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Kassy
04-05-2009, 04:58 AM
Arctic Watch 2008:
http://thisbluemarble.com/showthread.php?t=687

Kassy
04-05-2009, 05:00 AM
Ice-free Arctic Ocean Possible In 30 Years, Not 90 As Previously Estimated

ScienceDaily (Apr. 3, 2009) — A nearly ice-free Arctic Ocean in the summer may happen three times sooner than scientists have estimated. New research says the Arctic might lose most of its ice cover in summer in as few as 30 years instead of the end of the century.

The amount of the Arctic Ocean covered by ice at the end of summer by then could be only about 1 million square kilometers, or about 620,000 square miles. That's compared to today's ice extent of 4.6 million square kilometers, or 2.8 million square miles. So much more open water could be a boon for shipping and for extracting minerals and oil from the seabed, but it raises the question of ecosystem upheaval.

While the Intergovernmental Panel on Climate Change in 2007 assessed what might happen in the Arctic in the future based on results from more than a dozen global climate models, two researchers reasoned that dramatic declines in the extent of ice at the end of summer in 2007 and 2008 called for a different approach.

Out of the 23 models now available, the new projections are based on the six most suited for assessing sea ice, according to Muyin Wang, a University of Washington climate scientist with the Joint Institute for the Study of the Atmosphere and Ocean based at the UW, and James Overland, an oceanographer with the National Oceanic and Atmospheric Administration's Pacific Marine Environmental Laboratory in Seattle. Wang is lead author and Overland is co-author of a paper being published April 3 by the American Geophysical Union's Geophysical Research Letters.

Wang and Overland sought models that best matched what has actually happened in recent years, because, "if a model can't do today's conditions well, how can you trust its future predictions?" Wang says. Among the models eliminated were those showing too little ice or too much compared to conditions that have occurred.

Models also were chosen that are able to reflect the difference between summer and winter ice packs, which demonstrates a model's ability to take into account changing amounts of solar radiation from summer to winter, Wang says.

Among the six fitting the researchers' criteria, three have sophisticated sea-ice physics and dynamics capabilities.

Once the extent of ice at the end of summer drops to 4.6 million square kilometers -- it was actually 4.3 million square kilometers in 2007 and 4.7 million in 2008 -- all six models show rapid sea-ice declines. Averaged together the models point to a nearly ice-free Arctic in 32 years, with some of the models putting the event as early as 11 years from now.

"In recent years the combination of unusual warm temperatures from natural causes and the global warming signal have worked together to provide an earlier summer sea-ice loss than was predicted when scientists considered the effects from human-caused carbon dioxide alone," says Overland, who is also an affiliate UW professor of atmospheric sciences.

"The uncertainty in future timing for a September sea-ice free Arctic is strongly influenced by the chaotic nature of natural variability," the authors write in the paper. Still, "the one climate realization that we are living through appears to be a fast track for September sea ice loss," they write.

Scientists don't expect the Arctic to be totally ice free, figuring that ice still will be found along northern Canada and Greenland where powerful winds sweeping across the Arctic Ocean force ice layers to slide on top of each other, making for a very thick ice cover.

The National Oceanic and Atmospheric Administration funded the work.

http://www.sciencedaily.com/releases/2009/04/090402143752.htm

Kassy
04-05-2009, 05:08 AM
But that's in the long run ...let's see what'll happen this year. :beer:

Arctic Sea Ice Extent Graph:
http://nsidc.org/data/seaice_index/images/daily_images/N_timeseries.png

Ross
04-05-2009, 05:48 AM
Wang and Overland sought models that best matched what has actually happened in recent years, because, "if a model can't do today's conditions well, how can you trust its future predictions?" Wang says. Among the models eliminated were those showing too little ice or too much compared to conditions that have occurred.

Models also were chosen that are able to reflect the difference between summer and winter ice packs, which demonstrates a model's ability to take into account changing amounts of solar radiation from summer to winter, Wang says.


Pick your model of choice ? Is this science ? choose the model
and also choose the time period .




ps ... Eat the meek before they eat you .

Kassy
04-05-2009, 12:01 PM
Pick your model of choice ? Is this science ? choose the model
and also choose the time period .

