U.N. panel says it’s more certain that humans drive global warming

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Scientists are increasingly convinced that human activity is behind the increase in global temperatures since the 1950s, which has boosted sea levels and the odds of extreme storms, according to a leaked draft of an upcoming U.N. report.

“It is extremely likely that human influence on climate caused more than half of the observed increase in global average surface temperature from 1951 to 2010,” according to a summary of the draft obtained by CNN. “There is high confidence that this has warmed the ocean, melted snow and ice, raised global mean sea level and changed some climate extremes in the second half of the 20th century.”

That conclusion comes from the upcoming report of the U.N. Intergovernmental Panel on Climate Change, the fifth in a series of multiyear reports seen as a benchmark on the subject. The panel’s last report, in 2007, concluded that it was 90% certain that rising temperatures were due to human activity; the new draft raises that figure to 95%.

The science of global warming is politically controversial but generally accepted as fact by most researchers, who point to heat-trapping carbon emissions from the burning of fossil fuels as the major cause. A May study of research papers published between 1991 and 2011 found that more than 97% of those that expressed an opinion on the cause of increasing temperatures supported that consensus.

The panel’s report is slated for release in sections, starting in September.

http://www.cnn.com/2013/08/20/world/un-climate/index.html?hpt=hp_t2

North Pole now a lake

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Instead of snow and ice whirling on the wind, a foot-deep aquamarine lake now sloshes around a webcam stationed at the North Pole. The meltwater lake started forming July 13, following two weeks of warm weather in the high Arctic. In early July, temperatures were 2 to 5 degrees Fahrenheit (1 to 3 degrees Celsius) higher than average over much of the Arctic Ocean, according to the National Snow & Ice Data Center.

Meltwater ponds sprout more easily on young, thin ice, which now accounts for more than half of the Arctic’s sea ice. The ponds link up across the smooth surface of the ice, creating a network that traps heat from the sun. Thick and wrinkly multi-year ice, which has survived more than one freeze-thaw season, is less likely sport a polka-dot network of ponds because of its rough, uneven surface.

July is the melting month in the Arctic, when sea ice shrinks fastest. An Arctic cyclone, which can rival a hurricane in strength, is forecast for this week, which will further fracture the ice and churn up warm ocean water, hastening the summer melt. The Arctic hit a record low summer ice melt last year on Sept. 16, 2012, the smallest recorded since satellites began tracking the Arctic ice in the 1970s.

http://www.livescience.com/38347-north-pole-ice-melt-lake.html

Ancient Irish texts show volcanic link to cold weather

irish volcano

By Matt McGrath

Environment correspondent, BBC News

Researchers have been able to trace the impact of volcanic eruptions on the climate over a 1200 year period by assessing ancient Irish texts.

The international team compared entries in these medieval annals with ice core data indicating volcanic eruptions.

Of 38 volcanic events, 37 were associated with directly observed cold weather extremes recorded in the chronicles.

The report is published in the journal Environmental Research Letters.

In the dim light of the Dark Ages, the Irish literary tradition stands out like a beacon.

At monastic centres across the island, scribes recorded significant events such as feast days, obituaries and descriptions of extreme cold and heat.

These chronicles are generally known as the Irish Annals and in this report, scientists and historians have looked at 40,000 entries in the texts dating from AD431 to 1649.

The researchers also looked at the Greenland Ice Sheet Project (GISP2) ice-core data.

When volcanoes erupt, they produce sulphate aerosol particles which down the centuries have been deposited on and frozen in ice sheets, leaving an extremely accurate temporal record of the event.

Scientists say these particles reflect incoming sunlight and can cause a temporary cooling of the Earth’s surface. In a country with a mild maritime climate like Ireland, these colder events would have a significant impact.

When the weather that is cold enough to allow you to walk over a lake in Ireland, it is pretty unusual,” lead author Dr Francis Ludlow, from Harvard University, told BBC News.

“When it happened, it was remarkable enough to be recorded pretty consistently.”

