Global Warming In The Recent Past

The following article presents convincing, scientific evidence that the climate in the Northern Hemisphere and the Arctic was warmer than today, as little as 6,000 years ago. Whatever caused this warming was obviously not man's burning of fossil fuels and the emission of carbon dioxide. CO2, as we all know is being blamed for "global warming" and catastrophic climate change.

It makes no sense that the natural forces (solar energy) which controlled climate in the past are not at work in the same way today. The fear of global warming caused by carbon dioxide emissions is unfounded. Another thought, how did the polar bears, and other species, survive this past warming? Do the global warming alarmists pay any attention to facts and real world observations? It seems clear they do not.

Obviously, sea level was higher 6,000 years ago, there was far less sea ice in the Arctic, and humans lived in areas that became uninhabitable to them because of cooling, not warming. Climate scientists must address the causes of the climate changes of the recent past before spreading fear about carbon dioxide emissions. It has warmed and cooled many times, long before humans could possibly have had any impact. Blaming our current climate change on carbon dioxide emissions simply makes no sense, nor does it explain verifiable, real world observations as reported in the following article.

Peter

Less ice in the Arctic Ocean 6000-7000 years ago
Written by: Gudmund Løvø 20. October 2008 (source)

Recent mapping of a number of raised beach ridges on the north coast of Greenland suggests that the ice cover in the Arctic Ocean was greatly reduced some 6000-7000 years ago. The Arctic Ocean may have been periodically ice free.

BEACH RIDGE: The scientists believe that this beach ridge in North Greenland formed by wave activity about 6000-7000 years ago. This implies that there was more open sea in this region than there is today. (Click the picture for a larger image) Photo: Astrid Lyså, NGU

PACK-ICE RIDGE: Pack-ice ridges form when drift ice is pressed onto the seashore piling up shore sediments that lie in its path. (Click for a larger image) Photo: Eiliv Larsen, NGU”The climate in the northern regions has never been milder since the last Ice Age than it was about 6000-7000 years ago. We still don’t know whether the Arctic Ocean was completely ice free, but there was more open water in the area north of Greenland than there is today,” says Astrid Lyså, a geologist and researcher at the Geological Survey of Norway (NGU).

Shore features
Together with her NGU colleague, ICE COVER: Today, at the mouth of Independence Fjord in North Greenland, drift ice forms a continuous cover from the land. (Click for a larger image) Photo: Eiliv Larsen, NGUEiliv Larsen, she has worked on the north coast of Greenland with a group of scientists from the University of Copenhagen, mapping sea-level changes and studying a number of shore features. She has also collected samples of driftwood that originated from Siberia or Alaska and had these dated, and has collected shells and microfossils from shore sediments.

”The architecture of a sandy shore depends partly on whether wave activity or pack ice has influenced SETTLEMENT: Astrid Lyså in August 2007 in the ruined settlement left by the Independence I Culture in North Greenland. The first immigrants to these inhospitable regions succumbed to the elements nearly 4000 years ago, when the climate became colder again. (Click for a larger image) Photo: Eiliv Larsen, NGUits formation. Beach ridges, which are generally distinct, very long, broad features running parallel to the shoreline, form when there is wave activity and occasional storms. This requires periodically open water,” Astrid Lyså tells me.
Pack-ice ridges which form when drift ice is pressed onto the seashore piling up shore sediments that lie in its path, have a completely different character. They are generally shorter, narrower and more irregular in shape.

Open sea
”The beach ridges which we have had dated to about 6000-7000 years ago were shaped by wave activity,” says Astrid Lyså. They are located at the mouth of Independence Fjord in North Greenland, on an open, flat plain facing directly onto the Arctic Ocean. Today, drift ice forms a continuous cover from the land here.Astrid Lyså says that such old beach formations require that the sea all the way to the North Pole was periodically ice free for a long time.
”This stands in sharp contrast to the present-day situation where only ridges piled up by pack ice are being formed,” she says.

However, the scientists are very careful about drawing parallels with the present-day trend in the Arctic Ocean where the cover of sea ice seems to be decreasing.
“Changes that took place 6000-7000 years ago were controlled by other climatic forces than those which seem to dominate today,” Astrid Lyså believes.

Inuit immigration
The mapping at 82 degrees North took place in summer 2007 as part of the LongTerm project, a sub-project of the major International Polar Year project, SciencePub. The scientists also studied ruined settlements dating from the first Inuit immigration to these desolate coasts.

