Polar Bears to People: Momentum on Climate Change

In the past several months, there has been much troubling news for all who are concerned about polar bears. Atmospheric CO2 concentrations hit 400 parts per million , higher than any time in perhaps 3 million years . The global average air temperature for all of 2014 was the highest on record . The maximum extent of Arctic sea ice this winter was the lowest ever recorded . My colleagues and I published papers showing that: land-based foods cannot sustain polar bears forced off the melting ice; the key to polar bear survival is adequate sea-ice access, a finding that reaffirms my earlier conclusions; the polar bear population in northern Alaska, which I have studied for most of my adult life, declined 40% in the first decade of the 2000s. Yet, there are reasons to celebrate!

A new study showed that the peak warming influence from greenhouse-gas emissions occurs within a decade of their release into the atmosphere. Because our earlier work had shown a linear relationship between sea-ice extent and temperature, this new finding provides exciting confirmation we can stop rising temperatures in time to save much of the sea ice on which polar bears depend.

States have started to introduce legislation that would establish a fair price for carbon emissions, and Congress has held preliminary discussions of similar national efforts. If enacted, these laws no longer would allow us to hide the costs of emissions for our children to discover. Owning the costs of current carbon emissions is a critical step toward reducing them. The U.S. and China, the worlds' greatest carbon emitters, finally entered serious talks and developed a preliminary agreement to reduce emissions. And, even without formal international agreements in place, growth in renewable-generation capacity has now surpassed growth in generation from all fossil fuels combined.

Perhaps most important, influential voices in our society are speaking out about the need to stop global-temperature rise. Our military is pushing for recognition that continued warming multiplies security risks here and abroad. The Pope is speaking out about the humanitarian costs of continued warming. He and other religious leaders increasingly recognize that allowing developed societies to force ever-greater food and water insecurity onto the worlds' poor is incompatible with the concept of loving thy neighbor. At the same time, current multi-year droughts in the western U.S. and elsewhere force policy leaders to recognize that the challenge is not just for poor people living in faraway places. Challenges of food and water security are here now. Our leaders are awakening to the fact that, even if scientists cannot attribute current drought entirely to human-caused climate change, this is what climate change looks like -- and we don't like that look.

In 2010, my colleagues and I concluded that stopping temperature rise to save polar bears will benefit the rest of life on earth -- including people. Many challenges lay before us. We need national and international policy changes to prevent the worst of climate-change disasters. But, the conversations, statements, and yes, actions, of the last year offer greater hope than ever that we may get there. Some events of the past year indeed are worthy of celebration!

This post is part of a Huffington Post What's Working series on the environment. The series is putting a spotlight on initiatives and solutions that are actually making a difference -- whether in the battle against climate change, or tackling pollution or other environmental challenges. To see all the posts in the series, read here .