WASHINGTON, DC, February 26, 2009 (ENS) – The U.S. government’s Climate Change Science Program should expand its agenda to integrate research in the natural and social sciences that will enable the nation to tackle problems communities actually face, says a new report from the National Research Council.

Climate change already is changing people’s lives with extreme weather and climate events and disasters; sea level rise and melting ice; fresh water scarcity; agriculture and food security; ecosystems management; new and re-emerging diseases; and effects on the U.S. economy, the committee acknowledges.

But the Climate Change Science Program is hindered by its limited research into the social sciences and the separation of natural and social sciences research. Spending on research into the human dimensions of climate change has never exceeded three percent of the program’s research budget, the committee learned.

As a result, research, data collection, and modeling of how people interact with or affect their environments have lagged behind corresponding activities on the physical climate system.

At the same time, government scientists with the Climate Change Science Program should build on their successful research into the causes and processes of climate change, the report advises.

“CCSP has created a robust infrastructure for observations and modeling, which has enabled scientists to document trends in critical climate parameters and identify the human impacts on climate change,” said Veerabhadran Ramanathan, chair of the committee that wrote the report, and distinguished professor of atmospheric and climate sciences at the Scripps Institution of Oceanography, University of California, San Diego.

“Now we need to know how to respond to climate change, while working closely with policymakers on mitigation and adaptation strategies,” he said.

 A trained cadaver-locating dog works a pile of debris in Bolivar Peninsula, Texas, so that cleanup crews can start removing the mess months after Hurricane Ike left the area a disaster. December 6, 2008. Ike was the third most destructive hurricane to ever make landfall in the United States. (Photo courtesy FEMA)

The knowledge gained from this integrative approach would guide the nation on choices to reduce the costs and risks of climate change impacts, the committee said, and provide early warning of changes that are abrupt and large enough to push climate and human systems past tipping points.

The report sets forth a laundry list of priorities for the future of the Climate Change Science Program – establish a U.S. climate observing system; develop new modeling capabilities for regional and decadal scale forecasts; strengthen research on adaptation, mitigation, and vulnerability; initiate a periodic national assessment of climate impacts and responses; and routinely provide policymakers with crucial scientific information, tools, and forecasts.

In 2007, the committee issued its first report, which evaluated the program’s progress at the request of CCSP’s former director.

For this second report, the National Research Council was asked to identify future priorities and lay out a framework to guide the evolution of the program.

The program should make transformational changes to adopt a holistic approach that connects research across disciplines and engages policymakers and other stakeholders, the committee said.

Another priority should be to help establish a U.S. climate observing system that includes physical, biological, and social observations to ensure that data needed to address climate change are available, the committee said.

“Even if people significantly reduce their greenhouse gas emissions, further climate change is inevitable,” the committee warned. “Therefore, CCSP needs to have the capacity to explain what is happening to climate and why.”

The CCSP should work with federal, state, and international agencies to establish and maintain a climate observing system, and determine the agencies’ different roles and responsibilities for making the observations, archiving, and distributing data.

Climate modeling to date has been primarily at the global scale, with time scales only for the next hundred years, yet more information is needed at regional to local scales, the committee advised.

Finally, the CCSP should work with stakeholders to design and implement a comprehensive national assessment that identifies evolving science and human needs.

While CCSP is mandated to carry out a national assessment every four years, the last one involving a broad range of stakeholders was a decade ago.

The collection of 21 synthesis and assessment reports published from 2006 to 2008, although useful, the committee said, did not add up to a comprehensive national assessment.

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BEIJING, China, November 13, 2008 (ENS) – A brown cloud of pollution caused by human activities, three kilometers thick and stretching from the Arabian Peninsula across Asia to the western Pacific Ocean, is darkening cities, speeding the melting of Himalayan glaciers and affecting human health, finds a new report from the United Nations Environment Programme.

Atmospheric brown clouds, formed by the burning of fossil fuels, biofuels, wood and plants, absorb sunlight and heat the air, experts write in the study released today in Beijing.

The clouds also mask the actual warming impact of climate change by anywhere between 20 and 80 percent because they include sulfates and other chemicals which reflect sunlight and cool the surface, according to the report.

Dimming of between 10 and 25 percent is occurring over Beijing and Shanghai, in China, Karachi, Pakistan, and New Delhi, India.

