Vegetation recovery and adaptation shapes the post-Large Igneous Province carbon-climate regulation system

Abstract

Earth’s long-term climate evolution is regulated by feedback mechanisms that keep carbon inputs from geologic reservoirs by magmatic or metamorphic degassing in balance with carbon sink fluxes, such as silicate mineral weathering and organic carbon burial. Abrupt imbalances in the carbon cycle, for example due to the release of carbon during the emplacement of Large Igneous Provinces (LIP), potentially result in catastrophic climatic disruptions, biotic crises, and mass extinctions in the oceans and on land. However, it remains enigmatic what climatic, geologic, and biologic variables determine the resilience of Earth’s compartments to such carbon injections. Here, we evaluate how the evolutionary adaptation and dispersal capacity of terrestrial vegetation affect the temperature anomaly following a massive release of CO2 to Earth’s atmosphere and oceans. To do so, we develop an eco-evolutionary vegetation model that is coupled to a geologic carbon cycle model and a look up structure of intermediate complexity climate simulations, which we apply to different LIP degassing events during the Phanerozoic. In the model, the vegetation’s impact on global carbon fluxes (i.e., organic carbon production and plant-mediated enhancement of silicate rock weathering) depends on the vegetation’s capacity and speed of responding to LIP-induced climatic changes. We observe a strong sensitivity of both, the intensity and duration of climatic changes following a LIP emplacement to the vegetation’s climate adaptation capacity by evolutionary adaptation or by migration in geographic space. The interaction between the continental configuration (e.g., supercontinent vs. distributed continents) and the distribution of dispersal barriers for the terrestrial vegetation further result in the emergence of new, long-term climatic steady states by inducing a new balance between global organic and inorganic carbon fluxes. Modelled trajectories of bio-climatic disruption and recovery agree well with paleotemperature reconstructions from geochemical proxies for selected LIPs. A better understanding of biologically driven climate regulation mechanisms may help to explain unresolved changes in temperature over Earth’s history.