With Speed and Violence: Why Scientists Fear Tipping Points in Climate Change (36 page)

A small price to pay for what? What would we be buying with this trillion-dollar investment in a stable climate? That, of course, is impossible to answer, because we don't know the extent of what would be avoided. But we can easily see the scale of things, even today. Evidence of the cost of extreme weather is everywhere. The 1998 El Nino cost Asia at least $20 billion. Insured losses from extreme weather in 2004 hit a record $55 billion, which was promptly exceeded by an estimated $7o billion for 2005. Total economic losses for 2005, including uninsured losses, are expected to be three times higher: cleaning up after Hurricane Katrina alone may eventually cost $ ioo billion. Incidentally, a simple extrapolation of trends in insurance claims stemming from extreme weather in recent years suggests that they will exceed total global economic activity by 2060. That may be slightly wacky math, but it is sobering nonetheless.

Not surprisingly, economists disagree about the cost of inaction on climate change as much as they do about the cost of action. Some have attempted to assess the "social cost" of every ton of carbon put into the air. One recent review found a range from approaching $1,700 per ton down to zero. The British government, which commissioned the review, settled on a figure of $70 per ton. One reason for the wide range is accounting practices. Economists routinely apply a discount to the cost of anything that has to be paid for in the future. Dealing with climate change that may happen decades or even centuries ahead allows for huge discounts. Some economists say that very long-term impacts-such as the rise of sea levels as ice caps melt-should be discounted to zero.

This discounting of the future may be a convenient device for corporations, or even governments in their day-to-day business. But it is less clear how sensible it is for the management of a planet. If corporate finances or a nation's economy go wrong, shareholders can sell their shares and governments can print money or go cap in hand to the International Monetary Fund. But the planet, our only planet, is rather different.

Moreover, the existing estimates of social cost are based on IPCC studies that so far have not included many of the irreversible positive feedbacks to climate change that this book has concentrated on. So nobody has yet even asked what price should be attached to a century-long drought in the American West, or an enfeebled Asian monsoon, or a permanent El Nino in the Pacific, or a shutdown of the ocean conveyor, or the acidification of the oceans, or a methane belch from the ocean depths, or a collapse of the West Antarctic ice sheet, or sea levels rising by half a yard in a decade. Though, on reflection, these are perhaps questions best not answered by accountants.

GLOSSARY

Aerosols Any of a range of particles in the air, including soot, dust, and sulfates, that can intercept solar energy, sometimes scattering it and sometimes absorbing and reradiating it. Under different circumstances, they can either warm or cool the ground beneath and the air around.

African Humid Period The period after the close of the last ice age and before about 5,500 years ago, characterized by wet conditions in Africa, notably in the Sahara.

Albedo A measure of the reflectivity of a surface.

Anthropocene A new term to describe the past two centuries or so, during which human activities are seen to have dominated some key planetary processes such as the carbon cycle.

Arctic Oscillation A climate oscillation that occurs on timescales from days to decades. Measured by differences in air pressure between polar and nonpolar areas, and manifested in changing wind patterns that alter temperature. Related to (and sometimes synonymous with) the North Atlantic Oscillation.

Biological PUMP The process by which living organisms in the ocean draw carbon dioxide out of the atmosphere as they grow, and then deposit carbon on the ocean floor following their death. Has the effect of moderating the accumulation of CO2 in the atmosphere.

Biosphere That part of Earth's surface, atmosphere, and oceans that is inhabited by living things.

Carbon dioxide fertilization effect What happens when higher concentrations of carbon dioxide in the air "fertilize" the faster growth of plants or other organisms.

Carbon Cycle The natural exchange of carbon between the atmosphere, oceans, and Earth's surface. Carbon may be dissolved in the oceans, absorbed within living organisms and soils, or float in the air as carbon dioxide.

Carbon sink Anything that absorbs carbon dioxide from the air. Anything that releases carbon dioxide is a carbon source.

Chimneys A term coined by Peter Wadhams for giant whirlpools in the far North Atlantic that take dense water to the seabed. The start of the ocean conveyor.

Climate model A normally computerized simulation of the workings of the atmosphere. Often used to predict the effect of future changes such as an accumulation of greenhouse gases.

El Nino A periodic switch in the ocean currents and winds in the equatorial Pacific Ocean. A major perturbation in the global climate system.

