tagged w/ positive feedback loops
-
The ongoing rapid retreat of Arctic sea ice is often interpreted as the canary in the mine for anthropogenic climate change. In a new study, scientists have now systematically examined the validity of this claim. They find that neither natural fluctuations nor self-acceleration can explain the observed Arctic sea-ice retreat. Instead, the recent evolution of Arctic sea ice shows a strong, physically plausible correlation with the increasing greenhouse gas concentration. For Antarctic sea ice, no such link is found - for a good reason.
When scientists try to attribute some observed climatic change to a specific forcing, they usually use complex climate models. The scientists at Germany's Max Planck Institute for Meteorology (MPI-M), however, decided on a different strategy as they set out to identify the main driver for the observed sea-ice loss in the Arctic. Dirk Notz, lead author of the study that was now published in the journal Geophysical Research Letters [1], explains why: "Sea ice is so thin that it reacts very sensitive to the large natural fluctuations of weather and climate that prevail in the Arctic. Because these fluctuations are inherently chaotic, their specific timing cannot be reproduced by standard climate models. Such models therefore aren't necessarily the best tool to examine if natural fluctuations did cause the observed sea-ice loss."
The scientists instead used a historical record that described the natural variations of sea-ice extent between the early 1950s and late 1970s. These natural fluctuations were then compared to the magnitude of fluctuations of the Arctic sea-ice cover as measured from satellites since the late 1970s. From such comparison, the scientists found only a minute chance that the recently observed extreme sea-ice minima simply happened by chance - and they could exclude self acceleration as the main driver for the observed sea-ice retreat. "Whenever we had a strong sea-ice loss from one year to the next, the ice cover always recovered somewhat in the following year," explains Dirk Notz. This would not be the case if the sea-ice retreat were indeed self-accelerating.
Jochem Marotzke, Director at MPI-M and co-author of the study, describes what the scientists did next: "Having excluded natural fluctuations and self acceleration as the main driver for the sea-ice retreat, it was clear to us that some external driver was responsible for the observed sea-ice decline. We therefore set out to find an external driver that showed a physically plausible relationship with the observed sea-ice retreat." The scientists examined, for example, the strength of solar radiation. "Here, a physically plausible link to the observed sea-ice retreat can only be established if solar radiation had increased in recent years." However, solar radiation has slightly decreased in the past decades. Its fluctuations are therefore very unlikely to be the main driver of the observed sea ice loss. The scientists could not find a plausible link to changes in prevailing wind patterns, volcanic eruptions, oceanic heat transport, or cosmic rays, either.
"In the end, only the increase in greenhouse gas concentration showed a physically plausible link with the observed sea-ice retreat.
More at the linkThe ongoing rapid retreat of Arctic sea ice is often interpreted as the canary in the... more
-
-
Karina Pinasco watched in dismay as flames on a hillside at the edge of town lit up the sky one night in October 2010. A farmer had intended to clear a few hectares of land to plant coffee bushes, but the fire – set during an unusually hot, dry spell – quickly got out of hand.
Propelled by winds and high temperatures, it burned for 10 days, charring more than 250 acres of land.
"We realized we weren't prepared," says Pinasco, a biologist who heads Amazónicos por la Amazonía, a local environmental organization. "The firefighters weren't trained. It was the rain that finally put it out."
Scientists used to think the rainforest, especially in the western Amazon, was too wet to burn. But major fire seasons in 2005 and 2010 made them reconsider.
Fires are a major source of carbon emissions in the Amazon, and scientists are beginning to worry that the region could become a net emitter, instead of a carbon sink. New findings link rising ocean temperatures off the northern coast of Brazil to changing weather patterns: As the Atlantic warms, it draws moisture away from the forest, priming the region for bigger fires.
"We are reaching a tipping point in terms of drought, beyond which these forests can catch fire," says Daniel Nepstad, international program director at the Amazon Environmental Research Institute in Brasília, Brazil.
Once-a-century no more
The 2005 drought – considered a once-in-a-century event – resulted in unprecedented wildfires in Acre, the western Brazilian state bordering Peru. Flames scorched the tree canopy, and at one point the front face of the fire stretched nearly seven miles. As many as 1.2 million acres of forests were affected in Acre and the neighboring regions of Pando in Bolivia and Madre de Dios in Peru. Officials estimated upwards of $100 million in economic damages.
