Astronomically-modulated climate-carbon cycle interactions in the cGENIE Earth System Model

Abstract

Quasi-periodic fluctuations of the Eartha s astronomical parameters define the amount and distribution of solar radiation received by the Earth and dominate the pacing of Eartha s natural climate variation on long timescales. Climate-state dependent environmental boundary conditions such as variations in the extent and stability of polar of ice sheets and sea ice, the large-scale ocean circulation and especially the carbon cycle have been shown to shape the response of Earth climate to astronomical forcing. In this study I investigate the mechanisms which allow the carbon cycle to respond to atmospheric CO2, and define the global climate response to the resulting climate state. I apply the cGENIE Earth System Model of Intermediate Complexity to simulate the interactions of the carbon budget and global climate on different timescales. Specifically, the model is applied on astronomical timescales in order to test the climate response to carbon cycle perturbations in past and future and climate-carbon cycle interactions under greenhouse climate conditions.