Modeling the effect of management and climate change on mitigation from agriculture Paris meeting October 1,2 2012

Scientific questions Agriculture management (i.e crops, forest and grassland) can play an important role in carbon mitigation. What is the respective role of climate co2 and management on carbon stocks and fluxes ? What is the impact of management strategy on carbon mitigation ? Paris meeting October 1,2 2012

The Land use representation in ORCHIDEE ORCHIDEE as a tool for study of large scale impact of management The Land use representation in ORCHIDEE Natural veg Land use Change Bare soil ORCHIDEE PASIM ORCHIDEE ORCHIDEE - FM Paris meeting October 1,2 2012 Krinner et al. 2005, GBC

Some applications: 1. the crop sector Paris meeting October 1,2 2012

First example: Simulation of soil carbon changes over XXth century Ciais et al 2011 , Gervois et al 2007 Several scenarios are considered: S1: residue return (low/high) black S2: fertilizer input (low/high) blue S3: tillage (low/high) green Land use red

Impact on net flux and mitigation efficiency Paris meeting October 1,2 2012

Second example: abandonned crops in former URSS Large decrease since 1990 - 20 Mha 20 Mha Largest aband lmands in th eN hemisp... Mostl Ukraine, W Russia possibly Kazakh Mettre uneflèche sur graph moins 20 Mha Hurtt et al., Global Change Biology, 2006 ORCHIDEE-STICS used to: 1/ estimate carbon balance since abandonment 2/ potential for biofuels Vuichard et al 2007

Fertilizer input (USDA) Scenario defined Land used change (FAO) Orchidee-Stics Orchidee grassland time 1951 Crops 1993 2000 Fertilizer input (USDA) Fertilizer input management harvest-> export of grain+residues Tillage -> decrease of soil residence time of 30% Paris meeting October 1,2 2012

Map of net carbon change (1) Between 1993 and 2000: mean sink of 373 gC par m2 (64 TgC total) Paris meeting October 1,2 2012

t *= compensation point Total carbon storage t *= compensation point Total carbon gain for biofuel Soil carbon increase, natural regeneration Soil carbon increase biofuel Année Paris meeting October 1,2 2012

Spatial distribution of t* Paris meeting October 1,2 2012

3st example coupling functioning and economy Coupling ORCHIDEE with NEXUS land use: NEXUS use the distribution of yields per region in the economical model IMACLIM-R To define the fraction of land use (crop/forest/grassland) Orchidee estimate yield in response to climate for wheat/maize/millet) based on the distribution for each region, NEXUS calculate the land use Paris meeting October 1,2 2012

Global response for the XXIth century  A1B Scenario Change in précipitation Change in température Différence 2080-2100 v.s 2000-2020 Paris meeting October 1,2 2012

Change in winter wheat yield Change in maize yiel Change in millet yied Paris meeting October 1,2 2012

Attribution: role of CO2 and climate The wheat case Climate+CO2 Climate only Paris meeting October 1,2 2012

Impact on land use change U.S.A Europe Crops Pasture Impact of climate change Paris meeting October 1,2 2012

Second sector: forest ORCHIDEE-FM allow to estimate the net forest production using: Forest age distribution Biomass export from thinning and cut (calculated) wood demand Paris meeting October 1,2 2012

Impact of forest management on carbon sink on european forests Data estimation Model estimation Inventories Site biomass data Flux measurements ORCHIDEE ORCHIDEE-FM+age Grace aux inventaires forestier on constatait que les forêts européennes étaient un stock de carbone important (250gC/m2/an en moyenne), barre orange. Ceci a été confirmé plus récemment grâce à des mesures sur sites des des sites de tours à flux, qui donnent des estimations comparable. Cependant on ne savait pas expliquer ce puits. E particulier les études par modélisation qui permettent de représenter l’effet du climat et du CO2 ne permettait pas de reproduire ces observations (barre bleu foncé). Le changement climatique ne permet donc pas d’expliquer ce large puit. C’est en développant un nouveau module qui permet de représenter la gestion sylvicole et la structure en âge des forêts dans le modèle ORCHIDEE que l’on a enfin pu réconcilier modèle et mesure. Ce puits est ainsi pour l’essentiel relié au fait que l’on prélève une partie du bois qui n’est donc pas décomposé sur place et que l’essentiel des forêts européennes plantées après la seconde guerre mondiales son assez jeunes et donc stockent beaucoup de carbone. ( Bellassen et al 2012) Paris meeting October 1,2 2012

Attribution of management,co2 and climate on recent trend in european forest sink Weight of each parameters on mean Annual change Dominant parameter (relative Positive/negative effect) Paris meeting October 1,2 2012

3st sector: Grassland ORCHIDEE-PASIM allow to estimate herbage and animal production. Automatic management allow to define the optimum animal density Allow to estimate adaptation to climate. Paris meeting October 1,2 2012

Very preliminary results: adaptation of optimum animal densitu The increasing NPP of European grassland leads to an increasing bearing capacity of animals (NB_ANI) in recent decades (1961-2010) . Example of management adaptation at 2 sites Growth rate of NPP and adapted livestock density in recent 50 years Chang et al. in progress

Calculation of forage demand Paris meeting October 1,2 2012

Comparison with European statistics Grazing livestock densities (LSU/ha) from EUROSTAT and simulated by ORCHIDEE-GM Paris meeting October 1,2 2012

Conclusion ORCHIDEE can be use to test impact of several management option on mitigation of carbon The main 3 types of agrosystems can be optimized  It would be interesting to conduct such kind of study for China Paris meeting October 1,2 2012