PREFACE - A World Without Ice - Henry N. Pollack

A World Without Ice - Henry N. Pollack (2009)


This is a book about ice and people on Earth—the impact ice has had on our planet, its climate, and its human residents, and the reciprocal impact that people are now having on ice and the climate of the future. Ice has been on Earth much longer than people have—we are relative newcomers to the terrestrial menagerie. Humans have called Earth home for only some three million years, whereas ice has been a part of Earth’s landscape for billions of years.

Throughout most of Earth’s history, ice has been an indomitable force of nature. The creep of ice over the continents during past glacial epochs has profoundly shaped Earth’s surface. The sharp Alpine peaks of Europe, the vast Great Lakes of North America, the majestic valleys of California’s Yosemite National Park, and the deeply incised fjords of Norway—all are products of earlier glacial erosion. Today they grace Earth’s landscape as gifts from ice to humanity. Minute by comparison, people stand awestruck at the immense scale of nature’s handiwork.

But ice is much more than just a landscape sculptor and earth mover—it is a major player in Earth’s climate system. Of the sunshine falling onto Earth, about 30 percent of it is reflected back into space, mostly by white clouds in the atmosphere and white ice at the surface. The polar ice caps, covering virtually all of Antarctica, the Arctic Ocean, and Greenland, make up less than one tenth of Earth’s surface, but account for much of the sunshine reflected from the surface. Polar ice also generates huge wind streams that spill ferociously off the ice caps and flow far beyond the ice perimeter to shape weather systems that influence the entire globe.

Geologists have translated the book of rocks, layer by layer, and discovered that there have been many times in Earth’s history when the climate was different from that of today—episodes when ice blanketed half the globe, and times when the polar regions were free of ice. It is almost incredible to think that just twenty thousand years ago, at the places where New York, Detroit, and Chicago are today home to millions of people, the landscape was monochrome white, a massive sheet of ice a half mile thick. And there were no people in all of North America to see it, to marvel at it, or to cope with it. The Western Hemisphere had yet to welcome its first human immigrants.

Over the span of only the last three centuries, however, the rapid growth of the human population and the rise of industrial society have brought the relationship between ice and humankind to a precarious tipping point. Gone are the days when ice was unfazed by the few people living on its fringes. Today human activities are having a profound effect on Earth’s climate and destabilizing the world’s ice. Climate scientists warn that in the not-too-distant future we may see a world without ice.

It is difficult to envision a world without ice—it requires a stretch of the imagination no less than envisioning a world without trees, or flowers, or animals. The loss of ice will have dramatic consequences for planet and people alike. The drinking water and agricultural water for almost one quarter of Earth’s population—a number that exceeds the population of the entire Western Hemisphere—come directly from mountain glaciers. An even greater number of people depend on the seasonal replenishment of water from the melting of winter snow to nourish crops at the outset of the growing season. The dramatic shrinking of Arctic sea ice over the past few decades has already triggered international posturing over oil and minerals that perhaps will be discovered on the ocean floor. And the likely disappearance of summer sea ice later in this century will set the stage for exploitation of the Arctic’s fisheries, and will open maritime trade routes such as the fabled Northwest Passage between Europe and East Asia.

In the starkest terms, however, the melting of the ice now on the continents means adding more water to the oceans, and rising sea levels. The ensuing flooding will affect low-lying regions of all nations with a seacoast—more than a hundred countries. The loss of property and agricultural land, the damage to coastal infrastructure, and the pollution of fresh groundwater aquifers with salty seawater are all significant consequences with grave economic implications. But the most severe consequence will be the displacement of many millions of people who live near the sea. A sea level rise of only three feet would transform more than one hundred million coastal residents into climate refugees. Such a population displacement, a number equivalent to a third of the population of the United States, would be unprecedented in human history.

What can be done to forestall such consequences? One must recognize that some changes accompanying a warming world are unavoidable, because of the earlier inadvertent changes to the climate system that have already occurred and will continue to play out throughout this century. And it is equally clear that if no mitigation measures are taken, a broad spectrum of serious consequences will appear sooner, many within this century, and will grow larger with time. But there are a number of middle paths, some timid, some bold, that are being readied for the nations and peoples of the world to consider and perhaps embrace. The creativity of people has the potential to slow and even reverse the changes in global climate now taking place. However, the willingness of nations to take the difficult but necessary steps to do so has yet to be convincingly demonstrated.