The first people from Alaska and Canada, called the Independence I Culture, travelled north-east as far as they could go on land as long ago as 4000-4500 years ago. The scientists have found out that drift ice had formed on the sea again in this period, which was essential for the Inuit in connection with their hunting. No beach ridges have been formed since then.

”Seals and driftwood were absolutely vital if they were to survive. They needed seals for food and clothing, and driftwood for fuel when the temperature crept towards minus 50 degrees. For us, it is inconceivable and extremely impressive,” says Eiliv Larsen, the NGU scientist and geologist.

Glaciers and Sea Ice: Melting Or Growing?

Here is a link to a good website which deals with the issue of glaciers and sea ice. Are they melting or expanding? We've been bombarded with pictures of melting glaciers and rising sea levels. We're told we're headed for catastrophe because of global warming. Is any of this true? Check out this website: http://www.iceagenow.com/Growing_Glaciers.htm

For example:

Here's a (partial) list of the specific glaciers that are growing:
NORWAY Ålfotbreen Glacier Briksdalsbreen Glacier Nigardsbreen Glacier Hardangerjøkulen Glacier Hansebreen Glacier Jostefonn Glacier Engabreen glacier (The Engabreen glacier is the second largest glacier in Norway. It is a part (a glacial tongue) of the Svartisen glacier, which has steadily increased in mass since the 1960s when heavier winter precipitation set in.)
Norway's glaciers growing at record pace. The face of the Briksdal glacier, an off-shoot of the largest glacier in Norway and mainland Europe, is growing by an average 7.2 inches (18 centimeters) per day. (From the Norwegian daily Bergens Tidende.) See http://www.sepp.org/controv/afp.htmlClick here to see mass balance of Norwegian glaciers: http://www.nve.no/ Choose "English" (at top of the page), choose "Water," then "Hydrology," then "Glaciers and Snow" from the menu. You'll see a list of all significant glaciers in Norway. (Thanks to Leif-K. Hansen for this info.)

CANADA Helm Glacier Place Glacier
FRANCE Mt. Blanc
ECUADOR Antizana 15 Alpha Glacier
SWITZERLAND Silvretta Glacier
KIRGHIZTAN Abramov
RUSSIA Maali Glacier (This glacier is surging. See below)
GREENLAND See Greenland Icecap Growing Thicker Greenland glacier advancing 7.2 miles per year! The BBC recently ran a documentary, The Big Chill, saying that we could be on the verge of an ice age. Britain could be heading towards an Alaskan-type climate within a decade, say scientists, because the Gulf Stream is being gradually cut off. The Gulf Stream keeps temperatures unusually high for such a northerly latitude.
One of Greenland’s largest glaciers has already doubled its rate of advance, moving forward at the rate of 12 kilometers (7.2 miles) per year. To see a transcript of the documentary, go to http://www.bbc.co.uk/science/horizon/2003/bigchilltrans.shtml
NEW ZEALANDAll 48 glaciers in the Southern Alps have grown during the past year.The growth is at the head of the glaciers, high in the mountains, where theygained more ice than they lost. Noticeable growth should be seen at the foot of the Fox and Franz Josef glaciers within two to three years.(27 May 2003) Fox, Franz Josef glaciers defy trend - New Zealand's two best-known glaciers are still on the march - 31 Jan 07 - See Franz Josef Glacier

SOUTH AMERICA - Argentina's Perito Moreno Glacier (the largest glacier in Patagonia) is advancing at the rate of 7 feet per day. The 250 km² ice formation, 30 km long, is one of 48 glaciers fed by the Southern Patagonian Ice Field. This ice field, located in the Andes system shared with Chile, is the world's third largest reserve of fresh water. http://en.wikipedia.org/wiki/Perito_Moreno_Glacier - Chile's Pio XI Glacier (the largest glacier in the southern hemisphere) is also growing.

