The risks of disrupting climate.

• Author: O'Meara, Molly
• Position: Climate change's impact on humans and the environment

In ancient civilizations, questions of future risk were usually left to soothsayers. With the modern analytical tools of risk management, we've come a long way in shaping our fate. Does it make sense to throw those tools aside in the face of climate change?

Las Vegas and Monte Carlo, with their myriad roulette wheels and blackjack tables, are famed gambling meccas. Kyoto, Japan is not. Glitzy casinos cannot be found in Kyoto, center of Japanese culture since the late eighth century. The streets are lined instead with manicured gardens, ancient Buddhist temples, and Shinto shrines. But before the end of the year, Kyoto may become the site of a huge, high-stakes gamble. In December, the city will host a critical meeting of the parties to the 1992 United Nations Framework Convention on Climate Change. Delegates from 166 countries will address some of the largest risks the world has ever faced: the potentially catastrophic consequences of global climate change.

On the eve of the Kyoto conference, the Earth is experiencing a twentieth century warming trend. As economies around the world have industrialized, they have been powered by fossil fuels. Ever greater burning of these fuels and ever faster rates of deforestation have released precipitous increases in carbon dioxide. Along with other "greenhouse" gases, carbon dioxide traps heat, enhancing the natural greenhouse effect of the Earth's atmosphere. Continued, unrestrained emission of these gases, most scientists agree, will invite large-scale climate disruption (see box, page 12).

Already, phenomena consistent with an enhanced greenhouse effect abound. Polar ice shelves are cracking and splintering, and mountaintop glaciers around the world, from the Alps to the Andes, are in retreat. Temperature-sensitive coral reefs are bleaching under stress, the timing of seasons has changed, and the geographic range of optimal temperature for various plants, animals, and disease vectors has shifted (see map, pages 14-15). In theory, there is a small chance that this warming falls within the climate's natural variability. But it would be dangerous for the envoys sent to Kyoto to bet on that chance by allowing nations to maintain or accelerate their emissions of greenhouse gases. The resiliency of nature, availability, of food and water, health of human populations, and vibrancy of economics all hinge on climate. As Stanford University climate scientist Stephen Schneider puts it in his new book, Laboratory Earth, continuing to alter the climate at the current rate is akin to taking a "planetary gamble we can't afford to lose."

As gamblers, human societies have become ever more adept at working the odds. In fact, it was casino-style gambling that led us to the tools we now use to assess many risks. During the mid-seventeenth century, mathematician Blaise Pascal and lawyer-turned-math enthusiast Pierre de Fermat - actual Renaissance men - teamed up to calculate the odds in a game of chance. In doing so, they developed an important mathematical idea, one that is the basis for our modern concept of risk: the theory of probability. Peter Bernstein, author of Against the Gods: The Remarkable Story of Risk, describes risk as "the revolutionary idea that defines the boundary between modern times and the past... the notion that the future is more than a whim of the gods." Although many early peoples, such as the ancient Greeks, had mathematical skills, they did not apply them to predicting the future; for them, the future was the sole province of the oracles.

Today, however, a mathematical appraisal of the odds often informs our plans for the future. Assessment of risks helps patients to decide on surgery, investors to buy stocks, and military advisors to devise defense strategies. Modern patients seek explanations of medical conditions that are couched in probabilities: what could the worst outcome be? Is it more risky, to have surgery or to forego it? When faced with a range of potential outcomes - in health care, engineering, finance, defense, or any other field - we have learned to weigh risks, in order to ignore the small dangers and hedge against catastrophe. To underscore this point, a managing director at the large investment bank Morgan Stanley reportedly likes to quote J.R.R. Tolkien: "It doesn't do to leave a live dragon out of your calculations if you live near him."

