www.princexml.comPrince - Personal EditionThis document was created with Prince, a great way of getting web content onto paper.

Advance praise forClimate Code Red

This is a frightening but clear-eyed, well-informed, and sober consideration of theweight of evidence and argument on the im-minent and quite possibly cataclysmic im-pacts of climate change. It is a wake-up calland antidote to the sanitised reporting onthe state of the planet and global warming.As a social and environmental psychologistreader, this critical overview is impressive,comprehensive, and convincing.

DR JOSEPH RETTERRecent greenhouse gas emissions place

the Earth perilously close to dramatic cli-mate change that could run out of our con-trol, with great dangers for humans and oth-er creatures. There is already enough carbonin the Earths atmosphere for massive icesheets such as West Antarctica to eventually

melt away, and ensure that sea levels willrise metres in coming decades. Climate zonessuch as the tropics and temperate regionswill continue to shift, and the oceans will be-come more acidic, endangering much marinelife. We must begin to move rapidly to thepost-fossil fuel clean energy system.Moreover, we must remove some carbon thathas collected in the atmosphere since the In-dustrial Revolution. This is the story thatClimate Code Red tells with conviction. It isa compelling case for recognising, as the UNsecretary-general has said, that we face a cli-mate emergency.

Dr JAMES HANSEN, director of the Na-tional Aeronautics and Space AdministrationGoddard Institute for Space Studies

Climate Code Red applies an uncommondegree of common-sense to the latest climatescience, and is a well-researched basis forbuilding a truly meaningful response. Itmakes it abundantly clear that greenhouse-

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gas emissions have to stop entirely, and thateven this must sit in a larger plan to manageour destabilised earth-atmosphere system.

TIM HELWEG-LARSEN, Director,Public Interest Research Centre, UK

David Spratt and Philip Sutton haveprovided a valuable and sobering contribu-tion to the policy challenge of climate changeat a pivotal moment, with their key insightthat the expectation of failure has becomethe norm in climate policy. Climate CodeRed is a significant contribution whichshould be read by anyone seriously contem-plating how to set greenhouse emission-re-duction targets.

SENATOR CHRISTINE MILNE, Aus-tralian Greens Party

Having been involved with global warm-ing climate change as a researcher in envir-onmental health for 25 years, I can say thatthis is without question by far the best bookto date on this issue the first book to have

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the integrity to say how the situation reallyis.

DR PETER CARTER, Canada

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Scribe PublicationsCLIMATE CODE RED

David Spratt is a Melbournebusinessman, climate-policy analyst, and co-founder of Carbon Equity, which advocatespersonal carbon allowances as the most fairand equitable means of rapidly reducing car-bon emissions. He has extensive advocacyexperience in the peace movement, and indeveloping community-campaign commu-nication and marketing strategies.

Philip Sutton is the convener of theGreenleap Strategic Institute, a non-profitenvironmental-strategy think tank and ad-visory organisation promoting the very rapidachievement of global and local ecologicalsustainability. He is also the founder and dir-ector of strategy for Green Innovations, andan occasional university lecturer on global

warming science and strategies forsustainability.

Philip has worked on a number of advisoryand policy committees for Australian stateand federal governments, was the architectof the Victorian Flora and Fauna GuaranteeAct, and is a former president of the Aus-tralian and New Zealand Society for Ecolo-gical Economics (20012003).

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CLIMATECODE RED

the case for emergency action

David Spratt& Philip Sutton

Scribe Publications Pty Ltd

PO Box 523Carlton North, Victoria, Australia 3054Email: info@scribepub.com.au

Published in Australia and New Zealand by Scribe 2008

Copyright David Spratt and Philip Sutton 2008

All rights reserved. Without limiting the rights under

copyright

reserved above, no part of this publicationmay be reproduced,stored in or introduced into a retrieval sys-tem, or transmitted,in any form or by any means (electronic,mechanical, photocopying,recording or otherwise) without the priorwritten permission of thepublisher of this book.

Cover design by Tamsyn Hutchinson

Typeset in 11.5/15 pt Dante by the publishersPrinted and bound in Australia by GriffinPressOnly wood grown from sustainable regrowthforests is used in the manufacture of paperfound in this book.

National Library of Australia

Cataloguing-in-Publication data

Spratt, David.

Climate code red: the case for emergencyactionCarlton North, Vic.: Scribe Publications,2008.

9781921753022 (e-book)

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Global warming; Global temperature changes.

363.73874

www.scribepublications.com.au

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http://www.scribepublications.com.au

For Helen OShea David

To my children, Dan and Joey Philip

Contents

ForewordsIntroduction: A Lot More TroublePart One: The Big Melt

1 Losing the Arctic Sea-Ice2 Greenlands Fate3 Trouble in the Antarctic4 A Rising Tide5 The Quickening Pace6 Most Species, Most Ecosystems7 The Price of Reticence

Part Two: Targets8 What We Are Doing9 Where We Are headed10 Target 2 Degrees11 Getting the Third Degree12 Planning the Alternative13 The Safe-Climate Zone14 Putting the Plan Together

Part Three: The Climate Emergency15 This is an Emergency

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16 A Systemic Breakdown17 When Reasonable is Not Enough18 The Gap Between Knowing and Not-Knowing19 Making Effective Decisions20 The New Business-as-Usual21 Climate Solutions22 Can Politics as Usual Solve theProblem?23 What Does an Emergency Look Like?24 The Climate Emergency in Practice25 The Safe-Climate Economy26 In the End

Appendix: A Climate Code Red ScenarioNotes

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Note

All temperatures cited in this book are inCelsius, and increases in temperature arefrom 1750 pre-industrial levels unless other-wise stated.

Forewords

Ian Dunlop

As the worlds population rises towardnine billion by mid-century, the inevitablelogic of exponential growth in consumptionis now hitting the real limits of global ecosys-tems and resource availability. The immedi-ate pressure points are human-induced cli-mate change, water availability, and peakingglobal oil supply, which are converging rap-idly in a manner not previously experienced.But those pressure points constitute only thetip of the broader global-sustainability ice-berg: further constraints and limits will be-come increasingly evident as the major de-veloping countries move up the growthescalator.

This situation is not unexpected: it hasbeen forecast for decades, going back before

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the 1972 publication of The Limits toGrowth, a book that described how expand-ing human population and consumption pat-terns would run up against the limits of thenatural world. In the meantime, we have cre-ated a political and capitalist system whichhas proved incapable of recognising that themost important factor for its own survival isthe preservation of a global biosphere fit forhuman habitation. Our institutions aretotally short-term focused: politically, due tothe electoral cycle, and corporately, due toperverse incentives. Thus, we are uniquelyill-equipped to handle these major problems,which are all long-term.

Our ideological preoccupation with a mar-ket economy that is based on maximisingshort-run profit is rapidly leading us towardsan uninhabitable planet. As inconvenient asit may be, politically and corporately, con-ventional economic growth and rampantconsumerism cannot continue. Markets are

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important, but they operate within rules;henceforth, the rules must change to ensurelong-run sustainability.

Nationalism and short-term vested in-terests have so far prevented the develop-ment of a global governance framework cap-able of handling this Tragedy of the Com-mons, and the issue of global sustainability isnow much bigger than any nation state.Global warming, in particular, is moving farfaster than scientists had predicted, to thepoint that we are already in the danger zone.

The stark fact is that we face a global sus-tainability emergency, but it is impossible todesign realistic solutions unless we first un-derstand and accept the size of the problem.We know those solutions; what is lacking isthe political will, first, to honestly articulatethe problem and, second, to implement thosesolutions.

Unadorned by political spin, Climate CodeRed is a sober, balanced analysis of this

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challenge that proposes a realistic frame-work to tackle the emergency. It should beessential reading for all political and corpor-ate leaders and, particularly, for the com-munity. The extent of change that we requirewill only occur if the political and corporateworld sees that the community is demandingit.

If we are to have a reasonable chance ofmaintaining a habitable planet, placing ourefforts on an emergency footing is long over-due. We only play this game once; a trial runis not an option.

Ian Dunlop is a former internationaloil, gas, and coal industry executive. Hechaired the Australian Coal Association from198788 and the Australian Greenhouse Of-fice Experts Group on Emissions Tradingfrom 19982000, and he was CEO of theAustralian Institute of Company Directorsfrom 19972001. He is chairman of the Aus-tralian National Wildlife Collection

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Foundation (CSIRO) and deputy convenor ofthe Australian Association for the Study ofPeak Oil.

Ken Caldeira

For my PhD research, I studied whathappened to ocean chemistry at the time thedinosaurs became extinct. The meteorite thatdestroyed the dinosaurs also acidified theoceans, leading to the disappearance of coralreefs and many other marine organisms. It isbecoming clear that modern industrial civil-isation is generating a new mass extinction(with its own ocean acidification) of a mag-nitude not seen since that destruction of thedinosaurs some 65 million years ago.