UNITED STATES - Colorado (scroll down to see AP article) - Washington (Mount St. Helens, Mt. Rainier* and Mt. Shuksan) (scroll down to see photo of Mt. Baker) - California (Mount Shasta - scroll down for info) - Montana (scroll down for info) - Alaska (Mt. McKinley and Hubbard). (scroll down to see article on Hubbard Glacier)
Antarctic ice grows to record levels 13 Sep 07 - While the Antarctic Peninsula area has warmed in recent years and ice near it diminished during the Southern Hemisphere summer, the interior of Antarctica has been colder and ice elsewhere has been more extensive and longer lasting,See Antarctic ice grows to record levels..
Global Warming? New Data Shows Ice Is Back19 Feb 08 - A Feb. 18 report in the London Daily Express showed that there is nearly a third more ice in Antarctica than usual, challenging the global warming crusaders and buttressing arguments of skeptics who deny that the world is undergoing global warming.See Most snow cover since 1966..
Mount St. Helens’ Crater Glacier Advancing Three Feet Per Day 25 Jun 07 - See Crater Glacier..
Mount St. Helens glacier (Crater Glacier) growing 50 feet per year September 20, 2004 - See Mount St. Helens
Glaciers growing on California's Mount Shasta! 12 Oct 03 - See Mount Shasta Glaciers Growing
Geologists Unexpectedly Find 100 Glaciers in Colorado 7 Oct 01 See Colorado Glaciers Growing
Washington's Nisqually Glacier is GrowingSee Nisqually Glacier
Glaciers in Montana's Glacier Park on the verge of growing 5 Oct 2002. See Glacier Park
Antarctic Ice Sheet is growing thickerSee Antarctic Icecap Growing ThickerSee construction crane buried in the Antarctic Ice Sheet
* * *
Himalayan Glaciers Not ShrinkingGlacial Experts Question Theory of Global Warming15 Feb 07 - See Himalayan Glaciers Not Shrinking..Many people have asked why some glaciers in South America are melting. I think it is perfectly understandable. Remember, we have had two of the strongest El Ninos on record during the past 21 years. During an El Nino, a narrow band of the Pacific Ocean warms by as much as 14 degrees. This band of warm water travels east essentially along the equator until it slams into South America.
It seems logical that the increased rainfall caused by El Nino, plus the warmer winds blowing across the warmer water, could hasten glacial melt. But let me say it again. I do not believe that this is caused by humans, I think it is caused by the El Nino phenomenon, which is caused by underwater volcanism, which is increasing due to the ice-age cycle.
With this said, let me point out many glaciers in South America remain stable, and some - including the Pio XI Glacier and the Perito Moreno Glacier - are growing. The Pio XI Glacier is the largest glacier in the southern hemisphere. The Moreno Glacier is the largest glacier in Patagonia.
I find it curious that news reports do not mention these two glaciers.
* * *
Contrary to previous reports, Arctic ice did not thin during the 1990s, say researchers at the Department of Oceanography at Göteborg University in Göteborg, Sweden. http://www.envirotruth.org/images/ice-in-90s.pdf

.. Alaska Glacier Surges -17 Mar 06 See McGinnis Glacier ..Look at what's happening on Mt. Baker, in Washington State. (Mt. Baker is near Mt. Shukson, where glaciers are now growing.)
This is a photo of my friend Jim Terrell taken onMt. Baker, Washington. Jim is more than six feettall. See the black line about six feet above his head?That's where the snow from the winter of 1998/99stopped melting. Above that, is snow that nevermelted from the winter of 1999/2000. Why isn'tthe media reporting this sort of thing?..Click here to read this in Espanol: http://mitosyfraudes.8k.com/articulos-3/PorHielo.html
Thanks to Eduardo Ferreyra, who translated this material into Spanish for the Argentinean Foundation for a Scientific Ecology.)
Photo by Mazz Terrell19 July 2000
..See also Growing_Glaciers See also Greenland Icecap Growing Thicker and Antarctic Icecap Growing Thicker

Decline In Arctic Sea Ice Caused By Unusual Winds, Not Warming

The supposedly drastic and unusual melting of Arctic sea ice this past summer has made the news recently. The cause has always been attributed to global warming, which many people want us to believe is caused by man's carbon dioxide emissions.

However, here is an alternative theory. Scientists at NASA now say the disappearance of the ice may be caused by unusual winds, not purely warming. I wonder if they have told Global Warming Jim Hansen about this?
Peter

Recent Rapid Decline in Arctic Sea Ice caused by Unusual Winds, says NASA
Post below lifted from Accuweather. See the original for links and graphics
In a news release from NASA Monday, a group of scientists have determined that unusual winds caused the rapid decline (23% loss) in winter perennial ice over the past two years in the northern hemisphere. This drastic reduction is the primary cause of this summer's fastest-ever sea ice retreat in recorded history which has lead to the smallest extent of total Arctic coverage on record.

