Global Climate Change Science News

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Published online 31 March 2010 | Nature 464, 657 (2010) | doi:10.1038/464657a
News
River reveals chilling tracks of ancient flood
Water from melting ice sheet took unexpected route to the ocean.

Quirin Schiermeier


The Younger Dryas flood 13,000 years ago could have emptied into the Arctic Ocean through the Mackenzie River delta.W. LYNCH/PHOTOLIBRARY.COM
A thousand years after the last ice age ended, the Northern Hemisphere was plunged back into glacial conditions. For 20 years, scientists have blamed a vast flood of meltwater for causing this 'Younger Dryas' cooling, 13,000 years ago. Picking through evidence from Canada's Mackenzie River, geologists now believe they have found traces of this flood, revealing that cold water from North America's dwindling ice sheet poured into the Arctic Ocean, from where it ultimately disrupted climate-warming currents in the Atlantic.

The researchers scoured tumbled boulders and gravel terraces along the Mackenzie River for signs of the meltwater's passage. The flood "would solve a big problem if it actually happened", says oceanographer Wally Broecker of Columbia University's Lamont-Doherty Earth Observatory in Palisades, New York, who was not part of the team.


> larger image http://www.nature.com/news/2010/100331/ ... box/1.html
On page 740, the geologists present evidence confirming that the flood occurred (J. B. Murton et al. Nature 464, 740–743; 2010). But their findings raise questions about exactly how the flood chilled the planet. Many researchers thought the water would have poured down what is now the St Lawrence River into the North Atlantic Ocean, where the currents form a sensitive climate trigger. Instead, the Mackenzie River route would have funnelled the flood into the Arctic Ocean (see map).

The Younger Dryas was named after the Arctic wild flower Dryas octopetala that spread across Scandinavia as the big chill set in. At its onset, temperatures in northern Europe suddenly dropped 10 °C or more in decades, and tundra replaced the forest that had been regaining its hold on the land. Broecker suggested in 1989 that the rapid climate shift was caused by a slowdown of surface currents in the Atlantic Ocean, which carry warm water north from the Equator to high latitudes (W. S. Broecker et al. Nature 341, 318-321; 1989). The currents are part of the 'thermohaline' ocean circulation, which is driven as the cold and salty — hence dense — waters of the far North Atlantic sink, drawing warmer surface waters north.

Broecker proposed that the circulation was disrupted by a surge of fresh water that overflowed from Lake Agassiz, a vast meltwater reservoir that had accumulated behind the retreating Laurentide Ice Sheet in the area of today's Great Lakes. The fresh water would have reduced the salinity of the surface waters, stopping them from sinking.

“There's no way for that water to go out of the Arctic without going into the Atlantic.”

The theory is widely accepted. However, scientists never found geological evidence of the assumed flood pathway down the St Lawrence River into the North Atlantic; or along a possible alternative route southwards through the Mississippi basin. Now it is clear why: the flood did occur; it just took a different route.

The team, led by Julian Murton of the University of Sussex in Brighton, UK, dated sand, gravel and boulders from eroded surfaces in the Athabasca Valley and the Mackenzie River delta in northwestern Canada. The shapes of the geological features there suggest that the region had two major glacial outburst floods, the first of which coincides with the onset of the Younger Dryas. If the western margins of the Laurentide Ice Sheet lay just slightly east of their assumed location, several thousand cubic kilometres of water would have been able to flood into the Arctic Ocean.

"Geomorphic observations and chronology clearly indicate a northwestern flood route down the Mackenzie valley," says James Teller, a geologist at the University of Manitoba in Winnipeg, Canada, who took part in the study. But he thinks that the route raises questions about the climatic effects of the Lake Agassiz spill. "We're pretty sure that the water, had it flooded the northern Atlantic, would have been capable of slowing the thermohaline ocean circulation and produce the Younger Dryas cooling," he says. "The question is whether it could have done the same in the Arctic Ocean."

Broecker, however, says that the Arctic flood is just what his theory needed. He says that flood waters heading down the St Lawrence River might not have affected the thermohaline circulation anyway, because the sinking takes place far to the north, near Greenland. A pulse of fresh water into the Arctic, however, would ultimately have flowed into the North Atlantic and pulled the climate trigger there. "There's no way for that water to go out of the Arctic without going into the Atlantic," he says.

http://www.nature.com/news/2010/100331/ ... 4657a.html

[Fact-Man]

Politicians fiddle while Rome burns ...

