The Lancet Planetary Health Volume 6, ISSUE 4, e342-e349, April 01, 2022. Human impacts on earth-system processes are overshooting several planetary boundaries, driving a crisis of ecological breakdown. This crisis is being caused in large part by global resource extraction, which has increased dramatically over the past half century. We propose a novel method for quantifying national responsibility for ecological breakdown by assessing nations’ cumulative material use in excess of equitable and sustainable boundaries.