Antarctica and the Antarctica and the Global Climate System Global Climate System

(AGCS)(AGCS)John Turner, Andrew Carleton, John Turner, Andrew Carleton,

Maurizio Candidi, Jo Jacka,Maurizio Candidi, Jo Jacka,Paul Mayewski, Mike MeredithPaul Mayewski, Mike Meredith

+ many others+ many others

SSG/PS Programme Planning Group on SSG/PS Programme Planning Group on AGCSAGCS

The Climate Signals in Ice The Climate Signals in Ice CoresCores

Records such as the Records such as the Vostok and Dome C Vostok and Dome C ice cores show the ice cores show the major climate cycles, major climate cycles, such as the ice ages such as the ice ages occurring roughly occurring roughly every 100k yearsevery 100k years

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COLD

WARM

Age / kyr before present

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Dome C

High Resolution Ice Core High Resolution Ice Core DataData

Annual and sub-Annual and sub-annual resolution annual resolution of chemical of chemical species can be species can be linked to changes linked to changes in atmospheric in atmospheric circulation, sea circulation, sea ice extent and ice extent and oceanographic oceanographic conditions. This conditions. This allows the allows the identification of identification of some El Nino and some El Nino and La Nina events La Nina events

The Non-linearity of the The Non-linearity of the

LinkagesLinkages However, all ENSO However, all ENSO events are different events are different and span a range of and span a range of states of the states of the tropical Pacifictropical Pacific

Dome C

The classic El Nino The classic El Nino response is for cold response is for cold conditions over the conditions over the Antarctic Peninsula, Antarctic Peninsula, but may events but may events differ from thisdiffer from this

New Tools for Investigating The Antarctic New Tools for Investigating The Antarctic ClimateClimate

Five years of summer storm tracks over the Southern Ocean

• Meteorological re-analysis fields covering the last 30 years

• Back trajectories allowing the investigation of air masses arriving at ice coring sites

• Coupled atmosphere-ocean models

• Arrays of short ice cores giving information on the spatial variability of accumulation

The Antarctic The Antarctic

Circumpolar WaveCircumpolar Wave

The ACW can be The ACW can be observed in observed in anomalies of sea anomalies of sea ice, sea surface ice, sea surface temperatures and temperatures and mean sea level mean sea level pressure. The ACW pressure. The ACW has a wave number has a wave number two pattern taking two pattern taking 8-10 to circle the 8-10 to circle the Antarctic , giving a Antarctic , giving a periodicity of 4-5 periodicity of 4-5 years at any years at any location. location.

Dome C

The Antarctic The Antarctic Peninsula Peninsula WarmingWarming

The largest warming in the The largest warming in the SH over the last 50 years – SH over the last 50 years – 3 deg C in the annual 3 deg C in the annual mean temperature. mean temperature.

- Sea ice has decreasedSea ice has decreased- Precipitation has increased Precipitation has increased

as a result of atmospheric as a result of atmospheric circulation changescirculation changes

- Strong ENSO linkagesStrong ENSO linkages- Changes in water masses Changes in water masses

on the continental shelf?on the continental shelf?- What are the contributions What are the contributions

of natural climate of natural climate variability and variability and anthropogenic forcing?anthropogenic forcing?

Faraday Annual Mean Temperature

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Rationale & Fit to SCAR Strategic Rationale & Fit to SCAR Strategic PlanPlan

• Concerned with the links between the Concerned with the links between the Antarctic and the rest of the climate Antarctic and the rest of the climate system – fits to Earth System approachsystem – fits to Earth System approach

• Should provide advice to organisations Should provide advice to organisations such as IPCCsuch as IPCC

• Addressing questions of great public Addressing questions of great public concern, such as Peninsula warmingconcern, such as Peninsula warming

• Will build a strong oceanographic Will build a strong oceanographic element into SCAR scienceelement into SCAR science

• There is a role for all SCAR nations to There is a role for all SCAR nations to take part – modelling, observational, take part – modelling, observational, cruise datacruise data

Objectives/QuestionsObjectives/Questions• How does variability in tropical and mid-How does variability in tropical and mid-

latitude atmospheric and oceanic latitude atmospheric and oceanic conditions modulate the Antarctic conditions modulate the Antarctic climate?climate?

