BLOGGER'S NOTE: Be sure to click on the graphic to enlarge it. Note the severe pullback in the snow cover on the southwestern coast of Greenland -- Greenland is experiencing temperatures similar to the record-breaking temperatures of 1998. Note that it is not possible to use the site to compare the snow cover in 1998, as that data was not available.
Link to site: http://igloo.atmos.uiuc.edu/cgi-bin/test/print.sh?fm=05&fd=29&fy=2007&sm=05&sd=29&sy=2008
HOUSTON — The Rockefeller family built one of the great American fortunes by supplying the nation with oil. Now history has come full circle: some family members say it is time to start moving beyond the oil age.
Neva Rockefeller Goodwin and Peter O’Neill, descendants of John D. Rockefeller, are among those who want Exxon to shift priorities. Shareholders will vote Wednesday on four resolutions.
Rex W. Tillerson, the chief executive of Exxon, stands to lose his job as chairman of the company if a resolution passes.
The family members have thrown their support behind a shareholder rebellion that is ruffling feathers at Exxon Mobil, the giant oil company descended from John D. Rockefeller’s Standard Oil Trust.
Three of the resolutions, to be voted on at the company’s shareholder meeting on Wednesday, are considered unlikely to pass, even with Rockefeller family support.
The resolutions ask Exxon to take the threat of global warming more seriously and look for alternatives to spewing greenhouse gases into the air.
One resolution would urge the company to study the impact of global warming on poor countries, another would encourage Exxon to reduce its emissions and a third would encourage it to do more research on renewable energy sources like solar panels and wind turbines.
A fourth resolution, which the Rockefellers are most united in supporting, is considered more likely to pass. It would strip Rex W. Tillerson of his position as chairman of Exxon’s board, forcing the company to separate that job from the chief executive’s job.
A shareholder vote in favor of that idea would be a rebuke of Mr. Tillerson, who is widely perceived as more resistant than other oil chieftains to investing in alternative energy.
The Rockefellers say they are not trying to embarrass Mr. Tillerson, also Exxon’s chief executive, but think it is time for the company to spend more of its funds helping the nation chart a new energy future.
“Exxon Mobil needs to reconnect with the forward-looking and entrepreneurial vision of my great-grandfather,” Neva Rockefeller Goodwin, a Tufts University economist, said in a statement to reporters.
“The truth is that Exxon Mobil is profiting in the short term from investments and decisions made many years ago, and by focusing on a narrow path that ignores the rapidly shifting energy landscape around the world,” she added.
The resolution on Exxon’s chairmanship was offered for several years before the Rockefellers became publicly involved and last year was supported by 40 percent of shareholders who voted. Royal Dutch Shell and BP already separate the positions of chairman and chief executive, as do many other companies.
“You need a board asking the tough questions,” Peter O’Neill, a private equity investor and great-great-grandson of John D. Rockefeller, said in an interview. “We expect the company to figure out how in this changing world to adjust.”
Kenneth P. Cohen, vice president for public affairs at Exxon, said the shareholders pushing the resolutions were “starting from a false premise.” He added that the company was already concerned about “how to provide the world the energy it needs while at the same time reducing fossil fuel use and greenhouse gas emissions.”
Fifteen members of the family are sponsoring or co-sponsoring the four resolutions, but it appears that some have much more solid support in the sprawling family than others.
Mr. O’Neill said that 73 out of 78 adult descendants of John D. Rockefeller were supporting the family effort to divide the chief executive and chairman positions. The goal of that resolution is to improve the management of the company, which could strengthen its environmental policies and improve more traditional pursuits like exploring more aggressively for new oil reserves.
David Rockefeller, retired chairman of Chase Manhattan Bank and patriarch of the family, issued a statement saying, “I support my family’s efforts to sharpen Exxon Mobil’s focus on the environmental crisis facing all of us.”
The Rockefeller family has always been identified with oil and the legacy of Standard Oil, but for several generations, it has also been active in environmental causes and acquiring land for preservation. John D. Rockefeller’s grandsons devoted themselves to conservation issues, and Rockefeller charitable organizations have long promoted efforts to fight pollution.
Ms. Goodwin, one of the most vocal Rockefellers on the environment today, is co-director of the Global Development and Environment Institute at Tufts.
In recent years, family members have quietly encouraged Exxon executives to take global warming seriously, but their private efforts did not go far. Until now, they have avoided publicity in their efforts, and the youngest Rockefeller generations have generally shunned attention.
Exxon executives said the company spent $2 billion over the last five years on programs to reduce emissions and improve efficiencies and had plans to spend $800 million on similar initiatives over the next three years. They said the company reduced the release of greenhouse gases from its operations last year by 3 percent, and it was working with Stanford to research biofuels and solar and hydrogen energy.