Air pollution dims Beijing. July 2008.
(Photo credit unknown)

Professor Veerabhadran Ramanathan, head of the UNEP scientific panel carrying out the research, is based at the Scripps Institution of Oceanography in La Jolla, California.

The new report provides confirmation of the atmospheric brown clouds effects that Ramanathan’s research first documented six years ago.

“Our preliminary assessment, published in 2002, triggered a great deal of awareness but also skepticism,” he said. “That has often been the initial reaction to new, novel and far reaching, counter-intuitive scientific research.”

Ramanathan called for an international response to the report’s findings that “tackles the twin threats of greenhouse gases and brown clouds and the unsustainable development that underpins both.”

“One of the most serious problems highlighted in the report is the documented retreat of the Hind Kush-Himalayan-Tibetan glaciers, which provide the headwaters for most Asian rivers, and thus have serious implications for the water and food security of Asia,” he said.

The scientific team behind the report is drawn from universities and research centers in China, India, Japan, Korea, Singapore and Thailand as well as Europe and the United States.

The scientists found that the artificial lowering of temperature by atmospheric brown clouds is leading to sharp shifts in weather patterns, causing drying in northern China while increasing the risk of flooding in China’s south.

Monsoon precipitation over India and South-East Asia has dropped up to seven percent since the 1950s, with the summer monsoon both weakening and shrinking.

The possible impact of atmospheric brown clouds could include elevated levels of ground-level ozone, which could result in crop losses of up to 40 percent in Asia.

Smoke and soot rises into the air over Mumbai.
(Photo by Avinash Anand)

Achim Steiner, UNEP’s executive director, voiced hope that the report, “Atmospheric Brown Clouds: Regional Assessment Report with Focus on Asia” will serve as an early warning of the phenomenon, which he hopes will now be “firmly on the international community’s radar.”

He called on developed countries to help their poorer counterparts attain the technology needed to spur green economic growth.

“In doing so, they can not only lift the threat of climate change but also turn off the soot-stream that is feeding the formation of atmospheric brown clouds in many of the world’s regions,” Steiner said.

Atmospheric brown clouds start as indoor and outdoor air pollution consisting of particles called primary aerosols and pollutant gases, such as nitrogen oxides (NOx), carbon monoxide (CO), sulfur dioxide (SO2), ammonia (NH3), and hundreds of organic gases and acids.

“Widespread plumes resulting from the combustion of biofuels from indoors; biomass burning outdoors and fossil fuels, are found in all densely inhabited regions and oceanic regions downwind of populated continents,” the report states.

The report points to 13 megacities as being “hotspots” for atmospheric brown clouds – Bangkok, Beijing, Cairo, Dhaka, Karachi, Kolkata, Lagos, Mumbai, New Delhi, Seoul, Shanghai, Shenzhen and Tehran.

Soot levels in these cities make up 10 percent of the total mass of all carbon particles in the atmosphere that result from human activities.

The clouds contain toxic aerosols, carcinogens and other harmful particles, which could result in more people suffering from respiratory disease and cardiovascular problems.

More research is needed to determine the precise role of the clouds on food production and farmers’ livelihoods, the report states. More research is also required on the brown clouds that exist in parts of North America, Europe, Southern Africa and the Amazon Basin.

“The new research, by identifying some of the causal factors, offers hope for taking actions to slow down this disturbing phenomenon,” said Professor Ramanathan. But he cautioned that “significant uncertainty remains in our understanding of the complexity of the regional effects of ABCs and more surprises may await us.”

To read the report, “Atmospheric Brown Clouds: Regional Assessment Report With Focus on Asia,” click here [www.unep.org].

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SAN DIEGO, California, October 24, 2008 (ENS) – A gas used in manufacture of flat panel televisions, computer displays, microcircuits, and thin-film solar panels is 17,000 times more potent a greenhouse gas than carbon dioxide, and it is far more prevalent in the atmosphere than previously estimated.

The powerful greenhouse gas nitrogen trifluoride, NF3, is at least four times more widespread than scientists had believed, according to new research by a team at Scripps Institution of Oceanography at the University of California, San Diego.

Using new analytical techniques, a team led by Scripps geochemistry professor Ray Weiss made the first atmospheric measurements of nitrogen trifluoride, NF3.