• What are the mechanisms that transfer What are the mechanisms that transfer the tropical signals to the Antarctic?the tropical signals to the Antarctic?

• What controls the stability of coupled What controls the stability of coupled atmosphere-ocean phenomena, such as atmosphere-ocean phenomena, such as the Antarctic Circumpolar wave and the the Antarctic Circumpolar wave and the Southern Hemisphere Annular Mode?Southern Hemisphere Annular Mode?

• What are the quantitative relationships What are the quantitative relationships that reflect the non-linear linkages that reflect the non-linear linkages between climate signals in ice cores, between climate signals in ice cores, Antarctic sea ice and the Antarctic Antarctic sea ice and the Antarctic atmospheric circulation, and the varying atmospheric circulation, and the varying extra-polar signals?extra-polar signals?

Objectives/QuestionsObjectives/Questions

• Why do the teleconnections between the Why do the teleconnections between the tropics and the Antarctic vary on decadal tropics and the Antarctic vary on decadal timescales?timescales?

• How has the development of the Antarctic How has the development of the Antarctic ozone hole affected the teleconnections?ozone hole affected the teleconnections?

• What has been the impact on the Antarctic What has been the impact on the Antarctic environment of changes in the El Niño-environment of changes in the El Niño-Southern Oscillation over recent decades?Southern Oscillation over recent decades?

• How will Antarctic climate conditions change How will Antarctic climate conditions change on regional and continent-wide scales over on regional and continent-wide scales over the next century as a result of various the next century as a result of various greenhouse gas scenarios and other human greenhouse gas scenarios and other human source emissions into the atmosphere?source emissions into the atmosphere?

Why Now?Why Now?• Recent advances in analysis of ice cores Recent advances in analysis of ice cores

has given annual or sub-annual resolutionhas given annual or sub-annual resolution• Atmospheric re-analysis data sets provide Atmospheric re-analysis data sets provide

excellent data on variability over the last excellent data on variability over the last 30 years30 years

• Regional climate models covering the Regional climate models covering the Antarctic are only just becoming possible Antarctic are only just becoming possible with advances in computer powerwith advances in computer power

• High degree of interest in the media High degree of interest in the media regarding Antarctic climate changeregarding Antarctic climate change

• If we delay others will move forward in If we delay others will move forward in these areasthese areas

Why SCAR?Why SCAR?

• SCAR needs to be able to provide a SCAR needs to be able to provide a view on Antarctic climate change, e.g. view on Antarctic climate change, e.g. to IPCCto IPCC

• Will bring in an important Will bring in an important oceanographic element to our activitiesoceanographic element to our activities

• Will generate key data sets to be linked Will generate key data sets to be linked with SCAR’s name – the Antarctic ice with SCAR’s name – the Antarctic ice core data basecore data base

• Would be an important contribution to Would be an important contribution to the IPY, e.g. the high resolution array of the IPY, e.g. the high resolution array of ice coresice cores

Theme 1 - Decadal Time Scale Theme 1 - Decadal Time Scale

VariabilityVariability • Focussing on mechanisms of changeFocussing on mechanisms of change• Time scale of years to centuries – Holocene to Time scale of years to centuries – Holocene to

next 100 yearsnext 100 years• Covers the time scale on which much of the Covers the time scale on which much of the

ocean variability takes placeocean variability takes place• Have extensive ice core data, but atmospheric Have extensive ice core data, but atmospheric

analyses only extend back a few decadesanalyses only extend back a few decades• Will investigate variability of SO water massesWill investigate variability of SO water masses

ENSO links with West Antarctic mass balance

Theme 2 - Global & Regional SignalsTheme 2 - Global & Regional Signals

in Ice Coresin Ice Cores • Will investigate the routes by which global and regional Will investigate the routes by which global and regional

climate signals arrive at the drilling sitesclimate signals arrive at the drilling sites• Will focus on quantifying the relationships between signals in Will focus on quantifying the relationships between signals in

the cores and measures of the global climate systemthe cores and measures of the global climate system• A particular focus will be on the non-linearity of the systemA particular focus will be on the non-linearity of the system• Will use IPY as a Special Observing Period to investigate the Will use IPY as a Special Observing Period to investigate the

high resolution spatial variability of accumulation.high resolution spatial variability of accumulation.