Since taking over the company two years ago, Mr. Tillerson has gradually shifted the company’s positions away from those of his predecessor, Lee R. Raymond, who was considered a skeptic on the science of global warming.
But with gasoline prices soaring and concern growing over global warming, Exxon, the biggest of the investor-owned oil companies, is a target for politicians and environmentalists. Chevron, BP and Shell, Exxon’s largest competitors, have given their investments in renewable fuels a much higher profile.
Similar or identical environmental proposals have not passed at previous Exxon shareholder meetings, but the public support of the Rockefeller family has given old efforts new energy.
The involvement of the Rockefellers, said Robert A. G. Monks, a shareholder who has been urging a separation of the chairman and chief executive jobs for years, shows that “this is not just a matter of the self-appointed good guys against the cavemen, but also a matter of the capitalists wanting to make money.”
Nineteen institutional investors with 91 million shares announced last week that they would support resolutions asking Exxon to separate the top executive positions and tackle global warming. They included the California Public Employees’ Retirement System, the California State Teachers’ Retirement System and the New York City Employees’ Retirement System.
California’s treasurer, Bill Lockyer, who serves on the boards of the two California funds, said the company’s “go-slow approach” on global warming “places long-term shareholder value at risk.”
Under Exxon’s rules, a shareholder proposal that passes is not binding without the support of the board. But Andrew Logan, director of the oil program at Ceres, a coalition of institutional investors and environmentalists, said, “boards tend to strongly consider proposals that get significant support.”
Paul Sankey, an oil analyst at Deutsche Bank, said that he thought a separation of the chief executive and chairman jobs might be a good management move and that “we might see a mild benefit to Exxon’s public image.” But he added, “On balance, we wouldn’t expect any change in strategy.”
The Fraternal Order of Police, which represents public safety officers, whose pensions are invested in Exxon, has publicly opposed the shareholder effort to change company policy.
“The Rockefeller resolution threatens to degrade the value of Exxon Mobil,” the organization wrote in a letter to Mr. Tillerson that criticized the splitting of the top executive jobs.
Link to article: http://www.nytimes.com/2008/05/27/business/27exxon.html?ref=environment
I spent a few minutes Wednesday with F. Sherwood Rowland, the atmospheric chemist from the University of California, Irvine, who shared a Nobel Prize for his work revealing the threat to the ozone layer from CFC’s and similar synthetic chemicals. He has a very sobering forecast for levels of carbon dioxide in the atmosphere.
He’s in New York for the World Science Festival, along with a large flock of Nobel laureates and other luminaries. We discussed the body of science pointing to troubles ahead from rising carbon dioxide levels during a break after Mayor Michael R. Bloomberg’s speech on the “tragic lag between what we know and what we do.”
The seasonal ozone “hole.” (NASA)The response to the threat from CFC’s — a treaty and phaseout that is working — has been held up as a model for what humanity can do with carbon dioxide, the main emission linked to warming and the biggest threat, because of its long lifetime in the air, to drive temperatures dangerously higher. But Dr. Rowland, along with others at the meeting, including Steven Chu, a Nobel laureate and director of the Lawrence Berkeley National Laboratory, said there are big differences.
The main one is that CFC’s were produced by a handful of companies and affordable substitutes were within reach. (And nature provided a stark warning with the unpredicted “hole” in the ozone layer over Antarctica.) Carbon dioxide emissions result from almost every activity in lives both prosperous and poor — from burning forests to microwaving popcorn or flying to Tokyo.
That linkage between emissions and lifestyles is one reason the concentration of the gas has been rising relentlessly, to around 385 parts per million now after never topping 280 parts per million for at least 650,000 years. (United States emissions from energy use dropped slightly in 2006 but yesterday the Energy Department reported they rose 1.6 percent in 2007.)
Avoiding a lot of warming and climate change while heading toward 9 billion people seeking a decent life will require an utter transformation of the multi-trillion-dollar energy system, Dr. Chu said. An audience member wondered whether spiking gas prices would propel the change. Dr. Chu said higher energy prices would not be enough on their own, adding that the necessary energy transformation will also require decades of sustained research, development, and deployment of new technologies.
During a break, I asked Dr. Rowland two quick questions. The first: Given the nature of the climate and energy challenges, what is his best guess for the peak concentration of carbon dioxide?
(Keep in mind that various experts and groups have said risks of centuries of ecological and economic disruption rise with every step toward and beyond 450 parts per million, with some scientists, most notably James Hansen of NASA, saying the long-term goal should be returning the atmospheric concentration to 350 parts per million, a level passed in 1988.)