The scientists in the team identified 48 volcanic eruptions in the time period spanning 1,219 years. Of these, 38 were associated closely in time with extreme weather events identified in the Irish texts.

“These eruptions occur and they override existing climate patterns for a period of two or three years,” said Dr Ludlow.

“And it is clear from the sources that they cause a lot of devastation among societies at the time – whether it was the mass mortality of domestic animals or humans, or indirectly by causing harvest failure.”

The research team believe the texts are accurate as the annals also record solar and lunar eclipses which can be compared with other contemporary sources.

The keen recording of weather though had another motivation.

“A lot of these scribes are working in monasteries, in some time periods they are interpreting these weather events as divine omens or portents as signals of the coming of the last days,” said Dr Ludlow.

“That was one of their motivations so we are able to use the records that were created for a completely different purpose that the scribes would never have conceived.”

The researchers say that one expected effect of volcanic eruptions that occur in tropical regions is to make for milder winters in northern latitudes.

But in this study, they found several instances of these type of eruptions causing extremely cold winters in Ireland. The team believes their work shows the complex nature of volcanic impacts on climate, and they say there are lessons for the future in the ancient texts.

“That tells us a lot about what sort of weather we might expect in the British Isles when the next big eruption goes off,” said Dr Ludlow.

“We might want to buy a bit more salt for the roads.”

http://www.bbc.co.uk/news/science-environment-22786179

Thanks to Kebmodee for bringing this to the attention of the It’s Interesting community.

Sea Level Could Rise 5 Feet in New York City by 2100

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The U.S.’s largest metropolis and the entire east coast could face frequent destruction unless the region takes previously unthinkable actions

By Mark Fischetti

By 2100 devastating flooding of the sort that Superstorm Sandy unleashed on New York City could happen every two years all along the valuable and densely populated U.S. east coast—anywhere from Boston to Miami.

And unless extreme protection measures are implemented, people could again die.

Hyperbole? Hardly. Even though Sandy’s storm surge was exceptionally high, if sea level rises as much as scientists agree is likely, even routine storms could cause similar destruction. Old, conservative estimates put the increase at two feet (0.6 meter) higher than the 2000 level by 2100. That number did not include any increase in ice melting from Greenland or Antarctica—yet in December new data showed that temperatures in Antarctica are rising three times faster than the rate used in the conservative models. Accelerated melting has also been reported in Greenland. Under what scientists call the rapid ice-melt scenario, global sea level would rise four feet (1.2 meters by the 2080s, according to Klaus Jacob, a research scientist at Columbia University’s Lamont–Doherty Earth Observatory. In New York City by 2100 “it will be five feet, plus or minus one foot,” Jacob says.

Skeptics doubt that number, but the science is solid. The projection comes in part from the realization that the ocean does not rise equally around the planet. The coast from Cape Cod near Boston to Cape Hatteras in North Carolina is a hot spot—figuratively and literally. In 2012 Asbury Sallenger, a coastal hazards expert at the U.S. Geological Survey (USGS), reported that for the prior 60 years sea level along that section of the Atlantic coast had increased three to four times faster than the global average. Looking ahead to 2100, Sallenger indicated that the region would experience 12 to 24 centimeters—4.7 to 9.4 inches—of sea level rise above and beyond the average global increase.

Sallenger (who died in February) was careful to point out that the surplus was related only to ocean changes—such as expansion of water due to higher temperature as well as adjustments to the Gulf Stream running up along the coast brought about by melting Arctic ice—not changes to the land.

Unfortunately, that land is also subsiding. Since North American glaciers began retreating 20,000 years ago, the crust from New York City to North Carolina has been sinking, as the larger continent continues to adjust to the unloading. The land will continue to subside by one to 1.5 millimeters (0.04 to 0.06 inch) a year, according to S. Jeffress Williams, a coastal marine geologist with the USGS and the University of Hawaii at Mānoa. The boundary zone where rising crust to the north changes to falling crust to the south runs roughly west to east from central New York State through Massachusetts.

