Steven Amstrup spent 30 years studying polar bears in Alaska.

His research is what put polar bears on the threatened species list.

Amstrup is now working with Polar Bears International in Manitoba, Canada to communicate the threat climate change poses to the polar bear population.

“I left a research career because I already knew the answer,” Amstrup said. “Its now more important to inspire people to save them.”

Amstrup now travels to the tundra on the west side of Hudson Bay during the fall, where he shoots live webcasts with other scientists and experts on climate change and its relationship to polar bears. He also gets some amazing pictures of the bears.

You can see some of the polar bears from this live webcam set up by the Tundra Buggy company.

To start the journey to the tundra, Amstrup first travels to Churchill, Manitoba: the northernmost town in the area. Most people have to fly in because it's so remote. From Churchill it's only about a 5-mile trip out into the tundra, but getting there isn't easy. The tundra is a very harsh environment. It has a layer of permanently frozen ground and the growing season is only about 60 days. Temperatures average around negative 25 degrees during the winter. It's the perfect place for polar bears because under their skin they have a layer of fat about 4.5 inches thick that keeps them warm. To get to this frozen environment that polar bears thrive in, you need a Tundra Buggy. A van swings through Churchill to pick up Amstrup, his team, and any visitors on the way to the Tundra Buggy launch port. When out on the ice, the buggies move very slowly and have to stick to pre-existing trails that weave around obstacles. The Tundra Buggies are tall to keep the crew out of reach of the polar bears. 'Not very far out of reach, but far enough,' Amstrup said. The polar bears actually get pretty close to the buggies. They also see other inhabitants of the Tundra: caribou, arctic hares, and wolves. The polar bear population in Churchill is one of 19 polar bear populations around the world. According to Polar Bears International, there's been a 22% decline in the Churchill population since the 1980s. Climate change and disappearing ice sheets are the leading causes of this decline. The Hudson Bay is covered in annual ice -- meaning the ice melts entirely during the summer and refreezes. This habitat is essential to the polar bear's survival. From decades of research and study, scientists learned that the polar bears use these ice sheets to hunt for seals during the winter and spend the summers fasting. All their stored fat can keep them alive without eating for a while, but as the ice takes longer and longer to form, polar bears could end up starving. Polar bears are forced ashore as the floating ice begins to melt in the beginning of the summer and they start their period of fasting until the ice returns. Over the last 30 years this period of no ice has been increasing by nearly a day per year, Amstrup said. In the 1980s Amstrup said he was able to stand on the beach in the late summer and see the ice forming off the shore. Now the summer ice melts so much that it's 300 miles from the shore in the late summer. 'It's a profound change, and one I would never have imagined I'd see in my lifetime,' Amstrup said. The red areas on this map show areas where the quantity of sea ice is below normal, and the blue areas show where it is above normal. The areas with the darkest red colour show places that used to be completely covered with ice in the fall, but are now almost completely ice-free. The melting ice is also affecting polar bear reproduction. Amstrup was the first to discover where female polar bears give birth. The dens, like the one pictured, are the result of polar bears digging into an ice cap. But Amstrup has found that polar bear litters are getting smaller. The cubs are born weaker and not as healthy, and fewer of the cubs survive. This is probably the result of shorter feeding seasons. Seeing these devastating changes on the polar bear population has inspired Amstrup to become an activist. 'We really need leadership, policy leadership, to change our greenhouse gas policies,' Amstrup said. You can actually go see the bears before they're gone. 'The Tundra Buggy Adventure' offers tours launched from Churchill where you can spend the day on the tundra looking for polar bears. Prices start around $US1,500. Now check out pictures from this 'suicidal' Antarctic trip. See the pictures from the dangerous journey »

Business Insider Emails & Alerts Site highlights each day to your inbox. Email Address Join

Follow Business Insider Australia on Facebook, Twitter, LinkedIn, and Instagram.