or less) stabilized level. So CO2 warming has an amplified effect, beyond a purely CO2 effect.

Read more about the positive feedback caused by water vapor here and here.

…scientists using AIRS data have removed most of the uncertainty about the role of water vapor in atmospheric models. The data are the strongest observational evidence to date for how water vapor responds to a warming climate.

“The argument that the scientific community does not understand water vapor is one of the most durable urban legends in the climate change debate,” says Andrew Dessler, a climate scientist at Texas A&M University.

“AIRS temperature and water vapor observations have corroborated climate model predictions that the warming of our climate produced by carbon dioxide will be greatly exacerbated—in fact, more than doubled—by water vapor.”

Dessler says that most of the warming caused by carbon dioxide does not come directly from carbon dioxide, but from effects known as “feedbacks.” Water vapor is a particularly important feedback. As the climate warms, the atmosphere becomes more humid. Since water is a greenhouse gas, it serves as a powerful positive feedback to the climate system, amplifying the initial warming.

AIRS measurements of water vapor reveal that water greatly amplifies warming caused by increased levels of carbon dioxide. Comparisons of AIRS data with models and re-analyses are in excellent agreement.

“The implication of these studies is that, should greenhouse gas emissions continue on their current course of increase, we are virtually certain to see Earth’s climate warm by several degrees Celsius in the next century, unless some strong negative feedback mechanism emerges elsewhere in Earth’s climate system,” Dessler adds.

Read the full story here

‘Triple whammy’ takes toll on Arctic erosion

Coastal erosion is a growing problem related to AGW you don’t hear much about.  Erosion, and habitat and property loss, is related to sea level rise, but can be compounded by other things such as changes in storm intensity and frequency and by fetch and exposure duration, which in the Arctic is increasing due to sea ice loss.

U. COLORADO—The combined effect of declining sea ice, warming seawater, and increased wave activity is causing the northern coastline of Alaska to erode by up to one-third the length of a football field each year.

Robert Anderson, associate professor of geological sciences at the University of Colorado at Boulder, says the conditions have led to the steady retreat of 30 to 45 feet a year of the 12-foot-high bluffs.

The bluffs are actually frozen blocks of silt and peat containing 50 to 80 percent ice—which are toppled into the Beaufort Sea during the summer months by a combination of large waves pounding the shoreline and warm seawater melting the base of the bluffs.

Once the blocks have fallen, the coastal seawater melts them in a matter of days, sweeping the silty material out to sea.

The problem is caused by several factors, including increased erosion along the Alaskan coastline due to longer ice-free summer conditions and warmer seawater bathing the coast, Anderson says.

The third potential factor is that the longer the sea ice is detached from the coastline, the further out to sea the sea-ice edge will be.

This open-ocean distance between the sea ice and the shore, known as the “fetch,” increases both the energy of waves crashing into the coast and the height to which warm seawater can come into contact with the frozen bluffs.

“What we are seeing now is a triple whammy effect,” Anderson says.

“Since the summer Arctic sea ice cover continues to decline and Arctic air and sea temperatures continue to rise, we really don’t see any prospect for this process ending.

Read the full story on Futurity here

[youtube=http://www.youtube.com/watch?v=nSXpsg_gjms&w=425&h=344]

Probabilistic assessment of sea level during the last interglacial stage

During the last interglacial period ~ 125,000 years ago, sea level was roughly 6 m higher than today.  Evidence of this can be seen throughout the Caribbean, where 125,000 year old fossil coral reefs form much of the shoreline (see this image below).  This was presumably because temp. was higher during that period.  When they were alive, these reefs were under 3-5 m of water (at least).  You can still easily identify the coral species of the fossils and thus estimate the depth that section of reef must have been at based on the coral assemblages current depth profile.

A new study just published in Nature puts this into a probabilistic context with some smarty-smart stats and geo-chrono techniques.

PRINCETON—The planet’s polar ice sheets are vulnerable to large-scale melting even under moderate global warming scenarios. Such melting would lead to a large and relatively rapid rise in global sea level, submerging many coastal areas.

That finding is based on new analysis of the geological record of the Earth’s sea level, carried out by scientists at Princeton and Harvard universities and published in the Dec. 16 issue of Nature.