• Extensive use will Extensive use will be made of be made of meteorological re-meteorological re-analysis fields and analysis fields and the output of the output of climate model climate model runsruns

Theme 3 - Natural & Anthropogenic Theme 3 - Natural & Anthropogenic Forcing on the Antarctic Climate Forcing on the Antarctic Climate

SystemSystem • Will attempt to Will attempt to

separate and quantify separate and quantify natural and natural and anthropogenic changes anthropogenic changes over recent decadesover recent decades

• We will produce a We will produce a series of predictions for series of predictions for the next century based the next century based on various greenhouse on various greenhouse gas scenariosgas scenarios

• A major feature will be A major feature will be the use of regional the use of regional modelsmodels

One prediction of Antarctic temperature change for 2100

Theme 4 - The Export of Theme 4 - The Export of

Antarctic Climate SignalsAntarctic Climate Signals • Will examine the means by which Antarctic climate Will examine the means by which Antarctic climate

variability can affect the conditions at more variability can affect the conditions at more northerly latitudesnortherly latitudes

• Strong focus on Antarctic Bottom Water, plus other Strong focus on Antarctic Bottom Water, plus other water masses such as intermediate and mode water masses such as intermediate and mode waterwater

• Will examine the influence of removal of sea iceWill examine the influence of removal of sea ice

• Will consider the Will consider the influence of influence of atmospheric atmospheric variability on water variability on water mass propertiesmass properties

External LinksExternal Links

• These will be very important. These will be very important. Possible links will be:Possible links will be:– World Climate Research Programme World Climate Research Programme

Climate Variability (CLIVAR) projectClimate Variability (CLIVAR) project– Climate and Cryosphere (CliC) – Climate and Cryosphere (CliC) –

particularly the Southern Ocean panelparticularly the Southern Ocean panel– Intergovernmental Panel on Climate Intergovernmental Panel on Climate

ChangeChange– Scientific Committee on Ocean Scientific Committee on Ocean

ResearchResearch– International Geosphere Biosphere International Geosphere Biosphere

Programme PAGESProgramme PAGES

Risks?Risks?• We have to mobilise the Antarctic We have to mobilise the Antarctic

community behind our programme, but community behind our programme, but we’ve had a positive response from the we’ve had a positive response from the scientists who have seen the draft scientists who have seen the draft proposalproposal

• Need to find funding from the main Need to find funding from the main agencies and national bodies, but the agencies and national bodies, but the topics are of great scientific importancetopics are of great scientific importance

• Too ambitious? Hopefully not.Too ambitious? Hopefully not.• The problems are not trivial and we have The problems are not trivial and we have

to be realistic about what we can achieve to be realistic about what we can achieve in 6 yearsin 6 years

ImplementationImplementation

• Six years duration with a budget of $15K Six years duration with a budget of $15K per yearper year

• Steering committee made up of SSG/PS Steering committee made up of SSG/PS Chair, four Theme leaders, SCAR Chair, four Theme leaders, SCAR Executive Director, plus invited scientistsExecutive Director, plus invited scientists

• Will incorporate some successful SCAR Will incorporate some successful SCAR activities, e.g. ITASE, READER, ASPeCT, activities, e.g. ITASE, READER, ASPeCT, ATACATAC

• Work with JCADM over data managementWork with JCADM over data management

DeliverablesDeliverables• World class science with papers in peer World class science with papers in peer

reviewed journals.reviewed journals.• Input to the next IPCC assessmentInput to the next IPCC assessment• Advances in the representation of high Advances in the representation of high

latitude processes in climate models.latitude processes in climate models.• High visibility for SCAR science to High visibility for SCAR science to

workers in tropical and mid-latitude workers in tropical and mid-latitude climate studies.climate studies.

• Future climate predictions for the Future climate predictions for the Antarctic under various greenhouse gas Antarctic under various greenhouse gas emission scenarios will be of value to emission scenarios will be of value to other groups within SCAR, such as the other groups within SCAR, such as the marine and terrestrial life scientists.marine and terrestrial life scientists.

• Data sets of Antarctic ice core data and Data sets of Antarctic ice core data and possibly Southern Ocean observationspossibly Southern Ocean observations

Thank YouThank You