Category Archives: Sea ice habitat

Current ice conditions don’t bode well for Beaufort Sea polar bears

Thick spring ice along the shore of the Eastern and Southern Beaufort is bad news for polar bears, especially females emerging from their dens with new cubs. Are those conditions developing now?

Beaufort Sea pressure ridges_Spring 1949 wikipedia sm

Every 10 years or so, since at least the 1960s, nearshore ice gets too thick for ringed seals to maintain their breathing holes and many breeding seals depart the area. This leaves a lot of polar bears without the baby seals they need to consume to get them through the rest of the year (that’s if they don’t (or can’t) leave themselves).

I’ve discussed various aspects of this phenomenon before, with references – see the list at the end of this post.

Sadly, we are on schedule for such conditions to recur – could be this year, could be next. The last time of heavy spring ice was 2004 and previous heavy ice conditions occurred the springs of 1964, 1974 (the worst), 1984, 1992 and 2004. The 2004-2006 event was reportedly almost as bad as the 1974-1976 event.

So, prompted by reports of the heaviest sea ice conditions on the East Coast “in decades” and news that ice on the Great Lakes is, for mid-April, the worst it’s been since records began, I took a close look at ice thickness charts for the Arctic. I’m not suggesting these conditions are necessarily related to Beaufort ice, just that they got me thinking.

Here’s a screencap of the US Navy ice thickness animation chart for yesterday [from WUWT Sea Ice Page]

Figure 1. Arctic Sea Ice Thickness (NRL), for April 18, 2014. Look at thick ice (yellow, 3.5-4.0 meters thick) spreading along the north coast of Alaska. See the 30 day animation here.

Figure 1. Arctic Sea Ice Thickness (NRL), for April 18, 2014. Look at thick ice (yellow, 3.5-4.0 meters thick) spreading along the north coast of Alaska. See the 30 day animation here.

Below is a similar image from about the same time last year, with the Southeast Beaufort Sea marked.

Figure 2. Arctic Sea Ice Thickness (NRL), for April 13, 2013. Southeastern Beaufort marked.

Figure 2. Arctic Sea Ice Thickness (NRL), for April 13, 2013. Southeastern Beaufort marked.

I don’t think this bodes well for Beaufort bears but we’ll have to wait and see if there are any reports of starving bears bit later this spring and summer. Sea ice charts aren’t a guarantee that this heavy spring ice phenomenon is developing in the Beaufort, but they could be a warning.

Below are archived ice thickness charts from the US National Snow and Ice Data Center (NSIDC) for some previous years when Beaufort bears had trouble, especially 2004-2006, with which I compare this year’s conditions. [h/t Steve Goddard for alerting me to this resource]

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Polar bears move around as sea ice habitat changes – this is what resilience looks like

Oddly, it seems some people expect polar bears to sit around and suffer (or die) when local conditions deteriorate, rather than move elsewhere.

PolarBear_2008_USGS

While there are perhaps a few places where moving is not really an option over the short term, over the long term (more than one season) polar bears are free to shift to another locale if ice conditions change (either too much ice or too little).

An announcement by the WWF last week (10 April) caught my eye, as it talked about bears moving from one area to another because of changing ice conditions — as if this was surprising, extraordinary and newsworthy. That said, at least they weren’t suggesting the bears are all going to die because of declining ice, which is a huge improvement.

See what you think of this part of the press release (below), in the context of what we know about the movement of bears between regions:

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Tracking polar bears in the Beaufort Sea: March map

Here is the March 2014 follow-up to my post on the July 2013 track map for female polar bears being followed by satellite in the Beaufort Sea by the US Geological Survey (USGS) – “Ten out of ten polar bears being tracked this summer in the Beaufort Sea are on the ice.”

See that post for methods and other background on this topic, and some track maps from 2012 (also available at the USGS website here).

The USGS track map March 2014 is copied below (Fig. 1).

Compare this to February’s map (Fig. 2) – you’ll be surprised at how little has changed!

Figure 1. Movements of 5 satellite-tagged polar bears for the month of March, 2014. Polar bears were tagged in 2013 on the spring-time sea ice of the southern Beaufort Sea. All 5 of these bears have satellite collar transmitters. Note that the dots with the polar bear icons are the end points (end March), while the other end of the string is their position in early March. These are the same 5 females that were present in January. Click to enlarge.