Over the past few centuries, vast naturalecosystems on land and in the water havebeen converted to human use and abuse. Ourcarbon dioxide emissions are heating theplanet and acidifying the oceans. Our physic-al environment is changing at a rate that is

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faster than at any time in the past hundredsof millions of years, except for those rarecataclysmic events that have killed off mostlife on Earth. Spratt and Sutton point outthat if business as usual means losing Arcticecosystems, losing coral reefs, altering thegreat weather patterns, and so on, then wesimply cannot afford it the cost is toogreat.

At the risk of oversimplification: we areforced to make a choice. Either we can de-cide to live in a wilderness world in whichwe use our technology to minimise our envir-onmental footprint, and we grow and devel-op in ways that are consistent with long-termflourishing of the rich diversity of life in thisplanet; or we can continue heading towards anightmare vision of an Earth where climateis shifting and species are getting tossedoverboard every day, every hour. (Invasivegeneralists, including weeds and the wealthy,may do fairly well, but specialist species and

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poor people have a threatened future aheadof them.) We will either learn to live with theworld, or wreck it and in wrecking theworld, we will lose.

There is inertia both in the climate systemand in our industrial infrastructure. Inertiain the climate system means we can passthresholds now that set us on an irreversibletrajectory to future tragedy. Inertia in our in-dustrial infrastructure means that, undermost accepted scenarios, without early re-tirement of major segments of our industrialcapacity, it will take many decades to replacethe coal-, oil, and gas-burning devices thatpervade our planet. Business as usual is ac-celerating us into ever-greater environment-al risk and eventually, that risk will comehome to roost. As Spratt and Sutton pointout, business as usual must end now, if weare to allow our children and ourselves amore natural world in which humans treadlightly and live well. Sensibly, Climate Code

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Red asks us to take stock of the climate andsustainability emergency that is unravellingaround us and respond with a large-scaletransition to a post-carbon economy. Thereis no time for slow transitions.

Ken Caldeira is director of the CaldeiraLab of the Department of Global Ecology atStanford Universitys Carnegie Institution ofWashington, whose research focuses on im-proving the science base needed to allow hu-man civilisation to develop while protectingour environmental endowment. He also con-ducted research for the Energy and Environ-mental Sciences Directorate of the LawrenceLivermore National Laboratory from 1993 to2005.

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INTRODUCTIONA Lot More Trouble

This is an emergency, and for emergency situ-

ations we need emergency action

UN secretary-general Ban Ki-Moon, 10

November 2007

I cant end this email without acknow-ledging that we are in a lot more climatetrouble than we thought. This response froma US-based polar researcher during a discus-sion we were having about how quicklyGreenland might melt is not an orthodox sci-entific statement, but its disturbing tone ex-presses a level of anxiety and honesty that weheard many times while writing this book.

Perhaps the frankness of such responsesreflected the fact that we are not climate sci-entists, and that we were asking questionsnot as peers but as policy researchers. Inconducting our enquiries, we conversed withand drew on the work of many climate

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scientists who gave generously of their time,patiently answering sometimes-waywardquestions, and welcoming our enquiries. Al-though our previous work had included ad-vocacy on environmental and communityproblems, we found the scope and depth ofclimate research, the nuances, and interpret-ative differences between scientists a chal-lenge. Yet it is critical that non-scientists en-gage with the science if all of us are to plot apathway to a safe climate.

Climate scientists generally work in a spe-cialised field, and the release of their sci-entific results and projections incorporatesassessements of risks, probabilities, and un-certainties that can lead them to feel reticentabout commenting publicly on the broaderaspects of global-warming impacts andpolicies. Those outside the research com-munity, however, have a different vantage-point in viewing the disparate evidence,which may explain why some of the most

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compelling writing on global warming hascome from writers such as George Monbiot,Fred Pearce, Mark Lynas, and ElizabethColbert.

Climate Code Red explores what a lotmore climate trouble means, why it differsfrom the public story, and how we should goabout thinking of new solutions to this globalemergency. It concludes that we must castaside climate policies that are doomed to fail,and that we must act with foresight andcourage, because our task is urgent.

The evidence we have gathered has con-vinced us that we have only one chance tosolve the global warming problem. Just as inhospitals, where code red denotes a patientwho needs advanced life-support, the phrasesignals an emergency: an alarm that ringsnow, for all life on this fragile planet.

Debate over climate change took a radicalnew turn in September 2007, when researchdata revealed that the floating sea-ice in the

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polar north was disintegrating at a frighten-ing speed in the words of Penn StateUniversity climatologist Richard Alley, onehundred years ahead of schedule. Eight mil-lion square kilometres of Arctic sea-ice isbreaking up, and this demands that we lookanew at the impact of global warming, and atwhat we must do to return to a safe-climateworld.

Industrial activity is propelling the worldsclimate to a hot state not experienced for amillion years, at a time long before modernhumans evolved. We face a perilous journeyacross unfamiliar terrain, close to a precipicethat, should we cross it, will see changes bey-ond recognition to life on Earth.

This is not an exaggerated claim; it is thesober view of many of the worlds leading cli-mate scientists, including NASA scientist JayZwally. When he was a young man, Zwallyhauled coal for work. At the end of 2007, hetold a gathering of fellow climate experts:

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The Arctic is often cited as the canary in thecoalmine for climate warming and now asa sign of climate warming, the canary hasdied. It is time to start getting out of the coalmines.

Robert Corell, chairman of the ArcticClimate Change Impact Assessment(ACCIA), is equally blunt:

For the last 10,000 years we have been living in a

remarkably stable climate that has allowed the whole

of human development to take place Now we see

the potential for sudden changes of between 2 and 6

degrees Celsius [by the end of this century] .* We just

dont know what the world is like at those temperat-

ures. We are climbing rapidly out of mankinds safe

zone into new territory, and we have no idea if we can

live in it.

In the recent past, the story of climatechange has been one of sudden and disrupt-ive fluctuation as the Earth seesawedbetween ice ages and warm periods. This his-tory warns that we must expect the

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unexpected, because dramatic changes thattip regional climates from one state to anoth-er can set off chains of events that echoaround the globe.

Most of us think of climate change as agradual, linear process that involves asmooth relationship between increasinglevels of greenhouse gases and rising tem-peratures that like the kitchen oven, if weare slowly turning up the control, we willproduce a predictable warming. But climatedoesnt work like that.

In fact, we live in a climate world ofchaotic, non-linear transitions, where a smallincrease in the level of greenhouse gases, orin the energy imbalance of the climate sys-tem, can make a huge difference. An elementof the climate system can flip from one stateto another quickly and unpredictably. This isnow occurring at the North Pole, where a tip-ping point, or critical threshold, has been

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passed, and an area of summer sea-ice onceas large as Australia is disintegrating quickly.

Further south, if the changing climatewere to produce four or five consecutiveyears of drought in the Amazon, it might be-come sufficiently dry for wildfires to destroymuch of the rainforest and for burning car-bon to pour into the skies. This change in theregional climate pattern would further re-duce rainfall, and the drying and dead forestwould release very large amounts of green-house gases. These impacts, like many oth-ers, would cause further threshold events.

If this kind of momentum builds suffi-ciently, and enough tipping points arecrossed, we will pass a point of no return. Wewish it were otherwise. Indeed, this is not abook we intended to write; but when ourwork led us to understand that we hadalready entered the era of dangerous climatechange, it became a story we felt compelledto tell.

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Originally, we wrote this book as a reportto address three areas of climate policy thatwe wished to bring to the attention of theGarnaut Climate Change Review (the Gar-naut Review): the implications of recent cli-mate research, appropriate reduction tar-gets, and the case for emergency action. Thereview was commissioned by the Australianfederal Labor leader Kevin Rudd, and thestate and territory Labor governments, sixmonths prior to the November 2007 federalelection that swept Labor to power.

Our first concern in presenting ideas to thereview was to draw attention to the serious-ness of recent climate data.

Our second concern was to show that a re-sponse to the climate crisis in politics asusual mode would not be fast enough tosolve the problem.

Our third concern was to encourage the re-view to choose targets that would achieve asafe result and not replicate mistakes made

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elsewhere in setting targets that would be in-effective. An example of this was the SternReview, delivered to the UK government inlate 2006 and received enthusiastically inmost quarters. The economist Sir NicholasStern had graphically outlined the future im-pacts of rising global temperatures. An in-crease of 2 degrees above the pre-industriallevel was not acceptable, he explained, be-cause it would likely mean, amongst otherthings, the loss of 1540 per cent of species,a loss of fresh water of 2030 per cent invulnerable regions, and the potential for theGreenland ice sheet to begin melting irre-versibly, pushing sea levels up severalmetres.

Sterns conclusion, however, was chilling:to limit the rise to 2 degrees was, in his opin-ion, too challenging, politically and econom-ically. Instead, he suggested going for a 3-de-gree target. Yet a 3-degree rise would likelydestroy most ecosystems and take global

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warming beyond the control of human ac-tion. It seemed incomprehensible that so fewpeople spoke out forcefully against Sternstarget and the death sentence that he was ac-cepting for so many people and species. Howcould society be so mad as to go for a targetthat would kill much of the planets life?

