tagged w/ Albedo
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Let’s call it the polar express.
The multi-year ice floes that once dominated the Arctic Ocean have been shrinking fast over the past decade, replaced by pans that form anew each winter and melt away each spring. The increase in the extent of this seasonal ice has the potential to dramatically accelerate the warming of the planet’s far northern sea, according to a new four-year study published this week in Geophysical Research Letters.
It’s all hinges on how much sunshine gets absorbed and how much is bounced back into space over the course of a season, a physical process that scientists call albedo.
“My connection is really to answer a simple question — ‘Where does all the sunlight go?’” is how lead researcher Donald Perovich explained it in a You Tube video about the research near Barrow. “Or, to put it more scientifically, how is solar radiation partitioned among reflection, absorption and the ice in transmission to the ocean?”
The dazzling white and rugged surface of old, thick ice has the potential to reflect gobs of sunlight all summer. But the more fragile and flatter seasonal floes behave differently as the weeks pass — morphing from melting snow to standing ponds to the roiling green-gray of actual open water. As the ocean surface dominated by seasonal ice becomes less reflective, it absorbs more and more energy.
Self-fulfilling process
Spread the result over thousands of square miles season after season, and the Arctic Ocean will grow warmer at a much faster rate, boosting some forms of sea life while advancing the destruction of the seasonal ice cap, according to the findings in “Albedo evolution of seasonal Arctic sea ice.” In a sense, it’s becoming a self-fulfilling process, where the meltback of sea ice leads to an increasingly warmer upper ocean that leads to even greater ice loss in coming seasons.
“Once surface ice melt begins, seasonal ice albedos are consistently less than albedos for multi-year ice, resulting in more solar heat absorbed in the ice and transmitted to the ocean," wrote Perovich and co-author Christopher Polashenski, both with the U.S. Army’s Cold Regions Research and Engineering Laboratory in New Hampshire. This "shift from multi-year to seasonal ice cover has significant implications for the heat and mass budget of the ice and for primary productivity in the upper ocean.”
Tracking the dynamics of Arctic ice has never been more urgent. The extent and volume of the polar ocean’s ice cap has been shrinking fast over the past decade, climaxing each September with minimums at record and near record levels. (This spring, the extent of Arctic ice was greater than any late winter since the early 2000s, but still far below the long-term average for the time of year. See the May update from the National Snow & Ice Data Center.) Some climate models predict the Arctic will lose most of its multi-year ice by the end of the century if trends don’t change, with most of the ocean becoming ice-free by the end of every summer.
Theats to polar bears, walruses
An extensive polar ice cap has long played an essential role in stabilizing the world’s climate. It also provides essential habitat for healthy populations of polar bears, walruses and seals, and its disappearance during summer may threaten their survival. There are expensive indirect consequences too. The summer loss of ice has been creating fetches of hundreds of miles along the Chukchi and Beaufort sea coasts that now often expose Alaskan villages to catastrophic storms and erosion when fall weather starts bearing down.
More at the linkLet’s call it the polar express.
The multi-year ice floes that once dominated... more
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Last year the Arctic, which is warming faster than anywhere else on Earth due to global climate change, experienced its warmest twelve months yet. According to recent data by NASA, average Arctic temperatures in 2011 were 2.28 degrees Celsius (4.1 degrees Fahrenheit) above those recorded from 1951-1980. As the Arctic warms, imperiling its biodiversity and indigenous people, researchers are increasingly concerned that the region will hit climatic tipping points that could severely impact the rest of the world. A recent commentary in Nature Climate Change highlighted a number of tipping points that keep scientists awake at night.
"If set in motion, [tipping points] can generate profound climate change which places the Arctic not at the periphery but at the core of the Earth system," Professor Duarte, a climatologist with the University of Western Australia's Ocean Institute and co-author other paper, said in a press release. "There is evidence that these forces are starting to be set in motion. This has major consequences for the future of human kind as climate change progresses."
One of the tipping points is sea ice loss. The Arctic wasn't just relatively hot last year—beating the previous record set in 2010 by 0.17 degrees Celsius (0.3 degrees Fahrenheit)—it also experienced the lowest sea ice volume yet recorded, and the second-lowest extent. Sea ice is essential to many Arctic species, from polar bears to walrus, and narwhals to seals. In just over 30 years, sea ice volume has dropped precipitously, declining by 76 percent from 1979 (16,855 cubic kilometers) to 2011 (4,017 cubic kilometers). This loss of sea ice also leads to greater regional and global warming, as the Arctic's sea reflects the sun's light back into space, cooling not only the region but the world.
Sea ice loss may also be having a direct impact on weather in the mid-latitudes. In fact, recent research has suggested that, perhaps unintuitively, the extreme cold spell experienced by Europe this winter was linked to the sea ice decline in the Arctic. Researchers argue that the Arctic Oscillation, which is partially responsible for weather conditions in the Northern Hemisphere in winter, has become unhinged by the sea ice decline, causing more extreme winters, such as Europe's cold spell and the massive blizzards that hit the U.S. in 2009 and 2010.
