[A-CG09] Development and application of land and ocean biogeochemistry components of Earth system models

[ACG09-10] Climate-carbon cycle changes during 1000 years in doubled CO₂ concentration simulated by MIROC-ESM

*Tomohiro Hajima¹, Kaoru Tachiiri¹, Michio Kawamiya¹ (1.Japan Agency for Marine-Earth Science and Technology)

Keywords:carbon cycle, climate change, Earth system model, TCRE

Transient climate response to cumulative carbon emission, so called TCRE, is defined as the ratio of global warming to cumulative anthropogenic CO2 emission evaluated when CO2 concentration reaches the doubled CO2 level from pre-industrial state. This metric is useful because it gives us roughly estimates on future global warming induced by CO2 emission on the basis of current and future emission amounts. Since TCRE just characterizes the transient response of climate-carbon cycle, we cannot know what will happen after CO2 concentration is stabilized (or reduced) after mitigation policies adopted. To estimate the warming degree in such condition and to understand climate-carbon dynamics in the concentration-stabilized phase, we conducted simulations where CO2 concentration is abruptly doubled from pre-industrial state and fixed over 1000 years, by using an Earth system model (MIROC-ESM). We confirmed from the simulations that after 1000 years have passed, global warming and land carbon uptake almost ceased but weak carbon uptake by the ocean continues.