Life-cycle assessment to guide solutions for the triple planetary crisis

Climate change, biodiversity loss and pollution — the triple planetary crisis — increasingly threaten the Earth system, necessitating tools such as life-cycle assessment (LCA) that can evaluate the effectiveness of different prevention and mitigation strategies. LCA systematically quantifies the environmental impacts over the whole life cycle of products, processes or policy scenarios. LCA is frequently applied to uncover environmental hotspots and prioritize actions and is increasingly used to assess the environmental impacts of strategy implementation scenarios. In this Review, we discuss the role of LCA in evaluating and shaping strategies on the decarbonization of energy systems, circular economy, sustainable consumption and sustainable finance. We explore how emerging LCA-based approaches make use of the planetary boundaries framework and other environmental assessment tools to support decisions. Cross-comparisons between LCA applications for various mitigation strategies reveal differences in maturity level, methodological choices and the way that environmental assessment tools have been combined with LCA. Economy-wide LCAs on the decarbonization of energy systems and sustainable consumption are already common, whereas economy-wide applications to circular economy and prospective LCAs for sustainable finance are still in their infancy. Future research should develop systematic classification of decision-support problems, harmonized data and comprehensive guidance to improve robustness and credibility of prospective economy-wide LCA.