Potentially severe climate disruption is a lurking "dragon" that we must now include in our future planning. For instance, we must realign the energy industry if we are to see a reduction in the burning of fossil fuels. If the envoys in Kyoto choose to do so, they can improve the odds of the current climate "gamble." By agreeing to a legally binding climate treaty protocol with strict targets and timetables, they could produce perhaps the most important risk management strategy of the next century. In fact, dealing with the uncertainties of climate change in the twenty-first century may assume the same overiding importance as has military planning in the twentieth. Governments are spurred to build defense capacity not by the knowledge of certain conflict, but by the risk of war. It's the same kind of thinking that we use on a personal level, when we purchase car insurance. We know we might never have a car accident, or have only a small accident with minor costs. But, recognizing that we could total the car, or be found liable for a catastrophic injury, we buy the insurance to avoid financial ruin. Diplomats in Kyoto will have the chance to agree on some form of "insurance" too - but in their case the entire planet stands to lose from a "crash." These envoys will be crafting insurance not just for the citizens of their home countries, but for those without a seat at the bargaining table, including future generations.

As the Kyoto conference approaches, some skeptics continue to focus on a single question: "Is climate change real?" In doing so, they purposefully misguide public debate. The majority of scientists have agreed that climate change is real, but they also agree that the local effects of climate change are highly uncertain. Therefore, among the questions we should be asking are: "What do we know about the risks?"; "What level of risk is acceptable?"; and "How can we avoid unacceptable risks?" Even British Petroleum, a corporation that mines the fuels that stoke greenhouse warming, has recognized the importance of asking such questions. In explaining BP's decision to move into climate-friendly solar technologies, chief executive John Browne conceded in May 1997 that the grave risks of climate change "cannot be discounted."

Learning to Assess Climate Risks

If we approach climate change as we do other risky situations, then our first step is to systematically identify the range and probability of possible outcomes. For instance, companies that sell car insurance classify the riskiest clients - say, male teenagers who drive sportscars - by studying historical data on car crashes. Large investors, trying to ascertain the risks of investing abroad, consult Institutional Investor's country credit ratings, based on the economic, financial, and political risks in a given country. The closest analogue for climate change is the rapidly growing body of relevant scientific research, which is continually reviewed by a global network of climate experts. This group, the Intergovernmental Panel on Climate Change (IPCC), was created in 1988 by the World Meteorological Organisation and the United Nations Environment Programme to help decisionmakers around the world understand the scope of the climate change problem.

The IPCC has been as methodical as any actuary or financial analyst in its step-by-step approach to studying climate change. The scientists first examined the range of projections for future population growth, economic development and technological innovation - the key trends that will influence our emissions of greenhouse gases in the future. then, translating these scenarios into possible levels for carbon dioxide concentrations, the scientists determined. that we can expect to see at least a doubling of preindustrial levels of carbon dioxide by the middle of the next century. Consensus is that this doubling will raise the average global surface temperature 1 to 3.5 [degrees] C by 2100. This change far exceeds any recent natural fluctuation and will occur at a rate faster than any since the last Ice Age more than 10,000 years ago.

Climate is weather averaged over the long term: decades, centuries, and millennia. It is a tremendously complex system that comprises not only the atmosphere, but also the oceans, ice, the land and its features, as well as rivers, lakes, and sub-surface water. The Sun's output, the Earth's rotation, and the chemical composition of the atmosphere and ocean all affect this system. Changes in any of these internal or external factors are responsible for the climate's variability. While the climate has undergone some wild shifts over the course of geological history, it has been relatively stable during the period in which modern human society has evolved.

With the warming that is projected from the gases that humans are adding to the atmosphere, this stability may come to a man-made end. Sea level is expected to rise between 15 and 95 centimeters over the next century as oceans expand and ice melts. The largest rises in temperature will occur at higher latitudes. Higher temperatures will enhance evaporation and precipitation, altering the global cycling of water. Some areas will become wetter while others become drier. And dramatic events such as floods and storms could become more variable.

These changes may occur faster than we will be able to respond. And because both nature and climate are so complex, we may be startled by some unwelcome "surprises." For instance, climate change could magnify other global problems that stem from a larger human population. Even...