Tag Archive | "arctic"


Arctic Sea Ice Continues Decline

Arctic sea ice continues its precipitous decline: as we near the end of the summer ice-melt season, all indications suggest that the extent of sea ice has fallen to record or near-record lows this year. Satellite measurements by the National Snow and Ice Data Center found that the sea-ice extent was 1.68 million square miles, just 70,000 square miles above the all-time record low, set in 2007. That may seem like a substantial cushion over the minimum, but it’s a far cry from the 1979-2000 average September minimum of nearly 3 million square miles. NSIDC won’t be able to pinpoint the final minimum until the sea ice begins to re-form, but the 2011 extent is already below the previous second- and third-place years, 2010 and 2008. However, they report the rate of melt is slowing and might not surpass their records for 2007. That’s the good news.

The bad news is that another ice-tracking team, at the University of Bremen in Germany, reports that their measurements show 2011 ice extent reached the lowest extent that they have ever recorded, at 1.64 million square miles (Bremen’s measurement for 2007 was 1.65 million square miles). The Bremen team’s methodology differs from NSIDC’s, hence the slight differences in their figures. But the two groups are close enough to be clear that the Arctic is melting, and fast. And that’s not the worst news.

The worst news is that the trend in Arctic ice VOLUME is even more dramatic than the trend in area. The Polar Science Center in Seattle estimates that the current trend in sea ice volume is running well below 2007, even though the two years are running practically neck-and-neck on extent. The sharp decline in volume means that the ice that is there is thinner than in the past, and therefore more prone to melting in the future.

In 2007 the Intergovernmental Panel on Climate Change noted that Arctic sea ice had declined 2.7% per decade over the past 30 years and warned that “In some projections, arctic late-summer sea ice disappears almost entirely by the latter part of the 21st century.” The IPCC may have been overly optimistic: if ice continues to be lost at current rates, we could see complete loss of summer ice by 2040. .  And it’s that overall trend – not whether this year is the lowest or second lowest – that spells big trouble for Arctic wildlife like polar bears.

Posted in Alaska, Climate ChangeComments (0)

arctic refuge

Arctic Refuge Vulnerability Report

Few places on earth are set as squarely in the sights of climate change at the Arctic National Wildlife Refuge. Much of Alaska has warmed over 4oF over the past 50 years, and the northern part of the state where the refuge is located is projected to warm faster than any part of the continent – up to 7oF by mid-century. As the U.S. Fish and Wildlife Service prepares its conservation plan to guide the Arctic Refuge though the next 15 years, Defenders wanted to know what these changes will mean for 38 species of mammals that call the refuge home.

To get a clearer understanding of how climate change will affect the wildlife of the Arctic Refuge, we conducted a vulnerability assessment, which measures each species’ exposure to climate change, its sensitivity to the changes it will be exposed to, and its potential adaptive capacity in the face of such changes. Exposure is a result of regional climate changes, but may be modified by local microhabitat conditions. A species’ sensitivity is determined by factors including its ecological, genetic and physiological traits such as dependence on sensitive habitats, dietary flexibility, population growth rates and interactions with other species. Assessing adaptive capacity includes considerations such as the species’ dispersal ability, whether there are barriers to its movement, and the likelihood that the species could modify its physiology or behavior, or even has the potential to evolve to match changes in its environment.

We researched the known scientific information on each of the 38 refuge mammals, analyzed projected future climate change for the refuge using ClimateWizard, and input the information into the Climate Change Vulnerability Index, a tool developed by NatureServe to assess the relative vulnerability of species.

We found a wide variation in the vulnerability of the Arctic National Wildlife Refuge mammals to climate change. The species most vulnerable are the ones specially adapted to the cold, snow and ice. Six species ranked as “extremely vulnerable”: the polar bear, arctic fox, muskox, collared lemming, brown lemming and tundra vole. A further ten species ranked as “highly vulnerable”; that list included lynx, wolverine, caribou, Dall sheep and Alaska marmot. For the most part, species that live in the boreal forest in the southern portion of the refuge, have flexible habitat needs, or a distribution that extends well into warmer areas—like black bear, beaver, muskrat, gray wolf, and red fox—tended to be less vulnerable.

We hope the results of this assessment will help the refuge managers secure a future for the most vulnerable species, by protecting the sensitive tundra region from disturbance, investing in research and monitoring, and maintaining linkages to habitat areas outside of the refuge.

The full report is available here.

A 6-page summary is available here.  

A detailed description of the methods is available here.

Posted in Climate Change, Imperiled Wildlife, National Wildlife RefugesComments (0)

Fifty Years of the Arctic National Wildlife Refuge

Monday, December 6, marked 50 years since the Arctic National Wildlife Refuge (then known as the Arctic National Wildlife Range) was established under the Eisenhower administration. It’s a milestone that once again brings attention to the need to safeguard this iconic natural landscape from the destruction that would inevitably result from oil and gas development.  The Arctic Refuge deserves protection for ecological, scientific, cultural, aesthetic, and even spiritual reasons.  It also deserves protection for the value it gives to the larger system of which it is a part.

With more than 550 refuges, thousands of waterfowl production areas, and about 150 million acres, the National Wildlife Refuge System is the largest system of protected land and water in the world.  Yet beyond a tautological definition, most Americans would be hard pressed to explain what the National Wildlife Refuge System is – that is, if they had even heard of it at all.

Despite this, the Arctic Refuge is one of the world’s best-known protected areas.  As one of the largest and most recognizable unit of the National Wildlife Refuge System, the Arctic Refuge provides us the opportunity to put a face to the name, ‘Refuge.’  It gives an identity to the Refuge System and, in turn, a reason to care about it.  In the face of a $3.7 billion backlog and tightening budgets, it needs all the support it can get.

As one of our last large, intact landscapes, where ecological processes have persisted largely without human interference and evolution carries on unchallenged, the Arctic Refuge teaches and inspires us.  And as the National Wildlife Refuge System formulates a new vision for the future, it represents the possibility.  Rallying around the Arctic Refuge can help garner strength for the countless other unique and remarkable units that the Refuge System protects.

The importance of the Arctic Refuge can be evidenced by the fact that its 50th anniversary has been so highly celebrated, with a play, a gala, a new film from the U.S. Fish and Wildlife Service, and a presidential proclamation all marking the occasion.  In the fight to keep this treasured place free from oil and gas development for another 50 years, protecting the Arctic Refuge and the National Wildlife Refuge System will go hand in hand.

Posted in Alaska, National Wildlife Refuges, Public LandsComments (0)

dotWild is the blog of scientists and policy experts at Defenders of Wildlife, a national, nonprofit membership organization dedicated to the protection of all native animals and plants in their natural communities.