{"id":266535,"date":"2023-07-10T12:20:45","date_gmt":"2023-07-10T10:20:45","guid":{"rendered":"https:\/\/climatescience.press\/?p=266535"},"modified":"2023-07-10T12:20:47","modified_gmt":"2023-07-10T10:20:47","slug":"natural-flexibility-explains-w-hudson-bay-polar-bear-movements-at-breakup-better-than-climate-change","status":"publish","type":"post","link":"https:\/\/climatescience.press\/?p=266535","title":{"rendered":"Natural flexibility explains W Hudson Bay polar bear movements at breakup better than climate change"},"content":{"rendered":"\n
\"\"<\/figure>\n\n\n\n

<\/p>\n\n\n\n

From polarbearscience<\/a><\/p>\n\n\n\n

Hudson Bay in early July this year is a mosaic of more-than-average and less-than-average sea ice coverage but apparently, only the less-than-average ice areas constitute the \u201cearly breakup\u201d caused by climate change, and only \u201cdeniers\u201d would say otherwise.<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

I say some folks are cherry picking the ice conditions that support a story line they prefer, forgetting that polar bears know better than they do when to come in off they ice.<\/p>\n\n\n\n

Out of 40 males or young bears with ear tags (purple) or collared females (red and blue) captured in Western Hudson Bay in the last year shown on this map at 7 July 2023, 16 or 40% were onshore (one very far inland), while 24 or 60% were still out on what appears to be very little ice.<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

According to a tweet on 8 July by\u00a0Andrew Derocher<\/a>, who is in charge of attaching many of those tags, that 60% constitutes only \u201csome\u201d polar bears.<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

<\/p>\n\n\n\n

How much ice is there?<\/strong><\/p>\n\n\n\n

He also says it\u2019s \u201chard to see any ice\u201d on the satellite image he provides but if you look at more informative charts, it\u2019s apparent there is actually a fair amount of ice present. Even two days later, at 9 July, there was enough ice to support any bear that wanted to stay offshore for a while longer.<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

The weekly ice chart below, taken a few days before the bear tag map, shows very thick ice remaining over the bay at 3 July. At this time of year, ice may be covered in melt water, which confuses the satellites into interpreting it as low concentration ice or open water (Castro de la Guardia et al. 2017). This \u201cponding\u201d effect is a real, known source of measuring error for sea ice during breakup and Andrew Derocher knows this (or should) \u2014 but it\u2019s not what he tells the public.<\/p>\n\n\n\n

In general, passive microwave derived sea ice data are associated with an underestimation error of up to 30% during breakup and freeze-up throughout the marginal ice zone and seasonal ice regions in the Northern Hemisphere.\u00a0In Hudson Bay, passive microwave sea ice concentration can underestimate sea ice concentration by up to 50% compared with CISDA<\/strong>.\u00a0Underestimation biases of passive microwave data are associated with the presence of wet snow and melt ponds during breakup<\/strong>\u2026<\/em>\u00a0[Castro de la Guardia et al. 2017:227, my bold]<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

<\/p>\n\n\n\n

Big climate change cherry pick<\/strong><\/p>\n\n\n\n

In the weekly ice anomaly chart below, red is less than average but\u00a0blue is more than average<\/strong><\/em>. If the red areas in central and western Hudson Bay are forcing polar bears ashore early because of \u201cclimate change\u201d (as per Derocher tweet, above), what\u2019s causing southern Hudson Bay, Hudson Strait, Labrador Sea and Davis Strait to have more than average ice coverage? Do Western Hudson Bay polar bears really suffer harm due to global climate change at the very same time that Southern Hudson Bay and southern Davis Strait bears thrive in better-than-the-1980s conditions, even though some of them live further south? That sounds more like a big game of climate change picking-of-cherries than a scientific assessment of fact.<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

Here\u2019s a question:\u00a0<\/strong>If something on the order of 40-50% of Western Hudson Bay polar bears\u00a0don\u2019t come ashore<\/a>\u00a0until the very last bits of sea ice are truly melted in summer (e.g., in 2020, 45% of tagged bears were still offshore when only a small remnant block of ice remained), is\u00a0any definition of breakup based on a particular percentage of sea ice coverage<\/a>\u00a0of any use in describing when these bears come ashore? Or is this definition still used because\u00a0it\u2019s particularly useful for creating scary-sounding headlines<\/a>\u00a0to support the human-caused climate change agenda and the polar-bears-are-all-going-to-die narrative?<\/p>\n\n\n\n