According to the NASA study, the perennial ice shrunk by an area the size of Texas and California combined between the winter of 2005 and the winter of 2007. What they found was the Arctic Ocean north of Siberia and Alaska was dominated by thinner seasonal ice that melts faster compared to the thicker ice confined to the Arctic Ocean north of Canada. The thinner ice is more easily compressed and responds more quickly to being pushed out of the Arctic by winds.

"Unusual atmospheric conditions set up wind patterns that compressed the sea ice, loaded it into the Transpolar Drift Stream and then sped its flow out of the Arctic," said Son Nghiem of NASA's Jet Propulsion Laboratory and leader of the study. When that sea ice reached lower latitudes, it rapidly melted in the warmer waters. What about these unusual wind patterns. Well, the article does not go into that too much, but I must believe some of this is due to changes in the Arctic Oscillation (AO) and the North Atlantic Oscillation (NAO) which are large atmospheric circulations which have major impacts on the weather in certain parts of the world.

If you look at the two graphics below, you will notice that both the AO and the NAO have been predominately in the positive phase (red) between 1989-1995 and again from 1999 to current. The positive phase of the (AO) typically leads to milder than normal winters over Scandinavia and Siberia, while colder than normal conditions prevail across Greenland. The positive phase of the NAO again leads to colder conditions over Greenland, while much of the eastern U.S. is warmer than normal in general.

Arctic Sea Ice Melting Nothing New......

There is nothing new about observations and worries about Arctic sea ice melting. The global warming alarmists are jousting at windmills.
Peter


from: http://www.washingtontimes.com/apps/pbcs.dll/article?AID=/20070814/NATION02/108140063

Inside the Beltway
John McCaslinAugust 14, 2007

Before Gore
D.C. resident John Lockwood was conducting research at the Library of Congress and came across an intriguing Page 2 headline in the Nov. 2, 1922 edition of The Washington Post: "Arctic Ocean Getting Warm; Seals Vanish and Icebergs Melt."
The 1922 article, obtained by Inside the Beltway, goes on to mention "great masses of ice have now been replaced by moraines of earth and stones," and "at many points well-known glaciers have entirely disappeared."

"This was one of several such articles I have found at the Library of Congress for the 1920s and 1930s," says Mr. Lockwood. "I had read of the just-released NASA estimates, that four of the 10 hottest years in the U.S. were actually in the 1930s, with 1934 the hottest of all."

Worth pondering
Reacting yesterday to word that certain European governments and officials are suddenly trying to abandon their costly "global warming" policies, Royal Astronomical Society fellow Benny Peiser, of the science faculty at Liverpool John Moores University in Great Britain, recalls the teachings of Marcus Aurelius: "The object of life is not to be on the side of the majority, but to escape finding oneself in the ranks of the insane."

Arctic Sea Ice Melting

The Arctic sea ice has been melting since the end of the last ice age, around 12,000 years ago. It melts in the summer and freezes in the winter. Gee whiz, who would ever have thought? With the advent of satellites we can now see and measure with some precision how much ice there is and how much open water, even though the ice moves continuously. However, what is the significance of this? How long have these satellites been up there? Not long.

The cause of this greater melting this summer is pure speculation. For these scientists to blame it on man-caused global warming, and casually tossing out that cliche' phrase "greenhouse gases", is pure, irresponsible speculation. I for one, am getting really tired of hearing this excuse for every weather phenomena that science can not explain.
These ice scientists need to begin looking for another explanation for their unusual melting. Carbon dioxide emissions are not the culprit.
Peter

Arctic summer sea ice hits record low
Expert: In July 'it started to disappear at rates we had never seen before'

Arctic sea ice surrounds the U.S. Coast Guard Cutter Healy on July 22, 2006, as the icebreaker makes its way on a science expedition off Barrow, Alaska. This summer is likely to set a record in the minimum amount of Arctic sea ice.

The summer sea ice in the Arctic is melting at a rate never before seen by experts, setting a record low the last two days that's likely to continue through September, top sea ice experts said in two new reports that suggest mankind's emissions of greenhouse gases are at least partly responsible.
The National Snow and Ice Data Center on Friday said conditions on Thursday and Friday were already below the 2005 record and would likely stay that way through the end of summer.
“Today is a historic day,” said Mark Serreze, a senior research scientist with the center, which is located at the University of Colorado-Boulder. “This is the least sea ice we’ve ever seen in the satellite record and we have another month left to go in the melt season this year.”

