{"id":3965,"date":"2009-12-22T11:02:41","date_gmt":"2009-12-22T19:02:41","guid":{"rendered":"http:\/\/blogs.kqed.org\/climatewatch\/?p=3965"},"modified":"2009-12-22T11:02:41","modified_gmt":"2009-12-22T19:02:41","slug":"polar-bears-and-sea-ice-sorting-it-out","status":"publish","type":"post","link":"https:\/\/ww2.kqed.org\/climatewatch\/2009\/12\/22\/polar-bears-and-sea-ice-sorting-it-out\/","title":{"rendered":"Polar Bears and Sea Ice: Sorting it Out"},"content":{"rendered":"

\"87514496\"A recent post<\/a> I wrote to highlight a radio discussion of the current plight of polar bears, drew a challenge from Russell Steele, one of our regular readers. Steele questioned some of the scientific conclusions underlying dire predictions for the bears.<\/p>\n

To help sort some of this out, I asked for responses from two highly regarded scientists in the field. Here’s a response to the specific reader challenge from Mark Serreze<\/a>, Director of the National Snow & Ice Data Center<\/a>, in Boulder, CO:<\/p>\n

It is unclear what Mr. Steele is trying to get at with reference to the seasonal cycles in sea ice extent from the AMSR-E data. The AMSR-E data, while valuable, only go back to 2002. Through combining SSM\/I and SMMR satellite data with other information sources for earlier years, we have a decent record of Arctic sea ice extent going back to the early 1950s. The relevant issue is the long-term decline in end-of-summer (September) ice extent evident in this record, with the extreme September minima of recent years (represented in the short AMSR-E record) serving as exclamation points. The observed rate of September ice loss exceeds expectations from nearly all climate models.<\/p><\/blockquote>\n

I also turned to Waleed Abdalati<\/a>. Now director of the Earth Sciences Observation Center<\/a> at the University of Colorado, Abdalati is a veteran of the Cryospheric Sciences and Terrestrial Hydrology programs at NASA, and one of the most articulate people I’ve heard speak on the subject of polar ice. He offers the following:<\/p>\n

I am not an expert on polar bears, but I do think it is safe to say that\u2028 their primary habitat, the Arctic sea ice, is severely threatened.\u00a0 I, and \u2028most of my colleagues believe we are well on our way to an ice-free Arctic\u2028 in summer any time between this decade and the next 40 years.<\/p>\n

This\u2028 is because of two things:\u00a0 1) it will be decades before the ocean has \u2028finished its response to present-day greenhouse forcing, so the impacts of \u2028what we’ve done already have not been fully realized; and 2) the loss of\u2028 sea ice is self-compounding: when it starts to shrink, exposing a \u2028darker more (heat) absorbing ocean underneath, the likelihood of its continued\u2028 shrinking is greater (ice melts, exposes darker ocean, absorbs more heat, \u2028melts more ice, exposes darker ocean, and so-on).<\/p>\n

Of course the flipside\u2028 of this is that as ice starts to grow, it is more inclined to grow, but\u2028 against the backdrop of the increased warming, the former is far more likely \u2028than the latter. Finally, as thick multi-year ice disappears, it is\u2028 replaced with thinner and younger ice that is more vulnerable to surface \u2028melt from the atmosphere, bottom melting from sea water, and being carried\u2028 away to lower, warmer latitudes by ocean current and wind.<\/p>\n

So back to the polar bears: If their habitat disappears and they are unable \u2028to hunt seals, their main source of food, they seem to stand little or no\u2028 chance of survival. I am not a wildlife biologist but its hard for me to \u2028believe they as a population can sustain themselves on land and with only a\u2028 seasonally-present ice cover. In some cases, the fact that they face more\u2028 challenges on sea ice than in the past, has driven them to forage inland,\u2028 creating the illusion in some people’s minds that their populations are \u2028increasing, because there are more sightings on land. Who knows? Maybe \u2028they’ll evolve to hibernate in late summer, when there is no ice, and hunt\u2028 the rest of the year.<\/p>\n

There is an added effect that doesn’t get much attention.\u00a0 There was a \u2028fascinating study by a Canadian Biologist (Ian Stirling) and a sea ice\u2028 expert (Claire Parkinson) [Stirling, I., and C.L. Parkinson. 2006. Possible \u2028Effects of Climate Warming on Selected Populations of Polar Bears (Ursus\u2028maritimus) in the Canadian Arctic. Arctic<\/em> 59(3): 261-275.], which suggested \u2028that the bears are also losing weight, and approaching the weights at which \u2028they have historically not been able to bear cubs.\u00a0 So not only is the\u2028population threatened by starvation, the ability to replenish the population\u2028 seems diminished.<\/p>\n

I don’t believe we can say anything with absolute certainty,\u2028 so I, myself would not make the statement that the polar bears are doomed–but I will say that the outlook for them, in my view, looks very, very bad.<\/p><\/blockquote>\n","protected":false},"excerpt":{"rendered":"

