Hansen now claims that the missing heat is due to aerosols from Mt. Pinatubo’s 1991 eruption. That theory is beyond ridiculous. Temperatures in the upper atmosphere warmed after the eruption due to suspended particulates absorbing SW radiation. By 1995, essentially all of the particulates had cleared out and temperatures dropped below pre-eruption values.
If Hansen’s theory were correct, temperatures in the upper atmosphere would be elevated above 1991 levels.