But the forest loss wasn't the only concern for the Acre state government, said Foster Brown, a senior scientist at the Woods Hole Research Center and a professor at the Federal University of Acre in Rio Branco, the state capital. Choking smoke spiked respiratory ailments in the region and canceled flights.
Just five years later, another once-a-century drought struck, and fires spread out of control, especially in Acre, Bolivia's Pando region and Brazil's Mato Grosso state. Acre was better prepared, but in Bolivia, smoke from more than 20,000 fires reduced visibility and shut airports in several towns. The Bolivian government declared a state of emergency as more than 3.5 million acres of forest burned. In Mato Grosso, fires destroyed at least 100 homes.
Gigatons of carbon
The 2005 fires added 1.6 gigatons of carbon to the atmosphere, according to a study by Simon Lewis of the University of Leeds, who put emissions from the more widespread 2010 fires at 2.2 gigatons.
In a normal year, the Amazon forests store 0.4 gigatons of carbon a year in the trees and soil, meaning that two bad seasons like 2005 and 2010 could wipe out a decade of gain, according to Lewis' calculations.
And as humans push further into an increasingly drier Amazon, the problem could worsen.
In the western Amazon, humans are the chief source of sparks. With new roads being built and paved through once-inaccessible areas, Peru's Amazonian regions now have some of the country's highest population growth rates. Many of the newcomers clear a little land to farm, and where there are farms, there is fire.
Fire risks
In the Amazon, where weeds and insects run rampant, burning is the most cost-effective way for small farmers to control ticks in cattle pastures and unwanted plants in cassava fields, says Miguel Pinedo-Vásquez, director of international programs for the Columbia University Center for Environmental Research and Conservation, who also works with the Center for International Forestry Research.
More at the linkKarina Pinasco watched in dismay as flames on a hillside at the edge of town lit up... more
-
-
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.
snip
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
-
-
“Arctic Story,” a full-length documentary by photographer Jenny E. Ross, documents the changing lifestyle and environment of the Inuit people of Siorapaluk, the northernmost settlement on Earth. “The sea remains unfrozen along the coast in late fall, at a time of year when it should be covered with ice,” Ross writes on the film’s Vimeo page. “Glaciers are melting, and shedding huge quantities of ice and meltwater into the ocean. The animals inhabiting the land and water are threatened by rising temperatures and loss of sea ice. Greenlanders who have survived for generations by hunting are now losing their prey and their traditional way of life."
You can also view this in the comments below if it will not play here.“Arctic Story,” a full-length documentary by photographer Jenny E. Ross,... more
-
-
The agreement between these studies using a variety of different methods and approaches is quite remarkable. Every study concluded that over the most recent 100-150 year period examined, humans are responsible for at least 50% of the observed warming, and most estimates put the human contribution between 75 and 90% over that period (Figure 2). Over the most recent 25-65 years, every study put the human contribution at a minimum of 98%, and most put it at well above 100%, because natural factors have probably had a small net cooling effect over recent decades (Figures 3 and 4).
Additionally, in every study over every timeframe examined, the two largest factors influencing global temperatures were human-caused: (1) GHGs, followed by (2) human aerosol emissions. This is a dangerous situation because as we clean our air and reduce our SO2 emissions, their cooling effect will dissipate, revealing more of the underlying GHG-caused global warming trend. Note that not all studies broke out the effects the same way (i.e. only examining ‘natural’ and not solar or volcanic effects individually), which is the reason some bars appear to be missing from Figures 2 to 4.
Figure 2: Percent contributions of various effects to the observed global surface warming over the past 100-150 years according to Tett et al. 2000 (T00, dark blue), Meehl et al. 2004 (M04, red), Stone et al. 2007 (S07, green), Lean and Rind 2008 (LR08, purple), Stott et al. 2010 (S10, gray), and Huber and Knutti 2011 (HR11, light blue).
Figure 3: Percent contributions of various effects to the observed global surface warming over the past 50-65 years according to Tett et al. 2000 (T00, dark blue), Meehl et al. 2004 (M04, red), Stone et al. 2007 (S07, green), Lean and Rind 2008 (LR08, purple), Huber and Knutti 2011 (HK11, light blue), and Gillett et al. 2012 (G12, orange).
Figure 4: Percent contributions of various effects to the observed global surface warming over the past 100-150 years according to Meehl et al. 2004 (M04, red), Lean and Rind 2008 (LR08, purple), and Foster and Rahmstorf 2011 (FR11, green).