Certain municipalities such as Atlantic City, N.J., are sinking even faster because they are rapidly extracting groundwater. Cities around Chesapeake Bay, such as Norfolk, Va., and Virginia Beach, are subsiding faster still because sediment underneath them continues to slump into the impact crater that formed the bay 35 million years ago.

When all these factors are taken into account, experts say, sea level rise of five feet (1.5 meters) by 2100 is reasonable along the entire east coast. That’s not really a surprise: the ocean was 20 to 26 feet (six to eight meters) higher during the most recent interglacial period.

Now for the flooding: Sandy’s storm surge topped out at about 11 feet (3.4 meters) above the most recent average sea level at the lower tip of Manhattan. But flood maps just updated by the Federal Emergency Management Agency in January indicate that even an eight-foot (2.5-meter) surge would cause widespread, destructive flooding. So if sea level rises by five feet (1.5 meters_, a surge of only three feet is needed to inflict considerable damage.

How frequently could that occur? Municipalities rarely plan for anything greater than the so-called one-in-100-year storm—which means that the chances of such a storm hitting during any given year is one in 100. Sandy was a one-in-500-year storm. If sea level rises by five feet, the chance in any year of a storm bringing a three-foot surge to New York City will increase to as high as one in three or even one in two, according to various projections. The 100-year-height for a storm in the year 2000 would be reached by a two-year storm in 2100.

With hundreds of people still homeless in Sandy’s wake, coastal cities worldwide are watching to see how New York City will fend off rising seas. Scientists and engineers have proposed solutions to pieces of the complex puzzle, and a notable subset of them on the New York City Panel on Climate Change are rushing to present options to Mayor Michael Bloomberg by the end of May. But extensive interviews with those experts leads to several controversial and expensive conclusions: Long-term, the only way to protect east coast cities against storm surges is to build massive flood barriers (pdf). The choices for protecting the long stretches of sandy coastlines between them—New Jersey, Maryland, the Carolinas, Florida—are even more limited.

As for sea level rise, retreat from low-lying shores may be the best option. Despite the gut reaction of “No, we won’t go,” climate forces already in motion may leave few options.

http://www.scientificamerican.com/article.cfm?id=fischetti-sea-level-could-rise-five-feet-new-york-city-nyc-2100

As the Earth warms, 400 year old frozen plants are being revived

plants

Plants that were frozen during the “Little Ice Age” centuries ago have been observed sprouting new growth, scientists say. Samples of 400-year-old plants known as bryophytes have flourished under laboratory conditions. Researchers say this back-from-the-dead trick has implications for how ecosystems recover from the planet’s cyclic long periods of ice coverage. The findings appear in Proceedings of the National Academy of Sciences.

They come from a group from the University of Alberta, who were exploring an area around the Teardrop Glacier, high in the Canadian Arctic. The glaciers in the region have been receding at rates that have sharply accelerated since 2004, at about 3-4m per year. That is exposing land that has not seen light of day since the so-called Little Ice Age, a widespread climatic cooling that ran roughly from AD 1550 to AD 1850.

“We ended up walking along the edge of the glacier margin and we saw these huge populations coming out from underneath the glacier that seemed to have a greenish tint,” said Catherine La Farge, lead author of the study.

Bryophytes are different from the land plants that we know best, in that they do not have vascular tissue that helps pump fluids around different parts of the organism. They can survive being completely desiccated in long Arctic winters, returning to growth in warmer times, but Dr La Farge was surprised by an emergence of bryophytes that had been buried under ice for so long.

“When we looked at them in detail and brought them to the lab, I could see some of the stems actually had new growth of green lateral branches, and that said to me that these guys are regenerating in the field, and that blew my mind,” she told BBC News. “If you think of ice sheets covering the landscape, we’ve always thought that plants have to come in from refugia around the margins of an ice system, never considering land plants as coming out from underneath a glacier.”