“Accurately measuring small amounts of NF3 in air has proven to be a very difficult experimental problem, and we are very pleased to have succeeded in this effort,” Weiss said Thursday, announcing the results of his team’s research.

The research findings will be published October 31 in “Geophysical Research Letters,” a journal of the American Geophysical Union.

Scripps geoscientists Ray Weiss, left, and Jens
Muehle show cylinders used to collect air
samples that they analyzed for
concentrations of nitrogen trifluoride.
(Photo courtesy Scripps Institution of
Oceanography, UC San Diego)

The amount of the gas in the atmosphere, which could not be detected using previous techniques, had been estimated at less than 1,200 metric tons in 2006. The new research shows the actual amount was 4,200 metric tons.

In 2008, about 5,400 metric tons of the gas was in the atmosphere, a quantity that is increasing at about 11 percent per year.

This rate of increase means that about 16 percent of the amount of the gas produced globally is being emitted into the atmosphere, the researchers estimate.

Emissions of NF3 were thought to be so low that the gas was not considered to be a significant potential contributor to global warming.

Nitrogen trifluoride was not covered by the Kyoto Protocol, the 1997 agreement to reduce greenhouse gas emissions signed by 182 countries, although three other fluoride compounds are covered.

The protocol governs the emissions of carbon dioxide, methane, and nitrous oxide as well as other fluoride compounds – sulfur hexafluoride, hydrofluorocarbons, and perfluorocarbons.

In response to the growing use of the gas and concerns that its emissions are not well known, the scientists have recommended adding it to the list of greenhouse gases regulated by the protocol or its successor agreement now under negotiation.

“From a climate perspective, there is a need to add NF3 to the suite of greenhouse gases whose production is inventoried and whose emissions are regulated under the Kyoto Protocol, thus providing meaningful incentives for its wise use,” said Weiss.

Nitrogen trifluoride is one of several gases used during the manufacture of liquid crystal flat-panel displays, thin-film photovoltaic cells and microcircuits.

Many industries have used the gas in recent years as an alternative to perfluorocarbons, which are also potent greenhouse gases, because it was believed that no more than two percent of the NF3 used in these processes escaped into the atmosphere.

To obtain their information, the Scripps team analyzed air samples gathered in California and Tasmania over the past 30 years by the NASA-funded Advanced Global Atmospheric Gases Experiment network of ground-based stations.

The network was created in the 1970s in response to international concerns about chemicals depleting the ozone layer. It is supported by NASA as part of its congressional mandate to monitor ozone-depleting trace gases, many of which are also greenhouse gases.

The researchers found concentrations of NF3 rose from about 0.02 parts per trillion in 1978 to 0.454 parts per trillion in 2008.

Higher concentrations of NF3 were found in the Northern Hemisphere than in the Southern Hemisphere, which the researchers said is consistent with its greater use in Northern Hemisphere countries.

“This result reinforces the critical importance of basic research in determining the overall impact of the information technology industry on global climate change, which has already been estimated to be equal to that of the aviation industry,” said Larry Smarr, director of the California Institute for Telecommunications at University of California, San Diego, who was not involved in the Scripps study.

Michael Prather is a University of California, Irvine atmospheric chemist who predicted earlier this year that based on the rapidly increasing use of NF3, larger amounts of the gas would be found in the atmosphere. Prather said the new Scripps study provides the confirmation needed to establish reporting requirements for production and use of the gas.

“I’d say case closed. It is now shown to be an important greenhouse gas,” said Prather, who was not involved with the Scripps study. “Now we need to get hard numbers on how much is flowing through the system, from production to disposal.”

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SAN DIEGO, California, July 16, 2008 (ENS) – The University of California-San Diego calls itself “one of the nation’s greenest college campuses,” and to enhance that status, the university has begun to install the components of a multi-faceted sustainable energy program.

The university will soon be generating 7.4 megawatts of green energy, providing 10 to 15 percent of its own annual electrical usage.

The far-reaching program, which includes solar panels, biogas fuel cells and wind energy, began with the first installation of solar photovoltaic panels atop a campus utility plant.

Soon, buildings and parking garages across the 1,200-acre campus next to the Pacific Ocean will feature solar panels.