As we started to write our short submis-sion, events in the Arctic intervened todemonstrate dramatically that dangerous cli-mate change is not in the future, but is hap-pening now. Over one northern summer, itbecame clear that the task was not to weighup what would be a reasonable rise in tem-perature; rather, it was to ask: by how muchdo we need to lower the existing temperatureto return our planet to the safe-climate zone?Global warming now demands an emergencyresponse in which we put aside business andpolitics as usual, and devote our collectiveenergy and capacity for innovation to stop-ping a slide to catastrophe.

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Why do business leaders, politicians, com-munity advocates, and sectors of the envir-onment movement fail to grasp fully the mo-mentous problem that we face? How canthey not get it, when the evidence is now soabundant? We hope that this book will helpto identify why real action has so often beenblocked, and help to map out a pathwaythrough the barriers.

Many people, including UN secretary-gen-eral Ban Ki-Moon, now call the situation thatwe face a climate emergency; but it couldjust as easily be called a warming, water,food, or energy emergency. The issues ofglobal warming, water shortages, peak oil,ecosystem destruction, resource depletion,global inequity, and the threat of pandemicsintersect and intertwine. Together, thesethreats and risks constitute a sustainabilitycrisis, or emergency.

In exploring these ideas, our short submis-sion became this unintentional and lengthier

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book. The story we tell is disturbing andcompelling, in equal measure. It poses achoice: to act with great effort now, or toknow that it will soon be too late to act ef-fectively. It will be little comfort ten yearsfrom now to look back and think ruefully ofwhat we might have done, and of what mighthave been achieved.

Climate Code Red has three interrelatedparts.

The first section reviews the scientificevidence and a range of expert insights flow-ing from the increasing speed of the Arcticsea-ice melt. It also considers recent climatedata and analysis about critical subjects suchas carbon sinks, biodiversity loss, and cli-mate sensitivity. Drawing on this review, thesecond section analyses current debatesabout climate targets, and proposes a set ofreduction targets consistent with achieving asafe-climate future. The third section identi-fies the need for a rapid transition to a

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sustainable economy. It argues that the taskneeds to be constructed as a climate emer-gency that we cannot continue at the me-andering, slow pace dictated by businessand politics as usual, which today stands inthe way of necessary change.

* The increase to date has been 0.8 degrees.

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PART ONEThe Big Melt

We are all used to talking about theseimpacts coming in the lifetimes of our chil-dren and grandchildren. Now we know thatits us.

Professor Martin Parry, co-chairman of the In-

tergovernmental Panel on Climate Change (IPCC) im-

pacts working group, 18 September 2007.

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CHAPTER 1Losing the Arctic Sea-Ice

In the northern summer of 2007, the areaof sea-ice floating on the Arctic Oceandropped dramatically, reaching the lowestextent that we have seen since recordsbegan. This event has profound con-sequences for climate policy, the role andmethods of the Intergovernmental Panel onClimate Change (IPCC), and the assessmentof predicted sea-level rises, and it begs thequestion of whether we have already passeda critical tipping point beyond which humaninterference with the Earths climate systembecomes very dangerous.

In its February 2007 report on the physic-al basis of climate science, the IPCC said thatArctic sea-ice was responding sensitively toglobal warming: While changes in winterseaice cover are moderate, late summer sea-

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ice is projected to disappear almost com-pletely towards the end of the twenty-firstcentury. The IPCC thought it would take ahundred years for the sea-ice to disintegrate;but, even before its report was published, itsprojections lagged behind the changingphysical reality of the Arctic environment.

In a presentation to a Carnegie Institutionclimate conference on 1 November 2005,Tore Furevik, professor of oceanography atthe Geophysical Institute in Bergen, hadalready demonstrated that actual Arctic sea-ice retreat in recent years has been greaterthan had been estimated in any of the 19Arctic models of the IPCC.

In December 2006, data was presented toan American Geophysical Union (AGU) con-ference suggesting that the Arctic may befree of all summer sea-ice as early as 2030.According to Marika Holland of the US Na-tional Center for Atmospheric Research(NCAR) in Colorado, this would set up a

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positive feedback loop with dramatic implic-ations for the entire Arctic region. This viewwas then supported by studies published inMarch and May 2007 by Holland, along withMark Serreze and Julienne Stroeve of the USNational Snow and Ice Data Centre (NSIDC)at Colorado University.

Soon, events on the ground would outruneven this research. Despite the warnings, ex-perts were shocked at the extent of Arcticice-sheet loss during the 2007 northern sum-mer. Serreze told the Guardian on 4 Septem-ber: Its amazing. Its simply fallen off a cliffand were still losing ice.

A feature in the Washington Post on 22October 2007 painted a bleak picture:

This summer the ice pulled back even more, by

an area nearly the size of Alaska. Where explorer

Robert Peary just 102 years ago saw a great white

disk stretching away apparently infinitely from

Ellesmere Island, there is often nothing now but open

water. Glaciers race into the sea from the island of

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Greenland, beginning an inevitable rise in the oceans.

Animals are on the move. Polar bears, kings of the

Arctic, now search for ice on which to hunt and bear

young. Seals, walrus and fish adapted to the cold are

retreating north. New species salmon, crabs, even

crows are coming from the south. The Inuit, who

have lived on the frozen land for millennia, are seeing

their houses sink into once-frozen mud, and their

hunting trails on the ice are pocked with sinkholes.

On 16 September 2007, the Arctic sea-iceminimum fell to a record low of 4.13 millionsquare kilometres, compared to the previousrecord low of 5.32 million square kilometresin 2005. This represented a precipitous de-cline in the ice extent of 22 per cent in twoyears, an area roughly the size of Texas andCalifornia combined, or nearly five UnitedKingdoms, the NSIDC announced. Thiscompares to the decreasing trend in ice areaof 7 per cent per decade, between 1979 and2005.

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NSIDC research scientist Walt Meier toldthe Independent on 22 September that the2007 ice extent was the biggest drop from aprevious record that weve ever had and itsreally quite astounding Certainly wevebeen on a downward trend for the last thirtyyears or so, but this is really accelerating thetrend.

But it wasnt just the area, or extent, of thesea-ice that was declining rapidly; an evenmore dramatic story lay hidden beneath. Inthe early 1960s, the ice was 3.5 metres thick;by the late 1980s, it was down to 2.5 metres;and now, in 2008, large areas are only 1metre thick. This thinning is accelerating,with half of it having occurred in the pastseven years. Taken together, the shrinkingice area and the declining ice thickness meanthat the total mass of summer ice hasdropped to less than 20 per cent of thevolume that it was 30 years ago.

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Before the big melt of September 2007,Serreze had speculated that we may havealready reached the tipping point at whichthere is rapid sea-ice disintegration: The bigquestion is whether we are already there orwhether the tipping point is still ten or 20years in the future my guts are telling mewe may well be there now. His educatedguess was a transition to an ice-free Arcticsummer by 2030. His colleague at ColoradoTed Scambos agreed: 2030 is not unreason-able I would not rule out 2020, given non-linearity and feedbacks I just dont see ahappy ending for this.

These views were supported by Ron Lind-say of the University of Washington: Our hy-pothesis is that weve reached the tippingpoint. For sea-ice, the positive feedback isthat increased summer melt means de-creased winter growth and then even moremelting the next summer, and so on.

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In 2006, former Australian of the Year,palaeontologist, and climate-change activistTim Flannery suggested that at the traject-ory set by the new rate of melt, however,there will be no Arctic icecap in the next fiveto fifteen years. By the time September 2007was over, even these predictions would needto be revised: it was becoming a battle forscientists to keep up with a dramatic climateevent that was moving at unimagined speed.

Wieslaw Maslowski of the Naval Post-graduate College in California used US milit-ary submarine sonar mapping of the Arcticsea-ice during the many decades of the ColdWar in his research, in which he modelledthe processes of Arctic sea-ice loss. As earlyas 2004, he predicted a blue Arctic Oceanfree of sea-ice by the summer of 2013, havingrecognised that the thinning ice was losingvolume at a much faster rate than was indic-ated by satellite-derived surface-area data.

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The polar icecap is now floating in waterabout 3.5 degrees warmer than its historicalaverage. Maslowski found that the sea-ice isbeing thinned by the northward heat flux ofwarm summer Pacific and Atlantic waters,not just higher air temperatures. The US Na-tional Oceanic and Atmospheric Administra-tions (NOAA) Arctic report card for 2007also found that a new wind-circulation pat-tern is blowing more warm air towards theNorth Pole than during the previous century;in 2007, winter and spring temperatureswere all above average throughout the wholeArctic and all at the same time, unlike inprevious years.

A team led by Donald Perovich of the ColdRegions Research and Engineering Laborat-ory in New Hampshire reported in 2007 onresearch which calculated that, since 1979,the Arctic Ocean has been absorbing suffi-cient additional heat to melt up to 9300 cu-bic kilometres of sea-ice, which is equivalent

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to 3 million square kilometres of ice, 3metres thick. This is consistent with work byMaslowski and others suggesting that themajority of the ice loss is coming from warm-er seas, and not directly from changes in theArctic climate.