Selected for good criteria, yes that is science. Note half of the selected models had actual ice dynamics and the other three probably had some approximation built into them. The others didn't (or didn't do it the right way).

There are always constraints on the amount of processes that can be included in models due to the amount of processing time so some things have to be left out in every model. We learn more about the processes themselves every year. Newer more powerful and more complete models are on the way.

*

ps ... Eat the meek before they eat you .

'It's coming right for us!' :beer:

Mousehound
04-07-2009, 09:44 AM
According to a new satellite survey of the Arctic region, conducted by NASA, the University of Colorado in Boulder (UCB) and the US National Snow and Ice Data Center (NSIDC), the ice shelves at the North Pole are getting smaller and thinner.The decade-long trend of melting is thus appearing to continue, with no end in sight. These results again contradict those that say that global warming is nothing but a hoax, who claim that the melting in the Arctic, Antarctica and Greenland is only temporary, and that the planet will heal itself.

NISDC researcher Walt Meier stresses that all of the recorded annual minimums in terms of ice extent have been registered over the past 6 years, with the winter of 2008-2009 being the fifth in terms of ice loss. The expert also adds that the largest measured extent of ice for this winter was recorded on February 28th and that the shelves measured 5.85 million square miles, a 278,000 square-mile decrease from the average levels recorded between 1979 (the year when Arctic surveys begun) and 2000, when global warming really started taking a turn for the worse.

“Ice extent is an important measure of the health of the Arctic, but it only gives us a two dimensional view of the ice cover. Thickness is important, especially in the winter, because it is the best overall indicator of the health of the ice cover. As the ice cover in the Arctic grows thinner, it becomes more vulnerable to summer melt,” Meyer explains. Over the past few years, “young,” thinner ice has replaced “older,” thicker shelves, which means that the new sheets are more prone to melting in the summer than the previous ones.

“Heading into the 2009 summer melt season, the potential continues for extensive ice retreat due to the trend toward younger, thinner ice that has accelerated in recent years. A key question will be whether this second year ice is thick enough to survive summer melt. If it does, this might start a trend toward recovery of the perennial sea ice pack. If it doesn't, then this would be further evidence of the difficulty of re-establishing the ice conditions that were typical of 20 or 30 years ago,” James Maslanik, a research professor at CU's Aerospace Engineering Sciences Department, points out. He is also a member of the Cooperative Institute for Research in Environmental Sciences, and the leader of a 2008 study on the Arctic, published in the journal Geophysical Research Letters.

http://news.softpedia.com/news/Satellite-Data-Shows-the-Arctic-in-Worsening-Condition-108811.shtml

caonacl
04-07-2009, 05:00 PM
Arctic Ice Coverage Thinning



NASA said the dramatic decrease in ice thickness and coverage over the past 30 years is an important indicator of the health of the Arctic.

By K.C. Jones (kconley@techweb.com)


This winter marked the fifth lowest for ice coverage on record since satellite monitoring started 30 years ago, continuing a trend of record lows in coverage since 2004, NASA said.

Thin seasonal ice, which melts each year, now accounts for about 70% of ice coverage, up from 40% to 50% in the 1980s and 1990s, according to NASA. Thicker ice, which generally melts after two or more years, now makes up 10% of the winter ice cover, down from 30% to 40%, according to researchers. Seasonal ice averages about 6 feet deep, while the longer-lasting ice averages about 9 feet deep, the researchers reported.

"Ice extent is an important measure of the health of the Arctic, but it only gives us a two-dimensional view of the ice cover," Walter Meier, research scientist at the center and the University of Colorado, Boulder, said in a statement released Monday. "Thickness is important, especially in the winter, because it is the best overall indicator of the health of the ice cover. As the ice cover in the Arctic grows thinner, it grows more vulnerable to melting in the summer."

Coverage area for this winter was 5.85 million square miles, 278,000 square miles less than the average coverage from 1979 to 2000.

A team of researchers led by Ron Kwok of NASA's Jet Propulsion Laboratory in Pasadena, Calif., used two years of data from NASA's Ice, Cloud, and Land Elevation Satellite (or ICESat (http://icesat.gsfc.nasa.gov/)) to create the first map of sea ice thickness over the entire Arctic basin this year. They found that the average winter volume of Arctic sea ice holds so much water it could fill Lake Michigan and Lake Superior.

