A1256655709vFWic

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Quaternary QUESTRegulation of atmospheric carbon
dioxide on glacial-interglacial timescales and
its coupling to climate change
Tim Lenton School of Environmental Sciences
University of East Anglia t.lenton_at_uea.ac.uk htt
p//lgmacweb.env.uea.ac.uk/esmg/
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Quaternary QUEST Team
A new, high level of collaborationbetween data
specialists and modellers, and among experts in
palaeodata derived from the terrestrial, marine
and cryospheric domains

• Investigators
• Tim Lenton UEA
• Harry Elderfield Cambridge
• Chronis Tzedakis Leeds
• Gideon Henderson Oxford
• Ros Rickaby Oxford
• Neil Edwards Open University
• Andrew Watson UEA
• John Shepherd NOCS
• Jonathan Gregory Reading
• Tony Payne Bristol
• Martin Siegert Bristol
• Martyn Tranter Bristol
• Paul Valdes Bristol

• Project Partners
• Eric Wolff BAS
• Julia Hargreaves FRCGC, Japan
• Corinne LeQuere UEA
• Andy Ridgwell UBC, Canada
• Funded Posts
• Martin Johnson Coordinator
• Lisa Weber NOCS
• Agatha DeBoer UEA
• Kevin Oliver OU/Oxford
• Babette Hoogaker Cambs/Leeds
• Sonia Roudesli UEA
• A. Person Reading
• A. N. Other Bristol

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The Scientific Challenge
Blue Vostok data
Black EPICA Dome C data
Siegenthaler et al. (2005) Science 310 1313-1317
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Elucidate the mechanisms responsible for

• Glacial-interglacial CO2 change
• Setting the bounds on CO2
• Causing early and late glacial CO2 drawdown
• The rate of CO2 change
• The relative timing of CO2, temperature and ice
  volume changes
• At inception and termination

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What caused glacial-interglacial CO2 change?
Test these hypotheses by explicitly simulating
relevant processes and proxy records within fast
Earth system models
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Data synthesis strategy

• Time series for both forcing and testing models
• Forcing agents
• Temperature and ice volume
• Other climate and CO2 related variables, e.g.
• Pollen records (from terrestrial and paired
  marine cores)
• Marine productivity and nutrient utilization
  (d13C, Cd/Ca)
• Carbonate compensation depth (CO32- proxies)
• Two stages of data synthesis
• Synthesise different long time series records
• Suitable for testing low resolution simulations
• Develop a common timescale
• Essential wherever phasing is diagnostic of
  mechanism

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Earth system modelling strategy

• Spectrum of models
• GENIE-1, GENIE-2 (IGCM), FAMOUS, HadAM3
• Test hypothesised mechanisms for CO2 change
• individually, then in combination
• with or without carbonate compensation
• Prescribed boundary conditions ice, orbit, dust
• Transient experiments to examine phasing
• Eemian and inception CO2 change
• Deglaciation and Holocene CO2 change
• Last glacial-interglacial cycle
• Time slices for improved climate and variability
• Eemian, early glacial, late glacial,
  pre-termination

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Work plan
WP7 Coupling to the global climate system
WP6 Weathering, atmospheric transport and
sediment cycling
WP4 Ocean physics and testing Southern Ocean CO2
mechanisms
WP3 Marine biology and testing biogeochemical
CO2 mechanisms
WP1 Synthesising long time-series data from
marine, terrestrial and ice cores
WP2 Ocean carbon isotopes, Cd/Ca, Pa/Th, and
data-model integration
Quaternary QUEST
WP5 Ocean inorganic carbon, sediments and
carbonate compensation
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WP1 Long time-series data WP2 Ocean carbon
isotopes WP3 Biogeochemical CO2 mechanisms WP4
Physical CO2 mechanisms WP5 Carbonate
sediments WP6 Weathering, atmospheric
transport WP7 Coupling to the climate system
Leeds
WP1
UEA
WP5
WP4
OU
WP2
Oxford
BAS/Cambridge
WP6
WP3
Bristol
WP7
Reading
NOCS