In 1988, James Hansen from NASA said the warming trend was 99% certain to be caused by CO2.
A year later, Tom Karl from NOAA said that most of the warming occurred before CO2 started rising. A direct contradiction of what Hansen told Congress.
Hansen’s own 1981 graph showed that temperatures peaked around 1940, and then declined for 40 years. After the PDO shift of 1977, temperatures started to rise again. A direct contradiction of what he told Congress.
Hansen’s claim of 99% certainty to Congress was completely fraudulent. There was no scientific basis for it. He obviously didn’t believe it himself.