Researchers hope their findings will improve understanding of climate change. The world's climate system relies on Arctic sea ice as a sort of air conditioner.

http://www.informationweek.com/news/government/federal/showArticle.jhtml?articleID=216403263

caonacl
04-07-2009, 05:03 PM
BTW:
Even if the ice is currently floating, and melting won't raise sea levels, the melting ice will alter ocean salinity. A change in ocean salinity could effect ocean currents.

caonacl
04-07-2009, 10:33 PM
BTW:
Even if the ice is currently floating, and melting won't raise sea levels, the melting ice will alter ocean salinity. A change in ocean salinity could effect ocean currents.

Our sick seas
Scientists are documenting drastic, disturbing changes in the oceans

By Monique Beaudin, Canwest News ServiceApril 5, 2009

http://a123.g.akamai.net/f/123/12465/1d/www.ottawacitizen.com/sick+seas/1465937/1465938.bin (http://javascript<b></b>:setClass('storypage','story_photo_content');)

A tourist looks at icebergs and ice floating in the waters of Greenland's Disko Bay. Ice caps are melting faster than scientists had thought possible, raising ocean levels and altering their salinity.

Photograph by: Bob Strong, Reuters, Canwest News Service

Sea Sick:
The Global Ocean in Crisis
By Alanna Mitchell

Even if you think you understand what humanity faces in the enormous challenge that is climate change, reading Alanna Mitchell's new book Sea Sick: The Global Ocean in Crisis will make you realize how little humans understand about our impact on the planet.

Large swaths of the planet's population now accept -- after years of warning by scientists -- that the burning of fossil fuels like oil and coal is pumping greenhouse gases into the atmosphere and slowly raising the Earth's temperature. On land, we are already feeling the impacts of global warming: rising sea levels, melting glaciers and disappearing species.
That's nothing compared to what's going on in the water.

The ocean, which covers three quarters of the planet, is sick. And it's not just a head cold, Mitchell suggests.

The ocean absorbs one-third of the extra carbon we're putting into the atmosphere, and that's changing the water's pH level, making it more acidic. Water temperature is rising. Increasing amounts of fresh water -- from melting glaciers -- are affecting the ocean's salinity.

All bad news when you think of the importance of the ocean and marine life on Earth. For example, ocean currents move warmer water from around the equator to the north and south poles, making the planet livable. And, half the oxygen we breathe is produced from plankton, the microscopic organisms living in the ocean.

The ocean, a biologist told Mitchell, is like a switch for the planet, but instead of turning on a light, it turns on life. The switch can be flipped off, he told her, and humans have their hands on that switch right now.
Mitchell, a former Globe and Mail environment reporter, set out to explore what is going on in the oceans -- not an easy task for a woman with a paralysing fear of water, a result of nearly having drowned as a toddler.
What she found, by snorkelling along the Great Barrier Reef off Australia's east coast, hiking through Spain's Pyrenees mountain range and watching corals reproduce off the coast of Panama, were scientists documenting drastic and disturbing changes in the ocean.

She found coral reefs -- which she describes as the planet's maternity ward because of their incredible ability to create and sustain life -- dying off from pollution, overfishing and warming ocean waters.

In Spain, she hacked away at rock containing fossils from 55 million years ago, another time when the amount of carbon in the Earth's atmosphere rapidly increased -- not from pollution, but possibly because of warming in the ocean or a landslide. Scientists study the fossils they find there to try to understand the impact that great infusion of carbon had on life on Earth. On the last day of that trip, she realized one of the men with them was from a Texas oil company. His job was to figure out where to find new oil and gas reserves. Where the scientists saw evidence of catastrophic climate change, he was looking for more fossil fuels to burn -- the very cause of our current climate troubles.

Scientists exploring what is happening to the oceans -- and to the creatures that live in them -- are being criticized and their work negated by a world that's not ready to hear what they're finding, she writes. The skepticism is not surprising, considering the first major international scientific conference on climate change and oceans was held only last year, 10 years after the United Nations set up the International Panel on Climate Change.

