Red listing of polar bears

Prepared by: Dr. Øystein Wiig, PBSG member
Image: Morten Ekker

As of 2008 the polar bear is listed in the IUCN Red List of Threatened Species as a threatened species. It has been given the category of "Vulnerable", which is one of three categories for being threatened; Critically endangered, Endangered and Vulnerable.  
 

The polar bear has been listed as Special concern in Canada, as Vulnerable in Greenland and Norway, as Threatened by USA, and is listed in The Red Data Book of Russia.
 

Biodiversity loss is one of the world's most pressing crises and there is growing global concern about the status of the biological resources on which so much of human life depends. It has been estimated that the current species extinction rate is between 1,000 and 10,000 times higher than it would naturally be.
 

Many species are declining to critical population levels, important habitats are being destroyed, fragmented, and degraded, and ecosystems are being destabilized through climate change, pollution, invasive species, and direct human impacts. At the same time, there is also growing awareness of how biodiversity supports livelihoods, allows sustainable development and fosters co-operation between nations. This awareness is generated through products such as the IUCN Red List of Threatened Species™.

How is the IUCN Red List compiled?

There are nine categories in the IUCN Red List system: Extinct, Extinct in the Wild, Critically Endangered, Endangered, Vulnerable, Near Threatened, Least Concern, Data Deficient, and Not Evaluated. Classification into the categories for species threatened with extinction (Vulnerable, Endangered, and Critically Endangered) is through a set of five quantitative criteria that form the heart of the system. These criteria are based on biological factors related to extinction risk and include: rate of decline, population size, area of geographic distribution, and degree of population and distribution fragmentation.

For more detail see the IUCN Red List Categories and Criteria version 3.1. and the IUCN Red List Process.

The IUCN Red List, Species Survival Commission and Species Information Service

The Red List is produced by the IUCN Species Survival Commission (SSC) - a network of some 7,500 species experts working in almost every country in the world, and data from a number of partner organizations. Collectively, this network holds what is probably the most complete scientific knowledge base on the biology and current conservation status of species. To improve the previous ad hoc process of listing species, Red List Authorities (RLAs) are being established for all taxonomic groups included on the Red List RLA Terms of Reference. In most cases, the Authority is the SSC Specialist Group responsible for a species, a group of species, or a geographic area. All species on the list must be re-evaluated at least once every 10 years.
 
The Authority for evaluation of the polar bear is the SSC Polar Bear Specialist Group. A proposed assessment was reviewed and discussed by all the participants at the 14th Working Meeting of the IUCN SSC Polar Bear Specialist Group held in Seattle, Washington, USA during June 20-24, 2005. The final version was submitted to IUCN in September 2005 after having been reviewed and unanimously accepted by all members of the Polar Bear Specialist Group. The assessment concluded that the polar bear should be listed as “Vulnerable”.

The assessment was based on a suspected population reduction of  > 30% within three generations (45 years) due to decline in total area of distribution ( area of occupancy and extent of occurrence) and habitat quality (Schliebe et al. 2008).

Polar bears rely almost entirely on the marine sea ice environment for their survival so that large scale changes in their habitat will impact the population (Derocher et al. 2004). Global climate change posses a substantial threat to the habitat of polar bears. Recent modeling of the trends for sea ice extent, thickness and timing of coverage predicts dramatic reductions in sea ice coverage over the next 50–100 years (Hassol 2004). Sea ice has declined considerably over the past half century. Additional declines of roughly 10–50% of annual sea ice are predicted by 2100. The summer sea ice is projected to decrease by 50–100% during the same period. In addition the quality of the remaining ice will decline. This change may also have a negative effect on the population size (Derocher et al. 2004). The effects of sea ice change are likely to show large differences and variability by geographic location and periods of time, although the long term trends clearly reveal substantial global reductions of the extent of ice coverage in the Arctic and the annual time frames when ice is present.

While all bear species have shown adaptability in coping with their surroundings and environment, polar bears are highly specialized for life in the Arctic marine environment. Polar bears exhibit low reproductive rates with long generational spans. These factors make facultative adaptation by polar bears to significantly reduced ice coverage scenarios unlikely. Polar bears did adapt to warmer climate periods of the past. Due to their long generation time and the current greater speed of global warming, it seems unlikely that polar bear will be able to adapt to the current warming trend in the Arctic. If climatic trends continue polar bears may become extirpated from most of their range within 100 years.

There is little doubt that polar bears will have a lesser distribution area and habitat quality in the future. However, no direct relation exists between these measures and the abundance of polar bears. While some have speculated that polar bears might become extinct within 100 years from now, which would indicate a population decrease of  > 50% in 45 years based on a precautionary approach due to data uncertainty. A more realistic evaluation of the risk involved in the assessment makes it fair to suspect population reduction of  > 30%.

Other population stress factors that may also operate to impact recruitment or survival include toxic contaminants, shipping, recreational viewing, oil and gas exploration and development. In addition to this comes a potential risk of over-harvest due to increased quotas, excessive quotas or no quotas in Canada and Greenland and poaching in Russia.
 

History of polar bear redlisting by IUCN

2008 Vulnerable
2006 Vulnerable
1996 Lower Risk/conservation dependent
1994 Vulnerable
1990 Vulnerable
1988 Vulnerable
1986 Vulnerable
1982 Vulnerable

Next evaluation

A reassessment of the IUCN Red List status of the polar bear by the PBSG will at latest be undertaken by 2018 (10-year cycle).