A bipolar perspective on past climate change (and expectations for information from the Third Pole) Valérie Masson-Delmotte Laboratoire des Sciences du Climat et de l’Environnement (CEA-CNRS-UVSQ/IPSL) Gif-sur-Yvette, France 3 rd TPE Workshop, Reykjavik, Iceland – August 2011

Why study past climate change? Huybers and Curry, Nature, 2006 Expand the short instrumental records Natural climate variability « Slow » components: ocean, carbon cycle, ice sheets Understand the response of climate to forcings Detection / attribution Climate feedbacks Thresholds Natural case studies to benchmark Earth System models Seasonal cycle Glacial-interglacial cycles

Ice cores ICE Local climate AEROSOLS Regional atmospheric aerosol content: Sea salt, dust, volcanism, solar activity, pollutants… AIR Global atmospheric composition Firnification processes

Deep polar ice cores NorthGRIP ~ yrs EDML : yrsEDC : yrs European Project for Ice Coring in Antarctica (EPICA) NEEM ?

The greening of Greenland Masson-Delmotte et al, submitted; updates from Bhatt et al, 2010 and van den Broeke et al, 2009 Greenland ice sheet mass balance

Instrumental data Projections (A1B) Ice core perspective : the last years Greenland cultures Orbital forcing Ice core perspective : the last years Masson-Delmotte et al, submitted; data from NGRIP, Nature 2004 and Vinther et al, Nature, 2009 Past, present and projected changes

126 ka (orbital forcing)2xCO 2 DJF JJA ann Limited analogies between past and future climate change IPSL climate model Masson-Delmotte et al, Clim Past, in press Comparable magnitude of summer warming and feedbacks at mid to high latitudes north Major differences in low-high latitude temperature gradients and seasonality

Global impacts of Greenland melt in climate projections global sea level Atlantic meridional overturning circulation negative feedback on Arctic warming ITCZ shifts with major impacts on monsoon precipitation Masson-Delmotte et al, submitted; simulations from Swingedouw et al, J. Climate, 2009Masson-Delmotte et al, submitted; data from NGRIP, Nature 2004 and Vinther et al, Nature, 2009

EPICA, Nature, 2006; Steffenson et al, Science, 2008; Capron et al, Clim. Past, 2010; Masson-Delmotte et al, PNAS, 2010 The Greenland-Antarctic bipolar seesaw Full glacial conditions Glacial inception Precursors: dust from Chinese deserts, Greenland moisture origin shifts

Masson-Delmotte et al, PNAS, 2010 An Zhisheng et al, Science, 2011 Bipolar seesaw under interglacial conditions? Antarctica T Antarctic moisture source Asian monsoon Methane CO 2 N. Atlantic SST Greenland T Bipolar seesaw Links between abrupt shifts in Antarctic moisture origin and monsoon

New tools for new challenges Searching for the oldest ice in Antarctica Jouzel et al Science 2007, Loulergue et al Nature 2008, Lisiecki & Raymo Paleoceano 2005 Masson-Delmotte et al, QSR, 2010; Jouzel and Masson-Delmotte, QSR, 2011 Present-day Glacials Interglacials +5°C -9°C Cause for the shift between 40 ky to 100 ky climatic cycles ? Oldest ice challenge

Towards a tri-polar perspective on climate change Links between « northern pull », « southern push » and monsoon Sequence of events between tropical,mid latitude and polar atmospheric circulation Response of climate to major volcanic eruptions (importance for the decadal predictability of climate) Chunming Shi et al, Clim. Past, submitted

Towards a tri-polar perspective on climate change Exceptional monitoring effort for process-based understanding of the climatic drivers of precipitation isotopic composition Unique opportunity for a multi-archive TPE approach for reconstructing past precipitation  18 O (ice cores, tree rings, lake sediments, speleothems…) Need of data syntheses for benchmarking climate models (CMIP5 includes paleoclimate simulations) Yao Tandong et al, in preparation