One of the biggest problems is ocean acidification.

American marine ecologist/geologist Joanie Kleypas has found that carbon dioxide entering the atmosphere from burning fossil fuels is lowering pH levels in the ocean. Sea creatures like plankton and corals use calcium to build their shells and skeletons, but in a more acidic ocean, they won't be able to get it. In fact, their shells would dissolve in more acidic ocean water. The first time that Kleypas understood the impact of ocean acidification, she ran into the nearest bathroom and threw up.
It meant, Mitchell writes, marine Armageddon.

"This is the most worrying of all the changes to the ocean because we don't know and can't predict how marine life will react to the new ocean chemistry," she writes.

It's not hard to see why Mitchell found herself preparing for a trip to the ocean's floor utterly depressed and out of hope.

She understood just how sick the ocean is, and how little anyone -- besides the marine scientists -- knows or seems to care. But down in the cold dark salt water with a group of scientists who were trying to find a cure for cancer with the knowledge they glean from deep-sea creatures, she realized that choosing hope will be the only way to turn the ocean around.

Keeping the ocean's life switch turned on will require all of us to, like Mitchell, choose hope and to do something about it. Reading this book is a good first step.
http://www.ottawacitizen.com/News/sick+seas/1465937/story.html

caonacl
04-07-2009, 10:42 PM
Scientists track the ocean's rise as the globe warms

There's little doubt the ocean levels have risen in response to the warming climate, but scientists are struggling to fully understand the factors driving this rise. They hope research will enable them to make accurate predictions of future ocean levels. A panel at this year's meeting of the American Association for the Advancement of Science discussed the challenges.
By John Timmer (http://arstechnica.com/authors/john-timmer/) | Last updated March 31, 2009 |


http://static.arstechnica.com/assets/2009/03/topex_jason_pacific-thumb-640xauto-4099.jpg
A map showing regional variability in sea level changes. Image: NASA


Throughout the planet's history, ocean levels and temperatures have had a fairly straightforward relationship: when the earth cools down, ocean levels drop; when it heats up, they rise. The basics of this dynamic are pretty simple. When the climate is warm, land-based ice melts, and much of that water winds up in the oceans. The water in the oceans also occupies more volume, since water expands when it heats up. Cooling the climate reverses both of these processes.

Consistent with the rise registered in global temperatures, various measurements have shown that the oceans have been rising for at least the last century. Yet the steady rise that has been observed covers a fairly complex system, with seasonal variability and changes in the relative contributions of different factors. If we're to provide accurate forecasts of how the ocean levels might respond to further changes in the climate, it will be essential that we understand this complexity. A panel at February's meeting of the American Association for the Advancement of Science tried to tackle the issue.
What we know, and how we know it

The longest continual record of ocean levels comes from tide gauges. Unfortunately, these instruments produce very noisy data and, at earlier time points, were very sparsely distributed. In recent years, they've been supplemented by satellite measurements of ocean levels. The most significant is the Topex-Jason series, which dates back to 1983. That's the longest continuous satellite record but, at different points, a variety of other satellites have also provided measures of the altitude of the surface of the ocean. According to the speakers on the panel, all of these measures of sea level rise line up within the margins of instrument error, so they felt pretty confident in the basics.

Those basics show an accelerating sea level rise. Anny Cazenave, who chaired the session, noted that the average change over the years from 1950 to 2000 was about 1.8mm per year. Over the last 16 years, however, she said the average was 3mm a year.
http://static.arstechnica.com/Science/2009-3-31/sealevel_jason_topex.jpg
The satellite-era reconstruction of ocean levels.



In recent years, we've supplemented the basic measure of sea level with a variety of instruments that get at the underlying contributors. For example, the GRACE satellite system can measure that gravitational attraction of both ice sheets and the oceans they feed into, which produces estimates of mass changes. A series of floats—XBT, MBT, and Argo—have measured temperature and salinity down to a few thousand feet, although the record from these devices is a bit sparse.

