Update on the Antarctica and the Global Climate System (AGCS) Programme John Turner British Antarctic Survey

The Goals of AGCS To understand the mechanisms controlling the climate of the Antarctic – its cycles and variabilityTo understand the mechanisms controlling the climate of the Antarctic – its cycles and variability To explain why the climate has changed in the past – roughly the last 20K years since the Last Glacial MaximumTo explain why the climate has changed in the past – roughly the last 20K years since the Last Glacial Maximum To predict how the climate of the Antarctic might change over the next century under various greenhouse gas emission scenariosTo predict how the climate of the Antarctic might change over the next century under various greenhouse gas emission scenarios

The Four Themes of AGCS Theme 1 – Decadal time scale variability (Dave Bromwich)Theme 1 – Decadal time scale variability (Dave Bromwich) Theme 2 - Global & Regional Signals in Ice Cores (Paul Mayewski)Theme 2 - Global & Regional Signals in Ice Cores (Paul Mayewski) Theme 3 - Natural & Anthropogenic Forcing on the Antarctic Climate System (John Turner)Theme 3 - Natural & Anthropogenic Forcing on the Antarctic Climate System (John Turner) Theme 4 - The Export of Antarctic Climate Signals (Mike Meredith)Theme 4 - The Export of Antarctic Climate Signals (Mike Meredith)

The 500 hPa Temperature Trends (deg C/decade) Over from ECMWF 40 Year Re- analysis Project

Much greater than rate of warming of global ocean – global change 0.31 C since 1950sMuch greater than rate of warming of global ocean – global change 0.31 C since 1950s Strongly surface- intensified.Strongly surface- intensified. Decays to around zero by 100m depth.Decays to around zero by 100m depth. Warming of surf T greater than 0.3 deg per decade.Warming of surf T greater than 0.3 deg per decade. Temperature trends with Depth,

Ice core isotope proxy for temperature (AD ) indicates all sites within range of natural variability Schneider et al. (2006)

Annual Precipitation Trends: PMM5 E40 (% decade-1) Monaghan et al. (2006) There are no widespread trends of either sign.

Loss of ice Shelves Around the Antarctic Peninsula Strengthening of the westerlies in recent decades

Assessment of the Antarctic element of the IPCC Assessment Round 4 model predictions for the next centuryAssessment of the Antarctic element of the IPCC Assessment Round 4 model predictions for the next century Investigation of the mechanisms responsible for changes in the SAMInvestigation of the mechanisms responsible for changes in the SAM Research into mechanisms behind the mid-tropospheric warming above the Antarctic that occurred over the last 50 years.Research into mechanisms behind the mid-tropospheric warming above the Antarctic that occurred over the last 50 years. Investigation of the current state of the Antarctic climate in the context of the last several hundred years for purposes of assessing natural vs anthropogenic impact.Investigation of the current state of the Antarctic climate in the context of the last several hundred years for purposes of assessing natural vs anthropogenic impact. Interference between SAM and ENSO signals in Antarctica. Teleconnections between Austral - Midlatitudes* and the Antarctic “ (*Southern S-America, Southern ocean islands, and New Zealand”)Interference between SAM and ENSO signals in Antarctica. Teleconnections between Austral - Midlatitudes* and the Antarctic “ (*Southern S-America, Southern ocean islands, and New Zealand”) Targets for 2007 and 2008

A 200 year array of coastal cores from Antarctica including sea-ice extentA 200 year array of coastal cores from Antarctica including sea-ice extent Marine productivity to understand sea-ice extent in proxy record (MS)Marine productivity to understand sea-ice extent in proxy record (MS) Quantification of oceanic heat, volume, and fresh water fluxes in the southern ocean (Quantifying the current mean state)Quantification of oceanic heat, volume, and fresh water fluxes in the southern ocean (Quantifying the current mean state) Interaction of the ocean on the ice sheet, ice shelves, and the atmosphere at the Antarctic marginInteraction of the ocean on the ice sheet, ice shelves, and the atmosphere at the Antarctic margin Understanding the driving mechanisms in the Southern Ocean overturningUnderstanding the driving mechanisms in the Southern Ocean overturning Drifting buoy deploymentDrifting buoy deployment Contribute to Reanalysis effortsContribute to Reanalysis efforts Sea ice thicknessSea ice thickness Developments of data bases, such as READERDevelopments of data bases, such as READER Targets for 2007 and 2008

The new AGCS newsletter – NOTUS

AGCS session at EGU, Vienna April 2007

The AGCS White Paper State of the Antarctic and Southern Ocean Climate System (SASOCS)State of the Antarctic and Southern Ocean Climate System (SASOCS) Akin to the Arctic Climate Impact AssessmentAkin to the Arctic Climate Impact Assessment Deals with ice core data, met, climatology, oceanography, model projections, but not biology.Deals with ice core data, met, climatology, oceanography, model projections, but not biology. Covers the last 10,000 years and projections for the next 100 yearsCovers the last 10,000 years and projections for the next 100 years How does it link to the Nature paper and the Antarctic Climate Change and the Environment work?How does it link to the Nature paper and the Antarctic Climate Change and the Environment work? Publish Exec Summary in EOS?Publish Exec Summary in EOS? Have a draft ready.Have a draft ready.

The New OCEAN-READER Web Site

Science Highlight – Meredith & Hogg Links the stronger westerlies and Eddy Kinetic Energy in the ACC. Increased poleward heat flux may have played a significant role in the observed warming of the Southern Ocean

Science Highlight – John Fyfe He shows that the latest series of climate models reproduce the observed mid-depth Southern Ocean warming since the 1950s if they include time- varying changes in anthropogenic greenhouse gases, sulphate aerosols and volcanic aerosols in the Earth’s atmosphere. The full effect of human- induced warming of the Southern Ocean may not yet to be realized because of volcanic aerosols

Two areas of work - The role of Polar Stratospheric Clouds (PSCs) - Greater poleward advection of heat by the atmosphere Current Work on the 5 KM Warming

The Proposed Southern ice ocean model intercomparison project (SIOMIP) Put forward by Siobhan O’Farrell (CSIRO) and Todd Arbetter (BAS)Put forward by Siobhan O’Farrell (CSIRO) and Todd Arbetter (BAS) Scope - a detailed examination of the sea ice components in coupled climate models through a comparison with observational data sets.Scope - a detailed examination of the sea ice components in coupled climate models through a comparison with observational data sets. Relevant to AGCS, CliC, ASPECT, The Southern Ocean Implementation panel, IPY CASO and SASSIRelevant to AGCS, CliC, ASPECT, The Southern Ocean Implementation panel, IPY CASO and SASSI Links with interests in water mass formationLinks with interests in water mass formation But many errors come from the atmospheric forcingBut many errors come from the atmospheric forcing

The Next 100 Years – the Mean of 19 Different Models Annual mean surface air temperature changes (deg per decade) CO2 levels doubled over the next 100 years

Thank You