Two experts on polar ice help sort out differing views on disappearing sea ice and the future of polar bears.<\/p>\n","protected":false},"author":221,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[6],"tags":[135,151,181,401,434,501,581,677],"coauthors":[],"series":[],"affiliates":[],"programs":[],"collections":[],"interests":[],"class_list":["post-3965","post","type-post","status-publish","format-standard","hentry","category-thescience","tag-conservation","tag-cryosphere","tag-ecosystems","tag-oceans","tag-polar-bears","tag-sea-ice","tag-temperature","tag-wildlife"],"acf":{"template_type":"standard","featured_image_type":"standard","is_audio_post":false},"yoast_head":"\nPolar Bears and Sea Ice: Sorting it Out | Climate Watch<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/ww2.kqed.org\/climatewatch\/2009\/12\/22\/polar-bears-and-sea-ice-sorting-it-out\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Polar Bears and Sea Ice: Sorting it Out | Climate Watch\" \/>\n<meta property=\"og:description\" content=\"Two experts on polar ice help sort out differing views on disappearing sea ice and the future of polar bears.\" \/>\n<meta property=\"og:url\" content=\"https:\/\/ww2.kqed.org\/climatewatch\/2009\/12\/22\/polar-bears-and-sea-ice-sorting-it-out\/\" \/>\n<meta property=\"og:site_name\" content=\"Climate Watch\" \/>\n<meta property=\"article:published_time\" content=\"2009-12-22T19:02:41+00:00\" \/>\n<meta property=\"og:image\" content=\"http:\/\/ww2.kqed.org\/climatewatch\/wp-content\/uploads\/sites\/54\/2009\/12\/Polarbear87514496_blog.jpg\" \/>\n<meta name=\"author\" content=\"Craig Miller\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:creator\" content=\"@voxterra\" \/>\n<meta name=\"twitter:label1\" content=\"Written by\" \/>\n\t<meta name=\"twitter:data1\" content=\"Craig Miller\" \/>\n\t<meta name=\"twitter:label2\" content=\"Est. reading time\" \/>\n\t<meta name=\"twitter:data2\" content=\"4 minutes\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\/\/schema.org\",\"@graph\":[{\"@type\":\"WebPage\",\"@id\":\"https:\/\/ww2.kqed.org\/climatewatch\/2009\/12\/22\/polar-bears-and-sea-ice-sorting-it-out\/\",\"url\":\"https:\/\/ww2.kqed.org\/climatewatch\/2009\/12\/22\/polar-bears-and-sea-ice-sorting-it-out\/\",\"name\":\"Polar Bears and Sea Ice: Sorting it Out | Climate Watch\",\"isPartOf\":{\"@id\":\"https:\/\/ww2.kqed.org\/climatewatch\/#website\"},\"datePublished\":\"2009-12-22T19:02:41+00:00\",\"dateModified\":\"2009-12-22T19:02:41+00:00\",\"author\":{\"@id\":\"https:\/\/ww2.kqed.org\/climatewatch\/#\/schema\/person\/f7222c517400a6c4b0336fca3652c323\"},\"breadcrumb\":{\"@id\":\"https:\/\/ww2.kqed.org\/climatewatch\/2009\/12\/22\/polar-bears-and-sea-ice-sorting-it-out\/#breadcrumb\"},\"inLanguage\":\"en-US\",\"potentialAction\":[{\"@type\":\"ReadAction\",\"target\":[\"https:\/\/ww2.kqed.org\/climatewatch\/2009\/12\/22\/polar-bears-and-sea-ice-sorting-it-out\/\"]}]},{\"@type\":\"BreadcrumbList\",\"@id\":\"https:\/\/ww2.kqed.org\/climatewatch\/2009\/12\/22\/polar-bears-and-sea-ice-sorting-it-out\/#breadcrumb\",\"itemListElement\":[{\"@type\":\"ListItem\",\"position\":1,\"name\":\"Home\",\"item\":\"https:\/\/ww2.kqed.org\/climatewatch\/\"},{\"@type\":\"ListItem\",\"position\":2,\"name\":\"Polar Bears and Sea Ice: Sorting it Out\"}]},{\"@type\":\"WebSite\",\"@id\":\"https:\/\/ww2.kqed.org\/climatewatch\/#website\",\"url\":\"https:\/\/ww2.kqed.org\/climatewatch\/\",\"name\":\"Climate Watch\",\"description\":\"\",\"potentialAction\":[{\"@type\":\"SearchAction\",\"target\":{\"@type\":\"EntryPoint\",\"urlTemplate\":\"https:\/\/ww2.kqed.org\/climatewatch\/?s={search_term_string}\"},\"query-input\":\"required name=search_term_string\"}],\"inLanguage\":\"en-US\"},{\"@type\":\"Person\",\"@id\":\"https:\/\/ww2.kqed.org\/climatewatch\/#\/schema\/person\/f7222c517400a6c4b0336fca3652c323\",\"name\":\"Craig Miller\",\"image\":{\"@type\":\"ImageObject\",\"inLanguage\":\"en-US\",\"@id\":\"https:\/\/ww2.kqed.org\/climatewatch\/#\/schema\/person\/image\/dd8f4f4f978df3faac9db4c510939ea0\",\"url\":\"https:\/\/secure.gravatar.com\/avatar\/b91661df645e001a9cafe0861fa685f9?s=96&d=mm&r=g\",\"contentUrl\":\"https:\/\/secure.gravatar.com\/avatar\/b91661df645e001a9cafe0861fa685f9?s=96&d=mm&r=g\",\"caption\":\"Craig Miller\"},\"description\":\"Craig is a former KQED Science editor, specializing in weather, climate, water & energy issues, with a little seismology thrown in just to shake things up. 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