Category: Daily News

Spring feeding season almost over for polar bears & sea ice becomes less important

Reposted from Dr. Susan Crockford’s Polar Bear Science

Posted on June 4, 2020 |

Here are ice conditions at the end of May, which signals the near-end of the critical spring feeding period for polar bears. This is because young-of-the-year seals take to the water to feed themselves, leaving only predator-savvy adults and subadults on the ice from some time in June onward (depending on the region).

masie_all_zoom_4km 2020 May 31_Day 152masie_all_zoom_4km 2020 May 31_Day 152

Spring is the critical feeding period for polar bears (Crockford 2019, 2020; Lippold et al. 2020; Obbard et al. 2016):

“Unexpectedly, body condition of female polar bears from the Barents Sea has increased after 2005, although sea ice has retreated by ∼50% since the late 1990s in the area, and the length of the ice-free season has increased by over 20 weeks between 1979 and 2013. These changes are also accompanied by winter sea ice retreat that is especially pronounced in the Barents Sea compared to other Arctic areas. Despite the declining sea ice in the Barents Sea, polar bears are likely not lacking food as long as sea ice is present during their peak feeding period. Polar bears feed extensively from April to June when ringed seals have pups and are particularly vulnerable to predation, whereas the predation rate during the rest of the year is likely low. [Lippold et al. 2019:988]

NISDC comparative graphs shows 2020 ice extent at 31 May 2020 was higher than 2016 on the same date (and about the same as 2015).

Sea ice extent 2020 and 2016 with 2x deviation closeup at 31 May April 2020_NSIDC interactiveSea ice extent 2020 and 2016 with 2x deviation closeup at 31 May April 2020_NSIDC interactive

Below is the map for Arctic Canada at 31 May 2020, which has a noteable lack of open water in the Beaufort Sea:

Sea ice Canada 2020 May 31Sea ice Canada 2020 May 31

Compare to 31 May 2016:

Sea ice extent Canada 2016 May 31 CISSea ice extent Canada 2016 May 31 CIS

Last year (31 May 2019), however, was quite different again, especially in Hudson Bay and Hudson Strait:

Sea ice Canada 2019 May 31Sea ice Canada 2019 May 31

Stirling et al. (1981:54) discussed why polynyas can be so important in the Southern Beaufort and Hudson Bay (my bold):

“One useful approach is to ask what would happen if the polynya was not there? Obviously this is impossible to evaluate on an experimental basis, but by examining the consequences or natural seasonal variation, some useful insights can be gained. For example, the influence of rapidly changing ice conditions on the availability of open water, and consequently on populations of seals and polar bears, has been observed in the western Arctic. Apparently in response to severe ice conditions in the Beaufort Sea during winter 1973-74, and to a lesser degree in winter 1974-75, numbers of ringed and bearded seals dropped by about 50% and productivity by about 90%. Concomitantly, numbers and productivity of polar bears declined markedly because of the reduction in the abundance of their prey species. …If the shoreleads of the western Arctic or Hudson Bay ceased opening during winter and spring, the effect on marine mammals would be devastating.

Ice cover over Hudson Bay for the last week of May:

Hudson Bay weekly stage of development 2020 June 1Hudson Bay weekly stage of development 2020 June 1

Ice cover over the western Canadian Arctic (Eastern Beaufort Sea) for the last week of May:

Western Arctic weekly stage of development 2020 June 1Western Arctic weekly stage of development 2020 June 1

The Alaskan portion of the Beaufort was still predominantly multiyear ice at the end of May and thick first year ice in the Chukchi Sea (note this map does not show areas of open water): Chukchi Bering sea ice 2020 May 31_stage of development lgChukchi Bering sea ice 2020 May 31_stage of development lg

Areas of open water in the western Beaufort/Chukchi/Bering Seas at end May 2020:

Chukchi Bering sea ice 2020 May 31 concentration lgChukchi Bering sea ice 2020 May 31 concentration lg

Ice thickness at this time (less relevant for bears and seal, who prefer first year ice):

Sea ice thickness_DMI_2020_06_01_lgSea ice thickness_DMI_2020_06_01_lg

See previous posts on spring feeding here and here, with references, and on the Beaufort Sea polynya (recurrent open water) here and here.