But the retreating ice at Sverdrup Pass, where the Teardrop Glacier is located, is uncovering an array of life, including cyanobacteria and green terrestrial algae. Many of the species spotted there are entirely new to science.

“It’s a whole world of what’s coming out from underneath the glaciers that really needs to be studied,” Dr La Farge said.

“The glaciers are disappearing pretty fast – they’re going to expose all this terrestrial vegetation, and that’s going to have a big impact.”

http://www.bbc.co.uk/news/science-environment-22656239

Ozone Hole Shrinks to Record Low

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Good news from Antarctica: The hole in the ozone layer is shrinking, new measurements reveal.

Ozone is a molecule made of three oxygen atoms. It’s relatively highly concentrated in a particular layer of the stratosphere about 12 miles to 19 miles (20 to 30 kilometers) above Earth’s surface. This ozone layer prevents ultraviolet light from reaching Earth’s surface — a good thing, given that UV light causes sunburn and skin cancer.

Ever since the early 1980s, though, a hole in this layer has developed over Antarctica during September to November, decreasing ozone concentration by as much as 70 percent. The cause is human-produced chlorofluorocarbons (CFCs), which were once heavily used in aerosols and refrigeration.

By international agreement, CFCs have been phased out of use. The policy has real effects, new satellite observations reveal. In 2012, the hole in the ozone layer over Antarctica was smaller than it has ever been in the last 10 years.

The new observations, announced by the European Space Agency (ESA) on Feb. 8, come from Europe’s Met Op weather satellite, which has an instrument specifically designed to sense ozone concentrations. The findings suggest that the phase-out of CFCs is working, the ESA reports.

Antarctica is particularly vulnerable to ozone-depleting substances, because high winds cause a vortex of cold air to circulate over the continent. In the resulting frigid temperatures, CFCs are especially effective at depleting ozone. The result is that people in the Southern Hemisphere are at increased risk of exposure from UV radiation.

CFCs persist in the atmosphere for a long time, so it may take until the middle of the century for ozone concentrations to rebound to 1960s levels, the ESA reports. However, the hole in the ozone over Antarctica should completely close in the next few decades.

http://www.livescience.com/27049-ozone-hole-shrinks-record-low.html

Sunlight stimulates release of carbon dioxide in melting permafrost

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By Monte Morin, Los Angeles Times

Ancient plant and animal matter trapped within Arctic permafrost can be converted rapidly into climate-warming carbon dioxide when melted and exposed to sunlight, according to a new study.

In a report published Monday in the Proceedings of the National Academy of Sciences, a team of environmental and biological scientists examined 27 melting permafrost sites in Alaska and found that bacteria converted dissolved organic carbon materials into the greenhouse gas CO2 40% faster when exposed to ultraviolet light.

Study authors said that while it remained unclear just how much CO2 would be released as Arctic permafrost continues to melt, the findings were cause for concern. High latitude soils currently store twice the amount of carbon than is found in the atmosphere.

“What we can say now is that regardless of how fast the thawing of the Arctic permafrost occurs, the conversion of this soil carbon to carbon dioxide and its release into the atmosphere will be faster than we previously thought,” senior author George Kling, a University of Michigan ecologist and aquatic biogeochemist, said in a statement.

“That means permafrost carbon is potentially a huge factor that will help determine how fast the Earth warms,” Kling said.

Plant and animal matter has remained locked in frozen Arctic soils for thousands of years. When those soils begin to thaw, however, the organic matter begins to decay. As that matter decays, it is eaten by microbes, which produce either methane or CO2 as a byproduct. Methane — an even more powerful greenhouse gas than CO2 — occurs when the decaying matter is not exposed to oxygen.

Study authors examined melt water in so-called thermokarst impacted areas. Thermokarsts occur when long-frozen earth melts and the soil collapses into a sink-hole or causes a landslide.

As the permafrost melts, organic matter is dissolved in the melt water and exposed to sunlight in streams or pools.