With the basic sources of data described, Cazenave explained how these new instruments have changed our view of the generally smooth rise of the oceans. Prior to 2003, she said, about half of the annual change was contributed by thermal expansion of the oceans; since 2003, however, the surface temperatures of the oceans have stabilized, and thermal expansion has ground to a halt. That might be expected to halve the rate of sea level rise, but it hasn't. Instead, increases in the contributions from melting glaciers seem to have partially made up for the change, keeping the rise in the neighborhood of 2.5mm a year.

These results have told us that the underlying causes of sea level rises may change rapidly and be out of sync with each other. It's useful information, but it makes providing accurate predictions of future change that much harder. After delivering that message, Cazenave handed the podium over to a series of speakers that tackled the different contributors.

Thermal expansion: NOAA's Sydney Levitus described the use of ship-based instruments and floats to reconstruct the rise in sea levels that can be attributed to warming of the water itself. Two series of ship-based instruments, XBT and MBT, are now recognized to have suffered from some form of systemic instrument error, although Levitus didn't describe the precise problems in detail. Although this throws off the absolute numbers, the trends should still be trustworthy, and those show an acceleration of thermal expansion up until recent years. A number of groups have tried to correct for the errors, and the numbers seem to be converging on something in the range of .4-.6mm/year as the average since 1965, a figure that's consistent with the one generated by coupled ocean/climate models that include greenhouse forcings.

After his talk, Levitus and several audience members discussed why thermal expansion seems to have slowed down so much in recent years. The current generation of floats, called Argo, only sample down to 2,000 meters, and there are areas in the ocean where surface water circulates to well below that. Australia's John Church suggested that we're starting to see readings of warming below 3,000 meters, but we have very few records at this depth, so it's hard to know what to make of them. In any case, a more rapid mixing of surface and deep water was presented as a potential influence on sea level changes, and it appears that we are not in a good position to measure it.
Mountain Glaciers

Georg Kaser, who is based in Innsbruck, studies mountain glaciers. The remaining mountain glaciers are thought to only contain enough water to cause between 0.15 and 0.43 meters of sea level rise, so they're not likely to be as significant as the major ice caps—which is just as well, given that there are huge uncertainties involved. One of the big questions is whether the water from melting glaciers ever even reaches the oceans. In Alaska and Asia, a lot of it does; that's not the case in the Andes and Europe, where much of it gets used by the local populace. It probably does eventually enter the water cycle, but the timing of that is poorly understood. In any case, some calculations suggest that the extensive dam building of the last century may have partially offset seal level changes (http://arstechnica.com/science/news/2008/03/missing-ocean-rise-may-be-held-by-reservoirs.ars) by keeping significant volumes of water in reservoirs.

In any case, there isn't a good picture of what's happening to the actual glaciers. We've tended to track the big glaciers that reside at high altitudes, which has led us to largely ignore the numerous smaller ones at lower altitudes, many of which have completely vanished. Even when it comes to the big ones, most of what we know comes from Europe. Outside of that continent, monitoring is very erratic. The good news, Kaser said, is that there's a group called GLIMPS that's interested in doing the accounting. The bad news is that they have almost no resources, so we're not likely to balance the books on mountain glaciers any time soon.

There's little doubt the ocean levels have risen in response to the warming climate, but scientists are struggling to fully understand the factors driving this rise. They hope research will enable them to make accurate predictions of future ocean levels. A panel at this year's meeting of the American Association for the Advancement of Science discussed the challenges.

Ice sheets

Penn State's Richard Alley gave a talk on ice sheets, which he introduced by saying, "I'm going to take you to some pretty places and show you some ugly things." After discussing the two largest ice sheets—Greenland's is pretty clearly melting, while data from Antarctica is sparse, but suggests a recent shift to ice loss—Alley turned to attempts to model the dynamics of these ice sheets, and thus the identification of the factors that needed to be included in the models.

Some of the most dramatic changes observed in Greenland have come from the meltwater lakes on the surface of the Greenland icecap. This process is fairly dull, but the lakes have a penchant for vanishing dramatically (http://arstechnica.com/science/news/2008/04/greenland-lake-disappears-under-the-ice.ars), as they melt a passage clear to the base of the ice cap and drain abruptly. Initially, this was thought to provide lubrication between the ice and its substrate that could accelerate the flow of ice into the oceans, but it now appears that, once it reaches the ground, the water stays in a narrow channel that would only have very local effects. The big question, Allen said, is what happens to all the heat transferred to the base of the glacier with the water. Heat from a warming atmosphere can take centuries to reach the bottom of the icecap; draining the lakes does it in 10 minutes. Right now, Allen said the field doesn't know what the implications are, but he's confident that it will have better answers within a few years.