The researchers employed a novel statistical approach that reveals an additional 2 degrees of global warming could commit the planet to 6 to 9 meters (20 to 30 feet) of long-term sea level rise.

This rise would inundate low-lying coastal areas where hundreds of millions of people now reside. It would permanently submerge New Orleans and other parts of southern Louisiana, much of southern Florida and other parts of the U.S. East Coast, much of Bangladesh, and most of the Netherlands, unless unprecedented and expensive coastal protection were undertaken.

And while the researchers’ findings indicate that such a rise would likely take centuries to complete, if emissions of greenhouse gases are not abated, the planet could be committed during this century to a level of warming sufficient to trigger this outcome.

read the full article on Futurity here

read the press release here

see the paper in Nature here

From Nature: With polar temperatures ~3–5 °C warmer than today, the last interglacial stage (~125 kyr ago) serves as a partial analogue for 1–2 °C global warming scenarios. Geological records from several sites indicate that local sea levels during the last interglacial were higher than today, but because local sea levels differ from global sea level, accurately reconstructing past global sea level requires an integrated analysis of globally distributed data sets. Here we present an extensive compilation of local sea level indicators and a statistical approach for estimating global sea level, local sea levels, ice sheet volumes and their associated uncertainties. We find a 95% probability that global sea level peaked at least 6.6 m higher than today during the last interglacial; it is likely (67% probability) to have exceeded 8.0 m but is unlikely (33% probability) to have exceeded 9.4 m. When global sea level was close to its current level (≥-10 m), the millennial average rate of global sea level rise is very likely to have exceeded 5.6 m kyr-1 but is unlikely to have exceeded 9.2 m kyr-1. Our analysis extends previous last interglacial sea level studies by integrating literature observations within a probabilistic framework that accounts for the physics of sea level change. The results highlight the long-term vulnerability of ice sheets to even relatively low levels of sustained global warming.

A tale of two worlds

Darwin as a monkey – The view of the church of England and the conservative British press in 1860.

This week I travelled to Europe for an extended break (and offset my travel). From a climate change perspective what met me was such a breath of fresh-air. I’ve temporarily left Australia, a nation whose politics are torn apart by an inward looking, big business dominated, unrepresentative, and non-scientific political system whose rejection of the Emissions Trading Scheme only serves to remind me of the rejection of Darwin’s ‘then’ theory of evolution by Church of England back in 1860.

Although Europe is haemorrhaging in a barrage of disgusting neo-facism fronted by the alarming views and representations of characters such as Nick Griffin their exists so much development of opinion, media comment and personal action that can only be commended. Europe is far from perfect, but a feeling that even the most conservative right wing media outlets are mostly pushing an agenda of climate change as fact is refreshing.

I’ve witnessed competitions by employers keen to be have the greenest corporate car fleet, every conceivable renewable energy source being explored as a genuine potential power plant, and the average Joe in the street keen to do their bit by buying green electricity, and increasing recycling to 90% in some locations, and seeing low carbon economies as business opportunities. Europe is full of problems, its economies are in tatters, unemployment is high, and neo-facism is on the march. O2 emissions are enormous and car dependency is huge. But looking beyond this are the small but clear green roots of development towards a low carbon economy. If Europe can take such a path at a time of severe economic downturn then why must Australia be hesitant?

As my mother expressed yesterday: “these are not issues of economics or lifestyle, they’re about the future prosperity and happiness of our very own children and grand children. Inaction by politicians and governments about such an issue that will define our generation bring me to tears”.

The politicians of Australia need to remember that they are elected to undertake a mandate. Australia may be presented as a nation of climate sceptics by its politicians, its media, and its big business, but in 2007 the people democratically elected the Labor government with a mandate to join the Kyoto treaty and develop an ETS. The time is right for some politicians to respect the democratic will of the people and help introduce legislation intended to progress Australia towards that low carbon economy that is being developed in other regions of the World.

Copenhagen: Once a treaty, now an accord.

Copenhagen in the snow (Flickr User: larsdaniel)

After years of preparation and two weeks of intense negotiators among thousands, the text of the Copenhagen Accord could be perceived as a little underwhelming.   Five pages with nothing strictly binding.   After reading it carefully, however, there are some tracks in the sand as far as the future superhighway to a low emission future.