Chances of the summer ending at a record low are 92 percent, the Arctic Regional Ice Forecasting System group at the University of Colorado-Boulder said in a second report.
Just last April the group estimated only a 33 percent chance of a record. The forecast, researcher Sheldon Drobot said in a statement, was "dramatically revised ... following a rapid disintegration of sea ice during July."
"During the first week in July, the Arctic sea ice started to disappear at rates we had never seen before," said Drobot.

The 2005 record saw the September minimum for sea ice drop to 2.15 million square miles. Drawing on satellite data, Drobot's team expects the September minimum for 2007 to range between 1.96 and 1.75 million square miles. Sea ice researchers focus on September and March because they generally mark the annual minimum and maximum sea ice extents, said Drobot.
Sea-ice extent is defined as the area of an ocean covered by at least 15 percent of ice, and in the Arctic it has been declining at least since the late 1970s, when satellite data became available, said Drobot.

'Triple whammy' cited The snow and ice center said that, while the situation could improve in the next few weeks, Thursday and Friday saw the extent at 386,000 square miles less than the 2005 record, the center said. "The bottom line: 2007 has already unseated the 2005 record, but we don't yet know by how much," it added.

"Sea ice extent is particularly low in the East Siberian side of the Arctic (the Chukchi and East Siberian Seas) and the Beaufort Sea north of Alaska," the center stated. "Satellite data also indicates less ice in the channels of the Canadian Arctic Archipelago, with open water north of Ellesmere Island and Greenland — a region typically ice-covered year-round."
The center noted that in late June and early July "sea ice declined at a pace of up to 210,000 square kilometers (81,081 square miles) per day, or the equivalent of an area the size of Kansas each day. This rate was unprecedented in the satellite record."

NSIDC
White areas show Arctic sea-ice extent on Aug. 13. The magenta line, which is the median location of the ice edge from 1979-2000, shows how much smaller this year's extent is.
The center attributed the rapid sea ice losses to a "triple whammy;" unusually warm temperatures, winds that pushed ice away from the coast and unusually clear skies.
The center also cited a pattern that it said seems to reflect the "memory" of the ice to changes in recent decades. "In particular, there is mounting evidence of a shift from fairly thick ice to thinner ice, with this thinner ice more apt to completely melt out in summer," it said.
Drobot's team echoed the data about thinner ice.

"We have been seeing a sharp decline in thicker, multi-year ice that has survived more than one melt season," said researcher James Maslanik. "This has been replaced in many areas by a thin, first-year layer of ice as well as by younger, thinner types of multi-year ice. The thinner ice just does not have the mass to withstand the effects of warming climate."
'Significant' climate shiftCalling Arctic sea ice "one of the better predictors of climate change on Earth," Drobot noted that "there will probably be about two-thirds as much sea this September as there was 25 years ago — a good indication that something significant is happening with the climate."




Drobot said he was convinced that high levels of greenhouse emissions from smokestacks and tailpipes have combined with natural fluctuations, such as an increase in cloud-free days over the Arctic this summer, to spur the melt. "There is an element of human activity in the cause of this melt," said Drobot. "Natural variations can't explain everything."
The melt itself can act as a feedback loop and cause ever more melting, because water has a darker surface than snow. "Water acts like a sponge sucking up a lot more solar energy," or heat, Drobot said.

Serreze said that while some natural variability is involved in the melting “we simply can’t explain everything through natural processes.”
“It is very strong evidence that we are starting to see an effect of greenhouse warming,” he said.
The puzzling thing, he added, is that the melting is actually occurring faster than computer climate models have predicted. Several years ago he would have predicted a complete melt of Arctic sea ice in summer would occur by the year 2070 to 2100, Serreze said. But at the rates now occurring, a complete melt could happen by 2030, he said Friday. There will still be ice in winter, he said, but it could be gone in summer.

Weather, shipping implications
Such high levels of ice melting could have wide implications in coming years such as changes in temperature and rain patterns across much of the United States. "Similar to the way the El Nino pattern affects weather in the United States, more ice melt could change rain patterns and temperature patterns in the middle of the United States, which could have economic impacts on farmers," Drobot said.

It could also open the Northwest Passage along the northern coast of North America and connect the Atlantic and Pacific Oceans to shipping by as early as 2020 or 2025, he said. That could be a cheaper option for many shippers than the Panama Canal, and it could open the region to energy exploration.