His answer? “1,000 parts per million,” he said.
My second question was, what will that look like?
“I have no idea,” Dr. Rowland said. He was not smiling.
Link to article: http://dotearth.blogs.nytimes.com/2008/05/29/nobel-winner-co2-going-to-1000-parts-per-million
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1 Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543, USA
2 College of Oceanic and Atmospheric Sciences, Oregon State University, Corvallis, Oregon 97331, USA
3 Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543, USA
4 GEOTOP, Université du Québec à Montréal, CP 8888, Montreal, Quebec H3C 3P8, Canada
The retreat of the southern Greenland Ice Sheet (GIS) during the last deglaciation (Termination I: TI) is poorly dated by conventional means; there is even greater uncertainty about the penultimate deglaciation (Termination II: TII), leading to the assumption that the southern GIS has a significant lag in its response to deglacial warming. Here we use geochemical terrestrial sediment proxies ([Fe] and [Ti]) from a well-studied southern Greenland marine sediment sequence to examine the behavior of the southern GIS during TI and TII. Our records show that during TI and TII the southern GIS response was essentially synchronous with deglacial North Atlantic warming, implying greater climate sensitivity than previously assumed. During TI, elevated ablation lasted ~5 k.y., whereas ablation remained elevated for ~12 k.y. during TII, suggesting a reduced southern GIS during TII that contributed a significant fraction of the higher sea level during the subsequent interglacial.
Key Words: southern Greenland Ice Sheet • deglaciation • sea level • ice sheet response
Link to article: http://earthobservatory.nasa.gov/Newsroom/NasaNews/2008/2008050726747.html
by George Monbiot, The Guardian, November 14, 2006
Deniers are cock-a-hoop at an aristocrat's claims that global warming is a UN hoax. But the physics is bafflingly bad
Published in two parts on consecutive Sundays, it runs to a total of 52 pages, containing graphs, tables and references. To my correspondents, to a good many journalists and to thousands of delighted bloggers, this paper clinches it: climate change is a hoax perpetrated by a leftwing conspiracy coordinated by the United Nations.
So which was the august journal that published it? Science? Nature? Geophysical Research Letters? Not quite. It was the Sunday Telegraph. In keeping with most of the articles about climate change in that publication, it is a mixture of cherry-picking, downright misrepresentation and pseudo-scientific gibberish. But it has the virtue of being incomprehensible to anyone who is not an atmospheric physicist.
The author of this "research article" is Christopher Monckton, otherwise known as Viscount Monckton of Brenchley. He has a degree in classics and a diploma in journalism and, as far as I can tell, no further qualifications. But he is confident enough to maintain that -- by contrast to all those charlatans and amateurs who wrote the reports produced by the UN's Intergovernmental Panel on Climate Change -- he is publishing "the truth."
The warming effects of carbon dioxide, Lord Monckton claims, have been exaggerated, distorted and made up altogether. One example of the outrageous fraud the UN body has committed is the elimination from its temperature graphs of the "medieval warm period," which, he claims, was "real, global and up to 3C warmer than now." He runs two graphs side by side, one of which shows the temperature record over the past 1,000 years as rendered by the UN panel, and the other purporting to show real temperatures over the same period.
The world was so hot 600 years ago, he maintains, that "there was little ice at the North Pole: a Chinese naval squadron sailed right round the Arctic in 1421 and found none." By contrast, the planet is currently much cooler than climate scientists predicted. In 1988, for example, the world's most celebrated climatologist, James Hansen of NASA, "told the US Congress that temperature would rise 0.3C by the end of the century (it rose 0.1C), and that sea level would rise several feet (no, one inch)."
Most importantly, "the UN repealed a fundamental physical law," doubling the size of the constant (lambda) in the Stefan-Boltzmann equation. By assigning the wrong value to lambda, the UN's panel has exaggerated the sensitivity of the climate to extra carbon dioxide. Monckton's analysis looks impressive. It is nonsense from start to finish.
His claims about the Stefan-Boltzmann equation have been addressed by someone who does know what he's talking about, Dr Gavin Schmidt of NASA's Goddard Institute for Space Studies. He begins by pointing out that Stefan-Boltzmann is a description of radiation from a "black body"- - an idealised planet that absorbs all the electromagnetic radiation that reaches it. The Earth is not a black body. It reflects some of the radiation it receives back into space.
Schmidt points out that Monckton also forgets, in making his calculations, that "climate sensitivity is an equilibrium concept": in other words that there is a time-lag of several decades between the release of carbon dioxide and the eventual temperature rise it causes. If you don't take this into account, the climate's sensitivity to carbon dioxide looks much smaller. This is about as fundamental a mistake as you can make in climate science.