References

Crockford, S.J. 2019. The Polar Bear Catastrophe That Never Happened. Global Warming Policy Foundation, London. Available in paperback and ebook formats.

Crockford, S.J. 2020. State of the Polar Bear Report 2019. Global Warming Policy Foundation Report 39, London. PDF here.

Lippold, A., Bourgeon, S., Aars, J., Andersen, M., Polder, A., Lyche, J.L., Bytingsvik, J., Jenssen, B.M., Derocher, A.E., Welker, J.M. and Routti, H. 2019. Temporal trends of persistent organic pollutants in Barents Sea polar bears (Ursus maritimus) in relation to changes in feeding habits and body condition. Environmental Science and Technology 53(2):984-995.

Obbard, M.E., Cattet, M.R.I., Howe, E.J., Middel, K.R., Newton, E.J., Kolenosky, G.B., Abraham, K.F. and Greenwood, C.J. 2016. Trends in body condition in polar bears (Ursus maritimus) from the Southern Hudson Bay subpopulation in relation to changes in sea ice. Arctic Science 2:15-32 Doi 10.1139/AS-2015-0027 http://www.nrcresearchpress.com/doi/abs/10.1139/AS-2015-0027#.VvFtlXpUq50

Stirling, I, Cleator, H. and Smith, T.G. 1981. Marine mammals. In: Polynyas in the Canadian Arctic, Stirling, I. and Cleator, H. (eds), pg. 45-58. Canadian Wildlife Service, Occasional Paper No. 45. Ottawa. Pdf of excerpts of above paper here.

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June 5, 2020 at 08:29PM

Special Looting Hours?

Thanks to Benjamin Napier for this image.

The post Special Looting Hours? appeared first on Ice Age Now.

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June 5, 2020 at 08:15PM

Who Dares Argue with Divine Inspiration?

Do I have to add anything? Wait. I know. SCIENCE! Source:

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June 5, 2020 at 04:28PM

The Barmpot Is Back In Town

By Paul Homewood

 

 

Sir David King

 

Tony Blair’s old Chief Scientific Advisor, David King, has been back in the news lately, with his alternative SAGE Committee. It is stuffed with far left activists, and has clearly been set up to undermine the government.

King has a long history of cock ups, not least his key role in the government’s disastrous response to the Foot and Mouth epidemic in 2001.

He was also heavily involved in Blair’s calamitous decision to promote diesel cars in order to reduce emissions of carbon dioxide.

King later made an idiot of himself, when he led us to believe that we would all to live in Antarctica by the end of the century because of global warming.

 

Obviously not knowing when to stop digging himself into an ever deeper hole, the clown last year made news again last year, according to the BBC:

Scientists in Cambridge plan to set up a research centre to develop new ways to repair the Earth’s climate.

It will investigate radical approaches such as refreezing the Earth’s poles and removing CO2 from the atmosphere.

The centre is being created because of fears that current approaches will not on their own stop dangerous and irreversible damage to the planet.

The initiative is the first of its kind in the world and could lead to dramatic reductions in carbon emissions.

The initiative is co-ordinated by the government’s former chief scientific adviser, Prof Sir David King.

"What we do over the next 10 years will determine the future of humanity for the next 10,000 years. There is no major centre in the world that would be focused on this one big issue," he told BBC News.

Some of the approaches described by Sir David are often known collectively as geoengineering….

One of the most promising ideas for refreezing the poles is to "brighten" the clouds above them.

The idea is to pump seawater up to tall masts on uncrewed ships through very fine nozzles.

This produces tiny particles of salt which are injected into the clouds, which makes them more widespread and reflective, and so cool the areas below them.

Such ideas have many potential downsides and may prove to be unfeasible.

https://notalotofpeopleknowthat.wordpress.com/2019/05/10/potty-wadhams-and-king-want-to-fix-the-climate/

 

For some reason the media still treat him as if he knew what he was talking about!

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June 5, 2020 at 04:12PM