from the October 11, 2009 edition

Moscow – Mariners have dreamed for centuries of finding a commercially viable shortcut between Europe and Asia across the top of the world. Many have died trying, but none succeeded until late September, when two German freighters slipped quietly into Rotterdam Harbor after completing a historic month-long journey from Vladivostok, in Russia’s Pacific far east, through the once-impassable Arctic route.

The Bremen-based company that operates the two specially reinforced cargo ships, the Beluga Fraternity and the Beluga Foresight, that made the journey said that taking the new route saved 10 days and $300,000 per ship over the usual 11,000 nautical-mile voyage through the Indian Ocean, the Suez Canal, and the Mediterranean in order to reach the North Atlantic.

“We are all very proud and delighted to be the first Western shipping company which has successfully transited the legendary Northeast Passage,” the Beluga company said in a statement. It plans to begin using the route on a regular basis.

The bad news, scientists say, is that the feat only became possible because the Arctic icecap is retreating at an alarming rate, leaving vast swaths of open water where solid pack ice recently frustrated attempts at even summer navigation. This year saw the third-lowest amount of Arctic sea ice on record, after the record set in 2007.

“Our studies over the past 30 years show the rate of retreat by sea ice is growing very rapidly,” says Igor Mokhov, director of the official Institute of Atmospheric Physics in Moscow. “If these tendencies continue, the navigable period by the late 21st century might grow to several months” from the current six-to-eight week window the Northeast Passage offers each summer, he says.

‘Huge economic opportunity for Russia’

At least one climate-change skeptic, writing in Britain’s Daily Telegraph, has dismissed the Beluga expedition as a “warmist publicity stunt,” staged to take advantage of a statistical blip in Arctic ice formation. Other critics say that the German ships didn’t really do anything new: Large sections of the northern route had been routinely traversed by Soviet shipping in the past to service remote Arctic settlements, before falling into disuse after the collapse of the USSR. Moreover, the Beluga ships had to be accompanied by a nuclear-powered Russian icebreaker for part of their journey, though they apparently did not require any assistance.

Most Russian Arctic experts say that climate change appears undeniable, but some caution that its impact remains unpredictable.

“This phenomenon is complicated, and we can’t guarantee that the northern passage will become ice-free,” says Viktor Dmitriyev, an expert with the official Institute of the Arctic and Antarctic Regions in St. Petersburg. “But it looks very possible. And if it happens it will be a huge economic opportunity for Russia. It can mean a whole new impulse for northern development.”

A study by the US Geological Survey several years ago estimated that as much as 25 percent of the world’s remaining untapped oil deposits and 30 percent of its gas lie under the fast-receding Arctic icecap. Other resources, such as fisheries, could open up as well.

That prospect has triggered a flurry of activity at Russia’s Ministry of Transport, which regulates the country’s sea lanes. The ministry’s head of sea and river transport, Alexander Davydenko, says a new department to administer the northern sea route is being created to build infrastructure and oversee tariffs. He says the ministry is also building at least one massive new nuclear icebreaker to supplement its current fleet of six, and is establishing a new Arctic air-sea rescue unit.

“Scientists tell us that we face warming, and that the boundaries of the Arctic ice are receding,” says Mr. Davydenko. “Therefore we are taking a variety of measures … to safeguard the interests of the Russian Federation in the Arctic region.”

Greenpeace: No reason to rejoice over Arctic melting

Shipping experts say that, at least for the moment, bureaucratic obstacles remain more daunting than the threat of pack ice. The Beluga expedition was held up for nearly a month in Vladivostok while it obtained necessary permits and endured close scrutiny by the Federal Security Service. The need to be accompanied by an icebreaker is another factor that will increase costs and limit the route’s attractiveness in the near term.

“There are a lot of issues, including political ones, that remain to be worked out,” says Mr. Dmitriyev.

But if the ice disappears as predicted, the Russians say their route is the one shipping companies will likely choose. While the better-known Northwest Passage, which runs across the top of Canada, is more southerly, Russian experts say it is plagued by geographical and geopolitical problems that may prove insoluble. It runs through a maze of Arctic islands with narrow and shallow channels, they say. Moreover, Canadian sovereignty in the area is challenged by the US, which has lately begun waking up to Arctic possibilities. The Northeast Passage is Russian territory and clear water from Vladivostok to Norway.

