The Need for Mapping Polar Bear Habitat Collapse
|Timothy W. Foresman, PhD, is President of the International Centre for Remote Sensing Education. He has been director of United Nations Environment Programme’s Division of Early Warning and Assessment (Nairobi, Kenya) and national program manager for NASA’s Digital Earth (Washington, D.C.). He is editor of The History of Geographic Information Systems, 1998, Prentice Hall. Dr. Foresman was the Director-General for the 5th International Symposium on Digital Earth (www.isde5.org). |
Nothing captures the hearts and minds of people like pictures of cute little polar bear cubs frolicking on the snow. Holiday cards, calendars, and t-shirts reflect the tremendous attraction to humans of this animal species. Known as charismatic megafauna for the moreobjective in the scientific community, these creatures have been known to require crowd control measures when displayed in zoos.
Recently, Knut of the Berlin Zoo became an instant world-wide celebrity for millions, helping to create a merchandizing blitz of books and stuffed animals. Wildlife biologists have been warning that zoos may be the last refuge for the giant ice bears if Arctic trends continue, and in facing this challenge the remote sensing community could bolster the knowledge base for understanding exactly what is going on with our furry friends as the Arctic ice melt continues.
The International Polar Year of 2007/2008 is upon us (see related story on page 20) and nothing could be more iconic for this international awareness raising than to take a look at the plight of this symbolic and dominant Arctic species, the polar bear. Consider the role that remote sensing technologies might play in monitoring the fate of these marvelous Earth creatures. Experts estimate the remaining population of the Ursus maritimus (Latin for ‘sea bear’) to be around 20,000 to 25,000 individual animals living around the Arctic Circle environs.
Polar bears, one of eight bear species, evolved from the Alaska brown bear approximately 200,000 years ago to live in the harsh Arctic ecosystem. Wildlife biologists have been monitoring the 19 populations of these bears with increasing concern for their sustainability. Conservative estimates are for a 30% decline over the next 45 years, based on documentation of some populations over the past 25 years; for example, Canada’s Western Hudson Bay population has declined 22% over that time period (www.polarbearsinternational.org).
The U.S. has proposed the "threatened" status under the Endangered Species Act, while the international community has reclassified polar bears under the IUCN’s Red List as "vulnerable" (an equivalent to the threatened status). I emphasize ‘conservative’ above due to the real threat of accelerated Arctic warming that may overwhelm our deliberative and consensus-driven scientific understanding of the real picture, which is based on past trajectories and trends.
Geophysicists have recently raised the specter of a rapid decrease in summer Arctic ice that may push up the calendar for the polar bears by decades from previous projections. These scientists have been putting their heads together to study the astonishing recent exposure of over one million square miles of open water, as measured through remote sensing satellite monitoring. NASA’s Son Ngheim reported in a Fall 2007 issue of Geophysical Research Letters that, according to satellite and buoy data, winds have been pushing thick old ice out of the Arctic basin past Greenland, leaving behind only thinner ice that melts more rapidly under summer conditions (Andrew C. Revkin, October 2, 2007, New York Times).
More alarming are the projections of Wieslaw Maslowski, of the Naval Postgraduate School, for an ice-free Arctic summer ocean by 2013! The Maslowski-led research team, which included NASA and others, informed attendees at the December meeting of the American Geophysical Union in San Francisco that their team had accounted for the previous underestimates of processes driving ice loss by applying high-resolution regional models. Peter Wadhams, of Cambridge University, backs up Maslowski’s projections with Royal Navy submarine sonar data on ice thickness. The U.S. National Snow and Ice Data Center’s Mark Serreze acknowledged that while he previously was focused on 2050 or 2070 for ice-free summer oceans in the Arctic, "My thinking on this is that 2030 is not an unreasonable date to be thinking of." He added, "…and it would not surprise me if (Maslowski’s) projections came out."
Maslowski’s teams may be right. If so, the polar bears will rapidly die out as a result. As Andrew Derocher, of University of Edmonton, puts it, "Put the dots together: no habitat, no seals; no seals, no bears." Further, he points out, "The only effective conservation approach is to protect the habitat, and this is an issue of climate change."
There are many unknowns in the science community regarding specifics for the polar bears’ future, and importantly, remote sensing can and will play a critical role. Each of the 19 bear populations will be impacted differently in relation to their geographic niche in the Arctic ice ecosystem. Those populations closer to land may be more likely to find ways to adapt and perhaps hybridize with their southern brown bear cousins. But the previously cited estimate of 30% loss by 2050 will likely be more conservative by a whole order of magnitude when faced with newer, more precise satellite-derived measures and model projections.
Conservation biologists and international governing bodies will need more high-resolution measurements and assessments to guide them as they wrestle with the challenges of trying to preserve and protect the best remnant refuge areas for the declining polar bear populations. While the die may be cast for the survival of this species in the 21st Century, the readership of this magazine could possibly do wonders by improving cooperation and collaboration on this critical issue. The remote sensing community could fill in gaps with high-resolution data sets to further our scientific knowledge for this challenging Arctic situation.
Photo Credits: All polar bear images are courtesy of Robert and Carol Buchanan of Polar Bears International (www.polarbearsinternational.org). Arctic satellite image mocaics courtesy of NASA (svs.gsfc.nasa.gov/stories/arctic/index.html).
Editor's Note: Dr. Tim Foresman is author of the illustrated children's book, The Last Little Polar Bear (www.lastlittlepolarbear.org). Buy the book at http://www.bluelinepub.com/BookPub.htm.