Brian Walsh: Can Algae Impact Climate Change?

Abstract

© Oleksandr Umanets | Dreamstime

Net carbon sinks capable of avoiding dangerous perturbation of the climate system and preventing ocean acidification have been identified, but they are likely to be limited by resource constraints.

Land scarcity already creates tension between food security and bioenergy production, and this competition is likely to intensify as populations and the effects of climate change expand. Despite research into microalgae as a next-generation energy source, the land-sparing consequences of alternative sources of livestock feed have been overlooked. Here we use the FeliX model to show that microalgae as feedstock can free nearly 2 billion hectares of land currently used for pasture and feed crops. Short rotation biomass plantations established on these areas are capable of meeting over 50% of annual primary energy demand, resulting in emissions mitigation from the energy and LULUC sectors totaling 455 ± 126 PgC by 2100.

Further emissions reductions from carbon-sequestering technologies can reduce global atmospheric carbon concentrations close to preindustrial levels by the end of the present century. Though previously thought unattainable, carbon sinks and climate change mitigation of this magnitude are well within the bounds of technological feasibility.