Impacts and risks of “realistic” global warming projections for the 21st century

•The IPCC AR6 assessment of likely impacts and risks by 21st-century climate changes is highly uncertain.•Most climate models, however, run too hot, and the SSP3-7.0 and SSP5-8.5 scenarios are unlikely.•New climate change projections for the 21st century were generated using best-performing climate models,•Empirical climate modeling of natural cycles, and calibration on lower troposphere temperature data.•Net-zero emission policies are not necessary because SSP2-4.5 is sufficient to limit climate change hazards to manageable levels.