What of his other claims? Well, the reason the "medieval warm period" doesn't show up on the UN panel's graphs is simple. As far as climatologists can tell, there wasn't one. So why did the Vikings, as Monckton points out, settle in Greenland?
As a paper published in Reviews of Geophysics shows, Vikings first arrived in Greenland at the very beginning of the "warm period" Monckton discusses, when temperatures, even according to his graph, were lower than they are today. They did so because life had become too hot for them in their adopted home (Iceland): not climatically, but politically. There does appear to have been a slight warming in some parts of the northern hemisphere. There is no reliable evidence that this was a global phenomenon. As for the Chinese naval squadron sailing round the Arctic, it is pure bunkum -- a myth long discredited by serious historians.
So what of those graphs? Look at them carefully and you see that they are measuring two different things: global temperatures (the UN panel's progression) and European temperatures (Monckton's line). You will also discover that the scales are different.
As for James Hansen, he did not tell the US Congress that temperatures would rise by 0.3C by the end of the past century. He presented three possible scenarios to the US Senate -- high, medium and low. Both the high and low scenarios, he explained, were unlikely to materialise. The middle one was "the most plausible."
As it happens, the middle scenario was almost exactly right. He did not claim, under any scenario, that sea levels would rise by several feet by 2000. But a climatologist called Patrick Michaels took the graph from Hansen's paper, erased the medium and low scenarios and -- in testimony to Congress -- presented the high curve as Hansen's prediction for climate change. A memo sent in July from the Intermountain Rural Electric Association, a US company whose power is largely supplied by coal, revealed that Michaels has long been funded by electricity companies. "In February this year, IREA alone contributed $100,000 to Dr Michaels." Michaels, it says, meets periodically with industry representatives to discuss their activities in countering stories about climate change.
Pat Michaels's misrepresentation of Hansen's claims was picked up by Michael Crichton in his novel State of Fear, and somehow transmuted into an "error" of 300%. Monckton gives no source for his claim about Hansen, but Crichton's novel features in his references. The howlers go on and on. There is scarcely a line in Lord Monckton's paper which is not wildly wrong.
Yet none of this appears to embarrass the Sunday Telegraph, which championed his findings this week in a leading article. I think I know what the problem is. At a meeting of 150 senior journalists last year, who had gathered to discuss climate change, the chairman asked how many people in the audience had a science degree. Three of us raised our hands. Readers cannot expect a newspaper editor to possess a detailed understanding of atmospheric physics, but there should at least be someone who knows what science looks like whom the editor consults before running a piece.
A scientific paper is one published in a peer-reviewed scientific journal. This means it has been subject to scrutiny by other experts in the field. This doesn't suggest that it's the last word on the subject, but it does mean it is worth discussing. For newspapers such as the Sunday Telegraph the test seems to be much simpler. If they don't understand it, it must be science.
Link to article: http://www.guardian.co.uk/commentisfree/2006/nov/14/science.comment
Links to more of George Monbiot's writings: http://www.guardian.co.uk/profile/georgemonbiot
Update from May 26: a blogger from Holland, Leon, has sent a very interesting link to an animation of the last 30 days of 500-hPa height anomalies above the Arctic -- for those who understand such things or who just want to have a look, here is the link (you can see where Greenland is taking a beating):
by Jane George, Nunatsiaq News, May 23, 2008
Forecasts show Coast Guard icebreakers will no longer be necessary for shipping to Churchill after July 16.
That's 15 days earlier than the average ice-free shipping date of July 31, which means re-supply barges should able to reach communities in Nunavut's Kivalliq and Kitikmeot regions that much earlier.
But the down side to the retreat of the Arctic's thin ice cover is a 50-50 chance that the North Pole will become ice-free this September - for the first time in more than 100,000 years.
"The North Pole is where there's supposed to be ice," said environmental scientist Mark Serreze in a recent telephone interview from the U.S. National Snow and Ice Data Center in Colorado.
Scientists like Serreze say the weakness of the ice that's melting is responsible for the retreat of Arctic sea ice.
As old ice melts, a development linked to rising water and air temperatures, the new, thin ice that forms in its place in the winter tends to melt much more rapidly in the spring and summer.
During the month of April, scientists determined that the Arctic's increasingly flimsy sea ice cover shrank by 6,000 square kilometres every day.
If this ice continues to melt at the same rate as in 2007, scientists predict that only 2.22 million sq km of ice - less than the size of Nunavut - will remain in the Arctic Ocean this September. This would be much less than the record low of 4.28 million sq km set in 2007.
