The Earth’s climate has changed throughout history. While climate changes prior to the industrial revolution took place over millions or tens of millions of years and can be explained by natural causes, the cause of recent changes is not natural alone. The unprecedented rate of global warming since the mid-20th century is most likely the result of human acitivites and greenhouse gas emissions into the atmosphere. History does not know such a rapid temperature increase on the Earth before.
The Earth’s average annual air temperature does not necessarily rise in every single location across the globe. But climate change in the Arctic is faster than in the rest of the world. The Arctic is warming at a rate of almost twice the global average and the sea ice, a central component of the Arctic ecosystem, is dramatically dwindling. The species most vulnerable to the sea ice loss is the polar bear, the top predator of the Arctic food chain. Climate warming and the sea ice disappearance pose major threats to polar bears.
Polar bears are most at home on the sea ice, relying on it as a platform to hunt their main prey, seals. As the ice melts, the bears lose access to their food supply and are threatened by starving to death. Rapid developments leave too short a time for readaptation. The entire Arctic food chain will be affected and the species will decline. In addition to food shortage, polar bears will face the problem of overheating and a loss of breeding grounds. If global warming cannot be brought under control, scientists predict we can lose two thirds of the polar bear population by the middle of this century.
The greatest threat to polar bears is the Arctic sea ice decline caused by global warming. It is extremely likely that human activities have been the dominant cause of that warming. We can help polar bears by changing our consumption habits.