Figure 1. From original caption: “Movements of 5 satellite-tagged polar bears for the month of March, 2014. Polar bears were tagged in 2013 on the spring-time sea ice of the southern Beaufort Sea. All 5 of these bears have satellite collar transmitters.” Note that the dots with the polar bear icons are the end points (end March), while the other end of the string is their position in early March. These are the same 5 females that were present in January. Click to enlarge.

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Polar bear status changes in 2013 deconstructed, with a map to the good news

You can’t figure out what’s going on with status updates from the IUCN Polar Bear Specialist Group (PBSG) without deconstructing the spin and the 2013 update is no exception. Here’s my travel guide, with a map, to the good news.

Polar Bear Subpopulations 19_2013 updates_March 20 2014_sm

I’ve finally had a chance to go through all of the details provided with the 2013 PBSG status table (pdf here). It’s just about all good news, once you wade through the spin. Numbers aside, out of the 13 populations for which some kind of data exist, five populations are now classified by the PBSG as ‘stable’ (two more than 2009), one is still increasing, and three have been upgraded from ‘declining’ to ‘data deficient’ (I explain below why this is a promotion).

That leaves four that are still considered ‘declining’- two of those judgments are based primarily on concerns of overhunting, and one is based on a statistically insignificant decline that may not be valid and is being re-assessed (and really should have been upgraded to ‘data deficient’). That leaves only one population – Western Hudson Bay – where PBSG biologists tenaciously blame global warming for all changes to polar bear biology, and even then, the data supporting that conclusion is still not available.

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New genetic study confirms polar bears survived several warm Interglacials

There is a new polar bear genetics paper out in the Journal of Heredity, by University of Alaska Fairbanks genetics professor Matt Cronin and colleagues. Matt Cronin, in case you didn’t know, was the first to pick up the close genetic relationship between polar bears and grizzlies, as a result of research he and colleagues did back in the early 1990s (Cronin et al. 1991).

Figure1 from Cronin et al. 2014 (in press) showing the locations of bear samples used in their genetic study. MT, Montana; AK, Alaska; Polar bear samples were from the Chukchi, Beaufort and Barents Sea populations.

Figure 1 from Cronin et al. 2014 (in press) showing the locations of bear samples used in their genetic study. MT, Montana; AK, Alaska; Polar bear samples were taken from the Chukchi, Beaufort and Barents Sea populations.

While no earth-shattering new information was revealed in this new study, reported over the weekend by the Alaska paper SitNews (March 15), it used a more detailed method to confirm the results of previous work – that polar bears have been around long enough to have survived several past Interglacial periods that were warmer than today (with less ice in the Arctic) and are genetically distinct from grizzlies.

A feature that really set this work apart was how it was promoted.
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Davis Strait polar bear habitat higher now than in 1979 and early 1980s

The Davis Strait polar bear subpopulation is said to be ‘vulnerable’ to the supposed effects of global warming because, like Hudson Bay, Davis Strait sea ice retreats every summer, leaving polar bears on land for several months.

However, Davis Strait bears have been upgraded to ‘stable’ status, according to the latest table (2013) issued by the IUCN Polar Bear Specialist Group (see their boundary map for Davis Strait bears below). Recent development of sea ice in the region can only improve that rating.

[More background here and heremap-DavisStrait

It seems that sea ice in Davis Strait is well above normal for this time of year – a recent announcement by the Canadian Ice Service (CIS) says it’s 10% above average, higher than it’s been in 25 years (h/t S. Goddard).

The Canadian Ice Service, an arm of Environment Canada, said there is 10 per cent more ice this year compared to the 30-year average.

We probably haven’t seen a winter this bad as far as ice for the past 25 years,” said Voight, referring to both the amount and thickness of the ice.

He said the Gulf of St. Lawrence is covered and some areas are “quite severe.” [my bold]

Full story here.

Latest ice map (March 12) below from the US National Snow and Ice Data Service (NSIDC).

As I pointed out recently here, Barents Sea ice is below average this year, largely due to natural variation in the Atlantic Multidecal Oscillation (AMO), but is higher over the western Atlantic (Sea of Okhotsk ice is below average too but there are no polar bears there).

There is lots of ice around Labrador and Newfoundland, however.

Sea ice extent 2014 March 12 NSIDC

I thought I let you see exactly what CIS are talking about: what did the ice look like 25 years ago, in 1989? What about 35 years ago, in 1979, the start of the satellite record for sea ice? It might surprise you. Continue reading

Barents Sea polar bear condition varies with AMO and spring sea ice conditions

Fig. 1. NSIDC sea ice extent at March 8, 2014 (a "MASIE" product), with labels added. Click to enlarge.