But it's not just sea ice loss that has produced stark concerns: greenhouse gases from thawing permafrost could be just as disastrous. A study published in Nature late last year warned that greenhouse gas emissions due to permafrost thaw could equal the amount currently emitted by deforestation worldwide, a significantly larger estimate than has been put forward before. Moreover, since permafrost thaw emissions include methane, a more potent greenhouse gas than carbon, it could have an impact 2.5 times larger than deforestation overall.
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Further tipping points include an input of freshwater into the Atlantic Ocean from melting ice and glaciers, already increased by 30 percent, which Durate says "may affect the whole ocean current system and, as a result, the climate at a regional level."
Governments have responded to warming in the Arctic with a resource race. Governments with Arctic territories plan to drastically expand oil and gas exploitation, utilize new shipping routes, and increase mining. The industrialization of the Arctic, according to Duarte, may only accelerate impacts on the fragile region and push tipping points.
"[Arctic tipping points] represents a test of our capacity as scientists, and as societies to respond to abrupt climate change," Duarte said. "We need to stop debating the existence of tipping points in the Arctic and start managing the reality of dangerous climate change. We argue that tipping points do not have to be points of no return. Several tipping points, such as the loss of summer sea ice, may be reversible in principle—although hard in practice. However, should these changes involve extinction of key species—such as polar bears, walruses, ice-dependent seals and more than 1,000 species of ice algae—the changes could represent a point of no return."
The solution, Durate says, is to cut the fossil fuel emissions that are causing climate change.
CITATIONS: Carlos M. Duarte, Timothy M. Lenton, Peter Wadhams, Paul Wassmann. Abrupt climate change in the Arctic. Nature Climate Change, 2012; 2 (2): 60 DOI: 10.1038/nclimate1386.
Schuur, Edward A. G.; Abbott, Benjamin. Climate change: High risk of permafrost thaw. Nature. 480, 32–33. 2011. doi:10.1038/480032a.
Polar bears approach a U.S. attack sub 280 miles from the North Pole in an encounter that would have been unimaginable a century ago. As the sea ice melts and the Arctic warms, many nations see not a climate warming, but an opportunity to exploit the region for resources. Photo by: U.S. Navy.
Read more: http://news.mongabay.com/2012/0213-hance_arctic_tippingpoints.html?utm_source=dlvr.it&utm_medium=twitter#ixzz1mNBb8eGOLast year the Arctic, which is warming faster than anywhere else on Earth due to... more
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Can a whiter roof make your home cooler? What about your whole city?
The existing literature and theory suggests that increasing the albedo – or reflectiveness – of a building will reflect incoming sun light and associated heat, reducing the building’s cooling requirements and also reducing the “Urban Heat Island” effect. The City of Melbourne recently commissioned our team to look into whether these claims hold true for Melbourne’s climate.
The urban heat island (UHI) effect refers to the phenomenon whereby a metropolitan or built up area is significantly warmer than its surrounding areas. In some cases, the UHI effect makes average urban daytime air temperatures around 5-6°C higher than the surrounding rural areas in summer.
The urban heat island effect can be detected throughout the year, but it is of particular public policy concern during the summer. This is because higher surface air temperature is associated with air pollution, heat stress-related mortality and illness, and increases in electricity demand for air conditioning. For example, in Melbourne during the heat wave of February 2009 there were 374 “excess deaths” reported.
Increased vegetation, higher albedo surfaces and higher albedo pavements are cited as the main opportunities to reduce this urban heat island effect. During a typical sunny day, there is approximately 1 kW/m² of solar radiation hitting a roof’s surface. Between 20% and 95% of this radiation is absorbed – the difference is based on the different roof colours. This massive heat load affects the microclimate around our cities. The thermal or long wave radiation reradiated from building surfaces affects air temperature, relative humidity and wind speed.
Akbari and Konopacki have calculated the how much energy – used for cooling – would be saved by heat island mitigation strategies. They looked at the application of cool materials and increases in vegetation cover for 240 regions in the United States. They found that for residential buildings, the cooling energy savings vary between 12% and 25%; for office buildings between 5% and 18%; and for commercial (retail stores) buildings between 7% and 17%.
Our Melbourne-based research tested four buildings in a suite of six full-scale buildings of approximately 12m². We also constructed a smaller half-scale building to help us look at things that are hard to test on a real building: what happens when the roof gets dirty; where best to put sensors; and taking thermal images. The building treatments included three different types of paint, a control and a “green roof” (which we’ll be reporting on later). Our results are available in the full report on the City of Melbourne website.
We found that for older buildings (those that do not meet current Building Code of Australia insulation requirements), the high albedo paints will always provide a significant reduction in cooling requirements and increased comfort. Those that benefit the most are industrial buildings such as warehouses, airports, shopping centres, factories and commercial buildings.
Residential buildings show the least benefit. This is because homes need to be heated for a significant part of the year; painting the roof white loses the passive benefit of solar gain on the roof in winter (even if it’s minor). Further, when buildings have cooling systems on the roof, then the roof surface can be up to 40° cooler, leading to an efficiency benefit. That is, the system uses less energy to cool the air and the building requires less cooling because of the decreased solar gain in summer.