When the ice becomes sufficiently thin, itwill be sensitive to a kick from natural cli-mate variations, such as stronger wind andwave-surge action, which will result in rapidloss of the remaining summer ice cover. Itcould happen any year now. Louis Fortier,scientific director of the Canadian researchnetwork ArcticNet, says worst-case scenariosabout sea-ice loss are coming true, and thatthe Arctic Ocean could be ice-free in sum-mertime as soon as 2010. Maslowski told theDecember 2007 conference of the AGU thatour projection of 2013 for the removal of icein summer is not accounting for the last twominima, in 2005 and 2007 So given thatfact, you can argue that maybe our

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projection of 2013 is already too conservat-ive. NASA climate scientist Jay Zwally toldthe same conference that, after reviewing re-cent data, he had concluded that the ArcticOcean could be nearly ice-free at the end ofsummer by 2012, while Josefino Comiso ofthe NASA Goddard Space Centre said: Ithink the tipping point for perennial sea-icehas already passed It looks like [it] willcontinue to decline and theres no hope for itto recover [in the near period]. NASA satel-lite data shows the remaining Arctic sea-iceis unusually thin, making it more likely tomelt in future summers.

While the extent of the sea-ice in winter isabout the same as it has been over recentdecades, winter ice is becoming increasinglyfragile. As the summer extent shrinks, moreof the reset winter ice is new, first-year ice.In 2007, only 13 per cent of first-year ice sur-vived the melt season. Because the summer-ice minimum was a record low in 2007,

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almost two-thirds of the winter ice was first-year ice and, as such, is in a highly vulner-able state. As a result, the northern summerof 2008 is likely to see even more openwater.

How many more years will it be before theArctic is icefree in summer? The ice retreat islikely to be even bigger each summer, be-cause the refreezing of the ocean surface isstarting from a bigger deficit each year, andthe amount of older ice is continuing to de-crease. Looking at the trends, it is not diffi-cult to see why it may happen in 2009 or2010, depending on regional weatherpatterns.

Publicly and privately, many cryosphereclimate scientists are shocked and alarmed atthese developments. Some Australian cli-mate scientists have expressed similar senti-ments, privately acknowledging that the is-sues of dangerous climate change, caps, andmitigation strategies need urgent review, and

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that much of the orthodox thinking on theseissues is now out of date. What constitutesdangerous climate change is being urgentlyreviewed.

The reason so much [of the Arctic ice]went suddenly, is that it is hitting a tippingpoint that we have been warning about forthe past few years, says the head of NASAsGoddard Institute for Space Studies, JamesHansen. He has repeatedly warned that thealbedo flip trigger mechanism over largeportions of ice sheets could lead to eventualnon-linear ice sheet disintegration.

Hansen coined the phrase albedo flip todescribe a rapid change, or flip, in the cli-mate that occurs when large areas of icesheets are lost as a consequence of human-induced warming. In relation to climate, al-bedo is a measure of the proportion of solarradiation that is reflected (rather than ab-sorbed) when it hits the Earths surface.White ice reflects most of the radiation (with

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an albedo of 0.80.9), whereas dark sur-faces, such as bitumen or dark sea, can havean albedo of less than 0.1 (the Earths aver-age albedo is 0.3). So when light-reflectingice sheets are lost and replaced by dark sea,rock surface, or green vegetation, the Earthsuddenly absorbs a lot more solar radiation,and the region can heat rapidly. The heatingcauses more regional ice-sheet disintegra-tion, in a classic example of positive feed-back. This is now occurring in the Arctic.The eventual consequence is higher globaltemperatures, which we estimate will in-crease by around 0.3 degrees.

There are other factors that impact on thealbedo effect. As ice is lost and regional tem-peratures increase, the atmosphere holdsmore water vapour and the cloud-cover in-creases, and this negative feedback cancelsout some of the warming effect from the lossof reflective sea-ice. General climate modelsdo show that the cloud feedback can damp,

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or delay, the climate systems response, butthey also show that surface albedo changesfar outweigh the influence of cloud changes.There are no general climate model studieswhich specifically address the question of theglobal warming that is likely to occur as aconsequence of the total loss of the Arcticsea-ice and its albedo effect, but a finding ofa 0.01 degree warming for every 1 per cent ofice-sheet loss indicates that 0.3 degreeswould be the eventual global warming thatwould result from total Arctic sea-ice loss. Ahigher figure may be more consistent withrecent evidence, including typical temperat-ure flips in glacialinterglacial cycles. On theother hand, there is a small chance that laterthis century an abrupt change in the NorthAtlantic thermohaline circulation (the GulfStream), caused by global warming, couldgenerate a strong cooling effect along theNorwegian coast, which would lead to the

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reestablishment of year-round Arctic sea-icecover.

But there is much support for Hansensalbedo-flip predictions, including from PlPrestrud of Oslos Center for InternationalClimate and Environmental Research, whosays: We are reaching a tipping point, or arepast it, for the ice. This is a strong indicationthat there is an amplifying mechanism here.

The 2007 summer Arctic Ocean surfacetemperatures are estimated to have beenmuch warmer than in previous years, by upto 5 degrees, largely as a result of solar heat-ing of the upper ocean, which was the resultof less cloud cover increasing the albedofeedback. That feedback is the key to whythe models predict that the Arctic warming isgoing to be faster, Zwally told the 2007 AGUmeeting. Its getting even worse than themodels predicted.

There are also questions about the quant-ity of methane and carbon dioxide that will

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be released as a consequence of rapid region-al warming, as areas of tundra permafrost inthe polar north defrost. One initial estimateis that carbon dioxide released from perma-frost may contribute an extra 0.7 of a degreeover the next 100 years, based on predictedglobal warming of 2 degrees. But there is un-certainty about these figures, because theydepend on how much extra positive feedbackis included, for example, from water vapour;how much permafrost is thawed; and howmuch carbon is released. This figure is a con-servative estimate, because it does not in-clude the warming effect of methane release.

The Arctic summer of 2007 demands thatwe look in detail at its consequences. Sea-iceloss and Arctic warming are affecting thepermafrost in Siberia, Alaska, and other re-gions; they are triggering caribou decline inCanada; and they are shrubifying the tun-dra. What happens in the Arctic actuallydoes not stay in the Arctic, says

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oceanographer Richard Spinrad, who isdeputy chief of the NOAA. In this case, oneof the most significant knock-on impacts isgoing to be on the Greenland ice sheet.

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CHAPTER 2Greenlands Fate

Covering four-fifths of the landmass ofGreenland is an ice sheet almost 2400 kilo-metres long, more than 2 kilometres thick,and 1100 kilometres across at its widestpoint. It contains more than 2.8 million cu-bic kilometres of ice. If it were to melt en-tirely, it would raise sea levels by more than7 metres. The question is, will it melt andhow quickly?

The 2001 IPCC reports suggested thatneither the Greenland nor the Antarctic icesheets would lose significant mass by 2100.By the final IPCC report for 2007, this de-gree of certainty was evaporating, with aview that uncertainties in the full effectsof changes in ice sheet flow contributed toan unwillingness to put an upper bound onsea-level rises this century. The IPPC noted

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that partial loss of ice sheets on polar landcould imply metres of sea level rise Suchchanges are projected to occur over millenni-al time scales, but more rapid sea level riseon century time scales cannot be excluded.It suggested that the Greenland ice sheetwould be virtually eliminated, and wouldresult in a sea-level rise of 7 metres, if globalaverage warming were sustained for millen-nia in excess of 1.9 to 4.6 degrees. In otherwords, the IPCC felt that if the disintegrationof the Greenland ice sheet were to betriggered, the process of loss would take athousand years or more to conclude.

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This understanding was soon supersededwhen it was found that widening cracks inthe massive ice sheet were producing an un-expected effect: as surface-melt water ran

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across the ice, it formed streams thatwidened into a torrent of water which waspouring through the cracks and carving awider cavity as it rushed, like a giant water-fall, into an icy void below.

An already famous photograph by RogerBraithwaite of the University of Manchester(see previous page) shows the diminutive fig-ures of his fellow scientists, dwarfed by arapidly flowing gully of water several metreswide that gathered speed and then disap-peared into one of these cavities, winding itsway down many hundreds of metres througha honeycomb that the cracking and the waterflow had opened up. Reaching the base of theice sheet, the water acted to lubricate themovement of the ice sheet over the rockybottom.

This new wet process helps to explainwhy Greenland is losing ice mass morequickly than predicted. Two studies pub-lished in 2006 (one led by Eric Rignot of

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NASAs Jet Propulsion Laboratory in Pas-adena, and another from the University ofTexas) found that the Greenland ice cap maybe melting three times faster than indicatedby previous measurements, and that themass loss is increasing with time. Rignottold New Scientist: These results absolutelyfloored us The glaciers are sending us asignal. Greenland is probably going to con-tribute more and faster to sea-level rise thanpredicted by current models.