I suggest polar bears, due to\u00a0their evolutionary history<\/a>, are\u00a0simply more flexibl<\/a>e in their relationship to sea ice than polar bear experts have concluded based on limited evidence, and that the bears don\u2019t actually need to come ashore until the last of the ice is gone. As long as they are in good condition after a successful spring hunting season, it probably doesn\u2019t matter whether W Hudson Bay polar bears come ashore in June or August.<\/p>\n\n\n\n

<\/p>\n\n\n\n

References<\/strong><\/p>\n\n\n\n

Castro de la Guardia, L., Myers, P.G., Derocher, A.E., et al. 2017.<\/strong>\u00a0Sea ice cycle in western Hudson Bay, Canada, from a polar bear perspective.\u00a0Marine Ecology Progress Series<\/em>\u00a0564: 225\u2013233.\u00a0<\/p>\n\n\n\n

http:\/\/www.int-res.com\/abstracts\/meps\/v564\/p225-233\/<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

Hudson Bay in early July this year is a mosaic of more-than-average and less-than-average sea ice coverage but apparently, only the less-than-average ice areas constitute the \u201cearly breakup\u201d caused by climate change, and only \u201cdeniers\u201d would say otherwise.<\/p>\n","protected":false},"author":121246920,"featured_media":266548,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_coblocks_attr":"","_coblocks_dimensions":"","_coblocks_responsive_height":"","_coblocks_accordion_ie_support":"","_crdt_document":"","advanced_seo_description":"","jetpack_seo_html_title":"","jetpack_seo_noindex":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2},"jetpack_post_was_ever_published":false},"categories":[1],"tags":[691818056,691818250,691818745],"class_list":{"0":"post-266535","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","6":"hentry","7":"category-uncategorized","8":"tag-climate-change","9":"tag-hudson-bay","10":"tag-polar-bear","12":"fallback-thumbnail"},"jetpack_publicize_connections":[],"jetpack_featured_media_url":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/07\/image-279.png?fit=1536%2C1046&ssl=1","jetpack_likes_enabled":true,"jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/paxLW1-17kX","jetpack-related-posts":[{"id":290645,"url":"https:\/\/climatescience.press\/?p=290645","url_meta":{"origin":266535,"position":0},"title":"Despite hand-wringing about Churchill polar bears this year, 2023 wasn\u2019t their worst summer","author":"uwe.roland.gross","date":"10\/12\/2023","format":false,"excerpt":"For months, the media has been bleating about the poor polar bears of Churchill suffering from lack of sea ice blamed on human-caused climate change during the so-called\u00a0\u2018hottest year\u2019 on record: in\u00a0April,\u00a0July,\u00a0August,\u00a0November, and\u00a0December.","rel":"","context":"In \"2023\"","block_context":{"text":"2023","link":"https:\/\/climatescience.press\/?tag=2023"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/12\/image-201.png?fit=1200%2C800&ssl=1&resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/12\/image-201.png?fit=1200%2C800&ssl=1&resize=350%2C200 1x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/12\/image-201.png?fit=1200%2C800&ssl=1&resize=525%2C300 1.5x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/12\/image-201.png?fit=1200%2C800&ssl=1&resize=700%2C400 2x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/12\/image-201.png?fit=1200%2C800&ssl=1&resize=1050%2C600 3x"},"classes":[]},{"id":265498,"url":"https:\/\/climatescience.press\/?p=265498","url_meta":{"origin":266535,"position":1},"title":"Early sea ice breakup in W Hudson Bay caused by \u201crecord breaking\u201d warmth in 2023 but not 2015?","author":"uwe.roland.gross","date":"05\/07\/2023","format":false,"excerpt":"According to\u00a0Polar Bears International, the \u201c3rd-earliest\u201d breakup date for Western Hudson Bay was caused by a \u201crecord breaking\u201d heat wave in May. Western Hudson Bay sea ice hit the 30% coverage threshold used by PBI to define \u201cbreakup\u201d on 17 June this year, prompting speculation about potential future impacts on\u2026","rel":"","context":"In \"Bears Onshore\"","block_context":{"text":"Bears Onshore","link":"https:\/\/climatescience.press\/?tag=bears-onshore"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/07\/0OIGP-3.jpeg?fit=1024%2C1024&ssl=1&resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/07\/0OIGP-3.jpeg?fit=1024%2C1024&ssl=1&resize=350%2C200 