Workers install solar panels on a roof
at the University of California-San
Diego. (Photo courtesyUC-San Diego)

UC San Diego’s green energy capacity will eventually produce 29 million kilowatt hours a year, which is enough to provide electricity for more than 4,500 homes a year.

The amount of renewable energy is like removing 10,500 tons of carbon dioxide from the atmosphere each year, or removing 1,500 cars a year from the roads.

“This photovoltaic installation marks an historic event for a campus that has become a living laboratory for climate change solutions,” said Steve Relyea, vice chancellor of business affairs.

“Our sustainable energy program is the result of a campuswide commitment by students, faculty and administration to advance environmental sustainability on a local, national and global level,” he said.

This year the Scripps Institution of Oceanography at UC San Diego is celebrating the 50th anniversary of the Keeling Curve, the first measurement of greenhouse gas build-up, which was conducted by Scripps scientist Charles David Keeling.

Researchers and students at UC San Diego are working on a wide range of environmental sustainability projects. They are developing biofuels from algae and wood debris.

Planners design green dorms with automatic sun shading to save energy and drainage systems that stop all storm runoff from flowing into the nearby ocean.

Students and fleet managers have begun a biofuel shuttle bus line, which decreases UC San Diego’s reliance on greenhouse gas-generating fossil fuels.

The world’s top climate change researchers and post-docs are working to discover the impact of Asian brown cloud pollution on global climate and of rising temperatures on the western U.S. water supply.

UC San Diego’s green energy program will continue to unfold over the next year, as the first megawatt of solar photovoltaic panels is constructed and a second megawatt is planned and implemented.

Construction begins this fall on a project that will allow UC San Diego to produce another 2.4 megawatts of energy from fuel cells powered by renewable methane. The methane fuel will be transported to UC San Diego from the Point Loma sewage treatment plant, where it is produced.

Not only does this produce green energy that replaces carbon-based energy, but it also removes pollutants from local air, since the methane is currently flared into the atmosphere at the sewage plant.

UC San Diego also begins a unique program to swap fossil fuel-generated energy for wind power.

The university will throttle back its natural gas-powered cogeneration plant at night and replace the power with electricity purchased from California wind farms.

This project, the first of its kind in California, will generate up to three megawatts of green energy.

The solar photovoltaic and biogas fuel cell construction projects are cost-free for the university.

UC San Diego has negotiated power purchase agreements, in which investors construct, install and maintain the photovoltaic panels and fuel cells on campus property, and the university then buys the power from investors through long-term contracts.

UC San Diego has teamed up with local, national and international companies on its sustainable energy project.

Three partners are working with the university on the solar photovoltaic project. Borrego Solar, Inc., a national solar power contractor based in El Cajon, California, is the installer; Envision Solar, Inc., of San Diego is the designer of the solar “trees” that will be built on top of UC San Diego parking structures. Solar Power Partners Inc., of Mill Valley is the financier and owner of the solar photovoltaic arrays.

The biogas fuel cells are financed, constructed and owned by The Linde Group, an international industrial gases and engineering company.

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SAN DIEGO, California, May 7, 2008 (ENS) – Using advanced unmanned aircraft, research scientists at the Scripps Institution of Oceanography, UC San Diego are assessing Southern California’s potential for climate change and better understand the sources of air pollution.

The aircraft typically fly in formations of three, measuring a range of properties such as the quantity and size of the aerosols on which cloud droplets form and the temperature, humidity and the intensity of light that permeates clouds and masses of smog as they go.

The scientists are flying these autonomous unmanned aerial vehicles, AUAVs, from Edwards Air Force Base near Rosamond, California. The study began its first sortie of data-gathering flights on April 2 and will continue through January 2009, offering researchers a chance to view seasonal variations in air pollution.

Known by one of the few acronyms that uses another acronym as one of its letters, the California AUAV Air Pollution Profiling Study, CAPPS, dispatches the AUAVs to fly through clouds and aerosol masses in Southern California, gathering meteorological data.

Scripps Atmospheric and Climate Sciences Professor Veerabhadran Ramanathan, CAPPS’s lead scientist, said Southern California’s dry weather and tendency to trap rather than export smog could make it highly prone to climate change consequences such as accelerated snowmelt and dimming at ground level.

