August 19, 2006
Hurricanes Heating Up -- Berardelli 2006 (817): 2 -- ScienceNOW
Last year produced a record 15 Atlantic hurricanes, including four of the most severe Category 5 variety. One of those, of course, was Katrina, the most economically damaging storm in U.S. history. So it's no surprise that climate scientists are scrambling to learn whether these events merely constituted a freak coincidence or evidenced a frightening trend. Some studies have suggested that rising temperatures worldwide are to blame for the increased frequency of hurricanes (ScienceNOW, 27 June). The jury remains out on that issue, but new research suggests the first direct link between global warming and greater hurricane intensity.
James Elsner of Florida State University in Tallahassee studied data from the Intergovernmental Panel on Climate Change and the U.S. National Oceanographic and Atmospheric Administration stretching back over the past half century. In the 23 August Geophysical Research Letters, he reports that whenever average global air temperatures increased during the June-November hurricane season, water temperatures in the tropical Atlantic rose in lockstep. This nearly always produced a season with more powerful tropical storms.
Elsner's findings suggest that air temperatures tend to drive sea temperatures, but not the other way around--which implies a link between greenhouse gases and storm intensity. "The large increases in powerful hurricanes over the past several decades, together with the results presented here, certainly suggest cause for concern," Elsner says. "These results have serious implications for life and property throughout the Caribbean, Mexico, and portions of the United States."
Perhaps, says Gavin Schmidt, a climate specialist with NASA's Goddard Institute for Space Studies in New York City. Elsner's paper does add to evidence that recent increases in sea surface temperature result from the influence of greenhouse gases and other factors and don't simply reflect an upswing in a natural cycle, as some scientists have proposed, Schmidt says. He adds, however, that the findings do not necessarily pinpoint what increases in hurricane activity can be expected in the future, nor do they predict what level of hurricane damage increase we can expect.
August 18, 2006
Closing the Barn Door After the.....
DOT's Pipeline and Hazardous Materials Safety Administration will propose new rules to regulate some low-stress lines in rural areas, including BP's Prudhoe Bay lines.
Current US pipeline regulations exempt from oversight the 22-mile line operated by BP that leaked oil onto the Arctic tundra, spurring a shutdown of half the capacity of the 400,000 barrel-per-day field, the nation's biggest.
That's because low-stress lines like BP's Prudhoe Bay network -- ones that run at less than 20 percent of their rated capacity and are sited away from population centers -- are deemed to be less risky than high-pressure lines.
But the Transportation Department, which oversees the 200,000-mile network of pipelines that criss-cross the nation, is rethinking that equation after a BP pipeline in Prudhoe Bay ruptured in March, spilling at least 200,000 gallons of crude in the North Slope's worst onshore spill.
pipeline inspection proposal will cover 1,600 miles of roughly 5,000
miles of US low-pressure
pipelines. The rules will require cleaning and inspections of
lines every 5 years in "unusually sensitive" areas, such as
endangered species habitats or community drinking supplies.
Reportedly, BP's lines had not been cleaned for over 10 years.
Environmentalists want all pipelines inspected. Oil lobbyists argue
that inspecting lower risk pipelines would unduly stretch inspection
The pipeline inspection proposal will cover 1,600 miles of roughly 5,000 miles of US low-pressure pipelines. The rules will require cleaning and inspections of low-stress lines every 5 years in "unusually sensitive" areas, such as endangered species habitats or community drinking supplies. Reportedly, BP's lines had not been cleaned for over 10 years. Environmentalists want all pipelines inspected. Oil lobbyists argue that inspecting lower risk pipelines would unduly stretch inspection resources.The head of the federal pipeline agency was quoted as saying:
Prudhoe Bay could have been prevented if BP had paid more attention to its maintenance,...The standard of care up there was well below what we've seen from other companies ... and well below what I would expect from a company like BP.
Nanotechnology: carbon supercapacitors with nanoscale pores store more energy
When it comes to powering laptops and hybrid cars, batteries get most of the attention. But these gadgets and myriad others also contain devices known as capacitors that provide quick bursts of energy. Capacitors can't store as much power as batteries, but the latest "supercapacitors" have started to close the gap. Now, their storage capabilities may be about to take another big jump.
In a report published online this week by Science (www.sciencemag.org/cgi/content/abstract/1132195), researchers from the United States and France report that by carefully controlling the nanoscale structure of a carbon-based supercapacitor, they've managed to increase the amount of electrical charges it can hold by about 50%. "It looks like they've got something significant there," says John Miller, a physicist who runs JME Inc., a supercapacitor materials evaluation company in Shaker Heights, Ohio. If this performance translates to commercial devices, it could help manufacturers create smaller and cheaper power packs for everything from cameras to cars, Miller says. First, however, researchers need to learn more about how it works.