Authors found that the rate of CO2 conversion slowed at night, or during cloudy conditions.

“Although no estimates exist for what percentage of now-frozen carbon will be released to the surface as the Arctic warms, the alteration and fate of this carbon will depend on its susceptibility to coupled photobiological processing and the available light,” wrote study lead author Rose Cory, an assistant professor of environmental sciences and engineering at the University of North Carolina.

http://www.latimes.com/news/science/sciencenow/la-sci-sn-carbon-sunlight-permafrost-20130211,0,5550833.story

Thanks to Ray Gaudette for bringing this to the attention of the It’s Interesting community.

New map predicts timing of cities to avoid as sea levels rise

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As the world warms, ice melts and water expands, sea level will rise – but faster in some places than others. These simulations, which assume warming in the middle of the range indicated by climate models, provide the best view yet of probable regional variation in sea level rise over the coming decades. Use the play button or slider to control the animations.

Click the link below to view projections for high or low emissions scenarios.

http://sealevel.newscientistapps.com/

SYDNEY, Tokyo and Buenos Aires watch out. These cities will experience some of the greatest sea level rises by 2100, according to one of the most comprehensive predictions to date.

Sea levels have been rising for over 100 years – not evenly, though. Several processes are at work, says Mahé Perrette of the Potsdam Institute for Climate Impact Research in Germany. Some land is sinking, some is rising. Stronger currents create slopes in sea surface, and since all things with mass exert a gravitation pull, disappearing ice sheets lead to a fall in sea levels in their surrounding areas.

Perrette has modelled all of these effects and calculated local sea level rises in 2100 for the entire planet. While the global average rise is predicted to be between 30 and 106 centimetres, he says tropical seas will rise 10 or 20 per cent more, while polar seas will see a below-average rise. Coasts around the Indian Ocean will be hard hit, as will Japan, south-east Australia and Argentina (Earth System Dynamics, doi.org/kbf).

New York’s position may be less perilous than previously thought. A weakening of the Atlantic Gulf Stream will cause water to slop westwards, triggering a rapid rise on the eastern seaboard, but this will be counteracted by Greenland’s weaker gravitational pull. The city is not out of the woods, though, warns Aimée Slangen of Utrecht University in the Netherlands, whose own model suggests that Antarctica could lose a lot of ice, which would produce an above-average rise throughout the northern hemisphere.

For now, Perrette offers a warning to tropical countries. “You may have 120 centimetres of sea level rise on your coastline,” he says. “Build defences.”

This article appeared in print under the headline “Where not to be when seas rise up to meet us”

http://www.newscientist.com/article/mg21729034.900-new-map-pinpoints-cities-to-avoid-as-sea-levels-rise.html

Nicholas Stern: ‘I got it wrong on climate change – it’s far, far worse’

Nicholas Stern
Lord Stern now believes he should have been more ‘blunt’ about threat to economies from temperature rises. Photograph: Sarah Lee for the Guardian

Lord Stern, author of the government-commissioned review on climate change that became the reference work for politicians and green campaigners, now says he underestimated the risks, and should have been more “blunt” about the threat posed to the economy by rising temperatures.

In an interview at the World Economic Forum in Davos, Stern, who is now a crossbench peer, said: “Looking back, I underestimated the risks. The planet and the atmosphere seem to be absorbing less carbon than we expected, and emissions are rising pretty strongly. Some of the effects are coming through more quickly than we thought then.”

The Stern review, published in 2006, pointed to a 75% chance that global temperatures would rise by between two and three degrees above the long-term average; he now believes we are “on track for something like four “. Had he known the way the situation would evolve, he says, “I think I would have been a bit more blunt. I would have been much more strong about the risks of a four- or five-degree rise.”

He said some countries, including China, had now started to grasp the seriousness of the risks, but governments should now act forcefully to shift their economies towards less energy-intensive, more environmentally sustainable technologies.

