LAO TZU, the ancient Chinese philosopher, once warned that in the absence of a change in direction, we will very likely end up where we are headed. That captures the essence of this moment in human history. The only climate policy Americans saw from their national government in the first eight years of the twenty-first century was a stubborn commitment to business-as-usual, a policy that brought the ark of humanity eight years closer to the dangerous shoals emerging from climate change. But it is not too late to steer a new course into the open sea of opportunity. Although the inertia of our ark will surely carry us closer to danger, a sharp change of heading today will steer us away from calamity at mid-century.

Although this challenge is new, history holds instructive lessons about ways people have coped with imminent danger in the past. The American response to the surprise attack on Pearl Harbor in 1941 has relevance to our current challenge of confronting climate change-it demonstrated that once a problem gets our attention, we can muster both the determination and resourcefulness to rapidly confront it. Immediately after Pearl Harbor, the United States entered World War II and quickly transformed a peacetime industrial economy into one completely focused on meeting the challenges of a global war. Domestic manufacture of consumer goods ended abruptly, and within months American industries were turning out airplanes, tanks, jeeps, and ships in astounding numbers. By the end of 1943, just two years after the United States went to war, more airplanes were built at a single factory in Michigan than in all of j.a.pan. That should give us confidence that when people understand the severity of a situation they can refocus sharply and master the challenges they face.

But who is steering the ark of humanity today? In a sense, we all are. Just as billions of people through their individual actions have inadvertently caused Earth's climate to warm, so can we humans reverse this dangerous trend. In truth, however, it will not be easy, and will require us all to do much more than just replacing our old incandescent light bulbs with newer energy-efficient fluorescent bulbs. If we hope to preserve the climate system that sustains us, we must revisit individual decisions about where we live and work, about how much s.p.a.ce we require to live comfortably, about energy consumption and conservation in our homes, about our transportation choices, about how frequently we travel, and about how many children we will have. Those are all issues that we can address as individuals, as consumers, and as families.

But we need also to augment individual mitigation efforts with changes that can come only from collective action. We need to amplify our individual voices by joining with others to have larger-scale impacts. And there is no bigger megaphone for our voices than the ballot box at election time. The right to choose the people who will run our governments is the most significant tool we have to turn in a new direction. As individuals, we have little voice in determining how the electricity that comes to our homes is generated. But our collective voice can, through the actions of our government, determine how the energy we use is produced and distributed. Individually we have little control over tax incentives and regulatory controls-that playing field is the domain of government. Only governmental action can landscape that field to end the advantages long held by the coal and petroleum industries and offer incentives for investment in conservation and renewable energy. New government policies could place limits on greenhouse gas emissions and promote employment opportunities in enterprises that enhance rather than compete with the natural environment. Only government has the tools to reshape the regional development and transportation policies that would help us reintegrate into the natural world, and to abandon policies that unconsciously encourage us to live separate from it.

Government policies determine the level of support for scientific research, and for science education in our schools, both important elements in meeting the challenges of climate change. Only government can shape a foreign policy that encourages and promotes international cooperation in addressing global problems, including trade policies that set emissions reductions as a precondition of international commerce. And unless governments are willing to provide more educational opportunities for women, and address the cultural and religious taboos that enc.u.mber family planning in many places, little progress will be made in slowing population growth.

Many governments and inst.i.tutions, however, are not agents of change. Instead governments often act only as custodians of stability, and strive to protect the status quo. That is the very definition of inertia. Governmental and inst.i.tutional inertia, however, fundamentally derive from personal inertia. If we as individuals do not strive for new directions, our inst.i.tutions will simply carry us in the direction we are headed-toward dangerous irreversible climate change. Our voices need to be aggregated in many settings-schools, universities, religious congregations, labor halls, civic service organizations, investment clubs, corporate shareholder meetings-anywhere and everywhere we can shape public debate. Government offi cials everywhere, whether elected or not, must hear that people want and need a new course-because without that message, little will happen.

There is a Native American proverb that says we did not inherit Earth from our ancestors, but have only borrowed it from our children. Will we selfishly repay our children with a degraded planet devoid of ice, with seawater washing over our great coastal cities? Or will we pa.s.s on a planet that has been rescued from that fate by its people-the same people who inadvertently initiated climate change, but who also recognized their responsibilities to reverse it before the worst of consequences had drowned their sh.o.r.elines?

Climate change is an intergenerational problem, centuries in the making, yet many people around the world do not even understand that there is a problem, much less that it is rapidly reaching levels of serious consequence. They do not see the growing momentum of the climate system carrying us to unavoidable consequences, a momentum that without mitigation will make even more severe changes irreversible. People in all walks of life and in all regions of the world need a wakeup call, before rising seas lap at their doorsteps.

The world needs to chart a bold course into a new sea of sustainability. Whether Americans like it or not, the United States must provide a clear compa.s.s for the global family of nations, through direct and proactive leadership. While it is true that the problems of climate change are not solely American-made, it is also true that there will be no effective solutions without our full engagement. Much of the world is waiting to see what we do, and we must respond boldly, confidently, and quickly. Winston Churchill described a pessimist as a person who "sees difficulty in every opportunity," and an optimist as one who "sees opportunity in every difficulty." While our journey to the future will surely encounter some turbulent seas, we-like Magellan and Columbus centuries earlier-must never lose sight of the fact that we are sailing out onto a sea of unbounded opportunity. Let us all be Churchillian optimists in recognizing opportunity, and at the same time pragmatic realists in addressing the difficulties we will encounter along the way.