We looked at heat transfer, reflected energy off the roofs, internal ambient temperature, roof and ceiling temperatures and background weather data. We took into account variables such as insulation levels, paint tint and colour, roof pitch and overshadowing. All of these showed that there was still a benefit to using the white paint.
The only exception was a residence with R3.5 or greater insulation in the ceiling, because in Melbourne we spend 60% of the time heating and only 5-8% cooling. Under this scenario there was a benefit in summer but a cost in winter (though temperatures of twenty degrees or more can still build up in the roof cavity adding to the UHI).
This leads to the really interesting discussion which underpins this research. How does all this affect the larger context: urban heat islands, community benefits and the overall reduction of cooling energy use (and resulting greenhouse gas emission) across an entire city?
Our research, and that of the authors mentioned above, shows that there is a benefit to using the higher albedo treatments, green roofs and lighter roads and paths. The easiest and cheapest of these is paint. It will reduce cooling energy use, especially peak energy use. It will reduce the UHI and its associated health impacts. And it will lead to increased comfort.
To further enrich these findings we plan to continue our research for the next three years to look at different roofing materials, green roofs and photo-voltaic panel performance. We will also develop an urban microclimate model.
By Dominique Hes
Senior Lecturer in Sustainable Architecture at University of MelbourneCan a whiter roof make your home cooler? What about your whole city?
The existing... more
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I previously stated that I was going to recap 2011 regarding the extreme climate events we saw that have been the trend. I will say this is a much more daunting task than I had envisioned because without dispute, 2011 was the year climate change by our hand became indisputable. And even so, this was one of the underreported stories in 2011.
This is part 1 and covers not even barely the first three months nor all of the places where we saw these events occur. I will be continuing this in part 2 and perhaps even a part 3, with other different features to present the information.
I believe it is imperative that we understand the connection between our actions and the effects they are now having on the world we live in, our only home and the world community we share it with.
Thanks to those who supported the Climate Extremes Group in 2011. We will be here to continue providing information on this in the coming year with the hope that we will see the consciousness and perspective necessary to address this in the time we have left to do so.
This is about the survival of humanity! Our agriculture especially is being hard hit by this and food prices reflect that.
Part 2 coming soon.I previously stated that I was going to recap 2011 regarding the extreme climate... more
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"Accelerating melting on the world’s ice sheets and other new observations have scientists concluding that even a two-degree Celsius rise in temperatures – a benchmark long seen as safe in global climate talks and other emissions reductions scenarios – could lead to an 80-foot rise in sea levels.
“The dangerous level of global warming is less than what we thought a few years ago,” said James Hansen, director of NASA Goddard Institute for Space Studies. “It was natural to think that a few degrees wasn’t so bad…. (But) a target of two degrees is actually a prescription for long-term disaster.”
Antarctica and Greenland are losing ice at a surprising clip, Hansen said, and methane hydrates – a potent source of greenhouse gas frozen beneath the seas – are starting to bubble up.
The key question for climatologists: How sensitive is the climate to increasing amounts of fossil fuel emissions. Last year humanity pumped almost 10 billion tons of carbon dioxide into the atmosphere, a half-billion tons more than 2009 and the largest jump in any year since the Industrial Revolution, according to the Global Carbon Project.
See also Biggest Jump Ever in Global Warming Pollution in 2010, Chinese CO2 Emissions Now Exceed U.S.’s By 50%.
The problem, those researchers said, is the “hang time” for carbon dioxide in the atmosphere. Even if greenhouse gas emissions stopped tomorrow, “climatically important” amounts of carbon dioxide and other compounds emitted today would continue to influence the atmosphere for thousands of years, Caldeira said.
See also Fossil CO2 impacts will outlast Stonehenge and nuclear waste
That kind of pressure, or “forcing,” on the atmosphere could be devastating, he cautioned.
About 55 million years ago a tremendous amount of methane was released into the atmosphere over a period of about 1 million years, and the planet heated by five degrees to eight degrees Celsius, or 10 degrees to 14 degrees Fahrenheit. The result was an ice-free planet with sea levels 230 feet higher than they are today.
In the eons since, carbon dioxide levels dropped and the ice reformed. But humanity’s emissions have the potential to send the globe back to those conditions, Caldeira and Hansen said.
“If you doubled CO2, which practically all governments assume we’re going to do, that would eventually get us to the ice-free state,” Hansen said.
Scientists don’t expect that ice to melt quickly. Assuming the current accelerated melting continues on the world’s ice sheets and glaciers, various climate models predict the ocean would rise between 1.5 feet and 2.3 feet by century’s end, said Tad Pfeffer, a glaciologist with the University of Colorado.
But the ice melted with atmospheric carbon dioxide levels at about 1,000 parts per million, Caldeira said. And he suspects that even 750 ppm, or about double today’s levels, could send the globe spiraling toward an ice-free state. Current emissions trends suggest the globe could reach that by the end of the century.
“We can’t double CO2,” Hansen added. “We would be sending our climate back to a state we haven’t adjusted to as a species.”