Climate Bill On Hold After Lindsey Graham Threatens To Withdraw Support Over Immigration

MATTHEW DALY | 04/24/10 10:16 PM | Associated Press
http://www.huffingtonpost.com/2010/04/2 ... 50828.html

WASHINGTON — Long-awaited climate change legislation was put on hold by its authors Saturday when a dispute over immigration politics and Senate priorities threatened to unravel a bipartisan effort that took months of work.

Voicing regrets, Sen. John Kerry said Saturday he is postponing the much anticipated unveiling of comprehensive energy and climate change legislation scheduled for Monday. The Massachusetts Democrat made his announcement after a key partner in drafting the bill, Republican Sen. Lindsey Graham of South Carolina, threatened to withhold support if Senate Democratic leaders push ahead first with an immigration bill.

Graham is angry that Majority Leader Harry Reid of Nevada is considering that. Legislation to overhaul immigration laws and grant legal status to millions of long term immigrants unlawfully in the country could create problems for Republicans in the midterm elections. It's a top priority for Hispanic voters – and most Republicans are opposed. Reid's idea amounts to a "cynical political ploy," Graham asserted.

Kerry tried to assure environmentalists and other backers of the climate bill that the delay will be short. The legislation aims to cut emissions of pollution-causing greenhouse gases 17 percent below 2005 levels by 2020. It also likely will expand domestic production of oil, natural gas and nuclear power.

The bill would apply different carbon controls to different sectors of the economy, without a broad cap-and-trade approach.

"We all believe that this year is our best and perhaps last chance for Congress to pass a comprehensive approach," Kerry said in a statement. "Regrettably, external issues have arisen that force us to postpone only temporarily."

Kerry, Graham and Connecticut independent Sen. Joe Lieberman have spent more than six months working on the bill they had hoped to unveil Monday. White House energy adviser Carol Browner praised the three senators, reiterating that the Obama administration wants the energy and climate bill done this year.

Environmental groups said they were disappointed with the delay and they would push Democrats to follow through on their pledge to pass legislation.

Graham's threat to back away from the coalition came Saturday in a letter to groups that have supported his efforts on the climate bill.

He said putting immigration at the top of the legislative priority list would derail efforts to find common ground on climate change, a difficult issue involving critically important economic priorities. And he warned that Republican lawmakers would not take kindly to being put on the spot with Hispanics. Many in the Republican Party's political base are adamantly opposed to 'amnesty' for illegal immigrants.

"Moving forward on immigration – in this hurried, panicked manner – is nothing more than a cynical political ploy," Graham said. "Let's be clear, a phony, political effort on immigration today accomplishes nothing but making it exponentially more difficult to address in a serious, comprehensive manner in the future."

Praising Graham's work on the climate legislation, Kerry said the Republican "helped to build an unprecedented coalition of stakeholders from the environmental community and the industry who have been prepared to stand together behind a proposal."

Kerry said he deeply regrets that Graham "feels immigration politics have gotten in the way and for now prevent him from being engaged in the way he intended."

Lieberman also praised Graham's work, and said he's disappointed that "allegations of partisan politics will prevent us from introducing the bill on Monday as planned."

Pushing immigration ahead of climate legislation risks angering environmentalists, who see this as their best chance in recent years to pass a bill addressing global warming. But Reid told fellow Democrats this week he wants to pursue legislation that would offer legal status to many unlawful immigrants before tackling climate change.

Hispanics voted heavily Democratic in 2008, and they've been disappointed with President Barack Obama and congressional Democrats for not following up on campaign promises to reform immigration laws. Reid is up for re-election this year and trailing in polls in Nevada, where Latinos are an important constituency. With Democrats facing a tough political climate in the midterm elections, energized Hispanic voters could make a difference in several states.

In a statement Saturday that was both conciliatory and noncommittal, Reid said he is committed to passing both immigration and energy this year.

"Immigration and energy reform are equally vital to our economic and national security and have been ignored for far too long," he said.

Both measures will require bipartisan support, Reid said, "and energy could be next if it's ready." Comprehensive immigration reform requires significant committee work that has not yet begun, he noted.

Reid said he appreciates Graham's work on both issues, but added: "I will not allow him to play one issue off of another, and neither will the American people. They expect us to do both, and they will not accept the notion that trying to act on one is an excuse for not acting on the other."