Melting Arctic ice could also fuel a new "Cold War" — one in which nations claim energy-rich waters for themselves. A Russian team on Aug. 2 planted a flag at the bottom of the North Pole. The United States, Canada and Denmark have also made moves to bolster their positions in the Arctic.
Reuters contributed to this report

Website Devoted To Cryosphere

The following is from a very cool website concerned with the Earth's "cryosphere", that which is covered in ice. The site is worth saving and referring to.
Peter

from: http://arctic.atmos.uiuc.edu/cryosphere/



A webspace devoted to the current state of our cryosphere
Archive of daily polar sea ice cap concentrations (1979 - present)
Dowload the historical sea ice dataset here
Questions and/or comments to William Chapman
sea ice animations: 1978-2006 (46 MB quicktime) 2001-2006 (11 MB quicktime)
recent ice area
hemispheric ice area
hemispheric anomaly
seasonal sea ice

tale of the tapeThursday, August 9, 2007 - New historic sea ice minimum
Today, the Northern Hemisphere sea ice area broke the record for the lowest recorded ice area in recorded history. The new record came a full month before the historic summer minimum typically occurs. There is still a month or more of melt likely this year. It is therefore almost certain that the previous 2005 record will be annihilated by the final 2007 annual minima closer to the end of this summer.
In previous record sea ice minima years, ice area anomalies were confined to certain sectors (N. Atlantic, Beaufort/Bering Sea, etc). The character of 2007's sea ice melt is unique in that it is dramatic and covers the entire Arctic sector. Atlantic, Pacific and even the central Arctic sectors are showing large negative sea ice area anomalies.

While we use sea ice concentration data supplied by NASA via the National Snow and Ice Data Center (NSIDC), there are some differencesbetween the way we and NSIDC process our sea ice indices. NSIDC uses 10-day running means; we use 3-day running means. NSIDC will often report sea ice extent indices and records, we are reporting a new sea ice minima sea ice area. The ice area metric includes year-to-year variations within the central pack ice and not just variations in the southern sea ice edge. Regardless of these differences, the rapid rate of sea ice melt this summer, along with the current negative sea ice anomalies almost guarantees a record Northern Hemisphere summer sea ice minimum this summer, by any metric.
Follow this link for some background information on historic sea ice minima.

"Simply Incredible" Shrinking Of Floating Arctic Ice

There is a large amount of evidence that the Earth's climate is warming. The questions are: Is this unusual? What are the causes? Is it necessarily bad? Is there anything that can realistically be done to halt or reverse the global warming?
Peter


Analysts See ‘Simply Incredible’ Shrinking of Floating Ice in the Arctic
By ANDREW C. REVKIN
Published: August 10, 2007
The area of floating ice in the Arctic has shrunk more this summer than in any other summer since satellite tracking began in 1979, and it has reached that record point a month before the annual ice pullback typically peaks, experts said yesterday. The cause is probably a mix of natural fluctuations, like unusually sunny conditions in June and July, and long-term warming from heat-trapping greenhouse gases and sooty particles accumulating in the air, according to several scientists.

William L. Chapman, who monitors the region at the University of Illinois Urbana-Champaign and posted a Web report on the ice retreat yesterday, said that only an abrupt change in conditions could prevent far more melting before the 24-hour sun of the boreal summer set in September. “The melting rate during June and July this year was simply incredible,” Mr. Chapman said. “And then you’ve got this exposed black ocean soaking up sunlight and you wonder what, if anything, could cause it to reverse course.”

Mark Serreze, a sea-ice expert at the National Snow and Ice Data Center in Boulder, Colo., said his center’s estimates differed somewhat from those of the Illinois team, and by the ice center’s reckoning the retreat had not surpassed the satellite-era record set in 2005. But it was close even by the center’s calculations, he said, adding that it is almost certain that by September, there will be more open water in the Arctic than has been seen for a long time. Ice experts at NASA and the University of Washington echoed his assessment.

Dr. Serreze said that a high-pressure system parked over the Arctic appeared to have caused a “triple whammy” — keeping away clouds, causing winds to carry warm air north and pushing sea ice away from Siberia, exposing huge areas of open water. The progressive summertime opening of the Arctic has intensified a longstanding international tug of war over shipping routes and possible oil and gas deposits beneath the Arctic Ocean seabed.

Last week, Russians planted a flag on the seabed at the North Pole. On Wednesday, Stephen Harper, the Canadian prime minister, began a tour of Canada’s Arctic holdings, pledging “to vigorously protect our Arctic sovereignty as international interest in the region increases.”