There was a period of warming between 1910 and 1940 which was predominantly caused by increasing solar activity and an extended period of low volcanic activity, with some contribution by human effects. However, since mid-century, solar activity has been flat, there has been moderate volcanic activity, and ENSO has had little net impact on global temperatures. All the while GHGs kept increasing, and became the dominant effect on global temperature changes, as Figures 3 and 4 illustrate.
A wide variety of statistical and physical approaches all arrived at the same conclusion: that humans are the dominant cause of the global warming over the past century, and particularly over the past 50 years. This robust scientific evidence is why there is a consensus among scientific experts that humans are the dominant cause of global warming.
More at the linkThe agreement between these studies using a variety of different methods and... more
-
-
In the past, the bright surface of the Greenland Ice Sheet reflected well over half of the sunlight that fell on it. This reflectiveness helped keep the ice sheet stable, as less absorbed sunlight meant less heating and melting. In the past decade, however, satellites have observed a decrease in Greenland’s reflectiveness. This darker surface now absorbs more sunlight, which accelerates melting.
The map above shows the difference between the amount of sunlight Greenland reflected in the summer of 2011 versus the average percent it reflected between 2000 to 2006. Virtually the entire ice sheet shows some change, with some areas reflecting close to 20 percent less light than a decade ago. The map is based on observations from the Moderate Resolution Imaging Spectroradiometer (MODIS) instruments on NASA’s Terra and Aqua satellites. It was produced as part of the National Oceanic and Atmospheric Administration’s Arctic Report Card.
Climate scientists have long expected that Earth’s polar regions will become less reflective as global temperatures rise. Rising temperatures melt snow and ice, and the uncovered terrain—water, vegetation, bare ground—is darker and absorbs more sunlight. The loss of reflectiveness then amplifies the initial warming.
Most of the patterns on the map fit expectations. Warmer, lower-elevation areas of the ice sheet have darkened more than the colder, higher-altitude interior. Each summer, winter snow retreats from the edge of the ice sheet. Dark pools of melt water form on the surface of the ice, and windblown dust and other particles also collect near the surface, making it even less reflective.
But the darkening in the interior is just as remarkable as the changes at the margins, according to Jason Box of Ohio State University, who analyzed the reflectiveness data. The interior is the high point of the ice sheet, nearly two miles above sea level, and there is no visible melting in the summer. So why is the area becoming darker?
The darkening, says Box, is due to changes in the shape and size of the ice crystals in the snowpack. As temperatures rise, snow grains clump together and reflect less light than the many-faceted, smaller crystals (see lower image from a scanning electron microscope). Additional heat rounds the sharp edges of the crystals, and round particles absorb more sunlight than jagged ones.
More at the linkIn the past, the bright surface of the Greenland Ice Sheet reflected well over half of... more
-
-
From site: "Since we have such an active community of armchair oceanographers and spreadsheet Glaciologists here, I thought it would be useful to speak to the real thing, the people who actually spend time on the ocean, on the ice sheets, do the measurements, and come back to share that knowledge with us. I had just that opportunity at the American Geophysical conference in December.
I spoke to Josh Willis, Oceanographer with NASA at the Jet Propulsion Lab – Josh is one of best known young ocean scientists on the planet. He pointed me to the recent Kemp et al study of tidal marshes on the US East coast, which has produced a long record of sea level over the last 2000 years, complete with a very Hockey-stickish uptick during the last 200 or so.
Jason Box of the Byrd Polar Center at Ohio State was there, presenting evidence of acceleration in Greenland ice loss over the last 200 years. His bottom line – “If we talk 10 years from now, my expectation is that Greenland will be losing roughly double what it is now.”
I round out the video with takes from old pros lead NASA scientist Jim Hansen and Admiral David Titley, the US Navy’s Chief Oceanographer.
More at the link
~~~
And you can time it to the second how long it will take for the usual suspects who follow me to appear...They actually think they are converting people to believing their denier "religion" over actual scientists who are measuring the oceans and glaciers and what is right in front of our eyes. Laughable.From site: "Since we have such an active community of armchair oceanographers and... more
-
-
This is part two of my recap of climate extremes globally for 2011. The first video dealt with the global effects in other countries for almost the first half of 2011. This part deals with the U.S. Part 3 coming up will deal with the global effects from the second half of 2011 with some other information added. I hope this is at least informative and puts the totality and urgency of what we now face into perspective. I can say that making this even though I already understand these effects has been a sad and sobering experience.