“Look at a map, and you’ll see the Canadian route is difficult to navigate because of all the islands and fiords, while the Russian passage is wide open,” says Alexei Bezborodov, a shipping expert with Infranews, a Russian transport journal.

Amid economic optimism, Russian environmentalists are aghast.

“There is no possibility, in Russia or any other country, to develop this route in an ecologically safe mode,” says Vladimir Chuprov, head of Greenpeace-Russia’s energy program. “If this passage is opening up, it creates not only huge risks but possible disasters. That’s no reason to rejoice, but to tear our hair [out] in despair.”

By Louis Charbonneau

UNITED NATIONS (Reuters) – A key senator on Monday said the committee she leads should approve a bill to tackle global warming before a U.N. climate summit in December, and the U.S. energy secretary said he hoped the bill could be signed into law by then.

“I believe we will get this bill out of my committee soon,” Senator Barbara Boxer, who chairs the Environment and Public Works Committee, told reporters after a meeting with U.N. Secretary-General Ban Ki-moon.

“Certainly before Copenhagen, and we’re hoping maybe to even have it on the floor (of the Senate),” she said.

Energy Secretary Steven Chu was much more optimistic than Boxer when asked when the legislation could become law. He told reporters in London he remained hopeful President Barack Obama would be able to sign a domestic climate change bill before the Copenhagen conference.

“Whether there will be a bill on the president’s desk and he’ll sign it, I’m hopeful it will be,” he told reporters on the sidelines of a meeting on clean coal technologies.

Boxer co-authored the Senate Democrats’ 800-page draft bill on climate change with Foreign Relations Committee Chairman John Kerry.

Boxer said Ban, who has been lobbying U.N. member states to agree on a deal to fight global warming in Copenhagen, had asked Boxer about the timeline for the U.S. legislation.

Obama, in a sharp reversal from his predecessor George W. Bush, has vowed to impose mandatory limits on the emission of climate-warming greenhouse gases and made tackling global warming a signature issue of his administration.

The Bush administration had opposed mandatory emission limits, arguing that they would damage the competitiveness of U.S. industry.

GREENHOUSE GASES

The Boxer-Kerry draft bill would reduce U.S. industry emissions of carbon dioxide and other greenhouse gases by 20 percent by 2020, a smaller reduction than European Union countries have pledged.

Their proposal embraces central elements of a climate change bill passed in June by the Democratic-led House of Representatives.

The two senators face a tough fight to win over skeptical Republicans and some Democrats to get their proposal passed, but their prospects improved on Sunday when a Republican senator broke ranks with his party to outline a compromise with Democrats.

Republican Senator Lindsay Graham and Kerry wrote in an opinion piece in The New York Times that they believed they could pick up enough support to pass a wide-ranging bill to limit carbon emissions.

“We refuse to accept the argument that the United States cannot lead the world in addressing global climate change,” Graham and Kerry wrote. “We are also convinced that we have found both a framework for climate legislation to pass Congress and the blueprint for a clean-energy future.”

Graham is one of a few dozen fence-sitters who Kerry and Boxer have been courting in order to amass the 60 votes needed for passage in the 100-member Senate..

The Antarctic Peninsula juts into the Southern Ocean, reaching farther north than any other part of the continent. The southernmost reach of global warming was believed to be limited to this narrow strip of land, while the rest of the continent was presumed to be cooling or stable.

Not so, according to a new analysis involving NASA data. In fact, the study has confirmed a trend suspected by some climate scientists.

“Everyone knows it has been warming on the Antarctic Peninsula, where there are lots of weather stations collecting data,” said Eric Steig, a climate researcher at the University of Washington in Seattle, and lead author of the study. “Our analysis told us that it is also warming in West Antarctica.”

Figure at right: Red represents areas where temperatures have increased the most during the last 50 years, particularly in West Antarctica, while dark blue represents areas with a lesser degree of warming. Temperature changes are measured in degrees Celsius. Credit: NASA/GSFC Scientific Visualization Studio.

The finding is the result of a novel combination of historical temperature data from ground-based weather stations and more recent data from satellites. Steig and colleagues used data from each record to fill in gaps in the other and to reconstruct a 50-year history of surface temperatures across Antarctica.

Over the years, climate research in northern latitudes led researchers to believe that the Arctic is where impacts of global climate change would be seen first. Less certain is how climate is affecting Antarctica where inland temperatures are known to plunge to -112°F, and ground-based weather stations have been sparse.