1x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/07\/0OIGP-3.jpeg?fit=1024%2C1024&ssl=1&resize=525%2C300 1.5x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/07\/0OIGP-3.jpeg?fit=1024%2C1024&ssl=1&resize=700%2C400 2x"},"classes":[]},{"id":267566,"url":"https:\/\/climatescience.press\/?p=267566","url_meta":{"origin":266535,"position":2},"title":"Hudson Bay sea ice loss has not accelerated since 2014: in fact, summer ice cover has improved","author":"uwe.roland.gross","date":"15\/07\/2023","format":false,"excerpt":"This is only the third year since 2014 that the bay has had less than usual amounts of ice, which means most years since then have had normal or nearly normal ice coverage, similar to the 1980s. 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Hudson Bay and two tagged polar bears still on sea ice on 17 August","author":"uwe.roland.gross","date":"22\/08\/2022","format":false,"excerpt":"Before this, polar bear experts looked at the sea ice conditions in the 1980s and figured that was what polar bears absolutely required","rel":"","context":"Similar post","block_context":{"text":"Similar post","link":""},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2022\/08\/image-941.png?fit=1200%2C820&ssl=1&resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2022\/08\/image-941.png?fit=1200%2C820&ssl=1&resize=350%2C200 1x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2022\/08\/image-941.png?fit=1200%2C820&ssl=1&resize=525%2C300 1.5x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2022\/08\/image-941.png?fit=1200%2C820&ssl=1&resize=700%2C400 2x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2022\/08\/image-941.png?fit=1200%2C820&ssl=1&resize=1050%2C600 3x"},"classes":[]},{"id":228485,"url":"https:\/\/climatescience.press\/?p=228485","url_meta":{"origin":266535,"position":5},"title":"Polar bear habitat update: ice forming along Hudson Bay, Wrangel & Franz Josef Islands surrounded","author":"uwe.roland.gross","date":"10\/11\/2022","format":false,"excerpt":"Freeze-up this year has been a bit slower than 2020, which was\u00a0as early as the earliest freeze-ups in the 1980s, but not by much.","rel":"","context":"Similar post","block_context":{"text":"Similar post","link":""},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2022\/11\/00Wapusk-NP-Female-and-2-COYs-8-Nov-2022-still.webp?fit=1200%2C675&ssl=1&resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2022\/11\/00Wapusk-NP-Female-and-2-COYs-8-Nov-2022-still.webp?fit=1200%2C675&ssl=1&resize=350%2C200 1x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2022\/11\/00Wapusk-NP-Female-and-2-COYs-8-Nov-2022-still.webp?fit=1200%2C675&ssl=1&resize=525%2C300 1.5x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2022\/11\/00Wapusk-NP-Female-and-2-COYs-8-Nov-2022-still.webp?fit=1200%2C675&ssl=1&resize=700%2C400 2x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2022\/11\/00Wapusk-NP-Female-and-2-COYs-8-Nov-2022-still.webp?fit=1200%2C675&ssl=1&resize=1050%2C600 3x"},"classes":[]}],"_links":{"self":[{"href":"https:\/\/climatescience.press\/index.php?rest_route=\/wp\/v2\/posts\/266535","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/climatescience.press\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/climatescience.press\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/climatescience.press\/index.php?rest_route=\/wp\/v2\/users\/121246920"}],"replies":[{"embeddable":true,"href":"https:\/\/climatescience.press\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=266535"}],"version-history":[{"count":8,"href":"https:\/\/climatescience.press\/index.php?rest_route=\/wp\/v2\/posts\/266535\/revisions"}],"predecessor-version":[{"id":266550,"href":"https:\/\/climatescience.press\/index.php?rest_route=\/wp\/v2\/posts\/266535\/revisions\/266550"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/climatescience.press\/index.php?rest_route=\/wp\/v2\/media\/266548"}],"wp:attachment":[{"href":"https:\/\/climatescience.press\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=266535"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/climatescience.press\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=266535"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/climatescience.press\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=266535"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}