Greenland experienced more days of melt-ing snow in 2006 than the island had aver-aged over recent decades. According toNASA researcher Marco Tedesco, the areaexperiencing at least one day of melting hasbeen increasing since 1992 at a rate of35,000 square kilometres per year, and themelt extent for 2007 was the largest recor-ded since satellite measurements began, in1979. Thomas Mote of the Climatology Re-search Laboratory at the University of

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Georgia found the summertime melt in 2007to be the most extreme so far: 60 per centgreater than the previous highest rate, in1998. The edges of the ice sheet are meltingup to ten times more rapidly than earlier re-search had indicated, and the ice-sheetheight is falling by up to 10 metres a year.

The University of Colorados Konrad Stef-fen says that air temperatures on the Green-land ice sheet have increased by 4 degreessince 1991, and that the trend toward in-creases in the total area of bare ice that issubject to at least one days melting per yearis unmistakeable, at 13 per cent per year.Steffen says the ice-loss trend in Greenlandis similar to the trend of Arctic sea-ice in re-cent decades, suggesting the rate of loss maybe increasing exponentially.

Robert Corell, the chair of the IPCCs Arc-tic Climate Impact Assessment, says ofGreenland: Nobody knows now how quicklyit will melt This is all unprecedented in the

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science Until recently, we didnt believe itpossible, for instance, for water to permeatea glacier all the way to the bottom. But thatswhats happening. As the water pools, itopens more areas of ice to melting. As theice sheet cracks into huge pieces that are sev-eral cubic kilometres in size, it scrapes acrossthe bedrock and triggers earthquake-liketremors. And there is an acceleration of thespeed at which Greenland glaciers are mov-ing into the sea; some glacier velocities havemore than doubled. The Jacobshavn Glacier,a major Greenland outlet glacier that drainsroughly 8 per cent of the ice sheet, has spedup nearly twofold in the last decade. Anotherindication of Greenlands shrinking ice cap isevidence that its landmass is rising by up to4 centimetres per year, a buoyancy producedby carrying less weight of ice.

At some point, the trajectory of ice disin-tegration may pass a tipping point for the

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loss of, at least, a substantial portion ofGreenlands ice sheet.

Global warming has so far been greatest inthe high latitudes of the northern hemi-sphere, particularly in the subArctic forestsof Siberia and North America. And becauseArctic temperatures rise more than twice asmuch as the global average, a global warm-ing of 2 degrees is likely to result in averageannual warming over the Arctic of 3.26.6degrees. With Greenlands critical-meltthreshold estimated to be a regional warm-ing of 2.7 degrees, this point will be triggeredby a global rise of just over 1 degree a risethat is now considered impossible to avoid.

Tipping points may be looming, and wemay not be aware of it. Is Greenland such acase? Before the full extent of the dramaticArctic sea-ice loss for 2007 was known, TimLenton of the University of East Anglia told aCambridge conference that we are close tobeing committed to a collapse of the

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Greenland ice sheet. In recognition of thelimits of climate science models, LondonSchool of Economics statistician LennySmith told the same conference that weneed to drop the pretence that [the models]are nearly perfect. He said that there weretoo many unknown unknowns, and that weneed to be more open about ouruncertainties.

According to a 2006 report in New Scient-ist magazine, rising Arctic regional temperat-ures are already at the threshold beyondwhich glaciologists think the [Greenland] icesheet may be doomed.

But the issue is disputed, because the or-thodox climate and ice-loss models forGreenland do not include the processes thatresult in meltwater penetrating crevassesand lubricating the glaciers flow. So how canwe know at what pace the loss of ice volumeis likely to proceed? James Hansen says ice-sheet disintegration starts slowly, but

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multiple positive feedbacks can lead to rapidnon-linear collapse. He says that there is thepotential for us to lose control, because wecannot tie a rope around a collapsing icesheet.

Hansen identifies a scientific reticencethat, in at least some cases, hinders commu-nication with the public about dangers ofglobal warming. He says, Scientific reti-cence may be a consequence of the scientificmethod. Success in science depends on ob-jective scepticism. Caution, if not reticence,has its merits; however, in a case such as icesheet instability and sea-level rise, there is adanger in excessive caution. We may ruereticence, if it serves to lock in futuredisasters.

But there are useful sources, other thanmodels, for thinking about the likely futurerate of loss of the Greenland ice sheet, in-cluding expert assessment and paleoclimato-logy (the study of ancient climates). In

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response to the concerns expressed byCorell, Hansen, and many others about theIPCC process and the currency of some of its2007 report, Michael Oppenheimer and hiscolleagues from Princeton University haveproposed that the inputs into IPCC reportsbe broadened. They say that the observation-al data, past climate record, and theoreticalevidence of poorly understood phenomenashould be given a comparable weight withevidence from numerical modelling. Oppen-heimer notes that, in areas in which model-ling evidence is sparse or lacking, the IPCCsometimes provides no uncertainty estimateat all; and, in other areas, the use of modelswith similar structures leads to an artificiallyhigh confidence in projections that is notwarranted. He also calls on the IPCC to fullyinclude judgements from experts.

In the absence of reliable, computer-basedmodels of the workings of the Greenland ice

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sheet, what do the experts think? Hansenasks:

Could the Greenland ice sheet survive if the Arc-

tic were ice-free in summer and fall? It has been ar-

gued that not only is ice-sheet survival unlikely, but

its disintegration would be a wet process that can pro-

ceed rapidly. Thus an ice-free Arctic Ocean, because it

may hasten [the] melting of Greenland, may have im-

plications for global sea level, as well as the regional

environment, making Arctic climate change centrally

relevant to [the] definition of dangerous human

interference.

Arctic climate researchers will say, off therecord, that this is not an unreasonable view;on the record, they will say that there are noverifiable models that produce this result.These statements are not in contradiction.

As for the paleoclimate record, global av-erage temperatures have now surpassedthose that thawed much of Greenlands icecap some 130,000 years ago, when the plan-et experienced a warm interlude from

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continent-covering glaciers, and seas were56 metres higher than today. Global warm-ing appears to be pushing vast reservoirs ofice on Greenland and Antarctica toward asignificant long-term meltdown. The worldmay have as little as a decade to take thesteps to avoid this scenario, says Hansen.

Following the extraordinary Arctic sum-mer of 2007, along with the arrival of newdata, a number of leading climate scientistshave spoken out, most notably at the Decem-ber 2007 AGU meeting. There, Hansen saidthat, based on Greenland melt data, theEarth has hit one of its tipping points, andthat the level of carbon dioxide in the atmo-sphere is now enough to cause Arctic sea-icecover and massive ice sheets, such as thoseon Greenland, eventually to melt away.

In summary, in the polar north it is reas-onable to expect rapid loss of the Arctic sea-ice, with a significant impact on regionaltemperatures. It is also reasonable to expect,

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as a consequence, an acceleration of the rateof loss of Greenland ice, which may alreadybe past its disintegration tipping point for alarge part of the ice sheet a situation thathad previously been predicted to occur along way into the future.

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CHAPTER 3Trouble in the Antarctic

Big changes are also underway at the oth-er end of the world, in the Antarctic, wheremost of the worlds ice sits on the fifth-largest continent. The majority of Antarcticice is contained in the East Antarctic icesheet the biggest slab of ice on Earth,which has been in place for some 20 millionyears and which, if fully melted, would raisesea levels by more than 60 metres.

Considered more vulnerable is the smallerWest Antarctic ice sheet, which containsone-tenth of the total Antarctic ice volume. Ifit disintegrated, it would raise sea levels byaround 5 metres, a similar amount to whatwe would see with a total loss of the Green-land ice sheet.

While it was generally anticipated that theWest Antarctic sheet would be more stablethan Greenland at a 12 degree rise, recent

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research demonstrates that the southern iceshelf reacts far more sensitively to warmingtemperatures than scientists had previouslybelieved. Ice-core data from the AntarcticGeological Drilling joint project (being con-ducted by Germany, Italy, New Zealand, andthe United States) shows that massive melt-ing must have occurred in the Antarcticthree million years ago, during the Mio-cenePliocene period, when the averageglobal temperature in the oceans increasedby only 23 degrees above the present tem-perature. Geologist Lothar Viereck-Gttecalled the results horrifying, and suggestedthat the ice caps are substantially more mo-bile and sensitive than we had assumed.

The heating effect caused by climatechange is greatest at the poles, and the airover the West Antarctic peninsula haswarmed nearly 6 degrees since 1950. At thesame time, according to a report in theWashington Post on 22 October 2007, a

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warming sea is melting the ice-cap edges,and beech trees and grass are taking root onthe ice fringes.

Another warning sign was the rapid col-lapse in March 2002 of the 200-metre-thickLarsen B ice shelf, which had been stable forat least twelve thousand years, and whichwas the main outlet for glaciers drainingfrom West Antarctica. An ice shelf is a float-ing sheet, or platform, of ice. Largely sub-merged, and up to a kilometre thick, theshelf abuts the land and is formed when gla-ciers or land-based ice flows into the sea.Generally, an ice shelf will lose volume bycalving icebergs, but these are also subject torapid disintegration events. Larsen B,weakened by water-filled cracks where itsshelf attached to the Antarctic Peninsula,gave way in a matter of days, releasing fivehundred billion tonnes of ice into the ocean.