It’s this sparse data collection — from ground-stations on the Antarctic Peninsula and previous reports that much of East Antarctica has experienced cooling since 1978 — that led the International Panel on Climate Change to conclude in its most recent report that Antarctica is the one continent where we have failed to detect human-caused temperature changes.

With funding from the National Science Foundation’s Office of Polar Programs, Steig and colleagues set out to reconstruct Antarctica’s recent past. Ground-based stations have recorded temperatures since 1957, but most of those readings come from the peninsula and areas on the edges of the continent. But at the same time, scientists such as study co-author Joey Comiso of NASA’s Goddard Space Flight Center in Greenbelt, Md., have been gathering measurements from a series of Advanced Very High Resolution Radiometer (AVHRR) instruments deployed on satellites since 1981.

To construct the new 50-year temperature record, the team applied a statistical technique to estimate temperatures missing from ground-based observations. They calculated the relationship between overlapping satellite and ground-station measurements over the past 26 years. Next, they applied that correlation to ground measurements from 1957 to 1981 and calculated what the satellites would have observed.

The new analysis shows that Antarctic surface temperatures increased an average of 0.22°F (0.12°C) per decade between 1957 and 2006. That’s a rise of more than 1°F (0.5°C) in the last half century. West Antarctica warmed at a higher rate, rising 0.31°F (0.17°C) per decade. The results, published Jan. 22 in Nature, confirm earlier findings based on limited weather station data and ice cores.

While some areas of East Antarctica have been cooling in recent decades, the longer 50-year trend depicts that, on average, temperatures are rising across the continent.

Figure at right:The northern section of the Larsen B ice shelf, a large floating ice mass on the eastern side of the Antarctic Peninsula, shattered and separated from the continent on March 5, 2002, and represents a major impact that climate warming can have on the region. Credit: NASA Earth Observatory. > Larger image

West Antarctica is particularly vulnerable to climate changes because its ice sheet is grounded below sea level and surrounded by floating ice shelves. If the West Antarctic ice sheet completely melted, global sea level would rise by 16 to 20 feet (5 to 6 meters).

To identify causes of the warming, the team turned to Drew Shindell of NASA’s Goddard Institute for Space Studies in New York, who has used computer models to identify mechanisms driving Antarctica’s enigmatic temperature trends.

Previously, researchers focused on Antarctic ozone depletion, which influences large-scale atmospheric fluctuations around the continent — most notably, the Southern Annular Mode, which speeds up wind flow to isolate and cool the continent.

Shindell compared Steig’s temperature data with results from a computer model that can simulate the response of the atmospheric system to changes in land surface, ice cover, sea surface temperatures, and atmospheric composition. He found the ozone-influenced Southern Annular Mode is not necessarily the primary influence on Antarctic climate. Instead, it appears that smaller-scale, regional changes in wind circulation are bringing warmer air and more moisture-laden storms to West Antarctica.

“We still believe ozone depletion can increase wind speeds around Antarctica, further isolating the interior,” Shindell said. “But it’s clear now that it’s not such a dominant influence on temperature trends.”

The main anthropogenic global warming culprit is carbon dioxide (CO₂), but human activity produces a host of other, shorter-lived pollutants that contribute to climate change, among them gases that react to form ozone smog and fine particles such as black carbon. Until recently, most of the attention paid to these short-lived pollutants focused on their threat to human health. But because these pollutants disappear from the atmosphere relatively quickly, global efforts to reduce their emissions can produce an immediate benefit and help avoid dangerous tipping points in the climate system over the next few decades.

Our new study offers additional insight into the climatic role of these pollutants. These findings come at a time when activity on domestic and international climate policy in general and on black carbon policy in particular is ramping up.

We calculated the overall warming effect of the transportation and power generation sectors, two of the main contributors to CO₂ emissions, for the U.S. and the world. Effective mitigation of global climate change requires action in these sectors for which technology change options exist or are being developed. We primarily used a global climate model developed at the NASA Goddard Institute for Space Studies that simulates the transport of pollutants in the atmosphere by winds and the chemical and physical reactions that transform the pollutants into smog and particles and eliminates them from the atmosphere. The model also calculates the warming or cooling effect of the different pollutants. The results are shown in Figure 1.

We found that transportation would be a particularly good sector to target for emissions controls because it emits a lot of black carbon (most notably through diesel exhaust) and ozone-producing gases in addition to CO₂. In contrast, the power generation sector emits little black carbon, but instead creates much sulfate particle pollution, which although bad for air quality and acid rain, cancels out the warming effect of the sector’s CO₂ emissions in the short-term.

