Climate Change in the Polar Regions

449 Pages·2011·14.42 MB·English

by  John Turner

CLIMATE CHANGE IN THE POLAR REGIONS
The polar regions have experienced some remarkable environmental changes in recent
decades, such as the Antarctic ozone hole, the loss of large amounts of sea ice from the
Arctic Ocean and major warming on the Antarctic Peninsula. The polar regions are also
predictedtowarmmorethananyotherregiononEarthoverthenextcenturyifgreenhouse
gas concentrations continue to rise. Yet trying to separate natural climate variability from
anthropogenicforcingstillpresentsmanyproblems.Thisbookpresentsathoroughreview
ofhowthepolarclimateshavechangedoverthelastmillionyearsandsetsrecentchanges
within the long-term perspective, as determined from ice and ocean sediment cores. The
approach taken is highly cross-disciplinary and the close links between the atmosphere,
oceanandiceathighlatitudesarestressed.Thevolumewillbeinvaluableforresearchers
and advanced students in polar science, climatology, global change, meteorology, ocean-
ographyandglaciology.
John Turner isa research scientistat theBritishAntarctic Survey inCambridge, UK,
where he leads a project investigating recent Antarctic climate change and how it may
changeoverthenextcentury.HehashadalonginvolvementwiththeScientificCommittee
onAntarcticResearch(SCAR):hewastheChiefOfficerofthePhysicalSciencesStanding
Scientific Group from 2002 to 2006 and chaired the steering committee of the SCAR
programme on Antarctica and the Global Climate System from 2005 to 2008. He is the
co-author of Antarctic Meteorology and Climatology (1997) and Polar Lows: Mesoscale
WeatherSystemsinthePolarRegions(2003),bothofwhicharepublishedbyCambridge
University Press. He was awarded the International Journal of Climatology Prize of the
RoyalMeteorologicalSocietyin2005.
Gareth J.Marshall isaclimatologistattheBritishAntarcticSurveywhereheisthe
Climate programme coordinator. He has worked at BAS since 1995 after completing his
PhD at the University of Cambridge. His research has included field work in both polar
regions and he has contributed to more than 50 scientific papers. Recently, he was a
corresponding author on the Intergovernmental Panel on Climate Change Fourth
Assessment Report. He is also a member of the World Climate Research Programme
CLIVAR Southern Ocean panel, which addresses climate variability and predictability in
thisregion.

CLIMATE CHANGE IN THE POLAR
REGIONS
JOHN TURNER
BritishAntarcticSurvey
AND
GARETHJ. MARSHALL
BritishAntarcticSurvey
cambridge university press
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CambridgeUniversityPress
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Informationonthistitle:www.cambridge.org/9780521850100
©JohnTurnerandGarethJ.Marshall2011
Thispublicationisincopyright.Subjecttostatutoryexception
andtotheprovisionsofrelevantcollectivelicensingagreements,
noreproductionofanypartmaytakeplacewithoutthewritten
permissionofCambridgeUniversityPress.
Firstpublished2011
PrintedintheUnitedKingdomattheUniversityPress,Cambridge
AcataloguerecordforthispublicationisavailablefromtheBritishLibrary
LibraryofCongressCataloguinginPublicationdata
Turner,J.(John)
Climatechangeinthepolarregions/JohnTurnerandGarethJ.Marshall.
p. cm.
Includesbibliographicalreferencesandindex.
ISBN978-0-521-85010-0(hardback)
1. Climaticchanges–zPolarregions–History. 2. Meteorology–Polarregions–Observations.
3. Climaticchanges–Environmentalaspects–Polarregions. 4. Seaice–Polarregions.
5. Globalwarming–Polarregions. I. Marshall,Gareth. II. Title.
QC903.2.P73T87 2011
551.6911–dc22
2010052384
ISBN978-0-521-85010-0Hardback
CambridgeUniversityPresshasnoresponsibilityforthepersistenceor
accuracyofURLsforexternalorthird-partyinternetwebsitesreferredto
inthispublication,anddoesnotguaranteethatanycontentonsuch
websitesis,orwillremain,accurateorappropriate.
Contents
Preface page ix
1 Introduction 1
1.1 Theenvironmentofthepolarregions 1
1.2 Theroleofthepolarregionsintheglobalclimatesystem 9
1.3 Possibleimplicationsofhighlatitudeclimatechange 12
2 Polarclimatedataandmodels 16
2.1 Introduction 16
2.2 Instrumentalobservations 17
2.3 Meteorologicalanalysisfields 28
2.4 Remotelysenseddata 36
2.5 Proxyclimatedata 42
2.6 Models 51
3 Thehighlatitudeclimatesandmechanismsofchange 61
3.1 Introduction 61
3.2 Factorsinfluencingthebroadscaleclimatesofthepolarregions 63
3.3 Processesofthehighlatitudeclimates 71
3.4 Themechanismsofhighlatitudeclimatechange 80
3.5 Atmosphericcirculation 114
3.6 Temperature 126
3.7 Cloudandprecipitation 132
3.8 Seaice 142
3.9 Theoceancirculation 154
3.10 Concludingremarks 161
4 Thelastmillionyears 162
4.1 Introduction 162
4.2 TheArctic 164
4.3 TheAntarctic 181
4.4 Linkinghighlatitudeclimatechangeinthetwohemispheres 190
v
vi Contents
5 TheHolocene 194
5.1 Introduction 194
5.2 ForcingoftheclimatesystemduringtheHolocene 197
5.3 Atmosphericcirculation 202
5.4 Temperature 207
5.5 Theoceancirculation 234
5.6 Seaiceandseasurfacetemperatures 238
5.7 Atmosphericgasesandaerosols 245
5.8 Thecryosphere,precipitationandsealevel 247
5.9 Concludingremarks 254
6 Theinstrumentalperiod 256
6.1 Introduction 256
6.2 Themainmeteorologicalelements 257
6.3 Changesintheatmosphericcirculation 270
6.4 Theoceanenvironment 280
6.5 Seaice 289
6.6 Snowcover 299
6.7 Permafrost 307
6.8 Atmosphericgasesandaerosols 315
6.9 Terrestrialiceandsealevel 320
6.10 Attributionofrecentchanges 331
6.11 Concludingremarks 334
7 Predictionsforthenext100years 336
7.1 Introduction 336
7.2 PossiblefuturegreenhousegasemissionscenariosandtheIPCC
models 337
7.3 Changesintheatmosphericcirculationandthemodesofclimate
variability 340
7.4 Themainmeteorologicalelements 344
7.5 Theoceancirculationandwatermasses 353
7.6 Seaice 356
7.7 Seasonalsnowcoverandtheterrestrialenvironment 361
7.8 Permafrost 362
7.9 Atmosphericgasesandaerosols 364
7.10 Terrestrialice,theiceshelvesandsealevel 366
7.11 Concludingremarks 372
8 Summaryandfutureresearchneeds 374
8.1 Introduction 374
8.2 Gainingimprovedunderstandingofpastclimatechange 374
Contents vii
8.3 Modellingthehighlatitudeclimatesystem 381
8.4 Datarequired 382
8.5 Concludingremarks 385
References 386
Index 428