The last big unknown he discussed is the role of floating ice shelves, which he compared to the flying buttresses that keep the walls of cathedrals from spreading. The ice shelves seem to act in a similar manner to keep the weight of an ice cap from forcing it to spread. In recent years, several of these have collapsed suddenly (http://arstechnica.com/science/news/2008/03/prelude-to-an-ice-shelf-collapse.ars), and the exit glaciers nearby have shown signs of accelerating. Unfortunately, we don't have a good understanding of what conditions trigger these sudden collapses, or how long the exit glaciers will continue to flow at a higher rate.

The collapse of the Larsen B ice sheet (center) may affect the flow of outlet glaciers (left).

Overall, Allen said, we've got some good models for understanding any one of these factors at the level of individual glaciers, but we don't have a large-scale model of an entire ice cap that incorporates all of these smaller-scale models.
Geophysics

It's pretty apparent that a big ice sheet weighs a lot, but it's hard to truly grasp just how heavy they are. C.K. Shum of Ohio State described his efforts to figure out how the earth and oceans respond as the overlying ice sheets begin to vanish. According to Shum, the Earth's mantle is still rebounding from the previous ice age. Layered on top of that will be a release of the elastic loading of the crust caused by the shrinking of the existing ice sheets.

Shum's calculations suggest that this will cause the relative sea levels near the vanishing ice to drop, as the ground itself rebounds. That's actually not much in the way of good news, as very few people live near large ice sheets. Everywhere else (meaning everywhere that people actually live), the crustal rebound will accentuate the sea level rise.
One thing that didn't make it into Shum's talk was a paper (http://www.sciencemag.org/cgi/content/abstract/323/5915/753) that came out a week before the AAAS meeting. That paper suggested the ice itself exerted a gravitational attraction on the oceans, drawing water towards them. The loss of the ice sheets would end that pull, allowing the water to spread widely, which would cause sea levels to rise in other, more populated areas.
How much detail do we need to know?

The general picture is one where we have a good idea of what the ocean levels have actually been in the past, and a decent idea of how different factors have influenced the rise in sea levels. What we lack is a good grip of how each of those factors will respond to incremental changes in temperature, how quickly they'll respond to longer-term trends, and whether there might be any tipping points within those dynamics. As a result, in Allen's words, "projections on sea level have been reasonably stinky," with the rise consistently running above the error bars of IPCC estimates. That's a bit unnerving to some people in the field, given that, during some historic instances of climate change, sea levels have risen as quickly as four meters a century.

Although we appear to be on track to both have better data and better models to crunch the data with, Stefan Rahmstorf of the Potsdam Institute for Climate Impact Research is working on producing what he called a semi-empirical approach to projections that could work now. His approach uses a function based on the temperature change, a "fast response" term, and a compensation for water held in reservoirs. The equation he now has tracks the past century's data nicely—it deviates slightly in the 1930s but, at its worst, the deviation is only 7mm. Running it forward, however, produces some bad news. Even some IPCC low-emission scenarios can produce ocean level rises in the area of 1m, and the ocean goes on rising even after the atmosphere stabilizes.
Understanding vs. public recognition

http://static.arstechnica.com/Science/2009-3-31/Delaware_NJ_ocean_predicitons.jpg
The different colors represent different potential sea level changes.


There does seem to be a consensus forming that sea level rises are going to occur faster than we had recently thought, and are likely to continue well after any control on greenhouse gas emissions stabilizes their concentrations in the atmosphere. But it still seems likely that the pace is going to remain on the order of a few millimeters a year, which simply isn't fast enough to cause immediate worries and thus public recognition. But a few speakers suggested that the public may not fully appreciate what a few millimeters a year may mean.