Typically, a capacitor contains a pair of electrodes surrounded by an electrolyte. When a voltage is applied between the electrodes, oppositely charged ions in the electrolyte snuggle up to each electrode and remain there even when the applied voltage is turned off. When the two electrodes are connected by a wire, electrons flow from the negative electrode to balance the charges in the positive electrode and do work en route.
For many years, carbon has been the electrode material of choice for supercapacitors because it conducts electricity, is light, and can be formed into a meshlike structure that sops up ions like a sponge. The smaller the pores in the material, the larger its surface area and the more charge the capacitor can hold--at least up to a point. When ions move through an electrolyte, other molecules attracted to their charge normally encircle them like groupies mobbing a rock star. Researchers have long thought that if the pores in a carbon supercapacitor got too small--below about 1 billionth of a meter, or nanometer--the ion would not be able to squeeze through with its entourage, and thus the material's overall ability to store charge would drop. But because they had no way to carefully control the pore size throughout a large capacitor, they couldn't test this notion.
Figure 1 On demand. New supercapacitors store less charge than batteries but can supply it more quickly, making them ideal for hybrid cars.
CREDITS: (PHOTO) AP/ROB WIDDIS
Yury Gogotsi and his colleagues at Drexel University in Philadelphia, Pennsylvania, however, came up with a new way to do just that. They started with one of several commercially available compounds called a metal carbide, a mixture of a metal such as titanium and carbon. They then heated their material in a furnace while exposing it to chlorine gas. The gas reacted with the metal, forming volatile compounds that could easily be separated from the mixture, leaving behind carbon shot through with a continuous mesh of voids. By controlling the temperature and other conditions in their reactor, the researchers found they could tailor the holes in their carbon mesh to be a uniform size, between 0.6 and 2.25 nanometers across.
When Gogotsi and his students measured the charge-storing capabilities of the material, they got a shock. "We thought it would be useless" to study the smallest pores, Gogotsi says. But in powdered samples, their carbon with the 0.6-nanometer pores held 50% more charge than powders of standard supercapacitors. Gogotsi's group later teamed up with Patrice Simon, a leading supercapacitor expert at the University of Paul Sabatier in Toulouse, France, whose lab confirmed the results.
On a molecular level, it appeared that ions must be wiggling into the tiny pores, by either squeezing their entourage ions or perhaps abandoning them altogether. But how that could happen remains a puzzle, Miller says. In normal carbon supercapacitors, ions nestling up to an electrode form a layer about 1 nanometer thick. So if there is less space than that in the pores of the new material, it's not clear how they can get in. "That will be a bit controversial," Miller says. But both he and Gogotsi point out that thanks to the newfound control over pore size, researchers should quickly be able to figure out just what is going on.
250,000 US Climate Refugees
Those of us who track the effects of global warming had assumed that the first large flow of climate refugees would likely be in the South Pacific with the abandonment of Tuvalu or other low-lying islands. We were wrong. The first massive movement of climate refugees has been that of people away from the Gulf Coast of the United States.
Hurricane Katrina, which made landfall in late August 2005, forced a million people from New Orleans and the small towns on the Mississippi and Louisiana coasts to move inland either within state or to neighboring states, such as Texas and Arkansas. Although nearly all planned to return, many have not.
Unlike in previous cases, when residents typically left areas threatened by hurricanes and returned when authorities declared it was safe to do so, many of these evacuees are finding new homes. In this respect, the U.S. hurricane season of 2005 was different. Record-high temperatures in the Gulf of Mexico surface waters helped make Hurricane Katrina the most financially destructive hurricane ever to make landfall anywhere.
In some Mississippi Gulf Coast towns, Katrina’s powerful 28-foot-high storm surge (8.5 meters) did not leave a single structure standing. There was nothing for evacuees to return to. The destruction of housing and infrastructure in St. Bernard Parish, a low-lying 40-mile-long peninsula (64 kilometers) extending southeast from New Orleans, rendered most of it uninhabitable. The Katrina storm surge that raised the water level in Lake Pontchartrain so high that it breached the levees and flooded New Orleans left much of the city unfit to live in. Even today, a year later, large parts of the city are without basic infrastructure services such as water, power, sewage disposal, garbage collection, and telecommunications. Interestingly, the country to suffer the most damage from a hurricane is also primarily responsible for global warming.
Many evacuees were able to return in a matter of days, but many more were not. New Orleans’ population before Katrina struck was 463,000. Claritas, a private demographic data-gathering and analysis firm, reported that after the hurricane New Orleans’ population shrank to 93,000. By January 2006, it had recovered to 174,000. By July 2006, the city still had only 214,000 residents, less than half of its pre-Katrina population.
Three Louisiana coastal parishes (counties) also registered substantial population declines. The population of St. Bernard Parish plummeted from 66,000 residents to 15,000 in July 2006. South of New Orleans, the population of Plaquemines Parish declined from 29,000 to 20,000. Densely populated Jefferson Parish, also bordering New Orleans on the south, dropped from 453,000 to 411,000, a loss of 42,000.