A spokesman said Reid would continue to consult with Kerry on building bipartisan support for a climate bill.

The House last year narrowly passed a bill creating a system to cap emissions blamed for global warming, but has not acted on immigration. House Speaker Nancy Pelosi has long said the Senate must vote before the House on an immigration bill.

It appears the Congress can't walk and chew gum.

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Melting sea ice major cause of warming in Arctic, new study reveals

Melting sea ice has been shown to be a major cause of warming in the Arctic according to a University of Melbourne, Australia study.

Findings published in Nature today reveal the rapid melting of sea ice has dramatically increased the levels of warming in the region in the last two decades.

Lead author Dr James Screen of the School of Earth Sciences at the University of Melbourne says the increased Arctic warming was due to a positive feedback between sea ice melting and atmospheric warming.

"The sea ice acts like a shiny lid on the Arctic Ocean. 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," he says.

Using the latest observational data from the European Centre for Medium-Range Weather Forecasting, Dr Screen was able to uncover a distinctive pattern of warming, highly consistent with the loss of sea ice.

"In the study, we investigated at what level in the atmosphere the warming was occurring. What stood out was how highly concentrated the warming was in the lower atmosphere than anywhere else. I was then able to make the link between the warming pattern and the melting of the sea ice."

The findings question previous thought that warmer air transported from lower latitudes toward the pole, or changes in cloud cover, are the primary causes of enhanced Arctic warming.

Dr Screen says prior to this latest data set being available there was a lot of contrasting information and inconclusive data.

"This current data has provided a fuller picture of what is happening in the region," he says.

Over the past 20 years the Arctic has experienced the fastest warming of any region on the planet. Researchers around the globe have been trying to find out why.

Researchers say warming has been partly caused by increasing human greenhouse gas emissions. At the same time, the Arctic sea ice has been declining dramatically. In summer 2007 the Arctic had the lowest sea ice cover on record. Since then levels have recovered a little but the long-term trend is still one of decreasing ice.

Professor Ian Simmonds, of the University's School of Earth Sciences and coauthor on the paper says the findings are significant.

"It was previously thought that loss of sea ice could cause further warming. Now we have confirmation this is already happening."

Provided by University of Melbourne

http://pda.physorg.com/seaice-warming-s ... 65797.html

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Researchers find future temperatures could exceed livable limits

May 04, Space & Earth/Earth Sciences

This map shows the maximum wet-bulb temperatures reached in a climate model from a high carbon dioxide emissions future climate scenario with a global-mean temperature 12 degrees Celsius (21 degrees Fahrenheit) warmer than 2007. The white land areas exceed the wet-bulb limit at which researchers calculated humans would experience a potentially lethal level of heat stress. Credit: Purdue University/Matthew Huber
Reasonable worst-case scenarios for global warming could lead to deadly temperatures for humans in coming centuries, according to research findings from Purdue University and the University of New South Wales, Australia.

Researchers for the first time have calculated the highest tolerable "wet-bulb" temperature and found that this temperature could be exceeded for the first time in human history in future climate scenarios if greenhouse gas emissions continue at their current rate.

Wet-bulb temperature is equivalent to what is felt when wet skin is exposed to moving air. It includes temperature and atmospheric humidity and is measured by covering a standard thermometer bulb with a wetted cloth and fully ventilating it.

The researchers calculated that humans and most mammals, which have internal body temperatures near 98.6 degrees Fahrenheit, will experience a potentially lethal level of heat stress at wet-bulb temperature above 95 degrees sustained for six hours or more, said Matthew Huber, the Purdue professor of earth and atmospheric sciences who co-authored the paper that will be published in Thursday's (May 6) issue of the Proceedings of the National Academy of Sciences.

"Although areas of the world regularly see temperatures above 100 degrees, really high wet-bulb temperatures are rare," Huber said. "This is because the hottest areas normally have low humidity, like the 'dry heat' referred to in Arizona. When it is dry, we are able to cool our bodies through perspiration and can remain fairly comfortable. The highest wet-bulb temperatures ever recorded were in places like Saudi Arabia near the coast where winds occasionally bring extremely hot, humid ocean air over hot land leading to unbearably stifling conditions, which fortunately are short-lived today."