Firstly, the Accord (hence all countries present in Copenhagen) acknowledges that climate change is “one of the greatest challenges of our time” … “the scientific view that the increase in global temperatures should be below 2°C”.  Given final acceptance, this is a stunning outcome that contrasts with previous decades of denial and frustration.

Secondly, the Accord recognises “deep cuts in global emissions are required according to science, and as documented by the IPCC Fourth Assessment Report with a view to reduce global emissions so as to hold the increase in global temperature below 2 degrees Celsius”.

Again, remarkable given the recent past.

Thirdly, the Accord recognises that ” developed countries shall provide adequate, predictable and sustainable financial resources, technology and capacity-building to support the implementation of adaptation action in developing countries.”

Nice to see the first acknowledgements by developed countries of their collective responsibility as regards the more vulnerable developing countries.

The accord also outlines in broad details where, when and when not verification is appropriate to ensure that “national sovereignty is respected.”  There is even mention of long-term targets of 1.5°C and the need to support REDD-plus and other important initiatives.

In many ways, the judgement of whether or not COP15 was successful depends very much on expectations at the beginning.

For example, if success is defined as achieving a broad, science-based and equitable treaty signed in Copenhagen, then COP15 is an abject failure.   On the other hand, if the performance of COP15 is measured relative to progress even five years ago (remember the ‘ostrich days’ of Howard and Bush?), then it has been an outrageous success.  However, that wouldn’t be hard to beat.  The important thing is to measure it relative to where we need to go.

And in that regard, we have a long way to go.  This said, the success of Copenhagen will be judged on what happens post-Copenhagen.  My children and I are on the edges of our seats in this regard!

“Low targets, goals dropped: Copenhagen ends in failure”

My favourite, from The Guardian newspaper:

“Low targets, goals dropped: Copenhagen ends in failure”

Ban Ki-moon (UN Secretary General)

“It may not be everything we hoped for, but this decision of the Conference of Parties is an essential beginning.”

John Sauven (Executive Director, Greenpeace UK):

“It is now evident that beating global warming will require a radically different model of politics than the one on display here in Copenhagen.”

Dr Peter Barrett (NZ Climate Change Research Institute, Victoria University of Wellington):

We now have to ask what more we can do to convince political and business leaders that the future threat from fossil energy is real, imminent and that our legacy does matter.”

Professor Ove Hoegh-Guldberg (Global Change Institute, University of Queensland)

A brave face on total failure. This is a triumph for the fossil fuel lobby.”

Professor Tim Flannery (Chairman of the Copenhagen Climate Council)


“We’ve made a huge advance at this meeting on a number of fronts, one being those pledged emissions, another being the funding we’ve now got for adaptation and mitigation in developing countries. The third is the REDD negotiations, the world’s efforts to protect the tropical rainforests and that seems to be going very well indeed.”

Dr Jim Salinger (University of Auckland)

“I welcome the news that the big players: USA, China, India, Brazil and South Africa have committed to limit temperature increases to 2 degrees C. It is essential that all countries sign on to effective emissions reductions targets of greenhouse gases by 40% at 2020 and 80% by 2080 to prevent disruptive climate change and sea level rise later this century that so threaten peoples such as those in the tropical Pacific.”

Professor Suzi Kerr (Stanford University, Department of Economics)


“The agreement on a transparent monitoring mechanism is a relief and a major step forward with respect to some key developing countries.”

Dr Andy Reisinger (Senior Research Fellow, New Zealand Climate Change Research Institute)

“It is worrying that even those countries that brokered the deal have admitted that the specific emissions targets will not be stringent enough to reach their stated long-term goal, which is to limit global average temperature increases to no more than 2°C above pre-industrial levels. We will have to wait until the final numbers are on table to see how far the actual emissions targets fall short of that ultimate goal, and what amount of warming we might expect more realistically once the dust and celebratory rhetoric has settled.”

Monbiot vs Plimer on lateline

The Monbiot vs Plimer debate is getting a little beyond common sense (see here for our previous coverage). Below is an excerpt from Lateline featuring both ‘contestants’ –  Plimer simply can’t answer a very, very simple question put to him. If anyone want’s to jump to Plimer’s aid and support his case, please comment below. It’s beginning to look a little one-sided…
[youtube=http://www.youtube.com/watch?v=HPenmY5kYcc&w=480&h=295]

Here is the link to the ABC transcript, and here are the full versions on Youtube: Part 1, Part 2 & Part 3.