Neil Glasser of Aberystwyth Universityand Ted Scambos from the NSIDC found

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that as glacier flow had begun to increaseduring the 1990s, the ice shelf had becomestressed. The warming of deep SouthernOcean currents (which increasingly reach theAntarctic coastline) had also led to somethinning of the shelf, making it more proneto breaking apart. Scambos concludes thatthe unusually warm summer of 2002, partof a multi-decade trend of warming [that is]clearly tied to climate change, was the finalstraw.

Looking at the overall pace of events,Scambos says: We thought the southernhemisphere climate is inherently morestable, [but] all of the time scales seem to beshortened now. These things can happenfairly quickly. A decade or two of warming isall you need to really change the mass bal-ance Things are on more of a hair triggerthan we thought.

Much of the West Antarctic ice sheet sitson bedrock that is below sea level, buttressed

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on two sides by mountains, but held in placeon the other two sides by the Ronne andRoss ice shelves; so, if the ice shelves thatbuttress the ice sheet disintegrate, sea waterbreeching the base of the ice sheet willhasten the rate of disintegration.

In 1968, the Ohio State University glaci-ologist John Mercer warned, in the journal ofthe International Association of ScientificHydrology, that the collapse of ice shelvesalong the Antarctic Peninsula could heraldthe loss of the ice sheet in West Antarctica. Adecade later, in 1978, his views received awider audience in Nature, where he wrote: Icontend that a major disaster a rapid de-glaciation of West Antarctica may be inprogress within about 50 years. Mercersaid that warming above a critical levelwould remove all ice shelves, and con-sequently all ice grounded below sea level,resulting in the deglaciation of most of WestAntarctica. Such disintegration, once under

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way, would probably be rapid, perhaps cata-strophically so, with most of the ice sheetlost in a century. Credited with coining thephrase the greenhouse effect in the early1960s, Mercers Antarctic prognosis waswidely ignored and disparaged at the time,but this has changed.

( James Hansen says it was not clear at thetime whether Mercer or his many criticswere correct, but those who labelled Merceran alarmist were considered more authorit-ative and better able to get funding. Hansenbelieves funding constraints can inhibit sci-entific criticisms of the status quo. As hewrote in New Scientist on 28 July 2007: Ibelieve there is pressure on scientists to beconservative. Hansen is responsible forcoining the term The John Mercer Effect,meaning to play down your findings for fearof losing access to funding or of being con-sidered alarmist.)

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Another vulnerable place on the WestAntarctic ice sheet is Pine Island Bay, wheretwo large glaciers, Pine Island and Thwaites,drain about 40 per cent of the ice sheet intothe sea. The glaciers are responding to rapidmelting of their ice shelves and their rate offlow has doubled, whilst the rate of mass lossof ice from their catchment has now tripled.NASA glaciologist Eric Rignot has studiedthe Pine Island glacier, and his work has ledclimate writer Fred Pearce to conclude thatthe glacier is primed for runaway destruc-tion. Pearce also notes the work of TerryHughes of the University of Maine, who saysthat the collapse of the Pine Island and Th-waites glaciers already the biggest causesof global sea-level rises could destabilisethe whole of the West Antarctic ice sheet.Pearce is also swayed by geologist RichardAlley, who says there is a possibility that theWest Antarctic ice sheet could collapse and

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raise sea levels by 6 yards [5.5 metres], thiscentury.

Hansen and fellow NASA Goddard Insti-tute for Space Studies researcher MakikoSato agree:

The gravest threat we foresee starts with surface

melt on West Antarctica, and interaction among pos-

itive feedbacks leading to catastrophic ice loss. Warm-

ing in West Antarctica in recent decades has been lim-

ited by effects of stratospheric ozone depletion.

However, climate projections find surface warming in

West Antarctica and warming of nearby ocean at

depths that may attack buttressing ice shelves. Loss of

ice shelves allows more rapid discharge from ice

streams, in turn a lowering and warming of the ice

sheet surface, and increased surface melt. Rising sea

level helps unhinge the ice from pinning points At-

tention has focused on Greenland, but the most recent

gravity data indicate comparable mass loss from West

Antarctica. We find it implausible that BAU

[business-as-usual] scenarios, with climate forcing

and global warming exceeding those of the Pliocene,

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would permit a West Antarctic ice sheet of present

size to survive even for a century.

Even in East Antarctica, where total iceloss would produce a sea-level rise of 60metres, mass loss near the coast is greaterthan the mass increase inland (mass increaseinland is caused by the extra snowfall gener-ated from warming-induced increases in airhumidity).

While the inland of East Antarctica hascooled during the last 20 years, the coast hasbecome warmer, with melting occurring 900kilometres from the coast and in theTransantarctic Mountains, which rise up toan altitude of 2 kilometres.

Research published in January 2008 byRignot and six of his colleagues shows thatice loss in Antarctica has increased by 75 percent in the last ten years due to a speed-up inthe flow of its glaciers, so that the ice lossthere is now nearly as great as that observedin Greenland.

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CHAPTER 4A Rising Tide

Many climate scientists received the 2007IPPC reports suggestion of a sea-level rise of1859 centimetres by 2100 with dismay not because it was too high, but because itseriously underestimated the problem. Be-fore the report was released, satellite datashowed sea levels had risen by an average of3.3 millimetres per year between 1993 and2006; the 2001 IPCC report, by contrast,projected a best-estimate rise of less than 2millimetres per year.

Now three researchers from Taiwans Na-tional Central University have calculatedthat, in the last half-century, water run-offimpounded on land (principally in dams)would have raised sea levels by another 3centimetres, or an average of 0.55 milli-metres per year, if it had been allowed toreach the sea. This means that the

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contribution to sea-level rises from ice-sheetdisintegration has been underestimated,which leads to the conclusion that the runofffrom melting mountain glaciers, includingthe Himalayas, is much greater than previ-ously thought.

In late 2006, work by Stefan Rahmstorf ofthe Potsdam Institute for Climate ImpactResearch (PICIR) concluded that previousestimates of how much the worlds sea levelwill rise as a result of global warming mighthave been seriously underestimated. Rahm-storf, an ocean physicist, said that the datanow available raises concerns that the cli-mate system, in particular sea level, may beresponding more quickly than climate mod-els indicate. Even before the IPCCs first re-port for 2007 was released in February,Robert Corell said that any prediction of asea-level rise by 2100 of less than a metrewould not be a fair reflection of what weknow.

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The final IPCC 2007 report, released on 16November, drew together individual reportspublished earlier in the year. It contained thefollowing qualification: Because under-standing of some important effects drivingsea-level rise is too limited, this report doesnot assess the likelihood, nor provide a bestestimate or an upper bound for sea levelrise. It added that the official projected sea-level rise of 18 59 centimetres this centurydid not include uncertainties in climate-car-bon cycle feedbacks nor the full effects ofchanges in ice sheet flow, therefore the uppervalues of the ranges are not to be consideredupper bounds for sea level rise. This begsthe question: why were the official projec-tions included at all if, in this innovative turnof phrase, the upper values of the ranges arenot to be considered upper bounds?

So, how much will sea levels rise this cen-tury? At what rate will the Greenland andWest Antarctic ice sheets disintegrate, and

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what influence will the earlier-than-anticip-ated loss of the Arctic sea-ice have on Green-lands rate of loss? These questions havecaused turmoil in scientific circles, because itis generally acknowledged that the sea-levelrise will be a good deal higher than theearly-2007 IPCC report suggests.

The IPCCs projection of a sea-level rise ofwell under a metre by 2100 was based onmodels that IPCC critics, including MichaelOppenheimer of Princeton, say [do not] in-clude the potential for increasing contribu-tions from rapid dynamic processes in theGreenland and West Antarctic ice sheets,which have already had a significant effecton sea level over the past 15 years and couldeventually raise sea level by many meters.They say that, lacking such processes, mod-els cannot fully explain observations of re-cent sea level rise, and accordingly, projec-tions based on such models may seriouslyunderstate potential future increases.

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Writing in the Guardian on 7 September2007, environment correspondent PaulBrown reported that scientists monitoring[Arctic] events this summer say the accelera-tion could be catastrophic in terms of sea-level rise and make predictions this February[2007] by the [IPCC] far too low. This topicis now the subject of urgent collaborativework between a number of agencies and re-search centres. There is also new concernabout the contribution to sea-level rises thatmay be made by the West Antarctic ice sheet.

James Hansen and his collaborators havetaken a leading role in this discussion, in anumber of recent peer-reviewed papers.Their essential argument, based on the pa-leoclimate record, is that the sea-level rise islikely to be about 5 metres this century ifemissions continue down the business asusual trajectory.

Here is the core of Hansens expertopinion:

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I find it almost inconceivable that business as

usual climate change will not result in a rise in sea

level measured in meters within a century ... Because

while the growth of great ice sheets takes millennia,

the disintegration of ice sheets is a wet process that

can proceed rapidly

[T]he primary issue is whether global warming will

reach a level such that ice sheets begin to disintegrate

in a rapid, non-linear fashion on West Antarctica,

Greenland or both. Once well under way, such a col-

lapse might be impossible to stop, because there are

multiple positive feedbacks. In that event, a sea-level

rise of several meters at least would be expected.

