Radiative transfer models show that adding more CO2 to the atmosphere doesn’t have much affect on temperature, so Hansen made up a psychotic theory of positive feedbacks, which were going to push the Earth past a “tipping point.”
The most important feedback was loss of polar sea ice, which was theorized to amplify global warming. This hasn’t happened. In fact the amount of sea ice on Earth may challenge record levels later this year.
If positive feedbacks dominated, Earth would have passed many tipping points in the past. But like all long standing systems, negative feedbacks dominate and keep the climate relatively stable.
All real scientists understand this, which is why climate scientists don’t.