Feedback Any by-product of an event that has a subsequent effect on that event. A positive feedback amplifies the original event, while a negative feedback dampens it. Key climate feedbacks include ice, water vapor, and changes to the carbon cycle. See also ice-albedo feedback.

Fossil f uel A fuel made from fossilized carbon, the remains of ancient vegetation. Includes coal, oil, and natural gas.

Gaia The idea, developed by James Lovelock, that Earth and its living organisms act in consort, like a single organism, to regulate the environment of the planet, including atmospheric chemistry and temperature.

Global warming Synonym for the greenhouse effect and climate change.

Greenhouse gas Any one of several gases, including water vapor, carbon dioxide, and methane, that trap heat in the lower atmosphere.

Gulf Stream The tropical ocean current that keeps Europe warm, especially in winter. Part of the ocean conveyor, and may be turned off at times, such as during ice ages.

Holocene The geological era since the end of the last ice age. Sometimes regarded as recently succeeded by the Anthropocene.

Hydrological Cycle The movement of water between the oceans, the atmosphere, and Earth's surface through processes such as evaporation, condensation, rainfall, and river flow.

Ice ages Periods of several tens of thousands of years when ice sheets spread across the Northern Hemisphere and the planet cools. Believed to be triggered by Milankovitch cycles and amplified by positive feedbacks. Recent ice ages have occurred roughly every ioo,ooo years. The last ended io,ooo years ago.

Ice-albedo feedback A positive feedback on air temperature caused by the presence or absence of highly reflective ice. Thus, during warming, ice melts and is replaced by a darker surface of ocean or land vegetation that absorbs more heat, amplifying the warming. The reverse happens when cooling causes ice to form.

Ice Sheets The largest expanses of ice on the planet. There are currently three: Greenland, West Antarctica, and East Antarctica.

Interglacials Warm periods between ice ages.

Intergovernmental Panel on Climate Change (IPCC) Apanelofscientists appointed by the UN through national science agencies to report on the causes of, impacts on, and solutions to global warming.

Isotope One of two or more atoms with the same atomic number but containing different numbers of neutrons. For example: oxygen-16 and oxygen-18. The ratio of the isotopes in the air or oceans can vary according to environmental conditions, but will be fixed when the isotopes are taken up by plants, or air bubbles are trapped in ice. Thus isotopic analysis of ocean sediments, ice cores, and other leftovers from the past can be a valuable way of reconstructing past temperatures and other conditions.

Kyoto Protocol The 1987 agreement on climate change, whose provisions include cuts in emissions by most industrialized nations during the first compliance period, from 2008 to 2012. The U.S. and Australia subsequently pulled out.

Little ice age The period from the fourteenth to the nineteenth century when parts of the Northern Hemisphere were cooler than today.

Medieval warm period The period from the ninth to the thirteenth century when parts of the Northern Hemisphere were notably warm.

Methane clathrates Crystalline lattices of ice that trap large volumes of methane. Usually found at low temperatures and high pressures beneath the ocean bed or in permafrost.

Milankovitch wobbles Various wobbles in the orbit of Earth than can influence climate over timescales of thousands of years. Believed to be the trigger for ice ages. Named after the Serbian mathematician Milutin Milankovitch, but originally investigated by the forgotten Scottish amateur scientist James Croll.

Nuclear winter The theory that in a nuclear war, there would be so many fires that smoke would blanket the planet, causing massive cooling.

Ocean conveyor Global ocean circulation in which dense surface waterfalls to the ocean floor in the Arctic and near Antarctica, travels the oceans, and resurfaces about a thousand years later in the warm Gulf Stream of the Atlantic. Prone to switching on and off, and perhaps a major determinant of global climate.

Ozone hole An extreme thinning of the ozone layer seen in recent decades. Found each spring over Antarctica, but potentially could occur over the Arctic, too. Caused when man-made "ozone-eating" chemicals accumulate in the ozone layer. The immediate trigger for ozone destruction is low temperatures and sunlight.

Ozone layer The ozone within the lower stratosphere, which protects Earth from harmful ultraviolet radiation from the sun.

Permafrost Permanently frozen soil and rock found in the tundra regions of Siberia, Canada, Antarctica, and some mountain regions. Can reach a depth of more than 1.2 miles.

Precession One of the Milankovitch wobbles that affects the axis of Earth's rotation. Changes the season when Earth is closest to the sun. Implicated in some climate changes during the Holocene.