As an example, let us say that ice sheet melting

adds 1 centimeter to sea level for the decade 2005 to

2015, and that this doubles each decade until the

West Antarctic ice sheet is largely depleted. This

would yield a rise in sea level of more than 5 meters

by 2095.

Of course, I cannot prove that my choice of a

10-year doubling time is accurate but Id bet $1000 to

a doughnut that it provides a far better estimate of the

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ice sheets contribution to sea-level rise than a linear

response. In my opinion, if the world warms by 2C to

3C, such massive sea-level rise is inevitable, and a

substantial fraction of the rise would occur within a

century. Business as usual global warming would al-

most surely send the planet beyond a tipping point,

guaranteeing a disastrous degree of sea-level rise.

Although some ice sheet experts believe that the

ice sheets are more stable, I believe that their view is

partly based on the faulty assumption that the Earth

has been as much as 2 C warmer in previous intergla-

cial periods, when the sea level was at most a few

meters higher than at present. There is strong evid-

ence that the Earth now is within 1C of its highest

temperature in the past million years. Oxygen iso-

topes in the deep-ocean fossil plankton known as fo-

raminifera reveal that the Earth was last 2C to 3C

warmer around 3 million years ago, with carbon diox-

ide levels of perhaps 350 to 450 parts per million. It

was a dramatically different planet then, with no

Arctic sea-ice in the warm seasons and sea level about

25 meters higher, give or take 10 meters.

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There is not a sufficiently widespread appreciation

of the implications of putting back into the air a large

fraction of the carbon stored in the ground over

epochs of geologic time. The climate forcing caused by

these greenhouse gases would dwarf the climate for-

cing for any time in the past several hundred thou-

sand years the period for which accurate records of

atmospheric composition are available from ice cores.

Models based on the business as usual scenarios

of the Intergovernmental Panel on Climate Change

(IPCC) predict a global warming of at least 3C by the

end of this century. What many people do not realise

is that these models generally include only fast feed-

back processes: changes in clouds, water vapour and

aerosols. Actual global warming would be greater as

slow feedbacks come into play: increased vegetation

at high latitudes, ice sheet shrinkage and further

greenhouse gas emissions from the land and sea in re-

sponse to global warming.

The IPCCs latest projection for sea-level rise this

century is 18 to 59 centimeters. Though it explicitly

notes that it was unable to include possible dynamical

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responses of the ice sheets in its calculations, the pro-

vision of such specific numbers encourages a predict-

able public belief that the projected sea level change is

moderate, and indeed smaller than in the previous

IPCC report. There have been numerous media re-

ports of reduced predictions of sea-level rise, and

commentators have denigrated suggestions that busi-

ness as usual emissions may cause a sealevel rise

measured in meters. However, if these IPCC numbers

are taken as predictions of actual sea-level rise, as

they have been by the public, they imply that the ice

sheets can miraculously survive a business as usual

climate forcing assault for a millennium or longer.

There are glaciologists who anticipate such long

response times, because their ice sheet models have

been designed to match past climate changes.

However, work by my group shows that the typical

6000-year timescale for ice sheet disintegration in the

past reflects the gradual changes in Earths orbit that

drove climate changes at the time, rather than any in-

herent limit for how long it takes ice sheets to disin-

tegrate. Indeed, the paleoclimate record contains

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numerous examples of ice sheets yielding sea-level

rises of several meters per century when forcings were

smaller than that of the business as usual scenario.

For example, about 14,000 years ago, sea level rose

approximately 20 meters in 400 years, or about 1

meter every 20 years.

There is growing evidence that the global warm-

ing already under way could bring a comparably rapid

rise in sea level. The process begins with human-made

greenhouse gases, which cause the atmosphere to be

more opaque to infrared radiation, thus decreasing

radiation of heat to space. As a result, the Earth is

gaining more heat than it is losing: currently 0.5 to 1

watts per square meter. This planetary energy imbal-

ance is sufficient to melt ice corresponding to 1 meter

of sea-level rise per decade, if the extra energy were

used entirely for that purpose and the energy im-

balance could double if emissions keep growing.

So where is the extra energy going? A small part

of it is warming the atmosphere and thus contributing

to one key feedback on the ice sheets: the albedo flip

that occurs when snow and ice begin to melt. Snow-

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covered ice reflects back to space most of the sunlight

striking it, but as warming air causes melting on the

surface, the darker ice absorbs much more solar en-

ergy. This increases the planetary energy imbalance

and can lead to more melting. Most of the resulting

meltwater burrows through the ice sheet, lubricating

its base and speeding up the discharge of icebergs to

the ocean.

The area with summer melt on Greenland has in-

creased from around 450,000 square kilometers

when satellite observations began in 1979 to more

than 600,000 square kilometers in 2002. Seismomet-

ers around the world have detected an increasing

number of earthquakes on Greenland near the outlets

of major ice streams. The earthquakes are an indica-

tion that large pieces of the ice sheet lurch forward

and then grind to a halt because of friction with the

ground. The number of these ice quakes doubled

between 1993 and the late 1990s, and it has since

doubled again. It is not yet clear whether the quake

number is proportional to ice loss, but the rapid

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increase is cause for concern about the long-term sta-

bility of the ice sheet.

Additional global warming of 2C to 3C is expec-

ted to cause local warming of about 5C over Green-

land. This would spread summer melt over practically

the entire ice sheet and considerably lengthen the

melt season. In my opinion it is inconceivable that the

ice sheet could withstand such increased meltwater

for long before starting to disintegrate rapidly, but it

is very difficult to predict when such a period of large,

rapid change would begin.

Summer melt on West Antarctica has received

less attention than on Greenland, but it is more im-

portant. The West Antarctic ice sheet, which rests on

bedrock far below sea level, is more vulnerable as it is

being attacked from below by warming ocean water,

as well as from above by a warming atmosphere. Sa-

tellite observations reveal increasing areas of summer

melt on the West Antarctic ice sheet, and also a longer

melt season.*

[from Huge sea level rises are coming unless

we act now, New Scientist, 28 July 2007]

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Hansens argument has been cited atlength here because he is one of the worldsmost influential and outspoken climate sci-entists. He has provided a compelling cri-tique of the limitations of the IPCC models,and has helped to evolve a new understand-ing of the mechanics of rapid ice-sheet disin-tegration. He played a significant role inpublic debate in the US about global warm-ing, and twice testified before the Congresson climate change: the first occasion, in1987, caused a minor controversy whenHansen insisted that his group of climatemodellers could confidently state that majorgreenhouse climate changes are a certainty,and that the global warming predicted in thenext 20 years will make the Earth warmerthan it has been in the past 100,000 years.

Hansen has also endured having funds forthe NASA Goddard Institute for Space Stud-ies slashed by the Bush administration, be-cause he refused to stop his public advocacy

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on climate action and policy. Now he hasstaked his professional reputation on the is-sue of the speed of sea-level rises, with hispreparedness, in his own words, to bet$1000 to a doughnut that his view is closerto the mark than the view of the IPCC.

The incongruity of the IPCCs sea-levelprojection for 2100 can be seen in the follow-ing figure, which illustrates mean globaltemperature and sea level (relative to today)at different times in Earths history, along-side the IPCC projection for 2100 (the out-line circle). For the longer term, the paleocli-mate data suggests a much higher sea-levelrise at equilibrium than that projected by theIPCC for this century.

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Global temperature and sealevel

Mean global temperature and sea level (relative

to todays) at different times in Earths history, com-

pared with the IPCC projection for the year 2100.

Courtesy David Archer.

Now, with new Arctic data, Hansen hasfirmed his outlook. He told the December2007 AGU meeting that there is alreadyenough carbon in Earths atmosphere to en-sure that sea levels will rise several feet incoming decades, because the world, includ-ing Greenland, passed the tipping point formajor ice-sheet loss decades ago.

But long before the Greenland or WestAntarctic ice sheets fully disintegrate, eventhe loss of 20 per cent of Greenlands icevolume would be catastrophic. In his 2006report to the UK government, Sir NicholasStern noted that:

[C]urrently, more than 200 million people live in

coastal floodplains around the world, with two million

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square kilometres of land and one trillion dollars

worth of assets less than one metre elevation above

current sea level. One-quarter of Bangladeshs popu-

lation (~35 million people) lives within the coastal

floodplain. Many of the worlds major cities (22 of the

top 50) are at risk of flooding from coastal surges, in-

cluding Tokyo, Shanghai, Hong Kong, Mumbai, Kolk-

ata, Karachi, Buenos Aires, St Petersburg, New York,

Miami and London. In almost every case, the city re-

lies on costly flood defences for protection. Even if

protected, these cities would lie below sea level with a

residual risk of flooding like New Orleans today. The

homes of tens of millions more people are likely to be

affected by flooding from coastal storm surges with

rising sea levels. People in South and East Asia will be

most vulnerable, along with those living on the coast

of Africa and on small islands.