My heart goes out to those who lost loved ones, homes, wildlife and farms.
2012 must be the year we collectively wake up.This is part two of my recap of climate extremes globally for 2011. The first video... more
-
-
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
-
-
The recent scientific literature makes clear that while that death spiral could theoretically be reversed, it would require policies that climate science deniers have successfully demonized, policies many in the traditional media regularly pooh pooh or undercut.
So we have passed a de facto tipping point, “the critical point in an evolving situation that leads to a new and irreversible development.” If that wasn’t obvious from observations, then it should have been clear from a December study in Nature widely misunderstood by the media. That study showed sea ice extent crashing by two thirds by the 2030s and then collapsing to near-zero shortly thereafter — unless we cut global GHG emissions about 60% to 70% almost immediately and have further cuts after that, an implausible assumption the authors never spelled out clearly (as I explain here).
Now comes a new study that has also proven an irresistible source of confusion to both the deniers and the media, “A 10,000-Year Record of Arctic Ocean Sea-Ice Variability—View from the Beach” (subs. req’d). The news release is as misleading as the Nature article:
“The bad news is that there is a clear connection between temperature and the amount of sea ice. And there is no doubt that continued global warming will lead to a reduction in the amount of summer sea ice in the Arctic Ocean. The good news is that even with a reduction to less than 50% of the current amount of sea ice the ice will not reach a point of no return: a level where the ice no longer can regenerate itself even if the climate was to return to cooler temperatures,” [lead author Svend] Funder says.
Huh? How precisely is the climate going to return to cooler temperatures? It really bugs me when scientists who are very sophisticated in one arena — here, proxy reconstructions of ice coverage of part of the Arctic — exhibit magical thinking in another area.
The best recent models show staggeringly high Arctic warming this century if we stay on our current emissions path (see M.I.T. doubles its 2095 warming projection to 10°F — with 866 ppm and Arctic warming of 20°F). Cooling ain’t in the cards. Quite the reverse.
The Nature article projected a 50% decline in sea ice within 2 decades no matter what we do on emissions — and then total collapse even on a scenario with significant emissions reductions. As an aside, since that study almost certainly underestimated the rate of sea ice loss — for instance, it ignores black carbon, a major source of ice loss — I tend to think that the actual summer ice loss will be somewhere between what that study projected and the oversimplified quadratic projections in the figure above.
The BBC, which promised better coverage on climate change, failed to deliver this time — as can be seen in its story, “Arctic ‘tipping point’ may not be reached.”
NYT opinion blogger Andy Revkin wrote one of the worst pieces in his career, “On Arctic Ice and Warmth, Past and Future,” which quickly became a darling of the hard-core anti-science deniers for these absurd lines:
But even as I push for an energy quest that limits climate risk, I’m not worried about the resilience of Arctic ecosystems and not worried about the system tipping into an irreversibly slushy state on time scales relevant to today’s policy debates. This is one reason I don’t go for descriptions of the system being in a “death spiral.”
The main source of my Arctic comfort level — besides what I learned while camped with scientists on the North Pole sea ice — is the growing body of work on past variations* in sea ice conditions in the Arctic. The latest evidence comes in a study in the current issue of Science. The paper, combining evidence of driftwood accumulation and beach formation in northern Greenland with evidence of past sea-ice extent in parts of Canada, concludes that Arctic sea ice appears to have retreated far more in some spans since the end of the last ice age than it has in recent years.
“Not worried about the resilience of Arctic ecosystems“? Seriously?
Exactly what Arctic ecosystems are going to survive the accelerated warming humans are imposing, warming that will occur at twice the rate of the planet as a whole? And that is compounded by ocean acidification, which is equally devastating in the Arctic.
Revkin’s wishy-washy “energy quest” can’t stop either of those disasters. Indeed, Revkin never tells you what CO2 concentrations target he is questing for, but he endlessly criticizes those of us who actually spell out a target, like 450 ppm (or lower) and a path to achieve it. He dismisses such targets as a “magically safe level of carbon dioxide” — a reductio ad absurdum meant to put him above the fray, allowing him to critique all those trying to avert 800+ ppm — a CO2 level he once told me is where he expects we’ll end up.
