Impact of Global Warming on Polar Bears

Dr. Steven Amstrup discusses the dependence of polar bears on sea ice across four major ecoregions: Seasonal, Divergent, Convergent, and Archipelago. He explains how climate change affects these regions differently, impacting polar bears' ability to hunt and survive. The Seasonal Ice Ecoregion, including Hudson Bay, is experiencing earlier ice melt, forcing bears ashore. The Divergent Ice Ecoregion sees ice drifting away from shore, while the Convergent Ice Ecoregion benefits from ice piling up against the shoreline. The Archipelago Ecoregion remains cold, with persistent ice. Continued global warming threatens all ecoregions, endangering polar bears' survival.

What does the term 'circumpolar' mean in the context of polar bears?

• Polar bears live only in the North Pole.

• Polar bears are found only in Canada.

• Polar bears have a range that circles the Arctic.

• Polar bears migrate to the South Pole in winter.

How has global warming affected the Seasonal Ice Ecoregion?

• It has had no impact on the ice.

• It has led to earlier melting and later formation of ice.

• It has caused the ice to melt later in the year.

• It has increased the amount of ice.

Why are polar bears forced to come to shore in the Seasonal Ice Ecoregion?

• Because the ice melts in the summer.

• Because there are more seals on land.

• Because the ice is too thick.

• Because the water is too cold.

What is a key characteristic of the Divergent Ice Ecoregion?

• Ice remains stationary throughout the year.

• Ice forms along the shoreline and drifts away.

• Ice is thicker than in other regions.

• Ice never melts in this region.

What challenge do polar bears face in the Divergent Ice Ecoregion?

• They have to find food on land.

• They have to migrate to the South Pole.

• They have to compete with penguins for food.

• They have to swim long distances to find food.

How does the Convergent Ice Ecoregion benefit polar bears?

• It has more land for bears to roam.

• It is warmer than other regions.

• It has ice that drifts against the shoreline, maintaining habitat.

• It provides a constant supply of seals.

What is the main feature of the Archipelago Ecoregion?

• It is the warmest region for polar bears.

• It has no ice during the summer.

• It is located in the southern hemisphere.

• It consists of narrow channels between Arctic islands.

What might happen to polar bears if global warming continues?

• They will migrate to tropical regions.

• They will thrive in all ecoregions.

• They will likely survive only in the Convergent and Archipelago ecoregions.

• They will adapt to living without ice.

Why is the Archipelago Ecoregion important for polar bears?

• It is the only region with no ice.

• It is the largest ecoregion.

• It has the most abundant food supply.

• It remains cold and icy even with global warming.

What is the ultimate threat to polar bears if global warming is not addressed?

• They will migrate to Antarctica.

• They will lose all their sea ice habitat.

• They will become more aggressive.

• They will overpopulate the Arctic.