A major concern is whether the Arctic ice melt has reached a "tipping point," where even tough measures to curb global warming won't stop its final retreat.
After this tipping point is reached, the Arctic Ocean is expected to settle into an ice-free state every summer.
Tipping points were the hot topic at last week's Arctic Forum conference in Washington, D.C., where scientists looked at the potential consequences of these "points of no return" on the environment and people.
The impact of tipping points may explain why the Norse in Greenland died out during the 1400s.
The Norse settlers were unable to deal with several changes occurring at the same time, suggested researcher Tom McGovern in his talk, "Well adapted but still extinct: Norse Greenland in new perspective."
Today's sea ice loss is expected to deliver many environmental changes, which will compound other social, economic and political stresses in the circumpolar world.
New scientific information about Arctic sea ice loss played into last week's decision by the United States Fish and Wildlife Service to list polar bears as "threatened."
Scientists expect that as sea ice thins, melts and retreats, open water will allow even more heat to enter the Arctic Ocean. This warmer ocean will in turn heat the land and melt glaciers where they flow into the water.
As Greenland's ice sheet melts, sea levels may rise, threatening many coastal, low-lying communities.
The stream of icebergs, recently seen off Newfoundland and Labrador, originate from glaciers in Greenland. Scientists suspect these icebergs reflect the breakdown of the island's huge ice sheet, which is occurring many times faster than scientists believed possible.
Over the short term, an ice-free Arctic Ocean will open up new possibilities, including easier access to natural resources and new transportation routes.
The Northern sea route, the shipping lane from the Atlantic Ocean to the Pacific Ocean along the Siberian coast, is expected to open up this summer, and the Northwest Passage through Nunavut waters is also likely to be navigable by August.
Link to article: http://www.nunatsiaq.com/archives/2008/805/80523/news/climate/80523_1219.html
Large Lakes Observatory and Department of Geological Sciences, University of Minnesota Duluth, Duluth, MN 55812
The Younger Dryas interval, a cold snap that chilled many parts of the world for 1,500 years or so in the midst of the last deglaciation (
The Younger Dryas began and ended abruptly, at least as indicated in ice core records from Greenland, where temperature initially may have fallen by 15°C, with transitions no longer than a few decades (2); most of the final (warming) transition may have occurred in just a few years (3). At just about the time of the inception of the Younger Dryas, a major change in the routing of meltwater from the Laurentide Ice Sheet in North America seems to have occurred. The outlet of glacial Lake Agassiz, which fronted the Laurentide Ice Sheet across a vast section of the continental interior, appeared to have switched from Mississippi River drainage (and thence to the Gulf of Mexico) eastward to the Laurentian Great Lakes (and thence to the St. Lawrence River and the North Atlantic Ocean). The switch in outlets was accompanied by a major (>40 m) initial drawdown of Lake Agassiz during its Moorhead Phase, perhaps eventually reaching as much as 150 m below the southern outlet (4). The switch was also accompanied (within the uncertainties of radiocarbon dating) by an abrupt change in oxygen isotopes in the Gulf of Mexico (documented in many studies, most recently in ref. 5), interpreted as resulting from an increase in seawater salinity that accompanied the removal of Agassiz drainage down the Mississippi. Indeed, together with a plausible route for the eastern outflow, the evidence for an eastward switch in drainage seemed compelling. Ocean climate modeling studies (e.g., see references in ref. 6) suggested that the estimated increase in freshwater input to the North Atlantic would be sufficient to suppress Atlantic meridional overturning circulation, distinctly cooling the region where the Younger Dryas is best documented, as well as other areas. Oceanic proxy evidence for a slowdown or cessation of
The Younger Dryas began and ended abruptly with transitions no longer than a few decades.
Nevertheless, the inference that eastward routing of Lake Agassiz discharge was the cause of the Younger Dryas has not been without its problems. Isotopic evidence for a freshening of the North Atlantic off the mouth of the St. Lawrence has been equivocal at best (8, 9). In addition, the effect of Lake Agassiz inflow on the sediments of the Laurentian Great Lakes has not been clear; sedimentological and isotopic evidence from Lake Michigan was interpreted as a signal of Lake Agassiz inflow (10), whereas similar kinds of data from the Huron basin were interpreted differently (11).
Despite these difficulties, eastward routing of Lake Agassiz discharge as the trigger for the Younger Dryas was widely accepted. Until recently, the main issues were whether Younger Dryas meltwater rerouting provided an analog for mechanisms to explain earlier abrupt climate changes when the ice sheets were of intermediate size (12) and whether the changes in ocean circulation during the Younger Dryas were mostly due to the long-term increase in base discharge (12), the postulated initial catastrophic flood (13), or a combination of the two (6).