Indeed in 2008, he himself quoted Nobelist Sherwood Rowland who thinks we’re headed toward 1000 ppm, an unimaginable catastrophe. Back then he wrote, “Keep in mind that various experts and groups have said risks of centuries of ecological and economic disruption rise with every step toward and beyond 450 parts per million.” Now, by failing to identify even a range we should aim for, say 400 to 500 ppm or policies that could plausibly keep us near such a range — and worse, by mocking those of us who do — he is effectively endorsing the acceptability of the 800 to 1000 ppm range.
The science is clear that human-caused Arctic warming has overtaken 2,000 years of natural cooling, as a “seminal” 2009 Science study found” [see figure below]:
In short, “greenhouse gas emissions are overwhelming the system,” as David Schneider, a visiting scientist at the National Center for Atmospheric Research and one of the co-authors of the 2009 Science article put it.
Oh, but Revkin says he’s “not worried about the system tipping into an irreversibly slushy state on time scales relevant to today’s policy debates.”
Well, NOAA and the National Snow and Ice Data Center (NSIDC) are worried, and unlike Revkin, they have published science to back them up — see NSIDC bombshell: Thawing permafrost feedback will turn Arctic from carbon sink to source in the 2020s, releasing 100 billion tons of carbon by 2100.
More at the linkThe recent scientific literature makes clear that while that death spiral could... more
-
-
A wildfire that burned over 400 square miles of Alaska tundra in the scorching summer of 2007 poured as much carbon into the atmosphere as the entire Arctic normally absorbs each year, according to a new study in the scientific journal Nature.
The tundra fire, near the Anaktuvuk River of Alaska's North Slope, was considered an unprecedented event at the time. It was, by far, the largest single wildfire on treeless Arctic tundra ever recorded, and was twice as big as all previously recorded Alaska tundra fires combined.
But it may be an ominous sign of climate problems in the future, according to the study and the researchers who conducted it.
The study, published on Thursday, measured the volume of carbon emitted by the months-long fire -- although massive it covered only a tiny portion of the vast North Slope -- at 2.1 million metric tons.
"It was the same order of magnitude as what the Arctic takes up and stores in plant biomass," said Syndonia Bret-Harte of the Institute of Arctic Biology at the University of Alaska, Fairbanks, one of the study's authors.
That creates the potential for a "positive feedback" loop that would reinforce the warming trend in the far north, according to the study.
Repeated large fires might even cancel out any potential carbon-absorption benefits from increased plant growth in the Arctic that has been made possible by the region's warming climate, the researchers said.
Fires on the Arctic tundra are not unusual, but most blazes are very small and short-lived because of the cool climate and the dampness of the environment, Bret-Harte said.
The 2007 fire, however, occurred under extreme conditions -- an especially hot, dry year, marked by the smallest Arctic sea ice cover ever recorded by satellite, plus strong winds. The lightning-sparked blaze began in July of that year and smoldered for weeks before it was whipped up by winds in September, when tundra plants were dried out, she said.
All indications are that climate changes in the Arctic will make future fires more likely, Bret-Harte said. Lightning strikes on the North Slope have increased dramatically over the last 20 years, raising the potential for fire starts, while temperatures are rising, he said.
"The expectation would be that conditions that allowed that to happen could probably recur in the future," Bret-Harte said. "We'll probably see it more frequently than we have in the past."
One bright note in the study was the discovery that none of the material burned in the fire was older than 50 years, contrary to fears the fire released carbon that had been stored in the soils from vegetation that grew hundreds or thousands of years ago.
More at the link.A wildfire that burned over 400 square miles of Alaska tundra in the scorching summer... more
-
-
http://progressivesforgore.blogspot.com/2011/07/24-hours-of-reality.html
It's way past time to cut through all of the propaganda spewed forth incessantly by the same interests that care nothing for this planet or your future. It's the only way to have one now. We are running out of time.
We will not solve this crisis until we all resolve to be a part of the solution.
Will you participate in Reality?
I am going to try to put together a movie of my own that connects these dots and post it in as many places as I can.
I am going to be relentless in letting the US government know that as citizens we will not allow them to continue to betray our trust and the environmental stability that affects all of the other facets of our lives.
I am going to continue filming my own user created content program "Biorhythms" for the Current site under Earth Care, and on it I will continue to present news of the environment we do not see reported on MSM with a focus on humanity, environment and the meaning of the events taking place now.
I will also continue to pledge to live my own life by walking lightly upon this Earth and fighting to hold those who deliberately destroy it and the indigenous peoples of this world who inhabit those places accountable and to bring them to justice.
