Seth Wynes, Kimberly Nicholas: Current anthropogenic climate change is the result of greenhouse gas accumulation in the atmosphere, which records the aggregation of billions of individual decisions. Here we consider a broad range of individual lifestyle choices and calculate their potential to reduce greenhouse gas emissions in developed countries. We recommend four widely applicable high-impact (i.e. low emissions) actions with the potential to contribute to systemic change and substantially reduce annual personal emissions: having one fewer child, living car-free, avoiding airplane travel and eating a plant-based diet. These actions have much greater potential to reduce emissions than commonly promoted strategies like comprehensive recycling or changing household lightbulbs.