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The IPCC AR6 assessment of likely impacts and risks by 21st-century climate changes is highly uncertain.

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  Most climate models, however, run too hot, and the SSP3-7.0 and SSP5-8.5 scenarios are unlikely.

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  New climate change projections for the 21st century were generated using best-performing climate models,

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  Empirical climate modeling of natural cycles, and calibration on lower troposphere temperature data.

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  Net-zero emission policies are not necessary because SSP2-4.5 is sufficient to limit climate change hazards to manageable levels.

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