Ice shelves are retreating in the southern section of the Antarctic Peninsula due to climate change. This could result in glacier retreat and sea-level rise if warming continues, threatening coastal communities and low-lying islands worldwide.

Research by the U.S. Geological Survey is the first to document that every ice front in the southern part of the Antarctic Peninsula has been retreating overall from 1947 to 2009, with the most dramatic changes occurring since 1990. The USGS previously documented that the majority of ice fronts on the entire Peninsula have also retreated during the late 20th century and into the early 21st century.
The ice shelves are attached to the continent and already floating, holding in place the Antarctic ice sheet that covers about 98 percent of the Antarctic continent. As the ice shelves break off, it is easier for outlet glaciers and ice streams from the ice sheet to flow into the sea. The transition of that ice from land to the ocean is what raises sea level.

"This research is part of a larger ongoing USGS project that is for the first time studying the entire Antarctic coastline in detail, and this is important because the Antarctic ice sheet contains 91 percent of Earth's glacier ice," said USGS scientist Jane Ferrigno. "The loss of ice shelves is evidence of the effects of global warming. We need to be alert and continually understand and observe how our climate system is changing."

The Peninsula is one of Antarctica's most rapidly changing areas because it is farthest away from the South Pole, and its ice shelf loss may be a forecast of changes in other parts of Antarctica and the world if warming continues.

Retreat along the southern part of the Peninsula is of particular interest because that area has the Peninsula's coolest temperatures, demonstrating that global warming is affecting the entire length of the Peninsula.

The Antarctic Peninsula's southern section as described in this study contains five major ice shelves: Wilkins, George VI, Bach, Stange and the southern portion of Larsen Ice Shelf. The ice lost since 1998 from the Wilkins Ice Shelf alone totals more than 4,000 square kilometers, an area larger than the state of Rhode Island.

The USGS is working collaboratively on this project with the British Antarctic Survey, with the assistance of the Scott Polar Research Institute and Germany's Bundesamt fur Kartographie und Geodäsie. The research is also part of the USGS Glacier Studies Project, which is monitoring and describing glacier extent and change over the whole planet using satellite imagery.

The report, "Coastal-Change and Glaciological Map of the Palmer Land Area, Antarctica: 1947-2009" and its accompanying map is available online.

The other completed reports in the Coastal Change and Glaciological Maps of Antarctica series can be viewed online.

Source: USGS

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Coastal-Change and Glaciological Map of the Palmer Land Area, Antarctica: 1947-2009.

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WASHINGTON, D.C. - Secretary of the Interior Ken Salazar, Assistant Secretary for Fish and Wildlife and Parks Tom Strickland and U.S. Fish and Wildlife Service Director Sam Hamilton announced that the brown pelican, a species once decimated by the pesticide DDT, has recovered and is being removed from the list of threatened and endangered species under the Endangered Species Act.

"At a time when so many species of wildlife are threatened, we once in a while have an opportunity to celebrate an amazing success story," Salazar said. "Today is such a day. The brown pelican is back!"

The brown pelican was first declared endangered in 1970 under the Endangered Species Preservation Act, a precursor to the current Endangered Species Act. Since then, thanks to a ban on DDT and efforts by states, conservation organizations, private citizens and many other partners, the bird has recovered. There are now more than 650,000 brown pelicans found across Florida and the Gulf and Pacific Coasts, as well as in the Caribbean and Latin America.

The Fish and Wildlife Service removed the brown pelican population in Alabama, Georgia, Florida, and northward along the Atlantic Coast states from the list of endangered species in 1985. Today's action removes the remaining population from the list.

"After being hunted for its feathers, facing devastating effects from the pesticide DDT and suffering from widespread coastal habitat loss, the pelican has made a remarkable recovery," Strickland said at a press conference in New Orleans to announce the delisting. "We once again see healthy flocks of pelicans in the air over our shores."

The pelican's recovery is largely due to the federal ban on the general use of the pesticide DDT in 1972. This action was taken after former U.S. Fish and Wildlife Service biologist Rachel Carson published Silent Spring and alerted the nation to the widespread dangers associated with unrestricted pesticide use.

Hamilton praised the Gulf and Pacific Coast states for their constant efforts to restore this iconic coastal species. "Brown pelicans could not have recovered without a strong and continuing support network of partnerships among federal and state government agencies, tribes, conservation organizations, and individual citizens," said Hamilton. "This is truly a success story that the whole nation can celebrate."