The Future of Marine Fish Resources

eduffy

There is a very nice summary article about overfishing and fisheries management at ActionBioScience written by Dr. J. Emmett Duffy, one of the world’s leading marine ecologists. Emmett is a pioneer of work on the importance  marine biodiversity and he discovered the first known example of eusociality in a marine critter; shrimp that live within sponges.  You may have seen Emmett’s footage of this in the David Attenborough movie “Blue Planet”.  You can read about Emmett’s research here and his awesome blog the Natural Patriot here.

Ill exerpt some of Emmet’s article on “The Future of Marine Fish Resources” below.  Read the full articles here.

Currently, fishing pressure appears to be near—if not beyond—the ocean’s capacity to provide. Estimates based on fisheries catch data, which were corrected for over-reporting by China, suggest that global fish catch peaked in the late 1980s, and this number has remained flat or begun to decline since.1,9The Food and Agricultural Organization of the United Nations (FAO) conducts the most comprehensive analysis of global fish stocks every four years, and recently reported that “the maximum wild capture fisheries potential from the world’s oceans has probably been reached.”1 The situation is reminiscent of society’s reaching the point of peak oil—although fishery production is at least partially a renewable resource.

What about individual fish stocks? In 2008, the FAO estimated that roughly half of the world’s 523 assessed fishery stocks are “fully exploited,” meaning that they are harvested at rates near their maximum sustainable limits, while another 28% are “overexploited or depleted,” meaning that they are being harvested at rates not sustainable in the long term.1 Even these numbers are uncertain and possibly conservative since they do not include many small-scale commercial and artisanal tropical fisheries; furthermore, these numbers do not include stocks that have already collapsed and been abandoned.

Australian emissions proposal divides Copenhagen


Australia has led the charge on proposed land-use rule changes to the new global climate deal. The changes would open the door to the bonanza of green carbon that could be stored away in the world’s rural lands. UN figures show Australia’s greenhouse gas emissions have risen by 82 per cent since 1990, largely as a result of bushfires and drought. An Australian climate change negotiator has reportedly said the country could cut its emissions by 25 per cent by 2020 if it could count land use changes.

But the move is deeply dividing the Copenhagen conference, as Australia – and other big players – have been accused of trying to pull off an accounting rort. Australian Greens Senator Christine Milne, who is in Copenhagen, says the proposal is dishonest. (Read More)

“You need to reduce your emissions from fossil fuels and you need to sequester carbon in the landscape and protect your forests as carbon stores, but that isn’t happening,” she said.

“What we are seeing is dishonest systems so that we’re going to end up with something that doesn’t actually save the climate.”

AP Review: E-mails show pettiness, not fraud

Climate experts, AP reporters go through 1,000 exchanges

Also see our posts on this matter here, here, here and here

BY SETH BORENSTEIN, RAPHAEL SATTER and MALCOLM RITTER 
Associated Press Writers

LONDON (AP) — E-mails stolen from climate scientists show they stonewalled skeptics and discussed hiding data – but the messages don’t support claims that the science of global warming was faked, according to an exhaustive review by The Associated Press.

The 1,073 e-mails examined by the AP show that scientists harbored private doubts, however slight and fleeting, even as they told the world they were certain about climate change. However, the exchanges don’t undercut the vast body of evidence showing the world is warming because of man-made greenhouse gas emissions.

The scientists were keenly aware of how their work would be viewed and used, and, just like politicians, went to great pains to shape their message. Sometimes, they sounded more like schoolyard taunts than scientific tenets.

The scientists were so convinced by their own science and so driven by a cause “that unless you’re with them, you’re against them,” said Mark Frankel, director of scientific freedom, responsibility and law at the American Association for the Advancement of Science. He also reviewed the communications.

Frankel saw “no evidence of falsification or fabrication of data, although concerns could be raised about some instances of very ‘generous interpretations.'”

