Antarctica and the Global Climate System (AGCS) John Turner, Andrew Carleton, Maurizio Candidi, Jo Jacka, Paul Mayewski, Mike Meredith + many others SSG/PS Programme Planning Group on AGCS

The Climate Signals in Ice Cores Records such as the Vostok and Dome C ice cores show the major climate cycles, such as the ice ages occurring roughly every 100k years Dome C

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

The Non-linearity of the Linkages However, all ENSO events are different and span a range of states of the tropical Pacific Dome C The classic El Nino response is for cold conditions over the Antarctic Peninsula, but may events differ from this

New Tools for Investigating The Antarctic Climate 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 Circumpolar Wave The ACW can be observed in anomalies of sea ice, sea surface temperatures and mean sea level pressure. The ACW has a wave number two pattern taking to circle the Antarctic, giving a periodicity of 4-5 years at any location. Dome C

The Antarctic Peninsula Warming The largest warming in the SH over the last 50 years – 3 deg C in the annual mean temperature. -Sea ice has decreased -Precipitation has increased as a result of atmospheric circulation changes -Strong ENSO linkages -Changes in water masses on the continental shelf? -What are the contributions of natural climate variability and anthropogenic forcing?

Rationale & Fit to SCAR Strategic Plan Concerned with the links between the Antarctic and the rest of the climate system – fits to Earth System approachConcerned with the links between the Antarctic and the rest of the climate system – fits to Earth System approach Should provide advice to organisations such as IPCCShould provide advice to organisations such as IPCC Addressing questions of great public concern, such as Peninsula warmingAddressing questions of great public concern, such as Peninsula warming Will build a strong oceanographic element into SCAR scienceWill build a strong oceanographic element into SCAR science There is a role for all SCAR nations to take part – modelling, observational, cruise dataThere is a role for all SCAR nations to take part – modelling, observational, cruise data

Objectives/Questions How does variability in tropical and mid- latitude atmospheric and oceanic conditions modulate the Antarctic climate?How does variability in tropical and mid- latitude atmospheric and oceanic conditions modulate the Antarctic climate? What are the mechanisms that transfer the tropical signals to the Antarctic?What are the mechanisms that transfer the tropical signals to the Antarctic? What controls the stability of coupled atmosphere-ocean phenomena, such as the Antarctic Circumpolar wave and the Southern Hemisphere Annular Mode?What controls the stability of coupled atmosphere-ocean phenomena, such as the Antarctic Circumpolar wave and the Southern Hemisphere Annular Mode? What are the quantitative relationships that reflect the non-linear linkages between climate signals in ice cores, Antarctic sea ice and the Antarctic atmospheric circulation, and the varying extra-polar signals?What are the quantitative relationships that reflect the non-linear linkages between climate signals in ice cores, Antarctic sea ice and the Antarctic atmospheric circulation, and the varying extra-polar signals?

Objectives/Questions Why do the teleconnections between the tropics and the Antarctic vary on decadal timescales?Why do the teleconnections between the tropics and the Antarctic vary on decadal timescales? How has the development of the Antarctic ozone hole affected the teleconnections?How has the development of the Antarctic ozone hole affected the teleconnections? What has been the impact on the Antarctic environment of changes in the El Niño- Southern Oscillation over recent decades?What has been the impact on the Antarctic environment of changes in the El Niño- Southern Oscillation over recent decades? How will Antarctic climate conditions change on regional and continent-wide scales over the next century as a result of various greenhouse gas scenarios and other human source emissions into the atmosphere?How will Antarctic climate conditions change on regional and continent-wide scales over the next century as a result of various greenhouse gas scenarios and other human source emissions into the atmosphere?

Why Now? Recent advances in analysis of ice cores has given annual or sub-annual resolutionRecent advances in analysis of ice cores has given annual or sub-annual resolution Atmospheric re-analysis data sets provide excellent data on variability over the last 30 yearsAtmospheric re-analysis data sets provide excellent data on variability over the last 30 years Regional climate models covering the Antarctic are only just becoming possible with advances in computer powerRegional climate models covering the Antarctic are only just becoming possible with advances in computer power High degree of interest in the media regarding Antarctic climate changeHigh degree of interest in the media regarding Antarctic climate change If we delay others will move forward in these areasIf we delay others will move forward in these areas

Why SCAR? SCAR needs to be able to provide a view on Antarctic climate change, e.g. to IPCCSCAR needs to be able to provide a view on Antarctic climate change, e.g. to IPCC Will bring in an important oceanographic element to our activitiesWill bring in an important oceanographic element to our activities Will generate key data sets to be linked with SCARs name – the Antarctic ice core data baseWill generate key data sets to be linked with SCARs name – the Antarctic ice core data base Would be an important contribution to the IPY, e.g. the high resolution array of ice coresWould be an important contribution to the IPY, e.g. the high resolution array of ice cores