“These monthly UAV flights will provide unprecedented data for evaluating how long range transport of pollutants including ozone, soot and other particulates from the northwest United States, Canada, east Asia and Mexico mix with local pollution and influence our air quality and regional climate including the early melting of snow packs,” said Ramanathan.

V. Ramanathan with three of the unmanned
drone aircraft in the Maldives (Photo
courtesy Scripps Institution of
Oceanography/UCSD)

Ramanathan’s team revolutionized the gathering of atmospheric data in 2006 when the researchers first successfully deployed the unmanned high-tech aircraft in the Maldives AUAV Campaign. It was the first time such comprehensive measurements were made at a cost that was very low relative to traditional manned flights.

The Scripps researchers have used data from the Maldives and other field campaigns to observe that a pervasive mass of air pollution in south and east Asia, often referred to as the “atmospheric brown cloud,” can disrupt rainfall patterns and cause cooling at ground level but warming at higher altitudes.

The cloud typically contains a mix of dust, sulfates and soot and other forms of black carbon – the products of diesel combustion, agricultural biomass burning, use of wood-burning and cow dung-burning stoves in rural homes and the use of coal in home heating.

Ramanathan and his team linked the brown cloud to an observed acceleration of glacial melt in the Himalayas. Himalayan glaciers provide billions of people in Asia with their drinking water.

The CAPPS chief scientist dreams of launching a fleet of drone aircraft to patrol the skies.

In the California AUAV Air Pollution Profiling Study, the Scripps team hopes to determine how much of Southern California’s air pollution comes from Asia, Mexico and from regions north of the state.

“Black carbon and ozone are two major contributors to global warming, next to carbon dioxide,” said Ramanathan. “We hope to document the vertical profiles of black carbon and ozone and their climate warming effects for the first time over California, and this data will likely help California reduce its global warming commitment.”

The California Energy Commission’s Public Interest Energy Research program will employ CAPPS results in an analysis of the potential future economic and ecological consequences of Southern California air pollution.

Scientists also hope to combine CAPPS results with satellite data to better understand the role of aerosols at a larger regional scale.

“As we learn more about the air we breathe and seek solutions to reduce greenhouse gases, this important atmospheric research will help us address the serious challenges to California’s water resources, ecology, and the health of our residents,” said Energy Commissioner Arthur Rosenfeld. “With this study, California continues to demonstrate its commitment as a national leader in climate change research.”

The aircraft will profile atmospheric conditions at altitudes ranging between 2,000 and 12,000 feet and will create a separate file for data collected during wildfires.

Because of Federal Aviation Administration regulations that prohibit unmanned aircraft from flying in public airspace, the flight paths will be limited to military airspace, which is exempted from FAA rules.

The Scripps team hopes to conduct the flights at least once a month or as often as every two weeks.

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SAN DIEGO, California, March 23, 2008 (ENS) – Black carbon, particulate matter in the air produced by diesel exhaust, biomass burning, and cooking with solid fuels, has a warming effect in the atmosphere three to four times greater than existing estimates, according to scientists in an upcoming review article in the journal “Nature Geoscience.”

Atmospheric scientist V. Ramanathan with the Scripps Institution of Oceanography at University of California-San Diego and University of Iowa chemical engineer Greg Carmichael, said that soot and other forms of black carbon could have as much as 60 percent of the current global warming effect of carbon dioxide, more than that of any greenhouse gas besides carbon dioxide, CO2.

The researchers also say that mitigation would have immediate societal benefits in addition to the long-term effect of reducing greenhouse gas emissions.

The article, “Global and regional climate changes due to black carbon,” is posted in today’s online version of “Nature Geoscience.”

Professor V. Ramanathan explains his new
findings to reporters. (Photo
courtesy UC San Diego)

“Observationally based studies such as ours are converging on the same large magnitude of black carbon heating as modeling studies from Stanford, Caltech and NASA,” said Ramanathan.

“We now have to examine if black carbon is also having a large role in the retreat of arctic sea ice and Himalayan glaciers as suggested by recent studies,” he said.

In the paper, Ramanathan and Carmichael integrated observed data from satellites, aircraft and surface instruments about the warming effect of black carbon and found that its warming effect in the atmosphere, is about 0.9 watts per meter squared.