Troubles with the conventional wisdom began with recent expeditions to the remote terrain postulated as the route of the catastrophic eastward drainage of Lake Agassiz at the beginning of the Younger Dryas. These observations failed to find geomorphic evidence of major flood channels or depositional features (14). In addition, new radiocarbon and cosmogenic radionuclide dating on glacial features south of the proposed outlet suggested that the outlet area was not deglaciated until after the start of the Younger Dryas (14). Finally, new ages related to the Moorhead Phase of Lake Agassiz have been interpreted to mean that this phase occurred significantly after the start of the Younger Dryas (15). On the other hand, complexities exist in the geomorphic interpretations, and virtually all of the ages on glacial features are minimum ages or have large uncertainties (16). The differences in interpretation have wide-ranging climatic and oceanographic implications (7).
Given the well documented, if poorly dated, drawdown of Lake Agassiz during its Moorhead Phase, the massive amounts of water involved had to go somewhere. Some researchers have suggested that the water discharged through the northwestern Clearwater Outlet to the Arctic Ocean, although there are chronological problems with this scenario (7, 16). The new data presented by Carlson et al. (1) strongly suggest that the water did indeed discharge eastward, eventually through the St. Lawrence estuary. They use three different geochemical signatures of ambient water, preserved as trace elements in the shells of foraminifera eventually buried in dated sediment. Each of the geochemical tracers indicates a source of water from the Canadian interior plains, i.e., the drainage basin of Lake Agassiz. The authors also attempt deconvolve complex stable-isotope proxies in a way that is consistent with the geochemical tracers. The isotope exercise is less convincing because the isotope ratios depend in a complex way on temperature and salinity, as well as on the isotopic composition of river and ocean water. The interpretation of each tracer or proxy has its complications, but taken together, they make a strong case for major Lake Agassiz discharge through the St. Lawrence. The chronology for their sediment cores is good enough for Carlton et al. to argue convincingly that a surge in Lake Agassiz discharge through the St. Lawrence estuary coincided with the start of the Younger Dryas. Moreover, the authors were able to use mixing models with the geochemical tracer data to quantitatively estimate the amount of the Lake Agassiz discharge and how it varied with time (see Fig. 1). They infer substantial variations in discharge within the Younger Dryas interval. Although other studies have suggested variation in climate, vegetation, and ocean processes during the Younger Dryas (e.g., ref. 17, as well as the references cited by Carlson et al.), this is the first estimation, independent of changes in the level of Lake Agassiz itself, of quantitative variation in the purported driver of climate change at the time: discharge of fresh water to the North Atlantic.
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The question of the route of the discharge from Lake Agassiz to Lake Superior at the beginning of the Younger Dryas is still problematic. Seismic stratigraphic studies beneath Lake Superior are underway to help address this issue. The classical story of the switch from southward to eastward drainage of Lake Agassiz involved an initial massive and catastrophic flood (13). Carlson et al. (1) make no mention of this flood and instead explain their record entirely on the basis of increases and decreases in base flow down the St. Lawrence. Therein may lie an explanation for the lack of spectacular flood canyons on the drainage route to the east, such as those that are related to a younger, post-Younger Dryas drainage event. If the drawdown during the Moorhead Phase took place gradually (over decades to a couple of centuries, not resolvable in the records of Carlson et al.), the discharge may not have formed pronounced geomorphic features (16). If the discharge occurred near the ice margin but under (or over) the ice (7), bedrock erosion and large-scale depositional forms would also be minimized.
Whatever the issues that remain, the article by Carlson et al. (1) is a major contribution to the controversy over the Younger Dryas cold interval, and it is sure to stimulate a great deal of follow-up research. As for the recent differences of opinion that have arisen from reexamining the accepted history of the Younger Dryas, they have generated much new research, including the article by Carlson et al. Other creative theories, including the possibility of an extraterrestrial impact at this time,
Footnotes
Author contributions: S.M.C. wrote the paper.
The author declares no conflict of interest.
See companion article on page 6556. Click on the page number to go to the original article by Carlson et al.
| by Richard Black, Environment correspondent, BBC News website, May 23, 2008 |
 The Zeppelin station was among those showing a significant rise |
Higher atmospheric levels of the greenhouse gas methane noted last year are probably related to emissions from wetlands, especially around the Arctic.
Scientists have found indications that extra amounts of the gas in the Arctic region are of biological origin.
Global levels of methane had been roughly stable for almost a decade.
Rising levels in the Arctic could mean that some of the methane stored away in permafrost is being released, which would have major climatic implications.
