In 2020, humans were responsible for emitting around 50 GtCO2e (about 6.4 tonnes per person). Under the Paris Agreement, national governments have agreed to rein in these emissions to almost zero within 30 years. In order to accomplish this, greenhouse gas (GHG) emissions inventories are needed to prioritize initiatives and track progress. The task is too large and urgent to leave to national governments alone: communities and businesses must also identify their emissions, set ambitious targets, and monitor progress.