The time to act was a while ago, but now is much, much better than later."
Related Posts:
•A detailed look at climate sensitivity
•Climate Experts Warn Thawing Permafrost Could Cause 2.5 Times the Warming of Deforestation
More at the link
Around 28:00 minutes into the video is information on CO2."Accelerating melting on the world’s ice sheets and other new observations... more
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Recent arctic sea ice loss is 'unprecedented' over the past 1,450 years, concludes a reconstruction of ice records published in the journal Nature.
The study, which was led by Christophe Kinnard of Chile's Centro de Estudios Avanzados en Zonas Aridas, used terrestrial proxies including ice cores, lake sediments, tree ring data, and historical sea ice observations from the Arctic region to reconstruct past summer sea ice extent, the period when Arctic sea ice is at its minimum. They conclude that "both the duration and magnitude of the current decline in sea ice seem to be unprecedented for the past 1,450 years" and blame higher Atlantic water temperatures, which they link to human-caused climate change, for the trend.
Comparison between reconstructed late-summer Arctic ice extent and other Arctic sea ice, climate and oceanic proxy records. a, 40-year smoothed reconstructed late-summer Arctic sea ice extent. b, Chukchi Sea ice cover. c, Fram Strait sea ice cover. d, Normalized IP25 flux in the BASICC-8 sediment core, a proxy for springtime sea ice occurrence in the western Barents Sea. f, Reconstructed Arctic surface air temperature anomalies. Caption and image adapted from Kinnard et al 2011. Click image to enlarge.
"These results reinforce the assertion that sea ice is an active component of Arctic climate variability and that the recent decrease in summer Arctic sea ice is consistent with anthropogenically forced warming," the authors write.
This year summer sea ice levels fell to the second-lowest extent since record-keeping began in 1979, according to the National Snow and Ice Data Center (NSIDC). The lowest-ever extent occurred in 2007.
Predictions range widely, but many experts expect the Arctic to be free of sea ice entirely within a few decades. By almost all standards, however, sea ice is disappearing faster than expected, partly a consequence of a positive feedback loop triggered by retreating ice. Sea ice typically helps cool the Arctic by reflecting sunlight back into space. But when sea ice melts, the dark areas of open water absorb the sun's radiation, warming the region and worsening melting.
Environmentalists are concerned that the loss of summer sea ice could have dramatic implications for wildlife -- like polar bear and walrus -- that depend on pack ice for feeding.
The loss of sea ice is also driving more exploitative industries, such as gas and oil, into once untouchable regions; however burning the fossil fuels lying beneath the Arctic will only worsen climate change, and thereby exacerbate ice loss in the Arctic.
CITATION: Christophe Kinnard, Christian M. Zdanowicz, David A. Fisher, Elisabeth Isaksson, Anne de Vernal & Lonnie G. Thompson. Reconstructed changes in Arctic sea ice over the past 1,450 years. 24 November Nature Vol 479 509-512
Read more: http://news.mongabay.com/2011/1124-sea_ice_record.html#ixzz1egityp18Recent arctic sea ice loss is 'unprecedented' over the past 1,450 years,... more
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Time to get louder at government about this. Time to win this conversation with truth. CO2 traps heat. One of the main points of this, plus some others I divulge. ;l). Thanks Current for this venue for us to tell it like it is.
This video is dedicated to the indigenous peoples of our world and those experiencing the brunt of the effects of climate change/biodistress. May we find it within us to do what is right for all.Time to get louder at government about this. Time to win this conversation with truth.... more
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The area covered by Arctic sea ice reached its lowest point this week since the start of satellite observations in 1972, German researchers announced on Saturday.
"On September 8, the extent of the Arctic sea ice was 4.240 million square kilometres (1.637 million square miles). This is a new historic minimum," said Georg Heygster, head of the Physical Analysis of Remote Sensing Images unit at the University of Bremen's Institute of Environmental Physics.
The new mark is about half-a-percent under his team's measurements of the previous record, which occurred on September 16, 2007, he said.
According to the US National Snow and Ice Data Center (NSIDC), the record set on that date was 4.1 million sq km (1.6 sq mi). The discrepancy, Heygster explained by phone, was due to slightly different data sets and algorithms.
"But the results are internally consistent in both cases," he said, adding that he expected the NSIDC to come to the same conclusion in the coming days.
Arctic ice cover plays a critical role in regulating Earth's climate by reflecting sunlight and keeping the polar region cool.
Retreating summer sea ice -- 50 percent smaller in area than four decades ago -- is described by scientists as both a measure and a driver of global warming, with negative impacts on a local and planetary scale.
It is also further evidence of a strong human imprint on climate patterns in recent decades, the researchers said.
"The sea ice retreat can no more be explained with the natural variability from one year to the next, caused by weather influence," Heygster said in an statement released by the university.
"Climate models show, rather, that the reduction is related to the man-made global warming which, due to the albedo effect, is particularly pronounced in the Arctic."