The study did not provide new evaluations of the likelihood of future climate scenarios, but explored the impacts of warming. The challenges presented by the future climate scenarios are daunting in their scale and severity, he said.

"Whole countries would intermittently be subject to severe heat stress requiring large-scale adaptation efforts," Huber said. "One can imagine that such efforts, for example the wider adoption of air conditioning, would cause the power requirements to soar, and the affordability of such approaches is in question for much of the Third World that would bear the brunt of these impacts. In addition, the livestock on which we rely would still be exposed, and it would make any form of outside work hazardous."

While the Intergovernmental Panel on Climate Change central estimates of business-as-usual warming by 2100 are seven degrees Fahrenheit, eventual warming of 25 degrees is feasible, he said.

"We found that a warming of 12 degrees Fahrenheit would cause some areas of the world to surpass the wet-bulb temperature limit, and a 21-degree warming would put half of the world's population in an uninhabitable environment," Huber said. "When it comes to evaluating the risk of carbon emissions, such worst-case scenarios need to be taken into account. It's the difference between a game of roulette and playing Russian roulette with a pistol. Sometimes the stakes are too high, even if there is only a small chance of losing."

Steven Sherwood, the professor at the Climate Change Research Centre at the University of New South Wales, Australia, who is the paper's lead author, said prolonged wet-bulb temperatures above 95 degrees would be intolerable after a matter of hours.

"The wet-bulb limit is basically the point at which one would overheat even if they were naked in the shade, soaking wet and standing in front of a large fan," Sherwood said. "Although we are very unlikely to reach such temperatures this century, they could happen in the next."

Humans at rest generate about 100 watts of energy from metabolic activity. Wet-bulb temperature estimates provide upper limits on the ability of people to cool themselves by sweating and otherwise dissipating this heat, he said. In order for the heat dissipation process to work, the surrounding air must be cooler than the skin, which must be cooler than the core body temperature. The cooler skin is then able to absorb excess heat from the core and release it into the environment. If the wet-bulb temperature is warmer than the temperature of the skin, metabolic heat cannot be released and potentially dangerous overheating can ensue depending on the magnitude and duration of the heat stress.

The National Science Foundation-funded research investigated the long-term implications of sustained greenhouse gas emissions on climate extremes. The team used climate models to compare the peak wet-bulb temperatures to the global temperatures for various climate simulations and found that the peak wet-bulb temperature rises approximately 1 degree Centigrade for every degree Centigrade increase in tropical mean temperature.

Huber did the climate modeling on supercomputers operated by Information Technology at Purdue (ITaP), Purdue's central information technology organization. Sherwood performed the wet-bulb calculations.

"These temperatures haven't been seen during the existence of hominids, but they did occur about 50 million years ago, and it is a legitimate possibility that the Earth could see such temperatures again," Huber said. "If we consider these worst-case scenarios early enough, perhaps we can do something to address the risk through mitigation or new technological advancements that will allow us to adapt."

More information: Paper: http://www.pnas.org/content/early/2010/ ... 7.abstract

[macdoc]

Rare 114-Year Record, Kept by Generations, Logs Changing Climate



The rain gauge at Mohonk is the brass 1896 original, supplied by the US Weather Bureau (now called the National Weather Service). (Credit: Linda Keyes/Courtesy Mohonk Preserve)

ScienceDaily (May 7, 2010) — Every day since Jan. 1, 1896, an observer has hiked to a spot at The Mohonk Preserve, a resort and nature area some 90 miles north of New York City, to record daily temperature and other conditions there. It is the rarest of the rare: a weather station that has never missed a day of temperature recording; never been moved; never seen its surroundings change; and never been tended by anyone but a short, continuous line of family and friends, using the same methods, for 114 years.

On top of that, observers have for decades recorded related phenomena such as first appearances of spring peepers, migratory birds and blooming plants. At a time when scientists are wrestling to ensure that temperature readings from thousands of divergent weather stations can be accurately compared with one another to form a large-scale picture, Mohonk offers a powerful confirmation of warming climate, as well as a compelling multigenerational yarn.

The story is told in an article by researchers from Columbia University's Lamont-Doherty Earth Observatory and Mohonk in the current issue of the Journal of Applied Meteorology and Climatology.

