The report's main point is that we have no time to lose. It warns that, unless reductions in greenhouse gases start immediately, we face climate catastrophe. Rajendra Pachauri, head of the IPCC and recipient of the Nobel Peace Prize, was unequivocal: "What we do in the next two to three years will determine our future. This is the defining moment."

Sadly, the Bush Administration ignored the report. It continued its game of advancing the interests of the fossil fuel industry, claiming that mandatory actions would hurt the economy and saying that the United States would not act until all others-including those countries that have historically had the least impact on climate-do so. In other words, the Bush Administration pretended that, as Churchill once said, a "problem postponed is a problem solved." As Pachauri makes clear, in this case, a problem postponed is the making of a catastrophe.

Mr. President-elect, you are cursed and blessed with taking the reins of United States power on the eve of a catastrophe. The challenge is daunting. We have lost much time. Moreover, the roots of climate change are deep and not easily reversible. Almost everything we do generates carbon dioxide, the main anthropogenic greenhouse gas. Turning the corner on climate thus requires fundamentally redesigning our homes, cars and factories, and finding new ways to relate to food, forests and, most importantly, each other. It consists of nothing less than weaning ourselves off of fossil fuels and transitioning to a clean energy economy, and treating each other and the more-than-human world with greater respect and dignity. You'll need much luck.

The key to attracting such luck is to capitalize on the promise of climate change. Climate change is not simply a problem but an invitation. The United States is at the center of an unraveling global economy and in the midst of two wars. Climate change offers the opportunity to build a new kind of world economy, and base security not simply on military might. Economically, instead of bailing out insurance companies, banks and particular industries, you should undertake a huge public works program, akin to the Apollo Project, which would invest government funds into hybrid and electric cars; better mass transit; solar, wind, and tidal energy; and a more reliable electrical grid. Such investment will generate millions of green collar jobs, reinvigorate former manufacturing sectors, drive significant capital investment, stabilize energy prices, and open up whole new professional enterprises associated with carbon accounting, policy analysis, and so forth.

Where might you find the funds for such an endeavor? The good news is that the government has already appropriated them; they are simply deployed in the wrong arena. Today, we are spending $314.4 million per day to fight an immoral war in Iraq. By any measure, we are not winning (indeed, it is hard to imagine what "winning" might mean). More importantly, our efforts in Iraq are not reducing international terrorism but increasing it as the occupation continues to sow anti-Americanism. It is time to recognize that, whatever national security dangers Iraq may pose, they are eclipsed by a more significant global threat that demands U.S. attention and leadership. Raising the issue of climate change in the context of the Iraq War would enable you to devise an exit strategy that is not simply a matter of "cutting and running" but involves meaningfully engaging the most significant of the world's security challenges. People around the world will have a harder time criticizing the United States if we are at the forefront of a global climate change and energy security plan rather than deploying soldiers around the world. Such a plan would certainly get us out of the arrogant unilateralism of the past eight years that has made our country and the world more insecure.

Key to such an effort is a commitment to attend the next, crucial meeting of the Conference of the Parties to the United Nations Framework Convention on Climate Change. This meeting, scheduled to take place in Copenhagen in late November 2009, will set the stage for a post-Kyoto climate regime. Your presence will signal to the world that the United States will no longer sit on the sidelines of global climate commitments or, worse, seek to undermine them. Rather, it will underscore the urgency and significance of crafting a meaningful treaty and, informed by America's new Apollo Project, demonstrate that world leadership starts at home.

These are the types of policy responses required of you. Your administration must also cultivate moral and spiritual ones as well. Climate change is not only an environmental problem and an invitation for policy adjustment but also a diagnosis. It signals that we have been living beyond our ecological means and insensitive to the plight of others with whom we share the planet and of future generations. It also indicates that we have lost our bearings as to how we fit into the universe and how we can relate to the more-than-human world. As the economic crisis makes clear, many of us have been focused on making a fast buck and letting the consequences fall where they will. Pushed to post quarterly profits, corporations have been shedding worker safety protections, trimming benefits, lying about their earnings and, more recently, firing workers to remain at all profitable. Likewise, tickled by easy credit and enamored with seemingly limitless material choices, many of us have chosen the path of consumerism for our spiritual succor. We find some of our deepest pleasures in shopping and accumulating things. In such a commercially saturated world, it is hard to reflect on the existential meanings of our lives and our obligations to others. There is simply too much going on in front of our eyes, tongues, fingers, and ears to think about the immaterial questions of our larger relations.

Climate change is calling on us to remember the significance of our larger relations. It is doing this by reminding us that we are not the center of the universe. We are not the only beings on earth. There is a wider human and more-than-human world surrounding and cradling us, and if we continue to play tone-deaf to this, we will lose not simply our material comforts but our sense of being human. We have brought about climate change by trying to play God. We have assumed that the earth is here for our taking and that we can impose our will upon the earth rather than harmonize our lives with it. To put it differently, we have been living as if we are masters of the world who need not be bothered with the plight of that which we master.

Mr. President-elect, during the campaign, many accused you of inexperience. What your critics failed to appreciate is your longstanding practice in cultivating empathy. You have chosen to make sense of your background by seeing how others helped you and how important assisting others is so crucial to our lives. Responding to climate change is about seeing each other and the earth as deserving of our care, and practicing the virtue of generosity. As you move us toward a clean energy economy, may you pave the way with an empathetic sensibility focused on helping us to assume our role as fellow creatures on an increasingly hotter but still beautiful earth.

Paul Wapner directs the Global Environmental Politics Program at American University.  His books include Environmental Activism and World Civic Politics and Principled World Politics. His forthcoming book is titled The Future of Environmentalism.