It's time to raise our voices in truth and Reality.
Satyagraha.http://progressivesforgore.blogspot.com/2011/07/24-hours-of-reality.html
It's... more
-
-
James Hansen never expected to become a radical activist at the age of 65. He is a grandfather who loves nothing more than exploring nature with his grandchildren. He holds down a respectable job as the director of Nasa's Goddard Institute for Space Studies. But he is 70 now, and he has a police record.
Hansen gets himself arrested, testifies in court on behalf of others who have broken the law and issues public pronouncements that have made Nasa try to gag him – all because he can't bear the thought that his grandchildren might hold him responsible for a burned-out planet.
Hansen is the climate scientist's climate scientist. He has testified about the issue in front of Congress, but has had enough of the standard government response – "greenwash", he calls it. Last month, Hansen issued an uncompromising plea for Americans to involve themselves with civil unrest over climate change. "We want you to consider doing something hard – coming to Washington in the hottest and stickiest weeks of the summer and engaging in civil disobedience that will likely get you arrested," he says in a letter on grist.org.
However many Americans turn up to get arrested in Washington, it's unlikely that Hansen will end up sharing a cell with other scientists. He cuts a lone figure on the barricades; almost all scientists run shy of such public misbehaviour.
In private, science has always been a brutal, gladiatorial arena. To be successful you have to challenge established thinking, force out the old guard and prove beyond question that you are right. That takes extraordinary tenacity, resourcefulness and courage.
The tragedy is that these laudable attributes are rarely channelled into tackling areas where science highlights something of global concern. Yes, scientists compile and contribute to reports on issues such as climate change. But those reports are made public only when the scientists have agreed on the most conservative of conclusions, satisfying the lowest common denominator among those whose names appear on the documents.
The UN's climate monitor, the Intergovernmental Panel on Climate Change (IPCC), for example, issues reports that stand accused of underplaying sea level rises. According to a report published by the US National Academy of Sciences, levels may rise three times faster than IPCC estimates.
That is not to say that climate scientists don't privately agree about what is going on with our planet. In April 2010 a study published in the Proceedings of the National Academy of Sciences showed that nearly 98% of working climate scientists accept the evidence for human-induced climate change. The voices of dissent reported "for balance" come almost exclusively from researchers who are not publishing in the field.
Unfortunately, this consensus over climate change is in danger of becoming the world's best-kept secret. According to the World Bank's 2010 World Development Report, 17% of US citizens think that the properly scientific view is to be sceptical about climate change, while 43% believe that scientists are "evenly divided". Who is to blame for this gulf between reality and perception? The media? The government? No. When they are being honest, the scientists blame themselves.
And that's why Hansen – and a handful of other scientists – are bypassing traditional outlets for scientific results.
If Hansen gets arrested this summer, it will complete his hat-trick: he has already been arrested twice at environmental protests. In 2009 police dragged him and actor Daryl Hannah off a mountain road in West Virginia. They and hundreds of other protesters had sat down in protest at a local company's intention to access the mountain's coal deposits by packing it with explosives and blowing its top off. The second arrest came last year in Washington, at a protest over similar practices.
Hansen's attitude echoes that of Sherwood Rowland, who won a Nobel prize for his research into the effects of chlorofluorocarbon (CFC) gases on the ozone layer. "What's the use of having developed a science well enough to make predictions," Rowland said, "if all we're willing to do is stand around and wait for them to come true?"
Rowland's colleagues shunned him for his activism. Even the iconic environmentalist James Lovelock called for a "bit of British caution" in the face of what he saw as Rowland's "missionary" zeal for a ban on CFCs. In the end, it was only the terrifying discovery of a hole in the ozone layer over Antarctica that galvanised the politicians.
US academics Naomi Oreskes and Erik Conway have highlighted the disappointing timidity of scientists. On acid rain, climate change, tobacco marketing and the ozone crisis, they "would have liked to have told heroic stories of how scientists set the record straight" in their book Merchants of Doubt, but scientists fighting back have been "conspicuously scarce". "Clearly, scientists knew that many contrarian claims were false," they lament. "Why didn't they do more to refute them?"
The answer is, because of the party line established in the post-war era: offer advice only if asked.
More at the link
http://www.youtube.com/watch?v=H7wdKg8rYL0&feature=player_embeddedJames Hansen never expected to become a radical activist at the age of 65. He is a... more
-
-
In Zhejiang province, China, the worst drought in 50 years has been followed by deadly floods.