Some e-mails expressed doubts about the quality of individual temperature records or why models and data didn’t quite match. Part of this is the normal give-and-take of research, but skeptics challenged how reliable certain data was.

The e-mails were stolen from the computer network server of the climate research unit at the University of East Anglia in southeast England, an influential source of climate science, and were posted online last month. The university shut down the server and contacted the police.

The AP studied all the e-mails for context, with five reporters reading and rereading them – about 1 million words in total.

One of the most disturbing elements suggests an effort to avoid sharing scientific data with critics skeptical of global warming. It is not clear if any data was destroyed; two U.S. researchers denied it.

The e-mails show that several mainstream scientists repeatedly suggested keeping their research materials away from opponents who sought it under American and British public records law. It raises a science ethics question because free access to data is important so others can repeat experiments as part of the scientific method. The University of East Anglia is investigating the blocking of information requests.

“I believe none of us should submit to these ‘requests,'” declared the university’s Keith Briffa. The center’s chief, Phil Jones, wrote: “Data is covered by all the agreements we sign with people, so I will be hiding behind them.”

When one skeptic kept filing FOI requests, Jones, who didn’t return AP requests for comment, told another scientist, Michael Mann: “You can delete this attachment if you want. Keep this quiet also, but this is the person who is putting FOI requests for all e-mails Keith (Briffa) and Tim (Osborn) have written.”

Mann, a researcher at Penn State University, told The Associated Press: “I didn’t delete any e-mails as Phil asked me to. I don’t believe anybody else did.”

The e-mails also show how professional attacks turned very personal. When former London financial trader Douglas J. Keenan combed through the data used in a 1990 research paper Jones had co-authored, Keenan claimed to have found evidence of fakery by Jones’ co-author. Keenan threatened to have the FBI arrest University at Albany scientist Wei-Chyung Wang for fraud. (A university investigation later cleared him of any wrongdoing.)

“I do now wish I’d never sent them the data after their FOIA request!” Jones wrote in June 2007.

In another case after initially balking on releasing data to a skeptic because it was already public, Lawrence Livermore National Lab scientist Ben Santer wrote that he then opted to release everything the skeptic wanted – and more. Santer said in a telephone interview that he and others are inundated by frivolous requests from skeptics that are designed to “tie-up government-funded scientists.”

The e-mails also showed a stunning disdain for global warming skeptics.

One scientist practically celebrates the news of the death of one critic, saying, “In an odd way this is cheering news!” Another bemoans that the only way to deal with skeptics is “continuing to publish quality work in quality journals (or calling in a Mafia hit.)” And a third scientist said the next time he sees a certain skeptic at a scientific meeting, “I’ll be tempted to beat the crap out of him. Very tempted.”

And they compared contrarians to communist-baiting Sen. Joseph McCarthy and Somali pirates. They also called them out-and-out frauds.

Santer, who received death threats after his work on climate change in 1996, said Thursday: “I’m not surprised that things are said in the heat of the moment between professional colleagues. These things are taken out of context.”

When the journal, Climate Research, published a skeptical study, Penn State scientist Mann discussed retribution this way: “Perhaps we should encourage our colleagues in the climate research community to no longer submit to, or cite papers in, this journal.”

That skeptical study turned out to be partly funded by the American Petroleum Institute.

The most provocative e-mails are usually about one aspect of climate science: research from a decade ago that studied how warm or cold it was centuries ago through analysis of tree rings, ice cores and glacial melt. And most of those e-mails, which stretch from 1996 to last month, are from about a handful of scientists in dozens of e-mails.

Still, such research has been a key element in measuring climate change over long periods.

As part of the AP review, summaries of the e-mails that raised issues from the potential manipulation of data to intensely personal attacks were sent to seven experts in research ethics, climate science and science policy.

“This is normal science politics, but on the extreme end, though still within bounds,” said Dan Sarewitz, a science policy professor at Arizona State University. “We talk about science as this pure ideal and the scientific method as if it is something out of a cookbook, but research is a social and human activity full of all the failings of society and humans, and this reality gets totally magnified by the high political stakes here.”

