He has fixed two errors and the new corrected model finds the climate's sensitivity to carbon dioxide (CO2) is much lower than was thought.
Dr Evans says his discovery "ought to change the world". "But the political obstacles are massive," he said.
It's claimed that David was a climate modeller for the Greenhouse Office in Aus, but from what I can tell he was modelling carbon, and not climate.
He's been a denier for a long time, so this announcement is not surprising - he just keeps changing the reasons why he thinks climate change is not occurring.