Mississippi’s three coastal counties each lost population. The July tabulation showed Hancock County had lost 8,000 residents. Harrison County, which includes the town of Gulfport, lost 12,000, and Jackson County 4,000. (See data.)
As of July 2006, New Orleans, the three parishes, and the three counties in Mississippi had lost a total of 375,000 residents because of destruction from Katrina. Some evacuees are still returning, but the flow has slowed to a near trickle. We estimate that at least 250,000 of them have established homes elsewhere and will not return. They no longer want to face the personal trauma and financial risks associated with rising seas and more destructive storms. These evacuees are now climate refugees.
Have Your Students Ever Wondered Why Plants are Protected by the ESA?
The Collapse of Easter Island
In the Journal of Developing Societies, Nagarajan discusses simulation studies of the ecological suicide of Easter Island -- reminding us of the lessons of Easter Island about the consequences of unsustainable resource use. Easter Island
August 16, 2006
Sports Hunting Does Not Reduce Mountain Lion Attacks
Link: Puma Conservation Report
August 14, 2006
Mercury is not healthy for children and other living things
The Eighth International Conference on Mercury as a Global Pollutant Mercury issued an Official Conference Declaration last Friday, endorsed by 37 top international experts on mercury pollution and ratified by a large majority of conference participants. According to the declaration, mercury threatens the health of people, fish and wildlife everywhere, from industrial sites to remote corners of the planet, but reducing mercury use and emissions would lessen those threats. A significant portion of the mercury deposited near industrial sources comes from those sources, rather than from natural sources. Evidence of mercury's health risks is strong enough that people, especially children and women of childbearing age, should be careful about how much and which fish they eat.
According to the press release from University of Wisconsin at Madison where the conference was held:
"The declaration essentially says that mercury pollution is a problem of global magnitude," says James Hurley, assistant director of the University of Wisconsin-Madison Aquatic Sciences Center and a co-chair of the conference. David Krabbenhoft, a research scientist at the U.S. Geological Survey and also a co-chair of the conference, adds that the document declares that the social and economic costs of mercury are probably higher than currently estimated, because they don't take into account mercury's impact on wildlife.
Krabbenhoft says the conference declaration summarizes a yearlong effort of 37 top scientists to review the last decade of mercury science. All 37 scientists endorsed the declaration in full, Krabbenhoft says. He added that all participants at the conference were invited express their opinion of the findings, and a large majority of those who did so agreed with the conclusions. "The declaration summarizes what we know about mercury in the environment, from a wide array of expertise," Krabbenhoft says.
Grouped into four major topics, other points of the declaration included:
- Sources of atmospheric mercury deposition:
- On average, three times more mercury now falls out of the sky than before the Industrial Revolution 200 years ago.
- For the last 30 years, emissions from developing countries have increased, offsetting decreased emissions from developed nations.
- The amount of mercury in the atmosphere is apparently not changing. Thus, new findings of a shorter atmospheric lifetime suggest greater movement of mercury to and from the earth's surface.
- Understanding of the global mercury cycle is being confounded by climate change, increasing ozone levels and other nonmercury factors that may affect how long mercury stays in the atmosphere and how and where it falls.
- Risks to humans, fish and wildlife:
- There is solid scientific evidence to show that methylmercury has toxic effects, particularly to developing fetuses. New evidence indicates that methylmercury exposure may increase the risk of cardiovascular disease in humans, particularly in adult men.
- To increase the benefits and reduce the risks, consumers should choose fish with high levels of omega-3 fatty acids and low levels of methylmercury.
- There is no evidence that selenium in the diet protects people from the neurological and developmental effects of methylmercury.
- Reductions in local and regional point-source mercury emissions have lowered mercury levels in the fish and wildlife affected by them. However, increasing mercury concentrations are now being found in a number of fish-eating wildlife in remote areas.
- Methylmercury exposure may lead to population declines in birds and possibly in fish and mammals as well
- Recovery of mercury-contaminated fisheries:
The concentration of methylmercury in fish in freshwater and coastal ecosystems can be expected to decline with reduced mercury inputs. The rate of decline ranges from years to centuries, depending on the characteristics of a particular ecosystem.
- Socioeconomic impacts of mercury use and pollution:
- More information is needed about methylmercury contamination levels in marine fishes, the ingestion of which is the main way most people are exposed to methylmercury.
- The use of mercury in small-scale gold mining is polluting thousands of sites around the world, posing long-term health risks to up to 50 million inhabitants of mining regions and contributing more than 10 percent of the mercury in Earth's atmosphere resulting from human activities.
August 14, 2006 in Air Quality, Energy, Governance/Management, International, Mining, Physical Science, Social Science, Sustainability, Toxic and Hazardous Substances, US, Water Quality | Permalink | Comments (0) | TrackBack