Sequestering atmospheric carbon dioxide by increasing ocean alkalinity

Summary/Abstract

This paper presents a preliminary analysis of a geoengineering option based on the intentional increase of ocean alkalinity to enhance marine storage of atmospheric CO₂. Like all geoengineering techniques to limit climate change, this approach must be regarded as a potential strategic option that requires ongoing assessment to establish its potential benefits and side effects. CO₂would be absorbed from the atmosphere by the oceans at an increased rate if ocean alkalinity were raised. Ocean alkalinity might be raised by introducing the dissolution products of alkaline minerals into the oceans. The limited deposits of naturally occurring soda ash (Na₂CO₃) are readily soluble and easily mined. Limestone (CaCO₃) is abundant in the Earth’s crust but is not readily soluble. This analysis explores the potential feasibility and limits of such approaches.