John Church took a long-term, big-picture perspective on this trend. He said that calculations for Australia suggest that, in part due to sea level changes, "what is currently a 100-year event will be occurring several times a year in 2100." If that's true elsewhere, he said, it could have a staggering cost; the Bay of Bengal has been the site of several storm surges that have killed hundreds of thousands of people. Rising sea levels would send these surges traveling further inland.

Robert Wood from Risk Management Solutions gave a more focused talk about what sea level rises mean. He did give a nod to the global picture, noting that his company had calculated that there is about $1 trillion in building stock located within a meter of current sea levels, and all of that's at risk going forward. But his talk primarily focused locally, on the US Gulf Coast. Here, most of our conception of risk is based on assessments that are decades old, and were made at a time when sea levels were lower and (by chance) we were in a period where lower-strength hurricanes were typical. None of that's true anymore, but risk reassessments only occur in the wake of disasters like Katrina and Ike.

Wood's message was that the risk profile for the entire Gulf Coast (and, presumably, other areas of the country and the world) has shifted; areas that were assumed safe "are now in the flood risk area." But, because the risk affects so much—building codes, development decisions, insurance policies—it's considered "politically intolerable" for FEMA to go through and provide an accurate reassessment. Even in cases where it has, Wood pointed out, it wasn't doing a coherent job. By simply raising flood risk assessments in some areas, buildings were changed so that houses were being placed so high on stilts that they were now in risk of being toppled by hurricane-strength winds before the water even got there.

Wood's presentation, in a lot of ways, summarized the challenge. Even in cases where we can recognize the problems caused by ocean level rises, we lack the political will to act on them. Because of this, the average citizen isn't compelled to recognize the issues, which ensures that they remain abstract.

But the challenges of projecting sea level changes make it easier for them to remain abstract. As the panel described it, it's relatively easy to track what the ocean is doing and follow the major factors that are driving the system. But an understanding of why these factors are undergoing dynamic changes over recent decades will be necessary if we're to make accurate future projections, and we're just not there yet.

http://arstechnica.com/science/news/2009/03/scientists-track-the-oceans-rise-as-the-globe-warms.ars

Ross
04-09-2009, 06:36 PM
The Arctic today .

The data is collected from the US military web site http://imb.crrel.usace.army.mil.
All of the active military buoys show significant thickening ice
over the past six months to a year, as seen below.


http://imb.crrel.usace.army.mil/buoy_data/latest_buoy.gif

and yes I agree , 6 months data means nothing .

.

Kassy
04-11-2009, 06:56 AM
Arctic team: 'London, we have a problem'
By David Shukman
Science and environment correspondent, BBC News

After enduring ferocious weather, it has emerged that British explorers studying the Arctic are struggling with a series of technical problems.

A portable radar device, known as Sprite, designed to make millions of measurements of the ice thickness, has been dogged by breakdowns and uncertainties.

Another instrument, SeaCat, meant to measure the temperature and salinity of the water beneath the ice-cap, has malfunctioned as well.

The expedition's organisers insist that other research - such as regular drilling through the ice - has meanwhile been carried out successfully.

The radar system is dragged behind the sledge of expedition leader Pen Hadow and is meant to gather data about the ice for transmission via satellite to researchers.

But when the expedition, the Catlin Arctic Survey, set off in late February, it encountered an unexpected wind chill as low as minus 70 degrees Celsius, and the technology failed.

Cable break

I understand that on the fifth day in these conditions, one of the radar system's cables simply snapped. On the ninth day it became clear that this had led to all the cables breaking.

So with the team's early progress anyway hampered by the weather, the Sprite only gathered data over a total period of seven hours of trekking in the expedition's first 18 days.

A resupply flight, which landed last month, collected the device for repairs back in the UK, and that work is now complete.

But support staff are still having trouble accessing the ice data stored inside it.

The same resupply flight also delivered a replacement radar to the expedition but it's not yet known how well it has functioned over the past few weeks or if its data can be retrieved.

Another resupply flight on Wednesday brought the team the original Sprite device, now repaired, together with the communications system.

Expedition organisers are now hoping that at last, after nearly 40 days on the ice, the radar data can be gathered and transmitted as planned.

Assuming they can retrieve any data collected earlier, they hope to have lost only 13 days' worth of measurements in all - the period the original Sprite unit was out of action.