Mohonk was founded in 1869 by the Smileys, a close-knit Quaker family that still runs the 7,200-acre property on a high ridge in the Shawangunk Mountains. When the fledgling United States Weather Bureau (later the National Weather Service) founded an official station there, it supplied thermometers, log sheets and other materials; Albert K. Smiley, one of the twin brothers who founded the place, volunteered to man it. The thermometer (occasionally replaced by a new duplicate over the decades) has always been kept in a box out of direct sun, in the same place, a short walk from the Mohonk hotel; a brass rain gauge at the end of a boat dock is the 1896 original. In 1906, Albert's half-brother, Daniel, took over the readings.

In 1930, Daniel's sons Bert and Doc followed. In 1937, Bert's son Daniel Smiley Jr., picked up the job. In addition, Daniel Jr., an old-school amateur naturalist, started recording many other observations, including first spring sightings of various creatures, on some 15,000 index cards. In 1988, the year before Daniel Jr. passed away, he handed his duties to Paul Huth, a longtime friend and employee. Today Huth or one of his staff still walks up to the box at 4 pm every day. The weather log, for many decades kept on hand-written sheets, lacks only 37 days of precipitation data from 1901, 1908 and 1909, due to a missing data sheet, and a few days when observers apparently didn't look at the rain gauge. The temperature record is complete.

Enter another father-son team. In 1971, Edward R. Cook, then serving as a military policeman at nearby West Point, became friends with Daniel Smiley Jr. Later, Cook became a tree-ring scientist and climatologist at Lamont, and began studying conifer trees at Mohonk--some of which turned out to be over 400 years old. From these, he extracted a rough record of weather in the Hudson Valley before Europeans settled. Then Edward Cook's son, Benjamin I. Cook, became a climate modeler at Lamont. It was under Benjamin's leadership that the Cooks and their colleagues at Mohonk began studying the instrumental readings and other data.

Starting in 1990s, Mohonk staffers spent hundreds of hours digitizing the records so they could be analyzed. "It is incredibly rare to have the level of continuity that we have at Mohonk," said Benjamin Cook. "Any one record cannot tell you anything definitively about climate globally or even regionally. But looking closely at sites like this can boost our confidence in the general trends that we see elsewhere, and in other records."

Indeed, the new study finds remarkable correlations with many other widely spread, but less continuous records. At Mohonk, average annual temperatures from 1896-2006 went up 2.63 degrees Fahrenheit. Global measurements in the same time over both land and oceans put the rise at about 1.2 to 1.4 degrees; but land temperatures are rising faster than those over the oceans, and those at Mohonk track the expected land trend closely. As expected also, temperatures are up in all seasons, but increases have been especially evident in summer heat waves, and this has been accelerating in recent years. Prior to 1980, it was rare for the thermometer to surpass about 89 degrees more than 10 days a year; since then, such events have come to Mohonk on at least 10 days a year -- and often, on more than 20 days. At the same time, the number of freezing days has been decreasing--about a day less every five years over the long term, but since the 1970s, at the accelerated rate of a day every two years. This also matches wide-scale observations in North America and elsewhere.

The Mohonk records do not match wider trends in one area. The start of the growing season -- the date on which freezing temperatures end -- has been advancing steadily in many places, but not here. Instead, the total number of yearly above-freezing days is increasing because more unusually warm days are puncturing the winter. As described in an earlier study in the International Journal of Climatology, also by the Cooks and Mohonk staff, the effect has been a sort of an intermittent false spring that may expose some early-flowering plants to frost damage. The earliest flowering native plants like hepatica, bloodroot and red-berried elder are likely to be most affected, said Benjamin Cook. He said it is still too early to tell the ecological effects of such disruptions, but added: "The data from Mohonk will be invaluable for expanding our knowledge of how ecosystems respond to climate change." Temperature data after 2006 has not yet been analyzed, but Mohonk maintains an up-to-date online archive of the weather data accessible to the public.

The new study comes at a time when some skeptics have questioned the accuracy of long-term weather records, on the basis that many stations have been moved or that surroundings have changed, occasionally putting instruments nearer to buildings, parking lots or other possible heat sources that could skew readings upward. However, recent studies including one by scientists at the National Oceanic and Atmospheric Administration have found that such year-to-year inconsistencies cut both ways, and that instruments near developed spots actually more often read too cool rather than too hot. Researchers say every effort has been made to adjust for errors, and that errors one way or the other at individual stations basically cancel each other out, leaving the averages correct.

