This is a nice piece. Hard to believe that it was the US that started the world in believing in climate change.

30 years ago, James Hansen testified to Congress about the dangers of human-caused climate change. In his testimony, Hansen showed the results of his 1988 study using a climate model to project future global warming under three possible scenarios, ranging from ‘business as usual’ heavy pollution in his Scenario A to 'draconian emissions cuts’ in Scenario C, with a moderate Scenario B in between.

Changes in the human effects that influence Earth’s global energy imbalance ( a.k.a. ‘anthropogenic radiative forcings’ ) have in reality been closest to Hansen’s Scenario B, but about 20–30% weaker thanks to the success of the Montreal Protocol in phasing out chlorofluorocarbons (CFCs). Hansen’s climate model projected that under Scenario B, global surface air temperatures would warm about 0.84°C between 1988 and 2017. But with a global energy imbalance 20–30% lower, it would have predicted a global surface warming closer to 0.6–0.7°C by this year.

The actual 1988–2017 temperature increase was about 0.6°C. Hansen’s 1988 global climate model was almost spot-on.