The gas is about 25 times more potent than carbon dioxide as a greenhouse gas, though it survives for a shorter time in the atmosphere before being broken down by natural chemical processes.
Northern lights
Indications that methane levels might be rising after almost a decade of stability came last month, when the US National Oceanic and Atmospheric Administration (NOAA) released a preliminary analysis of readings taken at monitoring stations worldwide.
NOAA suggested that 2007 had seen a global rise of about 0.5%.
Some stations around the Arctic showed rises of more than double that amount.
One is the station at Mount Zeppelin in Svalbard, north of Scandinavia.
In addition to the long-term monitoring carried out there by Norway and Sweden, a British team has recently started gathering samples and analysing them in a way that could reveal where the methane is coming from.
Methane produced by bacteria contains a high proportion of molecules with the lighter form (isotope) of carbon, carbon-12, rather than the heavier form, carbon-13.
 |  I think 2007 is probably down to wetland emissions  Ed Dlugokencky, NOAA |
"Anything where bacteria form methane, you get depletion in C-13 because methanogens (the bacteria) preferentially use C-12," said Rebecca Fisher from Royal Holloway, University of London, who has been running the Svalbard experiments.
"The results we have so far imply a predominantly biogenic source," she told BBC News.
The researchers also match methane levels with wind direction, so they can see where the gas is being produced. This analysis also implies a source in the Arctic regions, rather than one further afield such as the additional output from Asia's rapid industrialisation.
Warm and wet
Ed Dlugokencky, the scientist at NOAA's Earth System Research Laboratory (ESRL) who collates and analyses data from atmospheric monitoring stations, agrees that the 2007 rise has a biological cause.
"We're pretty sure it's not biomass burning; and I think 2007 is probably down to wetland emissions," he said.
"In boreal regions it was warmer and wetter than usual, and microbes there produce methane faster at higher temperatures."
Dr Dlugokencky also suggested that the drastic reduction in summer sea ice around the Arctic between 2006 and 2007 could have increased release of methane from seawater into the atmosphere.
 Companies are looking to exploit the energy in methane hydrates |
A further possibility is that the gas is being released in increasing amounts from permafrost as temperatures rise.
Researchers will be keeping a close eye on this year's data which will indicate whether 2007 was just a blip or the beginning of a sustained rise.
Methane concentrations had been more or less stable since about 1999 following years of rapid increases, with industrial reform in the former Soviet bloc, changes to rice farming methods and the capture of methane from landfill sites all contributing to the levelling off.
In the recent past, concentrations have risen during El Nino events, whereas the world is currently amid the opposite climatic pattern, La Nina.
Solid evidence
An upturn in methane concentrations emissions could have significant implications for the Earth's climatic future.
A sustained release from Arctic regions or tropical wetlands could drive a feedback mechanism, whereby higher temperatures liberate more of the greenhouse gas which in turn forces temperatures still higher.
A particularly pertinent question is whether methane is being released from hydrates on the ocean floor.
These solids are formed from water and methane under high pressure, and may begin to give off methane as water temperatures rise.
The amount of the gas held in oceanic hydrates is thought to be larger than the Earth's remaining reserves of natural gas.
In collaboration with other British institutions, Dr Fisher's team will begin work this summer sampling water near hydrate deposits to look for indications of gas emerging.
Richard.Black-INTERNET@bbc.co.ukLink to article: http://news.bbc.co.uk/2/hi/science/nature/7408808.stm
New geologic evidence from the seafloor off the southern tip of Greenland shows that during the two past periods of global warming, the melting of Greenland glaciers was right in synch with rising global temperatures -- rather than lagging behind as models have predicted.
In other words, the ice is very sensitive to recent losses of ice there could be the beginning of a much larger melt than expected.
"People had thought that there was this thermal lag," said Anders Carlson of the University of Wisconsin in Madison.
But offshore sediments that record the debris that is washed out from valleys when glaciers recede tell another story. As Carlson said, "As soon as it starts warming, it starts to melt."
The evidence, which Carlson and his colleagues present in the May issue of the journal Geology, comes in the form of titanium and iron found in cores of sediments offshore at what's called Eirik Drift.
The only sources for the two elements are land-based rocks which wash out of glacial valleys and into the sea once glaciers melt back and expose the ground to the weather. That process, the scientists figure, is a pretty good sign of a warmer climate.
Those two warmer periods were about 120,000 to 132,000 years ago and 10,000 to nearly 15,000 years ago.
"The last very big change was the one that ended the last ice age," explained Kurt Cuffey, a professor in the Geography and Earth and Planetary Sciences departments at the University of California at Berkeley. "What they found pretty clearly is that the melt…began immediately."