“This is potentially so dangerous that we have to act strongly. Do we want to play Russian roulette with two bullets or one? These risks for many people are existential.”

Stern said he backed the UK’s Climate Change Act, which commits the government to ambitious carbon reduction targets. But he called for increased investment in greening the economy, saying: “It’s a very exciting growth story.”

David Cameron made much of his environmental credentials before the 2010 election, travelling to the Arctic to highlight his commitment to tackling global warming. But the coalition’s commitment to green policies has recently been questioned, amid scepticism among Tory backbenchers about the benefits of wind power, and the chancellor’s enthusiasm for exploiting Britain’s shale gas reserves.

Stern’s comments came as Jim Yong Kim, the new president of the World Bank, also at Davos, gave a grave warning about the risk of conflicts over natural resources should the forecast of a four-degree global increase above the historical average prove accurate.

“There will be water and food fights everywhere,” Kim said as he pledged to make tackling climate change a priority of his five-year term.

Kim said action was needed to create a carbon market, eliminate fossil-fuel subsidies and “green” the world’s 100 megacities, which are responsible for 60 to 70% of global emissions.

He added that the 2012 droughts in the US, which pushed up the price of wheat and maize, had led to the world’s poor eating less. For the first time, the bank president said, extreme weather had been attributed to man-made climate change. “People are starting to connect the dots. If they start to forget, I am there to remind them.

“We have to find climate-friendly ways of encouraging economic growth. The good news is we think they exist”.

Kim said there would be no solution to climate change without private sector involvement and urged companies to seize the opportunity to make profits: “There is a lot of money to be made in building the technologies and bending the arc of climate change.”

http://www.guardian.co.uk/environment/2013/jan/27/nicholas-stern-climate-change-davos

West Antarctica Ice Sheet is Warming Up

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One of the big environmental stories of 2012 was the record melting of sea ice in the Arctic, which reached its smallest extent this summer since satellite data began being kept in the late 1970s. But it’s not the Arctic alone that’s reacting to manmade climate change by transforming into a large puddle. On the other end of the Earth, the continent of Antarctica contains enough ice to swamp just about every coastal city on the planet were it all to melt. The Arctic is transforming before our eyes, but it’s changes in Antarctica that could make Waterworld into a documentary.

That day is still in the distant future—in fact, sea ice in Antarctica has actually increased in recent years, as more powerful northward winds refreeze ice on the continent. But as a new study published in Nature Geoscience shows, temperatures are on the increase in the massive West Antarctica Ice Sheet (WAIS)—and so is melting.

Using data from Byrd Station, a scientific outpost in West Antarctica, researchers from Ohio State University and other institutions have report that average annual temperatures in the region have risen by 2.4 C (4.3 F) since 1958. That’s nearly twice as much warming as had been previously estimated, and the data shows for the first time an increase in warming trends during the summer. The timing of the temperature increase is particularly alarming because while temperatures in Antarctica remain well below freezing for nearly the entire year, the Antarctic summer is when any melting is likely to occur—just as it does in the Arctic.

As lead author David Bromwich put it in a statement:

Our record suggests that continued summer warming in West Antarctica could upset the surface mass balance of the ice sheet, so that the region could make an even bigger contribution to sea level rise than it already does.

Even without generating significant mass loss directly, surface melting on the WAIS could contribute to sea level indirectly, by weakening the West Antarctic ice shelves that restrain the region’s natural ice flow into the ocean.

Today melting from the WAIS adds only a few millimeters to the ongoing global sea level rise. But there is potential for much, much more—if all the ice in the 10 million sq. mile WAIS were to melt, it would be enough to add 3.05 m (10 ft.) to sea levels. To put that in perspective, all the warming the world has experienced since the Industrial Revolution has cause sea levels to rise by a few inches. That’s scary, world-changing stuff.

Antarctica: It’s Getting Hot at the Bottom of the Planet

Thanks to Ray Gaudette for bringing this to the attention of the It’s Interesting community.