Archive for the 'Science & Education' Category
Rising sea levels and melting polar ice-sheets are at upper limits of projections, leaving some human population centers already unable to cope, top world scientists say as they analyze latest satellite data.A United Nations report by the Intergovernmental Panel on Climate Change (IPCC) in February projected sea level gains of 18-59 centimeters (7-23 inches) this century from temperature rises of 1.8-4.0 Celsius (3.2-7.8 Fahrenheit).
“Observations are in the very upper edge of the projections,” leading Australian marine scientist John Church told Reuters.
“I feel that we’re getting uncomfortably close to threshold,” said Church, of Australia’s CSIRO Marine and Atmospheric Research said.
Past this level, parts of the Antarctic and Greenland would approach a virtually irreversible melting that would produce sea level rises of meters, he said.
There has been no repeat in the Antarctic of the 2002 break-up of part of the Larsen ice shelf that created a 500 billion ton iceberg as big as Luxembourg.
But the Antarctic Peninsula is warming faster than anywhere else on Earth, and glaciers are in massive retreat.
“There have been doomsday scenarios that west Antarctica could collapse quite quickly. And there’s six meters of sea level in west Antarctica,” says Tas van Ommen, a glaciologist at the Hobart-based Australian Antarctic Division.
Doomsday has not yet arrived.
But even in east Antarctica, which is insulated from global warming by extreme cold temperatures and high-altitudes, new information shows the height of the Tottenham Glacier near Australia’s Casey Base has fallen by 10 meters over 15-16 years.
Scientists say massive glacier retreat at Heard Island, 1,000 km (620 miles) north of Antarctica, is an example of how fringe areas of the polar region are melting.
The break-up of ice in Antarctica to create icebergs is also opening pathways for accelerated flows to the sea by glaciers.
Church pointed out that sea levels were 4-6 meters higher more than 100,000 years ago when temperatures were at levels expected to be reached at the end of this century.
Dynamic ice-flows could add 25 percent to IPCC forecasts of sea level rise, van Ommen said.Australian scientist John Hunter, who has focused on historical sea level information, said that to keep the sea water out, communities would need to begin raising sea walls.
“There’s lots of places where you can’t do that and where you’ll have to put up with actual flooding,” he said.
This was already happening in the south of England, where local councils and governments could not afford to protect all areas from sea water erosion as land continued to sink.
About 100 million people around the world live within a meter of the present-day sea level, CSIRO Marine Research senior principal research scientist Steve Rintoul said. “Those 100 million people will need to go somewhere,” he said.
Worse, every meter of sea level rise causes an inland recession of around 100 meters (300 feet) and more erosion occurs with every storm.
“You can’t just say we’ll just put sea walls,” Hunter said.
By Michael Byrnes
Article Source: Reuters
LONDON — New “landmark” research finds that alcohol and tobacco are more dangerous than some illegal drugs like marijuana or Ecstasy and should be classified as such in legal systems, according to a new British study. In research published Friday in The Lancet magazine, Professor David Nutt of Britain’s Bristol University and colleagues proposed a new framework for the classification of harmful substances, based on the actual risks posed to society. Their ranking listed alcohol and tobacco among the top 10 most dangerous substances.
Prof. Nutt and his colleagues used three factors to determine the harm associated with any drug: the physical harm to the user, the drug’s potential for addiction, and the impact on society of drug use. The researchers asked two groups of experts — psychiatrists specializing in addiction and legal or police officials with scientific or medical expertise — to assign scores to 20 different drugs, including heroin, cocaine, Ecstasy, amphetamines and LSD.
Prof. Nutt and his colleagues then calculated the drugs’ overall rankings. In the end, the experts agreed with each other — but not with the existing British classification of dangerous substances.
Heroin and cocaine were ranked most dangerous, followed by barbiturates and street methadone. Alcohol was the fifth most harmful drug and tobacco the ninth most harmful. Cannabis came in 11th, and near the bottom of the list was Ecstasy.
According to existing British and U.S. drug policy, alcohol and tobacco are legal, while cannabis and Ecstasy are both illegal. Previous reports, including a study from a parliamentary committee last year, have questioned the scientific rationale for Britain’s drug classification system.
“The current drug system is ill thought-out and arbitrary,” said Prof. Nutt, referring to the United Kingdom’s practice of assigning drugs to three distinct divisions, ostensibly based on the drugs’ potential for harm. “The exclusion of alcohol and tobacco from the Misuse of Drugs Act is, from a scientific perspective, arbitrary,” write Prof. Nutt and his colleagues in The Lancet.
Tobacco causes 40 per cent of all hospital illnesses, while alcohol is blamed for more than half of all visits to hospital emergency rooms. The substances also harm society in other ways, damaging families and occupying police services.
Prof. Nutt hopes that the research will provoke debate within Britain and beyond about how drugs — including socially acceptable drugs such as alcohol — should be regulated. While different countries use different markers to classify dangerous drugs, none use a system like the one proposed by Prof. Nutt’s study, which he hopes could serve as a framework for international authorities.
Associated Press (Maria Cheng)
Article Source: Globandmail
The United States is developing a system to track atmospheric levels of carbon dioxide, the main greenhouse gas, which could help scientists project future climate change, a government researcher said.The CarbonTracker monitors carbon dioxide levels throughout North America to create an Internet-based map. Carbon-emitting areas, such as cities and industry centers, show up in red and carbon sinks, such as forests, are represented in blue.Pieter Tans, head of the National Oceanic and Atmospheric Administration’s greenhouse gas cycles group, which created the system, said it could help researchers verify their climate models. It could also facilitate any future trade in carbon credits by monitoring whether industries are actually cutting emissions, he said.The tracker will soon use more data from sources, including monitors in airplanes and countries beyond North America, to broaden the map.”We hope this will evolve into a much denser network, so we can say meaningful things about whether states or large metropolitan areas are successful in limiting net emissions of CO2,” Tans said in a telephone interview.The United States, the world’s top emitter of carbon dioxide, does not regulate greenhouse gases.
But banks, as well as carbon trading firms that took shape when the European Union started trading carbon credits in 2005, are gearing up for potential U.S. trade. They take heart in the growing political pressure in the country to tackle climate change by putting mandatory limits on the gas.
Canada’s federal environment office, Environment Canada, provided a quarter of the data for the project, Tans said.
Tans said the project was working with researchers from China and India to try to expand the project to those countries, which are growing carbon emitters.
Article Source: Reuters