"Pictures, anecdotes, and cursory glances of poorly sited or maintained sites and weather stations may suggest problems, but until the data is analyzed it is impossible to conclude that the record is compromised by cold or warm biases," said Cook. "The advantage to Mohonk is that we can revisit the record in detail, with minimal corrections. This helps confirm the large-scale trends, and it helps us identify stations with errors that need to be corrected."

As for the long history behind the studies, he said: "We and the Smileys all just happened to be in the right place, at the right time."

http://www.sciencedaily.com/releases/20 ... 101912.htm

[macdoc]

Was Nashville flooding spurred by global warming?
May 6th, 2010

From Green Right Now Reports

Seeing the pictures of the flooding in Nashville this past week may have reminded you of other recent U.S. floods — in Fargo, Iowa City and the Mississippi River Valley.

And if you keep up with global warming, you may be wondering if this trend isn’t proving what scientists have been telling us about extreme rain events growing more severe and more frequent under climate change.

That question certainly came up in Nashville, according Rich Hayes, deputy communications director at the Union of Concerned Scientists and a Nashville resident.

“A lot of my friends here have asked me if this disaster is related to global warming. The fact is that climate change increases the probability of some types of weather, including heavy rains and flooding. As average temperatures rise, more rain falls during the heaviest downpours. Unfortunately, that is exactly what we experienced in Nashville over the weekend,” Hayes said in a prepared statement on Thursday.

“Warmer air holds more moisture. We’ve all seen it. Next time you take a shower, notice how the water vapor hangs in the warm air after you turn off the hot water. When warm air holding moisture meets cooler air in the atmosphere, the moisture can condense onto tiny particles to form floating droplets. If those drops get bigger and become heavy enough, they fall as precipitation.

Hayes went on to cite a report by the United States Global Change Research Program, a collaborative effort involving 13 federal agencies, which found that “one of the most pronounced precipitation trends in the United States is the increasing frequency and intensity of heavy downpours.”

As for those climate skeptics who might think the Nashville event is just an extreme example of an otherwise good thing, i.e., more rain. Listen in to the rest of what that report predicts:

“More precipitation is falling during very heavy events, often with longer dry periods in between. Climate models project more heavy downpours and fewer light precipitation events.”

In other words, we get rain that doesn’t really work that well for us anymore. It comes in sudden, heavy downpours that produce a lot of runoff and erosion, and when the water can’t escape, flooding. In between, we get dry spells. Ask any farmer if this is a good thing.

It would be akin to having water to drink one week, but no water the next. Most organisms can’t live that way.

Hayes goes on to note that the rain that fell on Nashville was undoubtedly outside the norm. A record of 13 inches fell on Saturday and Sunday, nearly double the previous record set in 1979, and that followed a hurricane.

All these flood events are different. Fargo and the Mississippi Valley had their own distinct issues. Fargo faced rapid heavy snow melt. In Iowa, the flooding was exacerbated by monoculture farming that has left the flat lands susceptible to run off. But they seem to be happening more frequently.



Increases in Very Heavy Precipitation 1958-2007 (Image: U.S. Global Change Research Program)

In Nashville, the sheer volume of rain in a short time overwhelmed the city. Unfortunately, under climate change models, what’s been outside the norm is becoming the norm.

The report cited by Hayes notes that “very heavy rain and snow events, defined as the heaviest 1 percent of all precipitation events, now drop 67 percent more water on the Northeast; 31 percent more on the Midwest and 20 percent more on the Southeast than they did 50 years ago.” (See image above from the USGCRP.)

“If the fossil fuel emissions that cause global warming continue unabated, scientists expect the amount of rainfall during the heaviest precipitation events across the country to increase more than 40 percent by the end of the century. Even if we dramatically curbed emissions, these downpours would still increase, but by only a little more than 20 percent,” according to the UCS statement.

“It’s going to take Nashville a long time to recover from the flooding,” says Hayes. “But when the flood waters do recede, and local officials turn to the question of how we plan for the future, they need to take climate change into account.”

http://www.greenrightnow.com/kabc/2010/ ... l-warming/

[macdoc]

ouch

2010 on track to be hottest ever - U.S. climate data
Wed May 19, 2010 4:23pm IST Email | Print | Share | Single Page [-] Text [+]


LONDON (Reuters) - This year is on track to be the hottest ever after data published by America's climate agency this week showed record global temperatures in April and the first four months of 2010.