Albedo increases when an area once covered by reflective snow or ice -- which bounces 80 percent of the Sun's radiative force back into space -- is replaced by deep blue sea, which absorbs the heat instead.The area covered by Arctic sea ice reached its lowest point this week since the start... more
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A NASA analysis of satellite data quantified for the first time the amount of older and thicker "multiyear" sea ice lost from the Arctic through melt. A mosaic of satellite images show the movement of fragmented ice away from ice edge, which scientists use to track the loss of multiyear ice due to melt.
Since the start of the satellite record in 1979, scientists have observed the continued disappearance of older "multiyear" sea ice that survives more than one summer melt season. Some scientists suspected that this loss was due entirely to wind pushing the ice out of the Arctic Basin - a process that scientists refer to as "export."
In this study, Ron Kwok and Glenn Cunningham at NASA's Jet Propulsion Laboratory in Pasadena, Calif., used a suite of satellite data to clarify the relative role of export versus melt within the Arctic Ocean.
Kwok and Cunningham show that between 1993 and 2009, a significant amount of multiyear ice - 1,400 cubic kilometers (336 cubic miles - was lost due to melt, not export. "The paper shows that there is indeed melt of old ice within the Arctic basin and the melt area has been increasing over the past several years," Kwok said. "The story is always more complicated - there is melt as well as export - but this is a another step in calculating the mass and area balance of the Arctic ice cover."
The results have implications for understanding how Arctic sea ice gets redistributed, where melt occurs in the Arctic Ocean and how the ocean, ice and atmosphere interact as a system to affect Earth's climate. The study was published October 2010 in Geophysical Research Letters.
Scientists track the annual cycle of Arctic sea ice coverage as it melts through the summer to reach a minimum extent each September, before refreezing through fall and winter. Much of that ice is seasonal, meaning that it forms and melts within the year.
But multiyear ice that survives more than one season has also been declining, as noted in previous work by Joey Comiso of NASA's Goddard Space Flight Center in Greenbelt, Md., who shows a loss of about 10 percent per decade since the beginning of the satellite record in 1979. Scientists want to know where this loss is occurring.
"The decline of the multiyear ice cover of the last several decades has not been quantitatively explained," Kwok said.
To investigate the loss of multiyear ice, Kwok and Cunningham looked at a 17-year span of data from 1993 to 2009 from a range of polar-observing satellites and instruments including NASA's Quick Scatterometer (QuikScat); the Ice, Cloud and land Elevation Satellite (ICESat); the Advanced Microwave Scanning Radiometer (AMSR); and the European Space Agency's ERS-1 and ERS-2. Some instruments track ice coverage, while others track motion and concentration.
The team collected satellite images and tracked pixels of multiyear ice from April 1, prior to the onset of seasonal melt, and into the summer. Pixels that deviate away from images of the ice edge were considered lost to melt.
The team compared summertime melt of multiyear ice in the Beaufort Sea with estimates of ice lost from the Arctic basin through Fram Strait - a major passage through which ice can exit the Arctic Ocean. The comparison revealed how much multiyear ice was lost to export and how much was lost to melt.
They found that over the 17-year period, an area of 947,000 square kilometers (365,639 square miles), or about 32 percent of the decline in multiyear sea ice area, was lost in the Beaufort Sea due to melt.
A similar calculation using thickness estimates from NASA's ICESat from 2004 to 2009 show a volume loss of 1,400 cubic kilometers (336 cubic miles), or about 20 percent of the total loss by volume.
How and where multiyear ice is lost has impacts on the Arctic system. For example, more loss by melt means more freshwater remains in local Arctic waters rather than being transported southward.
"These results also show that thick multiyear sea ice is not immune to melt in the Pacific sector of the Arctic Ocean in today's climate," Kwok said.
cont.A NASA analysis of satellite data quantified for the first time the amount of older... more
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The Arctic region, also called the "planet's refrigerator," continues to heat up, affecting local populations and ecosystems as well as weather patterns in the most populated parts of the Northern Hemisphere, according to a team of 69 international scientists.
The findings were released Oct. 21, 2010 in the Arctic Report Card, a yearly assessment of Arctic conditions.
Among the 2010 highlights:
•Greenland is experiencing record-setting high temperatures, ice melt and glacier area loss;
•Summer sea ice continues to decline -- the 2009-2010 summer sea ice cover extent was the third lowest since satellite monitoring began in 1979, and sea ice thickness continues to thin. The 2010 minimum is the third lowest recorded since 1979, surpassed only by 2008 and the record low of 2007; and
•Arctic snow cover duration was at a record minimum since record-keeping began in 1966.
There is also evidence that the effect of higher air temperatures in the Arctic atmosphere in fall is contributing to changes in the atmospheric circulation in both the Arctic and northern mid-latitudes. Winter 2009-2010 showed a link between mid-latitude extreme cold and snowy weather events and changes in the wind patterns of the Arctic, related to a phase of the Arctic Oscillation.
"To quote one of my NOAA colleagues, 'whatever is going to happen in the rest of the world happens first, and to the greatest extent, in the Arctic,'" said Jane Lubchenco, Ph.D, under secretary of commerce for oceans and atmosphere and NOAA administrator. "Beyond affecting the humans and wildlife that call the area home, the Arctic's warmer temperatures and decreases in permafrost, snow cover, glaciers and sea ice also have wide-ranging consequences for the physical and biological systems in other parts of the world.