We have our work cut out for us. Carpamus diem! Carpamus diem!-Let us seize the opportunity!

ACKNOWLEDGMENTS.

I am grateful to Al Gore for contributing the foreword. I have been acquainted with him for almost two decades-not socially or politically, but in the context of our shared interest in climate science. In 1992, as then-Senator Gore from Tennessee, he held hearings about climate change in his position on the Senate Committee on Commerce, Science, and Transportation. I was invited to testify about the relatively new technique of reconstructing past climate using subsurface temperatures measured in deep boreholes (there is a description of this approach to climate reconstruction in chapter 4). He personally conducted the full day of hearings from start to finish, fully engaged and asking many questions that showed remarkable insight into the intricacies of climate science.

As my research into reconstructing the climate of the past from borehole temperatures matured, a few years later my colleagues and I published a global climate reconstruction using data from four continents: North America and Europe in the Northern Hemisphere, and Australia and Africa in the Southern Hemisphere. This paper125 appeared in appeared in Science Science, the prestigious flagship publication of the American a.s.sociation for the Advancement of Science, in 1998.

The day after publication, I received a phone call from a member of Al Gore's staff, who informed me that the then vice president had read the article and would like me to come to the White House to discuss it with him the next day. My first thought was-which of my professional colleagues was playing a well-orchestrated practical joke, with me as the target? But after a few minutes more of conversation, I realized that the call was no hoax. The next day I was in Washington visiting with Al Gore and Neal Lane, the president's science advisor, and with the staff in the Office of Science and Technology Policy (OSTP).

One new acquaintance from that visit was Dr. Rosina Bierbaum, an ecologist and OSTP's a.s.sociate director for environment, in whose hands the climate portfolio resided. Little did I know at the time that Rosina would later become a colleague of mine at the University of Michigan, when she was appointed dean of the School of Natural Resources and the Environment in 2001. Since her arrival in Ann Arbor, we have had many opportunities to interact scientifically and on issues of climate policy.

Al Gore's film An Inconvenient Truth An Inconvenient Truth recorded his famous and oft-presented lecture on climate change-its causes, consequences, and possibilities for remediation. At the invitation of Dean Bierbaum, and prior to the appearance of recorded his famous and oft-presented lecture on climate change-its causes, consequences, and possibilities for remediation. At the invitation of Dean Bierbaum, and prior to the appearance of An Inconvenient Truth An Inconvenient Truth, Gore presented this lecture in Ann Arbor in 2005. He informed the dean then that he was organizing a program-to become known as The Climate Project-to train volunteers to present his lecture in their communities. He sought a science advisor to help with the training, and Rosina suggested me. Thus, seven years after my visit to the White House, my third engagement with Al Gore began.

The Climate Project (TCP) training began in 2006, on the Gore family farm near Carthage, Tennessee, with an initial group of fifty volunteers from all over the United States and from all walks of life-retirees, students, public officials, businesspeople, entrepreneurs, athletes, housewives and househusbands-whose only common denominator was their desire to build public awareness about the realities of climate change. Since then, in a number of subsequent training sessions in Nashville and elsewhere around the world, Al Gore and the TCP team have trained thousands of volunteers to engage their communities in discussions about climate change. I have partic.i.p.ated as one of the teaching faculty at several of these training programs.

As I have come to learn, anything Al Gore does he does with his full energy and enthusiasm. He is a lifelong learner, always reading, inquiring, absorbing, and incorporating new knowledge into his endeavors. In truth, he and I cross paths infrequently-years can go by between one meeting and the next. But from my first meeting with him in the Senate hearings, to the later visit with him in the White House, and now the engagements with him in TCP training, I have seen him give full measure and then some to everything he undertakes. Would that we all accomplish as much as he.

I extend special thanks to my wife, Lana, and son, John, for their thorough critiques and edits of the ma.n.u.script at many different stages. Both are excellent writers and unsparing with the red pen. They have made the book more personally engaging and less professorially dry. Both have accompanied me to the Antarctic ice and know well the majesty of that white world.

I am indebted to Victoria Wheatley, staffing coordinator for Aber crombie & Kent, Inc., for giving me so many opportunities to spend time in the ice of the world. Kim Robertson Chater, one of my colleagues on several expeditions to Antarctica, and as capable a Zodiac driver as one can hope for in perilous polar waters, is also an extraordinary artist and created the ill.u.s.trations for this book. Dale Austin, staff ill.u.s.trator in the Department of Geological Sciences of the University of Michigan, prepared the maps and graphs.

I am grateful to Jason Smerdon of Columbia University, who cri tiqued the entire ma.n.u.script with his customary thoroughness. I am also grateful to my University of Michigan colleagues Dan Fisher, Ted Moore, Jim Walker, Shaopeng Huang, Josep Pares, Kacey Lohmann, and Bruce Wilkinson, with whom I have had many long discussions about climate. I have incorporated some of their research results into this book. Michael Jackson of the University of Minnesota helped me discover how frequently ice appears in literature, in the oddest of contexts.

Of course, no book sees the light of day without the help of capable professionals in the publishing world. My enthusiastic and talented agent, Gillian MacKenzie, helped me craft the initial concept for this book into a successful book proposal. My editors at Avery-Megan Newman, Rachel Holtzman, Travers Johnson, and Jeff Galas-shaped the ma.n.u.script into its final and much improved form.

Finally, I extend a broad umbrella of grat.i.tude to the thousands of glaciologists, oceanographers, biologists, geologists, and climate scientists who have over decades studied the ice and water and air and rocks of Earth to learn the operational secrets of this marvelous planet that we all call home.