Climate Change FAQ
Our chief scientist, Dr. Steven Amstrup, responds to frequent questions and clears up myths and misconceptions about polar bears and climate change.
Aren’t scientists still debating climate change?
Not at all. Ninety-seven percent of climate scientists, the experts in their field, have reached a consensus that climate change is real and is human-caused.
Can’t polar bears just start eating berries and other land-based foods like other bears?
We don’t have evidence that such foods could provide enough nutrients to sustain any of the existing populations of polar bears. It’s true that polar bears have evolved to eat seals, but they are opportunistic hunters and if seals are not available because the sea ice is absent, they will eat almost anything—including vegetation, berries, geese, and bird eggs. Unfortunately, few polar bears have been observed eating more nutritious foods like birds or eggs, and those foods are not abundant enough or distributed widely enough to be a population benefit. And plant foods are just not nutritious enough to compensate for lost seals. Much like a human eating a stalk of celery versus a juicy steak, the nutritional benefit is not the same.
Hasn’t the earth’s temperature stabilized?
No, satellite measurements show that more energy has been coming in from the sun than is escaping back to space.The earth’s heat load, therefore, has continued to increase in step with greenhouse gas increases. Luckily, over the past few years, air temperatures—the temperatures we feel—have risen more slowly, but the heat is still there, most of it in the oceans. At some point the ocean will release more of that heat into the air, and we will feel a surge of warmth.
Haven’t polar bears faced warmer times in the past and survived?
Polar bears never have faced periods as warm as we could see in the next 50 years. There have been warmer periods in the past, but they were not only cooler than what we will experience if we don’t reduce greenhouse gas emissions, they were part of natural cycles of warming and cooling. These cycles were driven mainly by the variations in the earth’s orbit around the sun and by events like massive volcanic eruptions. The current warming is not part of a cycle, and there can be no cooling unless humans take action.
Hasn’t the climate always changed?
The current warming is different from anything we have ever faced. It is manmade, caused by a build-up of greenhouse gases from burning fossil fuels. Changes in the earth’s orbit around the sun dictate that we should be undergoing a gradual cooling phase—yet we are overpowering that natural cooling with our greenhouse gas emissions.
How warm will it get?
The earth’s temperature can only continue to increase as long as greenhouse gas concentrations rise. The earth won’t heat up to some new stable level and then hold steady. Without our action, the planet can only continue to become hotter and hotter, beyond anything polar bears (or humans) have experienced before.
How can we have climate change when it has been so cold outside?
Scientists base their measurements on the global average temperature, not local or regional weather. Last winter when the American Midwest and East were so cold, much of the Far North was cooking. The global average temperature in January 2014 was the fourth warmest of any January ever recorded despite the natural variation that led to a deep freeze in some areas.
Aren’t there more polar bears now than ever?
We have never had firm numbers on the global population of polar bears. We do know that some polar bear populations, like those that I studied in Alaska for 30 years, were known to have grown after excessive hunting was controlled in the early 1970s. But we only recently have developed estimates of several populations and still have no estimates for others. Regardless of how many bears may have been around at times past, however, as long as temperatures warm and sea ice habitat continues to decline, polar bears ultimately can only decline. Wild polar bears will become extinct unless we take action to reduce greenhouse gas emissions.
Could polar bears survive by mating with grizzlies?
Increased interbreeding will not preserve the magnificent life form that is today’s polar bear. It might preserve some polar bear genes in an animal similar to today’s grizzly bear—but that is not what we are after. Scientists have observed a few polar bear-grizzly hybrids in the wild, and genetics studies indicate some interbreeding has occurred for millennia. Regardless, given the rapid pace of current sea ice losses, polar bears will starve out of their present range long before grizzlies swamp their genes.
Is it too late to save polar bears?
Definitely not! We have the power to stop human-caused climate change and save the arctic ecosystem by greatly reducing greenhouse gas emissions.