Claims of human produced CO2 causing climate change are based on output of computer models of the Intergovernmental Panel on Climate Change (IPCC). Programmed to produce predetermined results their output is used for global and national policies on energy even though projections have been consistently wrong.
Failures caused a switch from predictions to scenarios, but it didn’t help. Most recent scenarios projected increases between 1.3 and 2.8°C, but temperatures declined as CO2 increased. Since 2000 the trend is wrong and for the last five years is below the lowest IPCC projection.