Terrestrial uptake due to cooling responsible for low CO 2 during the Little Ice Age M. Rubino - Seconda Università di Napoli - CSIRO Oceans and Atmospheric Flagship

Etheridge D.M. (CSIRO, Australia) Trudinger, C. (CSIRO, Australia) Allison C. (CSIRO, Australia) Rayner P. (Melbourne Uni, Australia) Steele P. and Langenfelds R. (CSIRO, Australia) Curran, M. (Australian Antarctic Division) Mulvaney R. (BAS, UK) Sturges W.T. (University of East Anglia, UK) Smith A. (ANSTO, Australia) Co-authors

Motivations CMIP4, Friedilingstein et al. (2006)

Motivations Cox & Jones (2008)

A revised 1000 year atmospheric  13 C-CO 2 record from Law Dome and South Pole, Antarctica Rubino et al. (2013)

Geographical distribution of ice core drilling and firn sites DSS≡DSS0506 DE08 DML

Comparison among different sites

DSS (Law Dome) vs DML: CO 2

Double Deconvolution of DML

Two hypotheses Land use change : Gross Primary Productivity increased because of vegetation regrowth after abandonment of land by farmers due to pandemics Temperature response : Gross Primary Productivity decreased but respiration decreased more due to the higher temperature dependence of respiration

Carbonyl sulphide (COS): a proxy for GPP Aydin et al. (2008)

COS: a proxy for GPP F ocean + F anthropogenic + F biomass burning = (k OH + k terrestrial )*[COS] Berry et al. (2013) +18

Conclusions New CO 2 record from DML is consistent with the DSS CO 2 record. New  13 C-CO 2 record from DML unambiguously confirms that the terrestrial biosphere was the main contributor to the LIA CO 2 decrease. The first modelling of the COS LIA budget suggests that respiration decreased more than photosynthesis due to the temperature decrease. New sensitivity of the terrestrial carbon cycle to temperature can be estimated.