Here he is in 2006 saying “10 years”.
His activism got him in hot water with the heavily conservative NASA establishment figures at the time and the typical Republican players in American religion, TV shows and politics got hot under the collars about him and succeeded in getting him fired. [cancelled]
From that point there has been a right wing media blitz against global warming supported by the usual players in coal and gasoline industries, although the main big money player in coal died a year or two ago and some of the big oil have switched their strategies after they calculated negative profitability for oil/gas post 2050.