The Arctic is an important driver of climate and weather around the world and serves as a critical feeding and breeding ground that supports globally significant populations of birds, mammals and fish."
In 2006, NOAA's Climate Program Office introduced the annual Arctic Report Card, which established a baseline of conditions at the beginning of the 21st century to monitor the quickly changing conditions in the Arctic. Using a color-coded system of "red" to indicate consistent evidence of warming and "yellow" to show that warming impacts are occurring in many climate indicators and species, the Report Card is updated annually in October and tracks the Arctic atmosphere, sea ice, biology, ocean, land and changes in Greenland.
The Report Card can be found online at http://www.arctic.noaa.gov/reportcard.The Arctic region, also called the "planet's refrigerator," continues... more
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Arctic sea ice melted over the summer to cover the third smallest area on record, US researchers said Wednesday, warning global warming could leave the region ice free in the month of September 2030.
Last week, at the end of the spring and summer "melt season" in the Arctic, sea ice covered 4.76 million square kilometers (1.84 million square miles), the University of Colorado's National Snow and Ice Data Center said in an annual report.
"This is only the third time in the satellite record that ice extent has fallen below five million square kilometers (1.93 million square miles), and all those occurrences have been within the past four years," the report said.
A separate report by the National Oceanic and Atmospheric Administration (NOAA) found that in August, too, Arctic sea ice coverage was down sharply, covering an average of six million square kilometers (2.3 million square miles), or 22 percent below the average extent from 1979 to 2000.
The August coverage was the second lowest for Arctic sea ice since records began in 1979. Only 2007 saw a smaller area of the northern sea covered in ice in August, NOAA said.
The record low for Arctic sea ice cover at the end of the spring and summer "melt season" in September, was also in 2007, when ice covered just 4.13 million square kilometers (1.595 million square miles).
Mark Serreze, director of the NSIDC, said climate-change skeptics might seize the fact that Arctic sea ice did not hit a record-low extent this year, but said they would be barking up the wrong tree if they claimed the shrinkage had been stopped.
"Only the third lowest? It didn't set a new record? Well, right. It didn't set a new record but we're still headed down. We're not looking at any kind of recovery here," he told AFP.
In fact, Serreze said, Arctic sea ice cover is shrinking year-round, with more ice melting in the spring and summer months and less ice forming in the fall and winter.
"The Arctic, like the globe as a whole, is warming up and warming up quickly, and we're starting to see the sea ice respond to that. Really, in all months, the sea ice cover is shrinking -- there's an overall downward trend," Serreze told AFP.
"The extent of Arctic ice is dropping at something like 11 percent per decade -- very quickly, in other words.
"Our thinking is that by 2030 or so, if you went out to the Arctic on the first of September, you probably won't see any ice at all. It will look like a blue ocean, we're losing it that quickly," he said.
Losing sea ice cover in the Arctic would affect everything from the obvious, such as people who live in the far north and polar bears, to global weather patterns, said Serreze.
"The Arctic acts as a sort of refrigerator of the northern hemisphere. As we lose the ice cover, we start to change the nature of that refrigerator, and what happens up there affects what happens down here in the middle latitudes," he said.
"We might have less cold outbreaks, which you might say is a good thing, but it's not such a good thing in regions that depend on snowfall for their water supply."
NOAA noted in its report that the first eight months of 2010 were in equal first place with the same period in 1998 for the warmest combined land and ocean surface temperatures on record worldwide, and the summer months were the second warmest on record globally, after 1998.Arctic sea ice melted over the summer to cover the third smallest area on record, US... more
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In May, Arctic air temperatures remained above average, and sea ice extent declined at a rapid pace. At the end of the month, extent fell near the level recorded in 2006, the lowest in the satellite record for the end of May. Analysis from scientists at the University of Washington suggests that ice volume has continued to decline compared to recent years. However, it is too soon to say whether Arctic ice extent will reach another record low this summer—that will depend on the weather and wind conditions over the next few months.
Arctic sea ice extent averaged 13.10 million square kilometers (5.06 million square miles) for the month of May, 500,000 square kilometers (193,000 square miles) below the 1979 to 2000 average. The rate of ice extent decline for the month was -68,000 kilometers (-26,000 square miles) per day, almost 50% more than the average rate of -46,000 kilometers (18,000 square miles) per day. This rate of loss is the highest for the month of May during the satellite record.
Ice extent remained slightly above average in the Bering Sea, and below average in the Barents Sea north of Scandinavia, and in Baffin Bay.
As we noted in our May post, several regions of the Arctic experienced a late-season spurt in ice growth. As a result, ice extent reached its seasonal maximum much later than average, and in turn the melt season began almost a month later than average. As ice began to decline in April, the rate was close to the average for that time of year.
In sharp contrast, ice extent declined rapidly during the month of May. Much of the ice loss occurred in the Bering Sea and the Sea of Okhotsk, indicating that the ice in these areas was thin and susceptible to melt. Many polynyas, areas of open water in the ice pack, opened up in the regions north of Alaska, in the Canadian Arctic Islands, and in the Kara and Barents and Laptev seas.