Theme 1 - Decadal Time Scale Variability Focussing on mechanisms of changeFocussing on mechanisms of change Time scale of years to centuries – Holocene to next 100 yearsTime scale of years to centuries – Holocene to next 100 years Covers the time scale on which much of the ocean variability takes placeCovers the time scale on which much of the ocean variability takes place Have extensive ice core data, but atmospheric analyses only extend back a few decadesHave extensive ice core data, but atmospheric analyses 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 Signals in Ice Cores Will investigate the routes by which global and regional climate signals arrive at the drilling sitesWill investigate the routes by which global and regional climate signals arrive at the drilling sites Will focus on quantifying the relationships between signals in the cores and measures of the global climate systemWill focus on quantifying the relationships between signals in the 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 high resolution spatial variability of accumulation.Will use IPY as a Special Observing Period to investigate the high resolution spatial variability of accumulation. Extensive use will be made of meteorological re- analysis fields and the output of climate model runsExtensive use will be made of meteorological re- analysis fields and the output of climate model runs

Theme 3 - Natural & Anthropogenic Forcing on the Antarctic Climate System Will attempt to separate and quantify natural and anthropogenic changes over recent decadesWill attempt to separate and quantify natural and anthropogenic changes over recent decades We will produce a series of predictions for the next century based on various greenhouse gas scenariosWe will produce a series of predictions for the next century based on various greenhouse gas scenarios A major feature will be the use of regional modelsA major feature will be the use of regional models One prediction of Antarctic temperature change for 2100

Theme 4 - The Export of Antarctic Climate Signals Will examine the means by which Antarctic climate variability can affect the conditions at more northerly latitudesWill examine the means by which Antarctic climate variability can affect the conditions at more northerly latitudes Strong focus on Antarctic Bottom Water, plus other water masses such as intermediate and mode waterStrong focus on Antarctic Bottom Water, plus other water masses such as intermediate and mode water Will examine the influence of removal of sea iceWill examine the influence of removal of sea ice Will consider the influence of atmospheric variability on water mass propertiesWill consider the influence of atmospheric variability on water mass properties

External Links These will be very important. Possible links will be:These will be very important. Possible links will be: –World Climate Research Programme Climate Variability (CLIVAR) project –Climate and Cryosphere (CliC) – particularly the Southern Ocean panel –Intergovernmental Panel on Climate Change –Scientific Committee on Ocean Research –International Geosphere Biosphere Programme PAGES

Risks? We have to mobilise the Antarctic community behind our programme, but weve had a positive response from the scientists who have seen the draft proposalWe have to mobilise the Antarctic community behind our programme, but weve had a positive response from the scientists who have seen the draft proposal Need to find funding from the main agencies and national bodies, but the topics are of great scientific importanceNeed to find funding from the main agencies and national bodies, but the topics are of great scientific importance Too ambitious? Hopefully not.Too ambitious? Hopefully not. The problems are not trivial and we have to be realistic about what we can achieve in 6 yearsThe problems are not trivial and we have to be realistic about what we can achieve in 6 years

Implementation Six years duration with a budget of $15K per yearSix years duration with a budget of $15K per year Steering committee made up of SSG/PS Chair, four Theme leaders, SCAR Executive Director, plus invited scientistsSteering committee made up of SSG/PS Chair, four Theme leaders, SCAR Executive Director, plus invited scientists Will incorporate some successful SCAR activities, e.g. ITASE, READER, ASPeCT, ATACWill incorporate some successful SCAR activities, e.g. ITASE, READER, ASPeCT, ATAC Work with JCADM over data managementWork with JCADM over data management

Deliverables World class science with papers in peer reviewed journals.World class science with papers in peer reviewed journals. Input to the next IPCC assessmentInput to the next IPCC assessment Advances in the representation of high latitude processes in climate models.Advances in the representation of high latitude processes in climate models. High visibility for SCAR science to workers in tropical and mid-latitude climate studies.High visibility for SCAR science to workers in tropical and mid-latitude climate studies. Future climate predictions for the Antarctic under various greenhouse gas emission scenarios will be of value to other groups within SCAR, such as the marine and terrestrial life scientists.Future climate predictions for the Antarctic under various greenhouse gas emission scenarios will be of value to other groups within SCAR, such as the marine and terrestrial life scientists. Data sets of Antarctic ice core data and possibly Southern Ocean observationsData sets of Antarctic ice core data and possibly Southern Ocean observations

Thank You