We also considered a hypothetical example of switching the transportation sector to a zero-emissions or electric power source, such as in plug-in hybrid electric or pure electric technologies. The result was a hefty benefit for the climate. Such a switch would decrease the warming effect when looking just at CO₂. (Increased CO₂ emissions from the electricity generation sector would to some extent offset the decrease in emissions from vehicles.) But non-CO₂ pollutants provide an added benefit for the climate. The technology shift greatly reduces black carbon emissions. Furthermore, switching to electric power, generated predominantly with coal at present both in the U.S. and worldwide, increases emissions of cooling sulfate particles, further reducing global warming.

Of course, the power sector also needs to be cleaned up to address long-term climate damage from CO₂, as well as health problems from sulfate particles, ozone smog and other pollutants. Our results indicate that technology change options that target specific economic sectors may invoke decadal scale climate effects from the air pollutants that dominate the CO₂ effects. Assessment of the full impacts of technology and policy strategies designed to mitigate global climate change must consider the climate effects of ozone and fine aerosol particles.

Atmospheric carbon dioxide if coal emissions are phased out between 2010 and 2030.
Courtesy Hansen et al./Open Atmospheric Science Journal

A group of 10 prominent scientists says that the level of globe-warming carbon dioxide in the air has probably already reached a point where climate will change disastrously unless the level can be reduced in coming decades. The study is a departure from recent estimates that truly dangerous levels would be reached only later in this century.  The paper appears in the current edition of the Open Atmospheric Science Journal.

“There is a bright side to this conclusion,” says lead author James E. Hansen, director of the Goddard Institute for Space Studies, part of Columbia University’s Earth Institute. “”By following a path that leads to lower CO2, we can alleviate a number of problems that had begun to seem inevitable.” Hansen said these include expanding desertification, reduced food harvests, increased storm intensities, loss of coral reefs, and the disappearance of mountain glaciers that supply water to hundreds of millions of people.

The scientists say now that CO2 needs to be reduced to the level under which human civilization developed until the industrial age—about 350 parts per million (ppm)—to keep current warming trends from moving rapidly upward in coming years. The level is currently at 385 ppm, and rising about 2 ppm each year, mainly due to the burning of fossil fuels and incineration of forests. As a result, global temperatures have been creeping upward. The authors say that improved data on past climate changes, and the pace at which earth is changing now, especially in the polar regions, contributed to their conclusion. Among other things, ongoing observations of fast-melting ice masses that previously helped reflect solar radiation, and the release of stored-up “greenhouse” gases from warming soils and ocean waters, show that feedback processes previously thought to move slowly can occur within decades, not millennia, and thus warm the world further. Once CO2 gas is released, a large fraction of it stays in the air for hundreds of years.

The scientists, from the United States, United Kingdom and France, are optimistic that current atmospheric CO2 could be reduced if emissions from coal, the largest contributor, are largely phased out by 2030.  Use of unconventional fossil-fuel sources such as tar sands also would have to be minimized, they say. They predict that oil use will probably decline anyway as reserves shrink. So-called “geoengineering” solutions that would remove CO2 from the air have been proposed by others, but the group is skeptical; they estimate that artificially removing 50ppm of CO2 from the atmosphere would cost at least $20 trillion, or twice the current U.S. national debt. They suggest that reforestation of degraded land and use of more natural fertilizers could draw down CO2 by a similar amount.

“Humanity today, collectively, must face the uncomfortable fact that industrial civilization itself has become the principal driver of global climate,” says the paper.  “The greatest danger is continued ignorance and denial, which would make tragic consequences unavoidable.”

The other authors are Makiko Sato and Pushker Kharecha, both also of the Earth Institute; David Beerling of the University of Sheffield (UK); Robert Berner and Mark Pagani of Yale University; Valerie Masson-Delmotte of the University of Versailles (France); Maureen Raymo of Boston University; Dana Royer of Wesleyan University; and James Zachos of the University of California, Santa Cruz.