The polynyas are clearly visible in high-resolution passive microwave images from the Advanced Microwave Sounding Radiometer (AMSR-E) aboard NASA’s Aqua satellite. What do current ice conditions mean for the minimum ice extent this fall? It is still too soon to say: although ice extent at present is relatively low, the amount of ice that survives the summer melt season will be largely determined by the wind and weather conditions over the next few months.
Average ice extent for May 2010 was 480,000 square kilometers (185,000 square miles) greater than the record low for May, observed in 2006, and 500,000 square kilometers (193,000 square miles) below the average extent for the month. The linear rate of decline for May over the 1979 to 2010 period is now -2.41% per decade.
The rate of decline through the month of May was the fastest in the satellite record; the previous year with the fastest daily rate of decline in May was 1980. By the end of the month, extent fell near the level recorded in 2006, the lowest in the satellite record for the end of May. Despite the rapid decline through May, average ice extent for the month was only the ninth lowest in the satellite record.In May, Arctic air temperatures remained above average, and sea ice extent declined at... more
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An Australian study suggests melting sea ice as a major cause of arctic warming in the past two decades.
University of Melbourne researchers led by James Screen said the increased Arctic warming was due to positive feedback between sea ice melting and atmospheric warming.
"The sea ice acts like a shiny lid on the Arctic Ocean," Screen said. "When it is heated, it reflects most of the incoming sunlight back into space. When the sea ice melts, more heat is absorbed by the water. The warmer water then heats the atmosphere above it. What we found is this feedback system has warmed the atmosphere at a faster rate than it would otherwise."
The scientists said their findings conflict with previous hypotheses that warmer air transported from lower latitudes toward the pole, or changes in cloud cover, are the primary causes of enhanced Arctic warming.
The arctic region has experience the fastest warming of any area on Earth, partly caused by increasing human greenhouse gas emissions, Screen said. At the same time, the arctic ice has been declining dramatically.
Professor Ian Simmonds, of the university's School of Earth Sciences and co-author of the research paper says the findings are significant.
"It was previously thought that loss of sea ice could cause further warming," Simmonds said. "Now we have confirmation this is already happening."
The study appears in the journal Nature.An Australian study suggests melting sea ice as a major cause of arctic warming in the... more
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The multiyear ice covering the Arctic Ocean has effectively vanished, a startling development that will make it easier to open up polar shipping routes, an Arctic expert said on Thursday.
Vast sheets of impenetrable multiyear ice, which can reach up to 80 meters (260 feet) thick, have for centuries blocked the path of ships seeking a quick short cut through the fabled Northwest Passage from the Atlantic to the Pacific. They also ruled out the idea of sailing across the top of the world.
But David Barber, Canada's Research Chair in Arctic System Science at the University of Manitoba, said the ice was melting at an extraordinarily fast rate.
"We are almost out of multiyear sea ice in the northern hemisphere," he said in a presentation in Parliament. The little that remains is jammed up against Canada's Arctic archipelago, far from potential shipping routes.
Scientists link higher Arctic temperatures and melting sea ice to the greenhouse gas emissions blamed for global warming.
Barber spoke shortly after returning from an expedition that sought -- and largely failed to find -- a huge multiyear ice pack that should have been in the Beaufort Sea off the Canadian coastal town of Tuktoyaktuk.
Instead, his ice breaker found hundreds of miles of what he called "rotten ice" -- 50-cm (20-inch) thin layers of fresh ice covering small chunks of older ice.
"I've never seen anything like this in my 30 years of working in the high Arctic ... it was very dramatic," he said.
"From a practical perspective, if you want to ship across the pole, you're concerned about multiyear sea ice. You're not concerned about this rotten stuff we were doing 13 knots through. It's easy to navigate through."
Scientists have fretted for decades about the pace at which the Arctic ice sheets are shrinking. U.S. data shows the 2009 ice cover was the third-lowest on record, after 2007 and 2008.
An increasing number of experts feel the North Pole will be ice free in summer by 2030 at the latest, for the first time in a million years.
"I would argue that, from a practical perspective, we almost have a seasonally ice-free Arctic now, because multiyear sea ice is the barrier to the use and development of the Arctic," said Barber.
Fresh first-year ice always forms in the Arctic in the winter, when temperatures plunge far below freezing and the North Pole is not exposed to the sun.
http://www.reuters.com/article/environmentNews/idUSTRE59S3LT20091029?feedType=RSS&feedName=environmentNewsThe multiyear ice covering the Arctic Ocean has effectively vanished, a startling... more
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It's been a strange summer around here. We had the wettest, coldest June in memory. July and August weren't much better, and we're still waiting for our first official heat wave. But if you think this tells you anything about global warming, you're looking out the wrong window.
Instead, turn your gaze northward. Climate change is most visible at the extremes, the top and bottom of the earth. And the people who watch the poles most closely are more worried than ever.
