In the late 2000s, Al Gore made a series of high-profile statements suggesting the possibility that Arctic sea ice could be completely gone during the summer by around 2013 or 2014.

https://www.snopes.com/fact-check/ice-caps-melt-gore-2014/

The banning of chlorofluorocarbons actually increased global warming

 
Acid rain had in fact been around since the industrial revolution and it has been significantly reduced since the 90's