critical impacts on polar bear due to global

8/7/2019 Critical Impacts on Polar Bear Due to Global

1/12


2/12

Geographical distribution and

populationCircumpolardistribution in Arctic

20 distinct populationspread throughoutarctic

Top of the marine

food chain

22,000 population inthe wild and 60% in

Canada.


3/12

Habit and Diety Spends most of their time on sea ice

y Mainly prey on harp seals.

y During summer when ice melts, they are forced to move toland until the ice freezes up

y Otherwise polar bear are only in land when having cubs,finding mate, moving between feeding areas and resting.

y

Eats most of its food on late April and mid Julyy This time period is critical

Why?


4/12

y When polar bears are stranded inlands during ice free season theyfast for long periods becauselacking of food

y Fasting can last for 3~4 month andup to 8 month for female.

y Therefore plentiful access to food iscritical for maintaining bodycondition and or reproductivesuccess

2.5

3.5

6

Feeding

Fastingperiod onland

sea Ice


5/12

Current status of polar bear

y IUCN polar bear specialist group upgraded polar bearstatus to vulnerable based on IUCN Red List categories

in 2005.y The US government classified polar bear as

Endangered species Act. These agreement hadprohibited hunting of polar bear and protected its

habitat.However, it does not protect polar bears from menmade global warming!


6/12

Why are Polar Bears important?y Polar bears are top carnivores in arctic marine

ecosystem

y Its amazing adaptation in the harsh arcticenvironment and dependence on sea ice make them soImpressive, however vulnerable

y Therefore polar bears are a good indicator to see the

cumulative effects of ecological change in the arcticmarine ecosystem


7/12

Melting of Sea Icey In the past 100 years, air temperature in the arctic

increased about 5C average.

y Between 1978~1966, sea ice extent decreased by 3% perdecade.

y The summer minimum thickness of ice has decreasedby 40% in past 30 years

Green house gas emission!Global warming


8/12

The time series of April seaice extent in the Nordic Sea(1864-1998) shows

a 33% reduction in sea iceextent for the entire region(top curve) and itseastern (middle) and western(bottom) areas

Observed and modelledvariation of annual averagesof artic sea ice

Extent.

Model suggest that by 2080arcic sea ice will completelydisappear in summer months.


9/12

Impacts on Polar Bearsy Dramatic and rapid change of the ecosystem causes

reduction of sea Ice extent

y Sea Ice is important to polar bear sy Its the place where they hunt, rest, breed and move

from place to place

y Therefore, reduction of sea ice causes major threat to

polar bear hunting and reproductive success


10/12

Its already been Found!y In canada Hudson bay, sea ice is melting earlier in the

spring and forming later in the autumn.

yThe time period polar bears has on the sea ice, storingfood energy for fasting in the summer is becomingshorter

y This will increase nutritional stress to polar bears since

periods without food is extendedy As a result overall body condition of these polar bears

declines affecting in reproductive success


11/12

Studies have foundy Analysis suggests,

1C melting of sea ice happens

week early

Decrease the polar Loss of 10kg of

Litter size storage fat for female

This will decline the population of polar bear s

Scientists estimate that if current forecasts are correct

about the future extent of sea ice, then two-thirds of

The polar bear population will become extinct by 2050.


12/12

Recent finding

According to the report byBBC earth news report,first evidence of polar

bears swimming longdistance was found. Polarbears are known to swimbetween land and sea iceto hunt for seals, howevermelting of sea ice pushed

polar bears to swimgreater distances affectingtheir health and futuregenerations

First finding of polar bear swimming for 9days

critical impacts on polar bear due to global

Documents