Europe
1. Changes in leaf-unfolding and flowering and animal growing phases in 19
European countries: Examples are hazel, lilac, apple, linden, and birch
2. Earlier egg-laying of birds; earlier migration of birds (for example flycatchers)
3. Long-term changes within fish communities in Upper Rhone River
4. Glacier melting in the Alps
5. Rapid advance of spring arrival of long-distance migratory birds in Europe
6. Mountain birch tree-limit rise in Sweden
7. Changes in lake diatoms to warmer-adapted species in Finnish Lapland
8. Earlier pollen release in the Netherlands
9. Apple trees are leaving 35 days earlier in Spain

Asia
1. Greater growth of Siberian pines in Mongolia
2. Earlier break-up and thinning of river and lake ice in Mongolia
3. Change in freeze depth of permafrost in Russia
4. Earlier flowering of ginkgo in Japan

South America
1. Glacier wastage in Peru
2. Melting Patagonia icefields are contributing to sea-level rise

Africa
1. Decreasing aquatic ecosystem productivity of Lake Tanganyika

Australia
1. Early arrival of Australian migratory birds (examples – flycatcher, fantail)
2. Declining water levels in Western Victoria

Antarctica
1. Population of emperor penguins had declined by 50% on Antarctic Peninsula
2. Retreating glacier fronts

Ocean
1. Long-term decline in krill stock in Southern Ocean
2. Increasing abundance of tropical/subtropical species and decreasing abundances
of temperate/subpolar species in California current
3. Increasing plankton abundance in cooler reigons and decreasing plankton in
warmer regions in Northeast Atlantic

Next step: analyze change in Pacific Ocean

According to Sachs, “The next step is to determine if similar changes occurred in the much larger Pacific Ocean, studies he and Lehman are pursuing. If so, any human-induced changes to the ocean’s plumbing are likely to affect much of the mid-latitudes, where many large population centers are found.”

Columbia’s Broecker said the findings of rapid, wide temperature swings underscore other, recent research.

“In the last five years, it has been shown that these changes have been shown in the Santa Barbara basin, in the Arabian sea off of India, in the Cariaco Trench off of Venezuela, and now, in this beautiful, beautiful record that Julian has gotten on the sediment near Bermuda,” said Broecker. “These things confirm that these changes were not restricted to the north Atlantic — they were global. It beautifully replicates the Greenland record and just adds piece of information to indicate that the global system we live in is a strange one that is capable of doing outrageous things namely jumping form one state of operation to another.”

The mechanism by which temperature change in the warm Atlantic can affect climate globally is via the water vapor feedback. Warm ocean temperatures raise the water vapor content of the atmosphere and thus its heat-trapping or “greenhouse” capacity, with a one-degree rise in water temperature equating to a 6 percent increase in water vapor pressure.

Underscoring the importance of ocean currents, to the surprise of the researchers, the ocean-driven temperature fluctuations they observed were as great as those caused by changes in the tilt of the Earth, and changes in the Earth’s orbit: factors thought to have produced the series of ice ages in geological history.

“The warming at the end of the ice age was supported by the disappearance of enormous ice sheets, a one third increase in atmospheric CO2 levels, and changes in the seasonal distribution of the suns energy, whereas the abrupt changes we document here seem to be almost entirely ocean driven,” said Sachs and Lehman.

Although there had been earlier indications of ocean temperature changes farther south of the Greenland ice cores, those had been based on records of mineral deposits left by plankton-a record that can be unreliable because plankton growth can be influenced by factors besides temperature.

For their study, Sachs and Lehman used a 12-meter section of a 52.7-meter core of sediment drilled 4,462 meters underwater into the sea floor of the Bermuda Rise by French scientists as part of IMAGES (International Marine Global Change Study), an international coring project. The Bermuda Rise is a sediment drift formation where sedimentation rates of 10 to 100 centimeters per 1,000 years far exceed the average for the ocean, giving an unusually detailed picture of temperature over time-providing a method is available to deduce temperature from sediments.

Sachs and Lehman were able to do just that by streamlining and automating a technique developed in the 1980s by researchers at the University of Bristol, England. The technique is based on the observation that the ratio of two molecules produced by certain phytoplankton varies in direct proportion to the water temperature in which they live.

Although the biochemical function of the molecules-called alkenones-is still a mystery, they are thought to play a role in maintaining cell membrane stiffness. Much like butter is stiff while margarine is soft when removed from the refrigerator, plankton may produce more of the unsaturated or margarine-like variety of alkenone when in cold water and more of the saturated or butter-like variety in warm water.

Taking samples every 1 or 2 centimeters throughout the 12-meter section of sediment, each representing 33 to 67 years of deposition on average, the two extracted lipids (fatty substances) from each sample and then used gas chromatography to measure the ratio of alkenones.