Resupply flight

The broken SeaCat device was extracted on the first resupply flight and a replacement is due to be delivered in a fortnight's time.

Simon Harris-Ward, Director of Operations for Catlin Arctic survey told the BBC: "Given the very extreme conditions they are operating in during the Arctic winter we were always going to face potential difficulties with the array of advanced technology despite our robust testing programme.

"We have been cautious about making any statement about Sprite simply because of a combination of factors. First, an uncertainty about the exact nature of the problem and second, the inevitable delays in assessing data which had to be extracted on our re-supply flights before it could be analysed."

"Most of the Catlin Arctic Survey science programme does not require data from Sprite and the Ice Team has been continuing to collect valuable data in its wider science programme, including measurements of the floating ice's thickness. So we remain confident in our ability to deliver data to our scientific partners."

The expedition's other research tasks include drilling through the ice by hand, on average four times a day.

With 102 holes drilled so far, hundreds of measurements have been made of ice thickness and snow cover over the 243km covered so far.

The drillings have revealed a typical ice thickness of between 1.5 - 2 metres which is far thinner than a previous generation of explorers encountered.

All this data - and any that can be gleaned from the radar system - will be sent to Arctic specialists at the US Navy Postgraduate School in Monterey, California to help assess the likely fate of the ice-cap.

Story from BBC NEWS:
http://news.bbc.co.uk/go/pr/fr/-/1/hi/sci/tech/7991801.stm

Kassy
04-12-2009, 05:24 AM
Caonacl posted an interesting article in the Green Watch thread.
http://thisbluemarble.com/showthread.php?p=100047#post100047

I reposted Arctic ice data here:

ENVIRONMENT: Earth's Arctic Freezer Turning Into Hothouse
By Stephen Leahy

UXBRIDGE, Apr 10 (IPS) - The world is losing its northern freezer as Arctic winter ice is in sharp decline, NASA scientists reported this week. Even with below average winter temperatures, Arctic ice is thinner and covers less area than it did a decade ago.

Arctic sea ice is the cooling mechanism for the global climate system. As it declines and the region warms - already three to five degrees Celsius warmer - then inevitably there are local, regional and hemispheric climate impacts.

"We’ve already lost one third of the summer ice cover since the 1980s. There are already impacts from this," says Ron Kwok of NASA's Jet Propulsion Laboratory in Pasadena.

"A completely ice-free summer by 2013 is not impossible," Kwok said in a telephone news conference. "You would have been laughed out the room if you suggested this five years ago."

The new study shows that the maximum extent of the 2008-2009 winter sea ice cover was the fifth-lowest since researchers began collecting such information 30 years ago. The past six years have produced the six lowest maximums in that record.

More stunning, and indicative of the rapid warming of the region, is the decline in the thick, hard-to-melt multi-year ice, says Walter Meier, research scientist at the National Snow and Ice Data Centre in Boulder, Colorado. Multiyear ice is ice that is two or more years old and therefore doesn't melt in the summer.

"Less than 10 percent is multiyear now. It used to be 30 percent in 1981," Meier said at the news conference.

Polar amplification is the reason why climate change is warming the Arctic far faster than anywhere else. A combination of processes and feedbacks in the region have resulted a three to five degree Celsius warming already. In 50 to 100 years time if average global temperature rises three degrees Celsius, the Arctic freezer will be a hothouse - at least 10 degrees Celsius warmer.

"The polar cryosphere has long existed as a buffer against [global] climate warming to an extent," Dick Peltier, Director of the Centre for Global Change Science at the University of Toronto, told IPS.

The Earth’s great northern freezer is undergoing "great transformations of energy" away from cooling and shifting to warming. More ice melt means more open water resulting in more of the sun’s energy being trapped in the Arctic Ocean and warming water temperatures. That means winter freeze-up comes later, the ice is thinner, and more likely to melt when summer returns. This positive feedback loop is already operating and the meltdown of the Arctic sea ice looks to be irreversible he says.

"It's a bit like a flywheel now able to turn with reckless abandon."

more on:
http://www.ipsnews.net/news.asp?idnews=46462

Or the link above.