"The combined April global land and ocean average surface temperature was the warmest on record at 58.1 degrees Fahrenheit (14.5 degrees Celsius), which is 1.37 degrees F (0.76 degrees C) above the 20th century average of 56.7 F (13.7 C)," the National Oceanic and Atmospheric Administration (NOAA) said in a report on its website dated Monday, May 17.

http://in.reuters.com/article/topNews/i ... 9920100519

[macdoc]

Record heat recorded for Africa's greatest lake
By Daniel Howden in Nairobi
Tuesday, 18 May 201

Africa's deepest lake is warming at an "unprecedented" rate thanks to man-made climate change, scientists have warned. Lake Tanganyika, which stretches from Burundi and DR Congo on its northern shores to southern Tanzania and Zambia, is the second largest lake in the world by volume.

The 420-mile-long finger of water in south-central Africa is now warmer than at any point in the last 1,500 years, according to research published in the journal Nature Geoscience, and the consequences could be dire for the 10 million people who live around it and depend on its fisheries.

"Our records indicate that changes in the temperature of Lake Tanganyika in the past few decades exceed previous natural variability," the paper found. "We conclude that these unprecedented temperatures and a corresponding decrease in productivity can be attributed to anthropogenic global warming."

more

http://www.independent.co.uk/news/world ... 75612.html

and

Record high temperatures far outpace record lows across U.S.
February 11, 2010

http://climateprogress.org/2010/02/11/s ... cord-lows/

[macdoc]

Scientists detect huge carbon 'burp' that helped end last ice age
May 27, 2010

Scientists have found the possible source of a huge carbon dioxide 'burp' that happened some 18,000 years ago and which helped to end the last ice age.

The results provide the first concrete evidence that carbon dioxide (CO2) was more efficiently locked away in the deep ocean during the last ice age, turning the deep sea into a more 'stagnant' carbon repository - something scientists have long suspected but lacked data to support.

Working on a marine sediment core recovered from the Southern Ocean floor between Antarctica and South Africa, the international team led by Dr Luke Skinner of the University of Cambridge radiocarbon dated shells left behind by tiny marine creatures called foraminifera (forams for short).

http://www.physorg.com/news194187137.html

[macdoc]

and perhaps the lowest in thousands of years....

This should answer the "natural variance" nonsense

Arctic ice at low point compared to recent geologic history
June 2, 2010 by Pam Frost Gorder Arctic ice at low point compared to recent geologic history

Leonid Polyak

Less ice covers the Arctic today than at any time in recent geologic history. That's the conclusion of an international group of researchers, who have compiled the first comprehensive history of Arctic ice.

For decades, scientists have strived to collect sediment cores from the difficult-to-access Arctic Ocean floor, to discover what the Arctic was like in the past. Their most recent goal: to bring a long-term perspective to the ice loss we see today.

Now, in an upcoming issue of Quarternary Science Reviews, a team led by Ohio State University has re-examined the data from past and ongoing studies -- nearly 300 in all -- and combined them to form a big-picture view of the pole's climate history stretching back millions of years.

"The ice loss that we see today -- the ice loss that started in the early 20th Century and sped up during the last 30 years -- appears to be unmatched over at least the last few thousand years,"

more
http://www.physorg.com/news194719743.html

[macdoc]

1/10th of a degree..:boggled:

A cooler Pacific may have severely affected medieval Europe, North America
June 9, 2010

In the time before Columbus sailed the ocean blue, a cooler central Pacific Ocean has been connected with drought conditions in Europe and North America that may be responsible for famines and the disappearance of cliff dwelling people in the American West.

http://www.physorg.com/news195309866.html

good read

[macdoc]

NASA: Easily the hottest spring — and Jan-May — in temperature record
Plus another record 12-month global temperature
June 10, 2010

NASA 5-10

Lmonth tied May 1998 as the hottest on record in the NASA dataset. More significantly, following fast on the heels of easily the hottest April — and hottest Jan-April — on record, it’s also the hottest Jan-May on record [click on figure to enlarge].

Also, the combined land-surface air and sea-surface water temperature anomaly for March-April-May was 0.73°C above the 1951-1980 mean, blowing out the old record of 0.65°C set in 2002.

The record temperatures we’re seeing now are especially impressive because we’ve been in “the deepest solar minimum in nearly a century.” It’s just hard to stop the march of manmade global warming, well, other than by reducing greenhouse gas emissions, that is.