Rainforest Forest that depends on frequent rainfall, but also generates rain by recycling water into the atmosphere from its leaves.

Southern Hemisphere annular mode (SAM) The Antarctic equivalent of the Arctic Oscillation. Responsible for strong warming of the Antarctic Peninsula in recent decades.

Stratosphere A layer of the atmosphere starting about 6 to 9 miles up. Home of the ozone layer. Greenhouse effect causes it to cool, but it may act to amplify warming in the troposphere beneath.

Thermal expansion The warming and resulting expansion of water in the oceans. Along with the melting of land ice, it is causing a worldwide rise in sea levels.

Troposphere The lowest layer of the atmosphere, occupying the 6 to 9 miles beneath the stratosphere. The area within which our weather occurs. Greenhouse effect causes it to warm.

Ultraviolet radiation Solar radiation with wavelengths shorter than light but longer than X-rays. Harmful to living organisms, which are largely protected from it on Earth by the ozone layer.

ACKNOWLEDGMENTS

Where to start? In my twenty years of reporting on climate change for New Scientist magazine and others, innumerable scientists (and not a few editors and fellow journalists) have helped me get things mostly right. To all of them, thanks. I hope this book brings their work together in a form that many of them will find enlightening.

My greatest debt is to the synthesizers within the scientific community-the people who have tried to see the whole picture and to put their work into what seems to me an ever more frightening context. Their names recur throughout this book. But those who have specially helped me in person include Jim Hansen, Paul Crutzen, Jim Lovelock, Wally Broecker, Peter Cox, Peter Wadhams, Mike Mann, Richard Lindzen, Will Steffen, Richard Alley, Lonnie Thompson, Terry Hughes, Jack Rieley, Sergei Kirpotin, Euan Nisbet, Peter Liss, Torben Christensen, Crispin Tickell, Richard Betts, Myles Allen, Meinrat Andreae, Tim Lenten, Chris Rapley, Peter deMenocal, Joe Farman, Gavin Schmidt, Keith Briffa, John Houghton, Dan Schrag, Bert Bolin, Jesse Ausubel, Drew Shindell, Stefan Rahmstorf, Mark Cane, Arie Issar, Hans Joachim Schellnhuber, and the late Charles Keeling and Gerard Bond.

One always gets ideas from fellow writers. So thanks, too, to John Gribbin, Mark Lynas, Bill Burroughs, Doug Macdougall, Mark Bowen, Jeremy Leggett, Gabrielle Walker, and two historians of the climate change debate, Gale Christianson and Spencer Weart, whose books I have referred to in preparing this work. Thanks also to the organizers of the Dahlem conferences for making me welcome at an important event; to Carl Petter Niesen, in Ny-Alesund; and to the many people who have helped turn a germ of an idea into a completed book, including my agent, Jessica Woollard, and the editors Susanna Wadeson and Sarah Emsley.

NOTES ON THE REFERENCES

This is a far from complete list of the sources used in writing this book. But it includes the main written sources as well as others, summarizing information that could be of use to readers.

PREFACE

Wadhams's work on chimneys appears at greatest length in "Convective Chimneys in the Greenland Sea: A Review of Recent Observations" (Oceanography and Marine Biology: An Annual Review 2004, vol. 42, p. 29-56) and also in Geophysical Research Letters 2002 (vol. 29, no. 10, p. 76). Wadhams also spoke with me at length. For more on William Scoresby, see my article "Hell with a Harpoon" in New Scientist, 18 May 2002.

INTRODUCTION

The proceedings of the British government's Dangerous Climate Change conference appear at www.stabilisation2oo5.com. The resulting book can also be found at www.defra.gov.uk/environment/climatechange/internat/dangerous-cc .htm. Hansen's address to the AGU in late 2005 is at: www.columbia.edu/-jehi/ keeling-talk-and-slides.pdf. Three overviews on abrupt climate change are: Richard Alley's Abrupt Climate Change: Inevitable Surprises (National Academies Press, 2002), especially chapter four; "Abrupt Changes: The Achilles' Heels in the Earth System" by Steffen et al. in Environment (vol. 46, p. 9) and Rial et al., "NonLinearities, Feedbacks and Critical Thresholds with the Earth's Climate System" (Climate Change, vol. 65, p. T 1).