That would be the consortium of scientists known as International Polar Year. Its latest findings indicate that some of the dire predictions of climate scientists were off - in the wrong direction. Things are trending worse than the "worst case scenarios" envisioned in the most recent reports of the authoritative Intergovernmental Panel on Climate Change.
The melting of Arctic sea ice has been evident for years in NASA satellite photos and eyewitness accounts. CIA photos, classified under the Bush administration but declassified under President Obama, are even more dramatic, showing slushy ice - or no ice at all - in areas frozen solid not long ago.
The IPY repeated the measurements taken by an Arctic expedition in 1893, finding that the ice cap, which was typically 12 feet thick a century ago, is now between one and three feet thick. Summer sea ice could disappear completely by 2020, researchers say.
That's ahead of the models in the IPCC's 2007 report, mostly because the IPCC assumed the world would have begun to slow the growth of carbon dioxide emissions. No such luck.
There's more bad news coming out of Greenland, where the IPCC low-balled estimates of glacial melting. New, more sophisticated measurements show Greenland is now losing 52 cubic miles of ice every year. Since Greenland is a land mass with ice on top, its melting glaciers cause sea levels to rise, unlike the floating Arctic ice. While the IPCC estimated sea levels would rise 16 inches this century, Sharon Begley reports in Newsweek that IPY scientists now project a rise of at least 39 inches.
Even more disturbing is the news on Arctic permafrost, which is rapidly melting. As it melts, the permafrost releases carbon into the atmosphere, making global warming worse. New calculations project that, at its peak, the melting will put between 1 billion and 2 billion tons a year into the atmosphere, Begley reports - or up to six times as much carbon as generated each year by American cars and light trucks.
Another recalculation triples the estimate of CO2 locked in the permafrost: Experts now say there is two times as much carbon in the permafrost as is currently in the atmosphere.
These new findings are a reminder that climate change is a moving target, that scientists can get things wrong, and that projections can be off - on either the good side or the bad side. While many have hoped the doom and gloom projections would prove exaggerations, new data shows they were over-optimistic.
end of excerptIt's been a strange summer around here. We had the wettest, coldest June in... more
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Due to cloud formation on earth.... the planet may reverse global warming with out our help!!!!
The Earth's climate depends on the net sunlight deposited on the globe, which is critically sensitive to the Earth's albedo. A global and absolutely calibrated albedo can be determined by measuring the amount of sunlight reflected from the Earth and, in turn, back to the Earth from the dark portion of the face of the Moon (the `earthshine; or `ashen light').
What earthshine looks like on the moon, using photo enhancement on the lower left. BBSO uses a blocking filter to dim the moonshine crescent, typically about 10,000 times brighter than the earthshine.
The lower the albedo of the Earth, the greater amount of solar radiation it will absorb. The greater the albedo, the more solar radiation is reflected. This of course affects earthly temperatures.
The Earthsine project is producing interesting results. That the Earth's Albedo has risen in the past few years, and by doing reconstructions of the past albedo, it appears that there was a significant reduction in Earth's albedo leading up to a lull in 1997. 1998 has been touted as one of the warmest years on record, and the time lag may have had to do with the thermal inertia of the oceans. Then the albedo increased, making the earth more reflective. Clouds have the greatest potential for changing albedo on a short time scale.
(See Article for Paragraph explaining the Graph that shows the Data involved)
The most interesting thing here is that the albedo forcings, in watts/sq meter seem to be fairly large. Larger than that of all manmade greenhouse gases combined:
Carbon dioxide: 1.5 Watts per square meter.
Methane: 0.5 Watts per square meter.
Nitrous oxide: 0.2 Watts per square meter.
Halocarbons: 0.2 Watts per square meter.
Total from all greenhouse gases: 2.4 Watts per square meter.
This rapidly changing albedo lends some credence to Svensmark's theory of Earth's cloud cover being modulated by Galactic Cosmic Rays, but it could also be caused by other factors such as aerosols.
Whatever the cause for the rapid change in albedo, it seems to have quite an effect of earth's radiation budget. The California Instttute of Technology made a press release in 2004 that summed up the project fairly well:
By using a combination of earthshine observations and satellite data on cloud cover, the earthshine team has determined the following:
Earth's average albedo is not constant from one year to the next; it also changes over decadal timescales. The computer models currently used to study the climate system do not show such large decadal-scale variability of the albedo.
The annual average albedo declined very gradually from 1985 to 1995, and then declined sharply in 1995 and 1996. These observed declines are broadly consistent with previously known satellite measures of cloud amount.
The low albedo during 1997-2001 increased solar heating of the globe at a rate more than twice that expected from a doubling of atmospheric carbon dioxide. This dimming of Earth, as it would be seen from space, is perhaps connected with the recent accelerated increase in mean global surface temperatures.
2001-2003 saw a reversal of the albedo to pre-1995 values; this brightening of the Earth is most likely attributable to the effect of increased cloud cover and thickness.
These large variations, which are comparable to those in the earth's infrared radiation observed in the tropics by satellites, comprise a large influence on Earth's radiation budget.
Due to cloud formation on earth.... the planet may reverse global warming with out our... more
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