Preface
Thelastfewyearshaveseenanunprecedentedlevelofinterestintheclimateofthepolar
regions.ThediscoveryoftheAntarcticozonehole,thereductioninextentofArcticseaice,
thedisintegrationoffloatingiceshelvesaroundtheAntarcticandthehighlevelsofaerosols
reachingtheArctichaveallbeenreportedextensivelyinthemedia.Thishasbeencoupled
withclimatemodelpredictionsshowingthatthehighlatitudeareaswillwarmmorethanany
otherregiononEarthoverthenextcenturyif‘greenhousegas’concentrationscontinueto
rise.Yetsomehavepointedtorapidclimaticfluctuationsthathavetakenplaceinthepolar
regionsoverthelastfewcenturiesandmillenniaandquestionedwhethertherecentchanges
thatwehaveseenarenotsimplyaresultofnaturalclimatevariability.Hencethetimeisright
forareappraisalofourunderstandingofrecenthighlatitudeclimatechangeinthecontextof
increasing anthropogenic influence on the Earth and our greater understanding of the
reasonsforpastclimatevariability.
Thisbookseekstoassesstheclimaticandenvironmentalchangesthathavetakenplace
over the last century and set these in the context of our understanding of natural climate
variabilityinthepre-industrialperiod.Wewilldrawonmanyofthenewclimatedatasets
that have become available in recent years and also make use of the results of modelling
experiments.Thelastfewyearshaveseengreatadvancesinourabilitytoobserve,monitor
andmodelthepresentandpastpolarclimates.Inparticular,theInternationalPolarYearof
2007–08gaveusanunprecedentedamountofdatafromthetwopolarregionsandincreased
ourunderstandingofthemechanismsresponsibleforclimatevariabilityandchangeathigh
latitudes.
The record of in-situ meteorological measurements from observatories and research
stations extends back about a century in many parts of the Arctic and about 50 years in
the Antarctic. These observations provide us with the most accurate measurements of
atmospheric conditions, yet the early observations are widely separated in many areas,
with few observations from the ocean areas. However, from the mid 1970s an increasing
numberofobservationsbecameavailablefrompolar-orbitingsatellites,whichallowedthe
productionofincreasinglyreliableatmosphericanalysesofthehighlatitudeareas.Overthe
past few decades the historical archive of in-situ and satellite observations have been
reprocessedusingcurrentdataassimilationschemestoproduceso-called‘reanalysis’data
ix