Figure 1. NSIDC sea ice extent at March 8, 2014 (a “MASIE” product), with labels added. Click to enlarge.

In its end of February report, the US National Snow and Ice Data Center (NSIDC) noted that Barents Sea ice was below average for this time of year (see Fig. 1 above, and Fig. 5 below) but suggested this was primarily due to natural variation driven by the Atlantic Multidecadal Oscillation (AMO):

“The Barents Sea has experienced consistently low extents, particularly in winter, and this year has been no different. While the Barents and Kara seas normally have close to 2 million square kilometers (772,000 square miles) of ice in February, recent years have seen 500,000 square kilometers (193,000 square miles) of ice extent or lower. This year, the Kara Sea is near average, but the Barents Sea remains low (Figure 4a). Unlike other regions in the Arctic, longer records of Barents Sea ice extent exist from records of fishing, whaling, and other activities. A recent paper (Miles et al., 2013 [2014, now in print]) examined these records, along with paleoproxy data, to examine extent over the past four hundred years. They found a 60- to 90-year cycle in Barents and Greenland seas ice extent related to the Atlantic Multidecadal Oscillation (AMO); the AMO is a basin-wide cycle of sea surface temperature variability similar to the El Niño and La Niña cycles in the Pacific, but varying over much longer periods. This research shows that in addition to the warming trend in the Arctic, some sea ice regions are likely also responding to natural climate variability.” [my bold]

The paper they cite (Miles et al. 2014, discussed elsewhere in December 2013 here) described the AMO this way:

“The AMO is a coherent pattern of basin-wide sea surface temperature (SST) variations with a period of roughly 60–90 years. ..Paleoenvironmental studies suggest that the AMO has persisted through previous centuries [Gray et al., 2004] and even millennia [Knudsen et al., 2011].”

Note that Miles and colleagues were looking at ice records on or around the sea ice maximum in winter/spring.

The Polar Bear Twist: Norwegian biologists Jon Aars and Magnus Andersen, who I’ve discussed before, have pointed out that the condition of polar bear males and females around Svalbard (Fig. 2) they examined over the last 20 years varied with the AMO and sea ice levels in spring and early summer. [research results posted at the website for Environmental Monitoring of Svalbard and Jan Mayen (MOSJ), Norwegian Polar Institute].

Figure 1. The Barents Sea polar bear subpopulation, courtesy the IUCN Polar Bear Specialist Group. "Svalbard" is the largest archipelago, in the eastern portion.

Figure 2. The Barents Sea polar bear subpopulation boundaries, courtesy the IUCN Polar Bear Specialist Group. Svalbard is the largest archipelago, closest to the East Greenland Sea.

That makes a lot of sense to me, given that spring/early summer is the most critical feeding season for polar bears because it’s when fat young seals are most easily available.

It also makes sense to me that you may need a record hundreds of years long to understand the natural variability of Arctic Sea ice in its various regions. Recall that natural variation, not global warming, is now being used to explain the large variation in annual sea ice cover in the Bering Sea (home to Chukchi Sea polar bears). Continue reading

Of Labrador polar bears and sea ice way above normal off Newfoundland

A report yesterday of polar bears making a nuisance of themselves in Black Tickle, southern Labrador is the inspiration for this post. Those bears are part of the Davis Strait subpopulation (discussed previously here and here). Black Tickle is marked on the map below.

Black-tickle-map-Labrador

Arctic sea ice is tracking just at the edge of two standard deviations for this time of year but while extent is low in the Barents Sea, it is way up around the east coast of Canada.
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Tracking polar bears in the Beaufort Sea: February map

Here is the February 2014 follow-up to my post on the July 2013 track map for female polar bears being followed by satellite in the Beaufort Sea by the US Geological Survey (USGS) – Ten out of ten polar bears being tracked this summer in the Beaufort Sea are on the ice.

See that post for methods and other background on this topic, and some track maps from 2012 (also available at the USGS website here).

The USGS track map February 2014 is copied below (Fig. 1).

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Chukchi-Beaufort sea ice atlas: check out polar bear habitat 1850-2013

It’s here – as promised and right on schedule — the sea ice atlas put together by University of Alaska Fairbanks (UAF) now has ice concentration maps for Alaska going back to 1850 — and for every year up to 2013. 

Several examples are included below: August 1850 vs August 1870, and April 1850 vs. April 1920 and April 2012.

For background, see my post announcing the site preview, which was then limited to 1953-2012 data, when it became available in late January.

Sea ice atlas_1850_Aug
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