By immediately, Cuffey explained, he means geologically speaking -- within a few centuries or less.
The new method fills in a void of information caused by the glaciers themselves. Each new glacial advance tends to obliterate the evidence of past surges and retreats, unless it's left piled up at what was once the end of the glacier.
In the case of Greenland, however, the glaciers end in the sea, which complicates the job of locating and studying them.
As for how it all relates to the recent accelerated melt and net loss of ice mass over much of Greenland, Carlson said their data could herald a lot more of the same.
"What we can say is that (the Greenland Ice Sheet) responded very fast," said Carlson. "Our data suggest that the current negative mass balance is the beginning of a long-term trend."
Link to article: http://dsc.discovery.com/news/2008/05/08/greenland-ice-melt.html
Bruce Caron1
1The New Media Studio, New Media Research Institute, 417 Samarkand Drive, Santa Barbara, CA, 93105, USA, Phone 805-568-0115, Fax 805-966-1100, bruce@tnms.org
This talk will outline lessons learned from a public-art-based climate-change awareness/education project. In the summer of 2006 a group of Santa Barbara, California residents decided to catalyze public awareness of the future impacts of human-induced climate change (HICC) by marking these future impacts on the built environment. Marking the future impacts of HICC on the local scene would provide a daily reminder of the future impacts of current energy use choices. The hope was that awareness would lead to personal motivations to help stop HICC. The group decided that the best story to tell would be the tipping point for the melting of the ice sheet on Greenland. After a year of public meetings, the City Council approved the "lightblueline" project. Teams of volunteers would paint the seven-meter elevation contour (the amount of sea-level rise held in the Greenland ice sheet) on city streets. An anti-lightblueline effort, led by the local daily newspaper, succeeded in stalling the installation of these markings by feeding public fears about declining property values while fostering uncertainty about the science of climate change. The idea of anthropogenic climate tipping points was termed a "belief." Arguments that climate change was still being debated by scientists and that current climate models are inadequate sidelined the main conversation. Timescale factors played a part: any effect beyond, say, fifty years acquired insignificance in the face of current problems. Opponents spent twenty times the resources of the group to delay the project.
But two new studies by Eric Post of the Pennsylvania State University and colleagues show that global warming has thrown this system out of whack. Plants are emerging earlier, and all at once across the landscape, so the caribou are arriving to find the plants they rely on are past their prime.
"Because of warming, food is becoming available earlier in the year for caribou. That might sound like a good thing, because caribou come out of the long Arctic winter hungry," Post told Discovery News by e-mail from Greenland, where he is awaiting the spring calving season.
"But we also found that caribou are not adjusting their birth season to help keep up with changes in plant growth. As a consequence, their food is in a sense being taken off the table again before caribou have had a chance to get what they need."
Post documented that over a period of six seasons -- 1993, and 2002-2006 -- the average spring temperature rose by more than 8 degrees Fahrenheit and plants emerged about two weeks earlier, while calf mortality increased fourfold and calf production declined by a factor of seven. These results were published online earlier this month in Philosophical Transactions of the Royal Society B.
In the second study, appearing online today in the Proceedings of the Royal Society B, Post's team showed that warming is also causing plants across the landscape to mature all at the same time. Normally, caribou would start out in the valley where plants emerge first and move uphill, following new plants as the season progresses.
"As it gets warmer, there's less and less difference between the plants in the valley and those on the hilltop. So now, when the caribou goes uphill, counting on finding a good meal, it's out of luck," Post said. "The plants are past their peak."
"Overall, this means that the caribou isn't getting the best diet, and isn't able to provide its newborn calf with the best nutrition," he added. "We think that makes it harder for the calves to survive the first few days of life.""While we were collecting data on plant growth during those seven years, we also made observations on caribou calving, and found that in years when plant growth started almost simultaneously across the landscape, caribou had fewer calves," Post said.
The mismatch arises because caribou use changing day length in spring to cue their reproduction, while plants rely on temperature.
With global warming, "temperatures rise but day length stays exactly the same," said Marcel Visser at the Netherlands Institute of Technology in Heteren.
This is not the first example where climate change has skewed food supply and demand. Visser was the first to discover this relationship in great tits, whose caterpillar prey emerged earlier because of warming, before the birds' eggs hatched.
But "it's the first time people have shown this in mammals," Visser said.
For the animals to adapt, "they need genetic variation in the population that will push back the earliest date for reproducing," he added. "But that is a slow process. One of the worries is that climate change will occur faster than these changes can occur."
Link to article: http://dsc.discovery.com/news/2008/05/22/caribou-climate-change.html