China has evacuated more than 500,000 people from deadly floods that are devastating areas in the south of the country following the worst drought in 50 years.
At least 105 people have been swept to their deaths or killed in landslides and another 65 are missing after rivers burst their banks. The authorities have issued the highest level of alarm about dykes and dams under dangerous pressure.
Television channels that were only recently broadcasting images of dried-up lake beds are now carrying footage of flooded homes and boats plying their way through inundated streets. China Daily said 550,000 people have been forced to leave their homes.
The dramatic shift is in line with weather trends identified by the Beijing Climate Centre, which says rain is coming in shorter, fiercer bursts, interspersed by protracted periods of drought.
The worst affected province is Zhejiang, where some stretches of the Qiantang river have risen to their highest level since 1955, according to the Flood Control and Drought Relief Office.
In the Zhuji district, which has had 40.5cm of rain since the start of the month, the Puyang river inundated 88 villages and 13,000 hectares of crops.
In neighbouring Jiangxi province, troops have helped 122,400 residents evacuate from vulnerable lowlands, according to the China News Service. Roads have been closed and bridges have collapsed in the floods, which have also affected Hubei, Hunan, Sichuan and Guizhou provinces.
Monitoring stations on 40 rivers have recorded water levels above the safety limit, including Asia's biggest waterway – the Yangtze – which is simultaneously suffering a flood downstream and a drought closer to its source.
Meteorologists warned that the torrential downpours are forecast to move southwards or inland. Li Xiaoquan was quoted on China's weather news website as saying that the rains were expected to affect Sichuan, Chongqing and Guangdong provinces before easing on Sunday.
_________________________________In Zhejiang province, China, the worst drought in 50 years has been followed by deadly... more
-
-
The devastating string of tornadoes, droughts, wildfires and floods that hit the United States this spring marks 2011 as one of the most extreme years on record, according to a new federal analysis.
Just shy of the halfway mark, 2011 has seen eight $1-billion-plus disasters, with total damages from wild weather at more than $32 billion, according to the National Oceanic and Atmospheric Administration. Agency officials said that total could grow significantly, since they expect this year's North Atlantic hurricane season, which began June 1, will be an active one.
Overall, NOAA experts said extreme weather events have grown more frequent in the United States since 1980. Part of that shift is due to climate change, said Tom Karl, director of the agency's National Climatic Data Center.
"Extremes of precipitation are generally increasing because the planet is actually warming and more water is evaporating from the oceans," he said. "This extra water vapor in the atmosphere then enables rain and snow events to become more extensive and intense than they might otherwise be."
But for some kinds of extreme weather, teasing out a contribution from climate change is more difficult.
The second half of April brought a swarm of tornadoes that leveled parts of the Midwest, including the twister that killed 151 people in Joplin, Mo. So far, 2011 has seen the sixth-highest number of tornado deaths on record, prompting many people to wonder whether climate change has played a role. So far, scientists say there's no good evidence for or against a climate change influence on tornado behavior.
Meanwhile, computer models predict that droughts -- like those that have scorched large swaths of Texas, New Mexico and Arizona this year -- will become stronger and more frequent as climate change continues. But because patterns of drought vary widely from decade to decade, that makes it "very difficult and unlikely that we're going to be able to discern a human fingerprint, if there is one, on the drought record in the foreseeable future," Karl said.
cont.The devastating string of tornadoes, droughts, wildfires and floods that hit the... more
-
-
The valleys of the Interior of British Columbia are like slashes in the Earth’s skin — deep, steep, dramatic, falling precipitously into dark, narrow lakes. The landscape looks like frozen violence, the product of a time when tectonic plates collided, their edges crumpling and folding under the unimaginable force of crustal jockeying.
But the violence is not frozen, and the jockeying is not over. The plates are still moving. Their sudden shifts are earthquakes, and their vents are volcanoes. These mountains and valleys are part of a stupendous "Ring of Fire" that surrounds the entire Pacific Ocean.
We think of geology as finished, complete, the world having been made ready for its masters. But geology is never finished. Nature is always a work in progress. On our recent trip, Marjorie and I enjoyed the hot springs of Ainsworth and Nakusp. What heats that water? The hell-fires in the basement of the mountains.
