Nobody really knows how much it would cost to avoid the worst impacts of climate change. Yet historian Yuval Noah Harari’s analysis, based on the work of scientists and economists, indicates that humanity might avert catastrophe by investing the equivalent of just two percent of global GDP into climate solutions. He makes the case that preventing ecological cataclysm will not require the major global disruptions many fear and explains that we already have the resources we need – it’s just a matter of shifting our priorities.