In the southwest, the Texas Parks and Wildlife Department, The Nature Conservancy and numerous other conservation organizations helped purchase important nesting sites and developed monitoring programs to ensure pelican rookeries were thriving.

Louisiana, long known as the "pelican state," and the Florida Game and Fresh Water Fish Commission jointly implemented a restoration project. A total of 1,276 young pelicans were captured in Florida and released at three sites in southeastern Louisiana during the 13 years of the project.

Past efforts to protect the brown pelican actually led to the birth of the National Wildlife Refuge System more than a century ago in central Florida. German immigrant Paul Kroegel, appalled by the indiscriminate slaughter of pelicans for their feathers, approached President Theodore Roosevelt. This led Roosevelt to create the first National Wildlife Refuge at Pelican Island in 1903, when Kroegel was named the first refuge manager. Today, the system has grown to 550 national wildlife refuges, many of which have played key roles in the recovery of the brown pelican.

With removal of the brown pelican from the list of threatened and endangered species, federal agencies will no longer be required to consult with the Service to ensure any action they authorize, fund, or carry out will not harm the species. However, additional federal laws, such as the Migratory Bird Treaty Act and the Lacey Act, will continue to protect the brown pelican, its nests and its eggs.

The Service has developed a Post-Delisting Monitoring Plan, designed to monitor and verify that the recovered, delisted population remains secure from the risk of extinction once the protections of the ESA are removed. The Service can relist the brown pelican if future monitoring or other information shows it is necessary to prevent a significant risk to the brown pelican.

The monitoring will be done in cooperation with the State resource agencies, the Commonwealth of Puerto Rico, U.S. Virgin Islands, Mexico, other federal agencies, non-governmental organizations, and individuals. Further, the Service is working with state natural resource agencies where the brown pelican occurs to develop cooperative management agreements to ensure that the species continues to be monitored.

The final rule removing the bird from the list of threatened and endangered species will be published in the Federal Register and will take effect 30 days after publication.

Source: U.S. DOI

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Recent tree loss, largely driven by climate stress, in forests around the world could portend increased tree mortality under climate change, according to a U.S. Geological Survey (USGS) report recently released online in the journal Forest Ecology and Management.

The USGS-led review suggests that many of the world's forests are sensitive to climate-related drought and heat stress, raising the concern that forests may become increasingly vulnerable to future mortality, even in environments that are not normally considered water-limited. The results suggest risks to ecosystem services that are valuable to forests and societies around the world.

"Trees can die much more quickly than they grow," said Craig D. Allen, USGS scientist and lead author of the report. "The widespread examples of drought and heat-induced tree mortality that we document illustrate how climate can drive abrupt, broad-scale impacts to essential forest services ranging from timber and protection of watersheds and biodiversity to recreational, aesthetic and spiritual benefits."

Although tree mortality episodes occur in the absence of climate change, the report's results are consistent with projections of future increases in tree mortality due to climate-related stresses. These heat and drought stresses could fundamentally alter the composition, structure and biogeography of forests in many regions, as well as affect how forests sequester carbon.

"This work by USGS underscores multiple risks that climate change poses to our forests and our world," said Secretary of the Interior Ken Salazar. "It also illuminates the importance of our efforts to develop practical, on-the-ground land management strategies that will help us adjust to the stresses that climate change is placing on our forests."

The report details 88 cases of significant tree mortality around the world associated with heat and drought since 1970, documenting climate-induced tree losses from Africa, Asia, Australia, Europe, North America and South America.

"From northern forests of spruce, pine or oak to tropical savannas and rainforests, many forest types appear vulnerable to such climate-driven mortality and to forest pests that are also highly sensitive to temperature," Allen said.

The report also identifies key information gaps and scientific uncertainties that currently hinder our ability to identify climate-related trends in tree mortality and to predict future losses in response to climate change, including lack of species-specific knowledge about tree water and temperature stress limits and the absence of a globally coordinated observation system.

However, in conjunction with other recent observational and experimental studies indicating that higher temperatures can drive increases in tree mortality, this article highlights risks that tree mortality could become more frequent and extensive as global climate change progresses.

Source: USGS

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