Archive for the ‘Climate Change’ Category

<> on June 9, 2010 in Houma, Louisiana.

By Susannah Cullinane, CNN

The world’s oceans have become 26% more acidic since the start of the Industrial Revolution and continue to acidify at an “unprecedented rate,” threatening marine ecosystems, aquaculture and the societies that rely on them, scientists say.

In a report released Thursday, researchers say that carbon dioxide emissions from human activities such as fossil fuel burning are the primary cause of ocean acidification.

They say the rate of change may be faster than at any time in the last 300 million years, predicting that by 2100 there will have been a 170% increase in ocean acidity, compared to pre-industrial times.

The report is based on the findings from a September 2012 Symposium on the Ocean, at which 540 experts from 37 countries discussed research on ocean acidification, and has been updated with more recent research.

Unless carbon dioxide emissions are reduced, marine ecosystems will be damaged and the impact of climate change will be worsened, the scientists warn. “The only known realistic mitigation option on a global scale is to limit future atmospheric CO2 levels.”

The report says oceans currently act as a CO2 “sinkhole” absorbing approximately a quarter of emissions.

“As ocean acidity increases, its capacity to absorb CO2 from the atmosphere decreases. This decreases the ocean’s role in moderating climate change,” they write.

The increased acidity will also change the ocean environment, with evidence suggesting that some organisms will be less able to survive, while others, such as seagrass, may thrive.

Acidification is faster in Arctic waters because cold water is richer in CO2, while melting sea ice worsens the problem, they say.

“Within decades, large parts of the polar oceans will become corrosive to the unprotected shells of calcareous marine organisms,” the report says, while in the tropics the growth of coral reefs may be hampered.

“People who rely on the ocean’s ecosystem services are especially vulnerable and may need to adapt or cope with ocean acidification impacts within decades,” it says. “Tropical coral reef loss will affect tourism, food security and shoreline protection for many of the world’s poorest people.”

“Very aggressive reductions in CO2 emissions are required to maintain a majority of tropical coral reefs in waters favorable for growth,” the report says.

One of the report’s authors is Daniela Schmidt, from the University of Bristol, in the UK.

Schmidt said the research highlighted the impact acidification would have on biodiversity and aquaculture and the societies that rely on them for their food and economic well-being.

“We’re talking about countries that strongly depend on this, in warmer countries where there are complex problems with climate change as it is,” Schmidt said.

“What I’m hoping is that people realize that CO2 is not just a question of global warming. That we are acidifying the ocean at a rate that has been unprecedented — for millions and millions of years,” she said.

“The more CO2 emissions, the more acidification,” Schmidt said. “The ocean is in direct interchange with the atmosphere.”

If acidification continued to increase at its current rate, “you will definitely see damage,” she said. “The first signs we can already see today, in oyster farms off the West Coast of the United States.”

Schmidt said while 90% of the world’s ocean was in equilibrium with the atmosphere, some oyster hatcheries in this area were located in the 10% that wasn’t.

Oysters in the larval stage were much more vulnerable to damage, she said. “When (more acidic) water comes up and hits the hatchery, they close the whole thing.”

While tanks could be closed off to more acidic seawater, Schmidt said that by 2100 the issue would be there every day. “So we can’t just switch off that tap anymore.”

She said the report would be presented in Warsaw, Poland, on November 18, during the U.N. Conference of the Parties climate change meeting.

Schmidt said while she hoped the research would lead to stricter emissions limits, “the realist in me thinks that we’ve been discussing this for decades. This isn’t a problem that is just going to go away. It’s simple. The consequences are frightening.”

The 2012 symposium that led to the report was sponsored by the Scientific Committee on Oceanic Research, the Intergovernmental Oceanographic Commission of UNESCO, and the International Geosphere-Biosphere Programme.

http://www.cnn.com/2013/11/14/world/ocean-acidification-report/index.html?hpt=hp_t3

Some of the world’s top climate scientists say wind and solar energy won’t be enough to head off extreme global warming, and they’re asking environmentalists to support the development of safer nuclear power as one way to cut fossil fuel pollution.

Four scientists who have played a key role in alerting the public to the dangers of climate change sent letters Sunday to leading environmental groups and politicians around the world. The letter, an advance copy of which was given to The Associated Press, urges a crucial discussion on the role of nuclear power in fighting climate change.

Environmentalists agree that global warming is a threat to ecosystems and humans, but many oppose nuclear power and believe that new forms of renewable energy will be able to power the world within the next few decades.

That isn’t realistic, the letter said.

“Those energy sources cannot scale up fast enough” to deliver the amount of cheap and reliable power the world needs, and “with the planet warming and carbon dioxide emissions rising faster than ever, we cannot afford to turn away from any technology” that has the potential to reduce greenhouse gases.

The letter signers are James Hansen, a former top NASA scientist; Ken Caldeira, of the Carnegie Institution; Kerry Emanuel, of the Massachusetts Institute of Technology; and Tom Wigley, of the University of Adelaide in Australia.

Hansen began publishing research on the threat of global warming more than 30 years ago, and his testimony before Congress in 1988 helped launch a mainstream discussion. Last February he was arrested in front of the White House at a climate protest that included the head of the Sierra Club and other activists. Caldeira was a contributor to reports from the Intergovernmental Panel on Climate Change, Emanuel is known for his research on possible links between climate change and hurricanes, and Wigley has also been doing climate research for more than 30 years.

Emanuel said the signers aren’t opposed to renewable energy sources but want environmentalists to understand that “realistically, they cannot on their own solve the world’s energy problems.”