Based on the technique, the researchers were able to reconstruct the surface sea temperature, showing that it varied between 15.5 centigrade to 21 centigrade — close to the current water temperature of 22.5 Celsius.

“Our study shows that previously documented disruption of ocean currents during the last ice age produced unexpectedly large and rapid temperature changes in the warm Atlantic Ocean. That implies that Greenhouse warming – which could similarly disrupt ocean currents — could have consequences more global than some current predictions,” said Sachs.

Ice Age Ocean Temperature Swings Suggest Future Global Warming May Extend Farther South

By Lucas Held

Barnard Professor Julian Sachs

Wide swings in ocean temperature during the last ice age extended well south of the polar and subpolar Atlantic region and all the way into the warm, subtropical ocean, a new study demonstrates, suggesting that the effect of future global warming may extend farther south than some previous predictions.

The study, published in the Oct. 22 issue of Science, was undertaken by Julian Sachs, assistant professor of environmental science at Barnard College, and Scott J. Lehman, associate research professor of geological sciences at the Institute of Arctic and Alpine Research at the University of Colorado, Boulder. The two examined sediments recovered northeast of Bermuda from under more than two miles of water.

Measurements in Greenland ice cores by Pieter Grootes and coworkers at the University of Washington over the last decade documented large, rapid swings in air temperature during the last glacial period. Similar swings in polar and subpolar sea temperatures have been inferred from the distribution of micro-fossil shells in those sediments. But Sachs and Lehman are the first to demonstrate that dramatic temperature changes of up to 5 degrees Celsius (or 9 degrees Fahrenheit) occurred not only in the north, but well into the warm ocean, during the period 60,000 to 30,000 years ago.

“It has been known for the better part of a decade that Greenland and the polar Atlantic region experienced ocean-driven flip flops in temperature every few thousand years during the last glacial period approximately 80,000 to 100,000 years ago,” said Sachs and Lehman. “What is new here is the clear evidence that, like the polar Atlantic, the warm Atlantic was also undergoing related, very large, and very rapid – in terms of degree per decade-temperature changes.”

Where climate models predict subtropical sea temperature change of up to 5 degrees Celsius between maximum glacial and warm interglacial (i.e., modern) conditions, a period of 10,000 years, the large, rapid temperature swings the two scientists observed over a scant 250 years can probably only be caused by disruption or even halting of the North Atlantic conveyor-like circulation, a concept pioneered by Columbia’s Wallace Broecker, Newberry Professor of Earth and Environmental Sciences.

The circulation of the North Atlantic conveyor transports warm, tropical water north to the polar areas, via the Gulfstream and North Atlantic Drift currents. Once north, the salty warm water cools and then sinks to the bottom of the ocean, a process that draws more warm surface water from the south.

“This north-south conveyor is what keeps northern Europe far warmer than the Canadian provinces at the same latitude-in short, what keeps London from having a climate like Newfoundland,” said Sachs.

But if the salty water does not become cold enough to sink, due to global warming, or is diluted with too much freshwater, the North Atlantic conveyor halts. This appears to have happened repeatedly throughout the time period studied by Sachs and Lehman, since no other mechanism appears capable of producing the large, sudden temperature swings they document.

Most numerical models used to predict the climate response to increased greenhouse gas concentration do not predict the large temperature changes of the warm ocean documented by the two researchers, suggesting that those models may have to be altered.

“Most climate models developed over the past 10-15 years suggest the effects of a shutdown of the North Atlantic’s conveyor-like circulation, such as that due to global warming, will be localized in the far northeast Atlantic-Iceland and Scandinavia,” said Sachs. “Our data suggests the footprint may be much larger.”

“The fact that we observed such large temperature fluctuations in connection with changes in ocean circulation documented by Lloyd Keigwin, senior scientist at the Woods Hole Oceanographic Institute, and Ed Boyle, professor of chemical oceanography, at MIT, suggests future climate changes may not only be severe for Northern Europe but could affect more southerly latitudes,” Sachs added.

Observed Keigwin, “Because the climate system can respond this quickly means it could respond this quickly to man’s influence and it may respond unpredictably.”

While no single study will send climate modelers back to the drawing board, said Keigwin, “the kinds of changes they see may be greater than what the models predicted and that may lead to some recalculation.”

One caution, according to Sachs, is that the climate system today may have a different sensitivity than it did 30-60 thousand years ago, when ice sheets, solar radiation receipts and greenhouse gas concentrations were different.