That compares to estimates of between 0.2 watts per meter squared and 0.4 watts per meter squared that were agreed upon as a consensus estimate in a report released last year by the Intergovernmental Panel on Climate Change, a United Nations sponsored agency that periodically synthesizes the body of climate change research.

Ramanathan and Carmichael said the lower, more conservative estimates are based on widely used computer model simulations that do not take into account the amplification of black carbon’s warming effect when mixed with other aerosols such as sulfates.

The models also do not adequately represent the full range of altitudes at which the warming effect occurs, they said.

The most recent observations have found significant black carbon warming effects at altitudes in the range of 6,500 feet, levels at which black carbon particles absorb not only sunlight but also solar energy reflected by clouds at lower altitudes.

Between 25 and 35 percent of black carbon in the global atmosphere comes from China and India, emitted from the burning of wood and cow dung in household cooking and through the use of coal to heat homes.

Countries in Europe and elsewhere that rely heavily on diesel fuel for transportation also contribute large amounts.

“Per capita emissions of black carbon from the United States and some European countries are still comparable to those from south Asia and east Asia,” Ramanathan said.

Black carbon rises from land clearing fires on the island of Borneo. October 2006. (NASA image by Jeff Schmaltz, MODIS Rapid Response Team)

In south Asia, air pollution often forms a brownish haze. Ramanathan’s previous research has indicated that the warming effects of this smog appear to be accelerating the melt of Himalayan glaciers that provide billions of people throughout Asia with drinking water.

In addition, the inhalation of smoke during indoor cooking has been linked to the deaths of an estimated 400,000 women and children in south and east Asia.

Ramanathan said that an observation program for which he is currently seeking corporate sponsorship could dramatically illustrate the benefits. Known as Project Surya, the proposed venture would provide some 20,000 rural Indian households with smoke-free cookers and equipped to transmit data. At the same time, a team of researchers led by Ramanathan would observe air pollution levels in the region to measure the effect of the cookers.

Carmichael said he hopes that the paper’s presentation of the immediacy of the benefits will make it easier to generate political and regulatory momentum toward reduction of black carbon emissions.

“It offers a chance to get better traction for implementing strategies for reducing black carbon,” he said.

The National Science Foundation, the National Oceanic and Atmospheric Administration and the National Aeronautics and Space Administration funded the review.

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BOSTON, Massachusetts, February 17, 2008 (ENS) – Once plentiful sharks are vanishing from the world’s oceans, and some species are even at risk of extinction a shark expert told fellow scientists at the ongoing annual conference of the American Association for the Advancement of Science.

The global status of large sharks has been assessed by the IUCN-World Conservation Union, which maintains the Red List of Threatened Species.

The assessment finds that many large shark species have declined by more than half due to increased demand for shark fins and meat, recreational shark fisheries, as well as tuna and swordfish fisheries, where millions of sharks are taken as bycatch each year.

“As a result of high and mostly unrestricted fishing pressure, many sharks are now considered to be at risk of extinction,” said Julia Baum, a member of the IUCN’s Shark Specialist Group and a postdoctoral fellow at Scripps Institution of Oceanography in San Diego.

“Of particular concern is the scalloped hammerhead shark, an iconic coastal species, which will be listed on the 2008 IUCN Red List as globally ‘endangered’ due to overfishing and high demand for its valuable fins in the shark fin trade,” said Baum.

School of scalloped hammerhead
sharks at Isla del Coco, a Costa
Rican National Park and World
Natural Heritage Site. (Photo
courtesy USGS)

Baum pointed out that fishing for sharks in international waters is unrestricted, and she supports a recently adopted United Nations resolution calling for immediate shark catch limits. Baum also supports a ban on shark finning – the practice of removing only a shark’s fins and dumping the still live but helpless shark into the ocean to die.

Research at Dalhousie University over the past five years, conducted by Baum and the late Ransom Myers, demonstrated the magnitude of shark declines in the northwest Atlantic Ocean.

All species the team looked at had declined by over 50 percent since the early 1970s. For many large coastal shark species, the declines were much greater – tiger, scalloped hammerhead, bull and dusky shark populations have all plummeted by more than 95 percent.

The first complete IUCN Red List assessment of the status of all Mediterranean sharks and rays has revealed that 42 percent of the species are threatened with extinction. Overfishing, including bycatch, was identified as the main cause of decline by the study, which was released in November 2007.

