Sensitive Dependence of Global Climate to Continental Geometry

TL;DR

This study demonstrates that Earth's long-term climate variability is significantly influenced by the distribution and shape of continents, affecting weathering rates and carbon sequestration in ways not solely determined by tropical land area.

Contribution

It introduces a framework to analyze how continental geometry impacts global weathering and climate, revealing complex runoff patterns and sensitivities previously unstudied.

Findings

Global weathering rate depends on continent size and shape.

Runoff patterns are complex and sensitive to continental geometry.

Continental latitude poorly predicts runoff and weathering effects.

Abstract

Over its multibillion-year history, the Earth has experienced a wide range of climates. The long-term climate is controlled by the atmospheric carbon dioxide concentration, which is regulated by marine sequestration through chemical weathering. This chemical weathering sink is strongly linked to the distribution and composition of the continents. However, the effect of continental distribution has never been studied within a general framework. Here we show that the global weathering rate is sensitive to the size and shape of the continents, but is not well explained by the amount of land in the tropics. We construct synthetic continental configurations and use an ensemble of global climate model simulations to isolate the expected effect of continental arrangement on weathering and carbon burial. Runoff patterns are complex, sensitive to detailed features of continental geometry, and poorly predicted by continental latitude. These results help explain the long-term variability and irregularity of Earth's climate.