There is a vast array of information now available that outlines the many-faceted ways that the changing climate will impact people and ecosystems all over the world. From extreme weather to climate warming, the reach of climate change is broad. And the reason our climate is changing is known: human activities have driven the release of unprecedented levels of carbon dioxide into the Earth’s atmosphere. Carbon dioxide (CO2) is a greenhouse gas that effectively blankets the Earth, increasing the amount of heat that stays in our atmosphere. And while we typically associate carbon dioxide emissions with the burning of fossil fuels, such as gas and coal, there are other sources as well that are not as well known. One of the largest contributors to atmospheric carbon is deforestation. Each year, the burning and clearing of tropical forests contributes over 2 billion tons of carbon pollution to the atmosphere.
At the San Diego Zoo, our mission is to connect people to wildlife because that connection can be a powerful force for conservation. I can speak from personal experience as to the power of that connection. Destined for medical school, my career path shifted dramatically because of a chance connection with wildlife. For me, that connection started with the polar bear, a species whose plight has provided some of the defining images associated with climate change, a species whose future we hold in our hands.
As a graduate student, my first field season was spent working out of a remote field camp on the western Hudson Bay, about 15 miles east of Churchill, Manitoba (a.k.a. the Polar Bear Capital of the World). This area, so nicknamed because of the large number of polar bears that congregate there in the fall, was also home to an incredible array of wildlife, including Arctic nesting birds, large herds of caribou, and beluga whales. While polar bears are most numerous and visible during the fall, the bears actually start coming ashore during the summer as the ice on the Bay begins to melt out, and the bears are forced ashore to begin a long fast.
Our field research was primarily done on foot, with miles and miles of walking over the course of the long Arctic summer days, and the possibility of bumping into a polar bear meant that safety measures were taken seriously and practiced regularly. The most basic and important safety measure we had while walking in the field was to scan the horizon with binoculars every few minute, in hopes of spotting any polar bears in the vicinity while they were still a good distance away. On the day I saw my first bear, it was relatively early in the season for polar bears, but the ice had begun to break up on the Bay, a harbinger of polar bears to come. Scan after scan, I saw nothing and continued with my work. And then suddenly, I looked up, and saw a young male bear easily without binoculars, less than 50 feet away. How long had he been following me? Luckily, I was able to make my way safely back to camp. And while it was truly scary to see a bear so close, it was also an event that left an enormous impression on me. It initiated my love of the species and cemented my passion for conserving wildlife and wild places.
Around that same time (the mid-1990s), biologists studying polar bears in the Canadian Arctic documented changes that were occurring within that population of polar bears. These scientists found that reductions in reproductive parameters were correlated with the warming air temperatures that had been documented between 1950 and 1990 and, most importantly, with an increasingly long period where the Hudson Bay was ice free. Because polar bears are completely dependent upon the sea ice for their survival, the directional trend toward less and less ice was of great concern. Twenty years later, I am happy to say that the polar bear is one of the species that I get to study, but saddened to say that the Earth’s CO2 emissions have continued to increase and that the impacts of climate change on polar bears have intensified. No other species better illustrates the impact of climate change on wildlife. Like a real-life version of the game “Break the Ice,” the polar bear’s habitat is disappearing, the ice literally melting at their feet. Their fate is in our hands.
Chinook and Kalluk have been breeding for the past couple of weeks, and we are hopeful, as in years past, that this breeding season will result in the birth of a polar cub in the fall. We will monitor Chinook closely for behavioral and physiological signs of pregnancy and learn as much as we can about the reproductive biology of these amazing animals. Keepers, researchers, and visitors alike have an amazing opportunity to observe our bears in the water and on land at the San Diego Zoo, and in so doing, learn about climate change and the impact that this human-driven change is having on wild polar bears and the Arctic sea ice environment. Polar bears exemplify the role of “conservation ambassadors,” and it is hard to deny the impressive nature of their strength, intelligence, and adaptations to life on the frozen Arctic Ocean.
Climate change may sound like old news to some. Images of polar bears stranded on ice floes were once a common sight in the popular press, but like most news stories, many people have moved on. Unfortunately, climate change has not gone away, and the negative impacts of sea-ice losses on polar bears continue to eke away at their once-pristine Arctic home. I am hopeful that the reemergence of climate change into the news cycle will invigorate people’s interest in doing their part to reverse the trends in CO2 emissions. I am hopeful also that we all seek those connections to nature and wildlife that are so important for engaging us in conservation issues. We can all make a difference.
For those who love our polar bears, and for those who are interested in learning more about how climate change is impacting the species’ Arctic sea ice habitat, I recommend visiting the National Snow and Ice Data Center (NSIDC) website. This page provides daily updates on sea ice conditions in the polar regions, as well as year by year interactive graphics of the dynamic changes in sea ice extent.