Most significantly, the 12-month global temperature grew to 0.66°C — easily the highest on record.

more
http://climateprogress.org/

[macdoc]

Arctic Climate May Be More Sensitive to Warming Than Thought, Says New Study

ScienceDaily (June 30, 2010) — A new study shows the Arctic climate system may be more sensitive to greenhouse warming than previously thought, and that current levels of Earth's atmospheric carbon dioxide may be high enough to bring about significant, irreversible shifts in Arctic ecosystems.

http://www.sciencedaily.com/releases/20 ... 131318.htm

[macdoc]

ScienceDaily:

Hunting Weapon 10,000 Years Old Found in Melting Ice Patch

ScienceDaily (June 30, 2010) — To the untrained eye, University of Colorado at Boulder Research Associate Craig Lee's recent discovery of a 10,000-year-old wooden hunting weapon might look like a small branch that blew off a tree in a windstorm.

Nothing could be further from the truth, according to Lee, a research associate with CU-Boulder's Institute of Arctic and Alpine Research who found the atlatl dart, a spear-like hunting weapon, melting out of an ice patch high in the Rocky Mountains close to Yellowstone National Park.

Lee, a specialist in the emerging field of ice patch archaeology, said the dart had been frozen in the ice patch for 10 millennia and that climate change has increased global temperatures and accelerated melting of permanent ice fields, exposing organic materials that have long been entombed in the ice.

"We didn't realize until the early 2000s that there was a potential to find archaeological materials in association with melting permanent snow and ice in many areas of the globe," Lee said. "We're not talking about massive glaciers, we're talking about the smaller, more kinetically stable snowbanks that you might see if you go to Rocky Mountain National Park."

As glaciers and ice fields continue to melt at an unprecedented rate, increasingly older and significant artifacts -- as well as plant material, animal carcasses and ancient feces -- are being released from the ice that has gripped them for thousands of years, he said.

Over the past decade, Lee has worked with other researchers to develop a geographic information system, or GIS, model to identify glaciers and ice fields in Alaska and elsewhere that are likely to hold artifacts. They pulled together biological and physical data to find ice fields that may have been used by prehistoric hunters to kill animals seeking refuge from heat and insect swarms in the summer months.

"In these instances, what we're finding as archaeologists is stuff that was lost," Lee said. "Maybe you missed a shot and your weapon disappeared into the snowbank. It's like finding your keys when you drop them in snow. You're not going to find them until spring. Well, the spring hasn't come until these things started melting for the first time, in some instances, in many, many thousands of years."

The dart Lee found was from a birch sapling and still has personal markings on it from the ancient hunter, according to Lee. When it was shot, the 3-foot-long dart had a projectile point on one end, and a cup or dimple on the other end that would have attached to a hook on the atlatl. The hunter used the atlatl, a throwing tool about two feet long, for leverage to achieve greater velocity.

Later this summer Lee and CU-Boulder student researchers will travel to Glacier National Park to work with the Salish, Kootenai and Blackfeet tribes and researchers from the University of Wyoming to recover and protect artifacts that may have recently melted out of similar locations.

"We will be conducting an unprecedented collaboration with our Native American partners to develop and implement protocols for culturally appropriate scientific methods to recover and protect artifacts we may discover," he said.

Quick retrieval of any organic artifacts like clothing, wooden tools or weapons is necessary to save them, because once thawed and exposed to the elements they decompose quickly, he said.

An estimated 10 percent of Earth's land surface is covered with perennial snow, glaciers and ice fields, providing plenty of opportunities for exploration, Lee said. However, once organic artifacts melt out of the ice, they could be lost forever.

"Ninety-five percent of the archaeological record that we usually base our interpretations on is comprised of chip stone artifacts, ground stone artifacts, maybe old hearths, which is a fire pit, or rock rings that would have been used to stabilize a house," Lee said. "So we really have to base our understanding about ancient times on these inorganic materials. But ice patches are giving us this window into organic technology that we just don't get in other environments."

http://www.sciencedaily.com/releases/20 ... 131322.htm

[macdoc]

Superb piece from RealClimate

The Key to the Secrets of the Troposphere
Filed under:

* Climate Science

— rasmus @ 13 August 2010

http://www.realclimate.org/index.php/ar ... #more-4719