The test of all knowledge is experiment.
Experiment is the sole judge of scientific truth.
The possible outcomes resulting from the predicted rapid and dramatic rise in global temperature deserve serious thought. One starts by testing the computer simulations against the record of temperature change of the last 100 years. In the last 100 years, the global average surface temperature of the earth has risen about 0.5 C. Also during that interval the concentration of anthropogenic greenhouse gases has increased in the atmosphere. That substantial buildup gives a way to test the computer simulations of climate change due to greenhouse gases from human actions. But most of the anthropogenic greenhouse gases entered the atmosphere after 1940.