The vast majority of climate scientists say they’re now virtually certain that pollution from fossil fuels has increased global temperatures over the last 60 years. They say emissions need to be sharply reduced to prevent more extreme damage in the future.

In 2011 worldwide carbon dioxide emissions jumped 3 per cent, because of a large increase by China, the No. 1 carbon polluting country. The U.S. is No. 2 in carbon emissions.

Hansen, who’s now at Columbia University, said it’s not enough for environmentalists to simply oppose fossil fuels and promote renewable energy.

“They’re cheating themselves if they keep believing this fiction that all we need” is renewable energy such as wind and solar, Hansen told the AP.

The joint letter says, “The time has come for those who take the threat of global warming seriously to embrace the development and deployment of safer nuclear power systems” as part of efforts to build a new global energy supply.

Stephen Ansolabehere, a Harvard professor who studies energy issues, said nuclear power is “very divisive” within the environmental movement. But he added that the letter could help educate the public about the difficult choices that climate change presents.

One major environmental advocacy organization, the Natural Resources Defence Council, warned that “nuclear power is no panacea for our climate woes.”

Risk of catastrophe is only one drawback of nuclear power, NRDC President Frances Beinecke said in a statement. Waste storage and security of nuclear material are also important issues, he said.

“The better path is to clean up our power plants and invest in efficiency and renewable energy.”

The scientists acknowledge that there are risks to using nuclear power, but say those are far smaller than the risk posed by extreme climate change.

“We understand that today’s nuclear plants are far from perfect.”

http://www.ottawacitizen.com/technology/climate+scientists+environmentalists+support+nuclear+power/9118639/story.html

bnurning earth

Scientists will this week issue their starkest warning yet about the mounting dangers of global warming. In a report to be handed to political leaders in Stockholm on Monday, they will say that the burning of fossil fuels and deforestation have now led to a warming of the entire globe, including land surfaces, oceans and the atmosphere.

Extreme weather events, including heatwaves and storms, have increased in many regions while ice sheets are dwindling at an alarming rate. In addition, sea levels are rising while the oceans are being acidified – a development that could see the planet’s coral reefs disappearing before the end of the century.

Writing in the Observer ahead of the report’s release, the economist and climate change expert Lord Stern calls on governments to end their dithering about fossil fuels and start working to create a global low-carbon economy to curtail global warming. Governments, he states, must decide what “kind of world we want to present to our children and grandchildren”.

The fifth assessment report on the physical science of climate change by the Intergovernmental Panel on Climate Change (IPCC) warns that humanity is on course over the next few decades to raise global temperatures by more than 2C compared with pre-industrial levels. Such a rise could trigger the release of plumes of the greenhouse gas methane from the thawing Arctic tundra, while the polar ice caps, which reflect solar radiation back into space, could disappear.

Although the report does not say so, Earth would probably then be facing a runaway greenhouse effect.

The scientists’ warning – the most comprehensive and convincing yet produced by climate scientists – comes at a time when growing numbers of people are doubting the reality of global warming. Last week, the UK Energy Research Centre (UKERC) published a survey showing that the proportion of British people who do not think the world’s climate is changing has almost quadrupled since 2005.

Asked if they thought Earth’s climate was changing, 5% of respondents said “no” in 2005, a figure that rose to 11% last year and reached 19% this year.

But as the IPCC report underlines, scientists are becoming more and more certain that climate change poses a real danger to the planet.

Many believe the disconnection between popular belief and scientific analysis has been engineered by “deniers” explicitly opposed to the lifestyle changes – including restrictions on fossil fuel burning – that might be introduced in the near future.

“There are attempts by some politicians and lobbyists to confuse and mislead the public about the scientific evidence that human activities are driving climate change and creating huge risks,” said Stern.

“But the public should be wary of those who claim they know for certain that unmanaged climate change would not be dangerous. For they are not only denying 200 years of strong scientific evidence – the overwhelming view of the world’s scientific academies and over 95% of scientific papers on the subject – but they are often harbouring vested interests or rigid ideologies as well.”

The report will be discussed this week by political leaders meeting in Stockholm. The study – the work of more than 200 scientists – outlines the physical changes that are likely to affect Earth’s climate this century.

Future reports will cover the social impact of these changes and the efforts required to offset the damage caused by global warming. A United Nations meeting in Paris in 2015 will then debate what actions are needed to mitigate climate change.

According to the new report, humanity has emitted about half a trillion tonnes of carbon by burning fossil fuels over the past 250 years, a process that has caused atmospheric carbon dioxide levels to rise by 40%. The world is now on target to release another half trillion tonnes in the next few decades which could trigger a major jump in global temperatures.

Most measures that have been proposed for tackling global warming rely on curtailing the burning of fossil fuels and these will form the focus of the 2015 UN meeting in Paris. Given the poor record of previous summits, many are pessimistic an agreement can be reached.

However, other measures have been suggested to curb global warming. In particular, many scientists have backed geo-engineering projects that would involve either spraying particles into the atmosphere to reflect solar radiation back into space or extracting carbon dioxide from the atmosphere in order to bury it in mines or depleted oil fields.

Both suggestions get short shrift in the new report: atmospheric aerosols could have widespread side-effects that could produce major disruptions to weather patterns, while not enough is known about the effectiveness of carbon dioxide extraction or burial. “We have to face up to the prospect of weaning ourselves off our addiction to oil and coal,” said one report author. “It is as simple as that.”

http://www.theguardian.com/environment/2013/sep/21/climate-change-ipcc-global-warming

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

Global-warming1

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

n pole

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

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 nyc

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