“From devil rays to angel sharks, Mediterranean populations of these vulnerable species are in serious trouble,” said Claudine Gibson, Programme Officer for the IUCN Shark Specialist Group and co-author of the report.

“Our analyses reveal the Mediterranean Sea as one of the world’s most dangerous places on Earth for sharks and rays,” Gibson said. “Bottom dwelling species appear to be at greatest risk in this region, due mainly to intense fishing of the seabed.”

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SAN DIEGO, California, February 12, 2008 (ENS) – There is a 50 percent chance Lake Mead, a key source of water for millions of people in the southwestern United States, will be dry by 2021 if the climate changes as expected and future water use is not limited, warn researchers at Scripps Institution of Oceanography at the University of California-San Diego.

Without Lake Mead and neighboring Lake Powell, the Colorado River system has no buffer to sustain the population of the Southwest through an unusually dry year, or worse, a sustained drought.

In such an event, water deliveries to cities such as Las Vegas, Los Angeles and San Diego would become unstable and variable, say research marine physicist Tim Barnett and climate scientist David Pierce.

The researchers say that even if water agencies follow their current drought contingency plans, it might not be enough to counter natural forces, especially if the region enters a period of sustained drought or human-induced climate changes occur as currently predicted.

“We were stunned at the magnitude of the problem and how fast it was coming at us,” said Barnett. “Make no mistake, this water problem is not a scientific abstraction, but rather one that will impact each and every one of us that live in the Southwest.”

“It’s likely to mean real changes to how we live and do business in this region,” Pierce added.

The researchers estimate that there is a 10 percent chance that Lake Mead could be dry by 2014. They further predict that there is a 50 percent chance that reservoir levels will drop too low to allow hydroelectric power generation by 2017.

Lake Mead as seen from the Hoover Dam.
Water levels once covered the white
ring around the lake. (Photo credit
unknown)

Lake Mead is the largest human-made lake and reservoir in the United States. It is located on the Colorado River about 30 miles southeast of Las Vegas, Nevada, in the states of Nevada and Arizona. Formed by water impounded by Hoover Dam, it extends 110 miles behind the dam, holding approximately 28.5 million acre feet of water.

Barnett and Pierce conclude that human demand, natural forces like evaporation, and human-induced climate change are creating a net deficit of nearly one million acre-feet of water per year from the Colorado River system that includes Lake Mead and Lake Powell. This amount of water can supply roughly eight million people.

Their analysis of Federal Bureau of Reclamation records of past water demand and calculations of scheduled water allocations and climate conditions indicate that the system could run dry even if mitigation measures now being proposed are implemented.

The Lake Mead/Lake Powell system includes the stretch of the Colorado River in northern Arizona. Aqueducts carry the water to Las Vegas, Los Angeles, San Diego, and other communities in the Southwest. Currently the system is only at half capacity because of a recent string of dry years, and the team estimates that the system has already entered an era of deficit.

“When expected changes due to global warming are included as well, currently scheduled depletions are simply not sustainable,” wrote Barnett and Pierce in their paper, “When will Lake Mead go dry?,” which has been accepted for publication in the peer-reviewed journal “Water Resources Research,” published by the American Geophysical Union.

Barnett and Pierce note that a number of other studies in recent years have estimated that climate change will lead to reductions in runoff to the Colorado River system. Those analyses consistently forecast reductions of between 10 and 30 percent over the next 30 to 50 years, which could affect the water supply of between 12 and 36 million people.

Barnett said that the researchers chose to go with conservative estimates of the situation in their analysis, though the water shortage is likely to be more dire in reality.

The team based its findings on the premise that climate change effects only started in 2007, though most researchers consider human-caused changes in climate to have likely started decades earlier. They also based their river flow on averages over the past 100 years, even though it has dropped in recent decades. Over the past 500 years the average annual flow is even less.

“Today, we are at or beyond the sustainable limit of the Colorado system. The alternative to reasoned solutions to this coming water crisis is a major societal and economic disruption in the desert southwest; something that will affect each of us living in the region,” the report concludes.

The research was supported under a joint program between UC San Diego and the Lawrence Livermore National Laboratory and by the California Energy Commission.

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