Underground water is the largest reserve of fresh

water on the planet, and more than two billion people

depend on it. Long before rising seas inundate the

land, aquifers will be contaminated. The 2006 confer-

ence of the International Association of

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Hydrogeologists heard that rising sea levels would

lead to salt-water inundation of the aquifers used by

cities such as Shanghai, Manila, Jakarta, Bangkok,

Kolkata, Mumbai, Karachi, Lagos, Buenos Aires, and

Lima. Fred Pearce described this problem in New

Scientist on 16 April 2006:

The water supplies of dozens of major cities

around the world are at risk from a previously ignored

aspect of global warming. Within the next few decades

rising sea levels will pollute underground water re-

serves with salt Long before the rising tides flood

coastal cities, salt water will invade the porous rocks

that hold fresh water The problem will be com-

pounded by sinking water tables due to low rainfall,

also caused by climate change, and rising water usage

by the worlds growing and increasingly urbanised

population.

In the low-lying eight-island Pacific nationof Tuvalu, contamination of water for do-mestic and agricultural use is already seri-ous, and it is a growing concern in other

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regional states, including Kiribati and theMarshall Islands.

While large sea-level-rise figures mayseem abstract, a rise of 1 metre will have adevastating impact on densely populatedriver deltas in the developing world, ashomes and agricultural land are lost anddamaged by storm surges. In industrialisedregions, small rises will have severe impactson coastal infrastructure: loss of beaches,ports, and shipping facilities; flooding oftransport links; inundation of undergroundfacilities, including sewers, water, electricitytransmission, and communications infra-structure; as well as the loss of industrial anddomestic buildings.

The degree to which this rise would phys-ically impinge on these coastal areas is hardto imagine, but one can get a powerful visualsense of it by using Google Maps with a sea-level rise overlay (for example,lood.firetree.net), which is instructive for

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understanding the lessons from the Arcticsummer of 2007, and from West Antarctica.

* All warmings in this quoted material are relative to the

temperature in 2000.

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CHAPTER 5The Quickening Pace

How sensitive is the Earth to changes ingreenhouse gases and other influences thatshape or force the climate? In 1977, meteor-ologist Jule Charney developed what has be-come the yardstick for comparing estimatesof climate sensitivity (which is the warmingestimated to occur if carbon dioxide levelswere doubled from pre-industrial levels).

Climate-sensitivity research has producedquite divergent results, particularly earlieron, but a warming of 3 degrees is now thewidely accepted estimate, known as theCharney 3C. The main point is that, thehigher the figure, the more trouble we aregoing to be in.

The 2007 IPCC report uses EquilibriumClimate Sensitivity (ECS) models to concludethat the warming is likely to be in the rangeof 2 to 4.5 degrees with a best estimate of

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about 3 degrees, and is very unlikely to beless than 1.5 degrees. Values substantiallyhigher than 4.5 degrees cannot be excluded,but agreement of models with observationsis not as good for those values. Nevertheless,a number of studies have found larger pos-sible ranges, including ranges of 110 de-grees and 1.47.7 degrees. One study evensuggested that there is a 54 per cent likeli-hood that climate sensitivity lies outside theIPCC range.

In 2006, Barrie Pittock, a former seniorclimate scientist for Australias Common-wealth Scientific and Industrial Research Or-ganisation (CSIRO), suggested that thedated IPCC view might underestimate theupper end of the range of possibilities,adding that there is a much higher probabil-ity of warmings by 2100 exceeding the mid-level [climate sensitivity] estimate of 3 de-grees. He wrote in the journal Ecos that re-cent data suggests critical levels of global

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warming may occur at even lowergreenhouse-gas concentrations than wereconsidered to be the danger level in the 2001IPCC report, and identifies at least eightareas of concern. These include the lesseningof global dimming, increased permafrostmelting, release of soil carbon, Arctic sea-iceretreat, circulation change in mid to high lat-itudes, rapid changes in Greenland andAntarctica, increasing intensity of tropicalcyclones, and a slowing of the Gulf Stream.

A doubling of greenhouse gases would takethe pre-industrial carbon dioxide level of280 parts per million to 560 parts per mil-lion. Given that carbon dioxide levels in theatmosphere are now at 387 parts per million,we are already one-third of the way to thatdoubling. And if we take into account thewarming of 0.8 degrees that weve experi-enced so far, and add the delayed warming(still in the pipeline) of 0.6 degrees, alongwith the 0.3-degree effect of the Arctic

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albedo flip, current climate-energy imbal-ances alone will, eventually, warm the planetby around 1.7 degrees. It seems likely, then,that the global temperature-increase whichwill occur at 560 parts per million of carbondioxide will be a lot more than the mid-rangeclimate-sensitivity estimate of 3 degrees especially if major ice sheets and rainforestsare lost, and carbon sinks (such as theoceans and the soils, which absorb and re-lease carbon as parts of the natural cycle)continue to weaken along the current trends.

The 3-degree sensitivity estimate onlytakes into account fast feedbacks that comeinto play quickly. Water vapour, for example,is a greenhouse gas, and the air holds morewater vapour as the temperature increases,which produces a fast feedback. Other fastfeedbacks include changes in cloud cover,snow cover, and sea-ice extent.

The problem is that ECS models omitslow feedbacks, such as ice sheet growth

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and decay, change in vegetation cover, per-mafrost melting and methane release, andcarbon-cycle feedbacks, all of which amplifyclimate changes on time scales of decades tocenturies.

Hansen and Sato argue that, while theCharney 3C is reasonable in the short run,the total long-term climate sensitivity for fastand slow feedbacks is likely to be about 6degrees for doubled carbon dioxide, basedon the paleoclimate data. In terms of thetime scale of the last three decades, they say:

[T]he Charney sensitivity is a good approxima-

tion, as little contribution from slow feedbacks would

be expected. Thus climate models with 3-degree sens-

itivity for doubled carbon dioxide, incorporating only

the fast feedbacks, are able to achieve good agreement

with observed warming of the past century. We sug-

gest, however, [that] these models provide only a

lower limit on the expected warming on century time

scales due to the assumed forcings. The real world will

be aiming in the longer run at a warming

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corresponding to the higher climate sensitivity [of 6

degrees].

Hansen and Sato say that slower feed-backs (including the pole-ward movement offorests, shrinking and loss of ice sheets, andrelease of methane from melting tundra) arelikely to be significant on decade-to-centurytimescales, as we are now starting to witness.Those slower feedbacks mean that coming toan understanding of what would constitutedangerous climate change becomes moreurgent, as does finding a path to avoid it.

Paleoclimate data identifies the impactthat these missing slow feedbacks have inpushing temperatures higher than expected.New research matching greenhouse-gaslevels with the Earths temperature over thelast 450,000 years has established the cli-mate sensitivity with slow feedbacks to be 6degrees. Fifty-five million years ago, in theArctic, temperatures were 11 degrees warmerthan the ECS models would predict which

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also suggests that other feedback mechan-isms were at work.

A paper published in the June 2005 issueof Nature supports the theory of even higherclimate sensitivity. It describes research ledby Meinrat Andreae of the Max Planck Insti-tute for Chemistry in Germany, which usedclimate models and various aerosol-coolingassumptions to find the best fit for the datainvolved in a climate sensitivity in excess of 6degrees. By studying the planets climate his-tory over the last 50 years and fitting it tovarious climate-model options, they con-cluded that the effects of airborne particlepollution (or aerosols: soot and exhaustsfrom burning fossil fuels, industrial pollu-tion, and dust storms) and climate sensitivityare both much higher than generally as-sumed. They say that greater pollution con-trols and clean air legislation will removemuch of the aerosol cooling, and that if car-bon dioxide levels are double their pre-

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industrial levels by 2100, a rise of 6 degreescan be expected. When this understanding iscombined with predictions that parts of thenatural carbon cycle after 2050 will reversefrom being net absorbers to net emitters ofcarbon, they say that warming by 2100 maybe as high as 10 degrees.

These findings have enormous implica-tions. A long-term climate sensitivity of 6 de-grees would mean that we have alreadypassed the widely advocated 2-degreethreshold of dangerous anthropogenic inter-ference with the climate. It would, therefore,require us to find the means to engineer arapid reduction of current atmosphericgreenhouse gas even to restrict global warm-ing to below 2 degrees a target which webelieve is, in any case, far too high.

A key question is whether the slow feed-backs have started to operate. In the case ofthe Greenland and Antarctic ice sheets, thedata is already disturbing. One of the most

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important slow feedbacks to be considered isthe reversing of the carbon cycle as theoceans and soils take up less carbon dioxide and the significant amounts of methaneand carbon dioxide that are released by thepermafrost.

Understanding how the carbon cycleworks and how changes in the cycle will af-fect global warming are important in under-standing the scale of action required to avoidcatastrophic climate changes.

The carbon cycle is the flow and exchangeof carbon in its various forms (including car-bon dioxide, methane, and calcium carbon-ate) between the planets four large, inter-connected carbon reservoirs: the atmosphere(carbon dioxide); the oceans (carbon dioxidedissolved in seawater, carbon incorporatedin living and non-living plants and animals,and methane trapped under pressure on theocean floor); fossil organic carbon (coal, gas,and oil); and the land-surface biosphere

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(including soils, plants, and freshwater sys-t