Tag Archives: maximum

At the winter maximum, still about the same polar bear habitat this year as 2006

There is no evidence that slightly less winter sea ice than the average since 1979 has had any negative impact on polar bear health or survival: the difference is simply not biologically meaningful to Arctic animals.

PB_male on ice_Regehr USFWS_March 2010_labeled

Polar bear on winter sea ice around the yearly maximum in the Beaufort Sea, 2010 (March 21).

NASA’s 23 March 2018 announcement regarding the Arctic sea ice maximum this year:

“Sea ice in the Arctic grew to its annual maximum extent last week, and joined 2015, 2016 and 2017 as the four lowest maximum extents on record, according to scientists at the NASA-supported National Snow and Ice Data Center (NSIDC) and NASA.”

Except, what they don’t tell you is that 2006 had almost the same extent as 2018 and 2006 wasn’t far behind according to the official, averaged data presented at NSIDC’s Arctic Sea Ice News & Analysis:

Arctic sea ice Maximum 10 lowest extents_NSIDC 23 March 2018

Current conditions at the winter maximum (at 17 March 2018, from NSIDC Masie, extent measured at 14.7 mkm2, using software able to discern more ice than used for the figures in Table 1), shown below: Continue reading

Winter polar bear sea ice habitat by early March 2018 varied little from 2006 or 2017

Here’s a polar bear habitat update for early March: some folks are wringing their hands over the relatively extent of ice this season but ice maps show that as far as polar bear habitat is concerned, conditions are not materially different this year from what they were in 2006 or 2017. There is still plenty of late winter sea ice for polar bears needing a platform from which to hunt Arctic seals, which in some areas will have already begun giving birth to their fat furry pups (harp seals first, other species later).

The MASIE map for 5 March 2018 (Day 64) shows ice extent at 14.5 mkm2:

masie_all_zoom_4km 2018 March 5

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2016 record low maximum will make headlines but unlikely to affect polar bears

Never mind that the sea ice maximum this year came almost a month later than last year (and close to latest since 1979) – and was lower by only .02 – the US National Sea Ice Data Center (NSIDC) today trumpeted a new record low.  What this means to polar bears, if anything, remains to be seen.

Sea ice extent 2016 March 24 NSIDC_max 14_52mkm2 sm

2015: maximum set February 25 (day 56), at 14.54 mkm2

2016: maximum set March 24 (day 84), at 14.52 mkm2

[The difference in area? Smaller than the Islands of the Bahamas]

Latest maximum extent (since 1979) occurred in 2010 on April 2 (Day 92).

The average date for maximum extent is March 12.

I note, however, that given the lateness of the winter sea ice surge meant that the amount of ice present at 24 March 2016 (see NSIDC Interactive) was more than was present on the same date in 2006, 2007 and 2015.

Clearly, there was plenty enough sea ice in the spring of those years for most polar bears to hunt seals successfully and put on the weight they needed to survive the summer fast ahead. I see no reason to expect 2016 to be different.

Polar_Bear_male_Regehr photo_March 21 2010_labeled
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