The slopes of these valleys should be a uniform swath of green: spruce and fir, pine and cedar. In 2010, however, great rusty smudges on the mountainsides mark the corpses of vast numbers of dead trees. British Columbia is suffering from a massive mountain pine beetle infestation, and more than a billion of its trees have died. The infestation stretches south to Colorado and east to Alberta.
The villainous beetle is a little black bug about the size of a grain of rice. It lays its eggs under the bark of pine trees, and when the eggs hatch, the larvae eat the white phloem layer under the bark, cutting off the tree’s supply of water and nutrients. The beetle does have predators — woodpeckers, for instance — but the predators have been overwhelmed by the sheer size of the infestation.
The factor that normally controls the beetle population is cold weather. For the last decade, however, even the normally-cold Interior has had mild winters, while the summers have been sizzling. Marjorie and I spent 21 broiling days in B.C. last month, and the alleged rainforest gave us only one day of rain. This is thoroughly novel. B.C.’s summers used to be warm but moist.
This is climate change in action. And here’s the kicker: B.C.’s forests have normally been a huge sink for carbon, sucking carbon dioxide out of the air and sequestering its carbon within the trees. When trees die, however, they slowly but inexorably release all that stored CO2.
The shocking result is that B.C.’s forests have not only stopped absorbing carbon, they’re now emitting it and on a huge scale. Last year, the carbon emissions from the dying forests were larger than all the human emissions in B.C. and roughly double the size of the emissions from the Alberta tarsands.The valleys of the Interior of British Columbia are like slashes in the Earth’s... more
-
-
A new study using satellite imaging released by JPL scientists this week shows a substantial deterioration of the Arctic ice shelf since 2004.
The images show thin, seasonal ice replacing thick, older ice as the predominant type on the Arctic ice shelf for the first time on record. The findings demonstrate Arctic temperatures are on the rise, said Ron Kwok, the Jet Propulsion Laboratory senior research scientist who co-authored the study.
"Global warming is definitely warming up the Arctic," Kwok said. "The only reason the ice would melt is heat."
The findings were based on data gathered from 2004 to 2008 by NASA's Ice, Cloud and Land Elevation Satellite (ICESat) and represent the first comprehensive survey of the thickness of arctic ice.
The Arctic's ice cap changes seasonally: Intense cold causes it to build up in the winter and heat and wind patterns reduce the ice in the summer. But the older ice that usually stays intact during the summer is gradually diminishing.
The study found that overall Arctic sea ice decreased by about 7 inches per year, totalling 2.2 feet over four winters. Thicker "multi- year" ice that has survived one or more summers shrank by 42 percent over the study period.
If current trends persist, the Arctic's summer ice cover could be gone in 30 to 50 years, scientists said.
"If the multi-year thick ice keeps shrinking and disappearing, eventually in the summer you'll have no ice up there," said JPL scientist Glenn Cunningham.
Those trends, Kwok cautioned, are not guaranteed to continue.
"The current trends might continue but there's a lot of science we don't understand," he said.
With less ice in the Arctic during the summers, the ocean is forced to absorb more heat, thereby increasing water temperatures. Warmer water then melts the ice caps at a greater rate.
The study's findings come as world leaders convened at
Satellite images showing the deterioration of the arctic ice shelf in 2008. The deep red is thickest part of the ice, and deep blue is the water. (Courtesy JPL)the G-8 summit Thursday, where participants discussed how difficult it will be to persuade the world to make the lifestyle and economic sacrifices needed to save the planet from global warming.A new study using satellite imaging released by JPL scientists this week shows a... more
-
-
Even if you do not believe in anthropogenic climate change, the effect of rapidly melting ice in the Arctic is not only about CO2. What is even more urgent is the amount of methane released from the melting ice caused by higher GHG emissions that is being released into the atmosphere. By not working to decrease GHG emissions that cause the greenhouse effect now we are essentially setting up a catastrophic scenario of runaway warming due to methane emissions from melting permafrost.
This article comprehensively lays out what we are doing and the consequences of it if we do not get serious THIS YEAR to address this. That means politicians not playing any more games and holding subcommittee meetings and hearings simply to continue the empty debate of whether this is natural or not. By doing so and continuing to ignore getting down to action they are pushing this planet closer to a tipping point that much faster. This isn't only about CO2 (or political partisanship and grandstanding,) but about the methane being released due to increasing fossil fuel emissions and deforestation and other positive feedback loops.Even if you do not believe in anthropogenic climate change, the effect of rapidly... more
-