In the past three weeks since the e-mails were posted, longtime opponents of mainstream climate science have repeatedly quoted excerpts of about a dozen e-mails. Republican congressmen and former vice presidential candidate Sarah Palin have called for either independent investigations, a delay in U.S. Environmental Protection Agency regulation of greenhouse gases or outright boycotts of the Copenhagen international climate talks. They cited a “culture of corruption” that the e-mails appeared to show.

That is not what the AP found. There were signs of trying to present the data as convincingly as possible.

One e-mail that skeptics have been citing often since the messages were posted online is from Jones. He says: “I’ve just completed Mike’s (Mann) trick of adding in the real temps to each series for the last 20 years (from 1981 onward) and from 1961 for Keith’s to hide the decline.”

Jones was referring to tree ring data that indicated temperatures after the 1950s weren’t as warm as scientists had determined.

The “trick” that Jones said he was borrowing from Mann was to add the real temperatures, not what the tree rings showed. And the decline he talked of hiding was not in real temperatures, but in the tree ring data which was misleading, Mann explained.

Sometimes the data didn’t line up as perfectly as scientists wanted.

David Rind told colleagues about inconsistent figures in the work for a giant international report: “As this continuing exchange has clarified, what’s in Chapter 6 is inconsistent with what is in Chapter 2 (and Chapter 9 is caught in the middle!). Worse yet, we’ve managed to make global warming go away! (Maybe it really is that easy…:).”

But in the end, global warming didn’t go away, according to the vast body of research over the years.

None of the e-mails flagged by the AP and sent to three climate scientists viewed as moderates in the field changed their view that global warming is man-made and a threat. Nor did it alter their support of the conclusions of the Intergovernmental Panel on Climate Change, which some of the scientists helped write.

“My overall interpretation of the scientific basis for (man-made) global warming is unaltered by the contents of these e-mails,” said Gabriel Vecchi, a National Oceanic and Atmospheric Administration scientist.

Gerald North, a climate scientist at Texas A&M University, headed a National Academy of Sciences study that looked at – and upheld as valid – Mann’s earlier studies that found the 1990s were the hottest years in centuries.

“In my opinion the meaning is much more innocent than might be perceived by others taken out of context. Much of this is overblown,” North said.

Mann contends he always has been upfront about uncertainties, pointing to the title of his 1999 study: “Northern Hemisphere Temperatures During the Past Millennium: Inferences, Uncertainties and Limitations.”

Several scientists found themselves tailoring their figures or retooling their arguments to answer online arguments – even as they claimed not to care what was being posted to the Internet

“I don’t read the blogs that regularly,” Jonathan Overpeck of the University of Arizona wrote in 2005. “But I guess the skeptics are making hay of their (sic) being a global warm (sic) event around 1450AD.”

One person singled out for criticism in the e-mails is Steve McIntyre, who maintains Climate Audit. The blog focuses on statistical issues with scientists’ attempts to recreate the climate in ancient times.

“We find that the authors are overreaching in the conclusions that they’re trying to draw from the data that they have,” McIntyre said in a telephone interview.

McIntyre, 62, of Toronto, was trained in math and economics and says he is “substantially retired” from the mineral exploration industry, which produces greenhouse gases.

Some e-mails said McIntyre’s attempts to get original data from scientists are frivolous and meant more for harassment than doing good science. There are allegations that he would distort and misuse data given to him.

McIntyre disagreed with how he is portrayed. “Everything that I’ve done in this, I’ve done in good faith,” he said.

He also said he has avoided editorializing on the leaked e-mails. “Anything I say,” he said, “is liable to be piling on.”

The skeptics started the name-calling said Mann, who called McIntyre a “bozo,” a “fraud” and a “moron” in various e-mails.

“We’re human,” Mann said. “We’ve been under attack unfairly by these people who have been attempting to dismiss us as frauds as liars.”

The AP is mentioned several times in the e-mails, usually in reference to a published story. One scientist says his remarks were reported with “a bit of journalistic license” and “I would have rephrased or re-expressed some of what was written if I had seen it before it was released.” The archive also includes a request from an AP reporter, one of the writers of this story, for reaction to a study, a standard step for journalists seeking quotes for their stories.

Associated Press writers Jeff Donn in Boston, Justin Pritchard in Los Angeles contributed to this report. Troy Thibodeaux in Washington provided technical assistance. Satter reported from London, Borenstein from Washington and Ritter from New York.