In the '70s - a "mini-ice age" was coming, and we were all going to freeze to death.
In the '80s - "acid rain" was going to poison the worlds water supply, and kill tons of vegetation - ending life on earth.
In the '90s - the "hole in the ozone layer" was going to rapidly expand, exposing all life to deadly cosmic radiation.
As of 2000 - "global warming" was going to rise uncontrollably, the oceans would rise, coastal cities would be submerged, and the remaining land would become desert. Survivors would devolve into a Mad Max like society.
Sometime around 2010 - "Global Warming" became "Climate Change", where weather patterns would shift, become 'extreme' and we would all die.
Kooks with half-baked man-made ecological disaster theories have been predicting doom for better than the last 40 years, and the only thing that seems to have changed is the brand of doom they are predicting - in a mere 40 years, the earth has gone from too cold to too hot according to them.
The only thing these 'predictions' have in common, is that each one has resulted in tighter government control, because the simple-minded folks that these predictions have fooled end up demanding it. A person who isn't blinded by fear would realize that if the scientists could get it so wrong (ice age, etc.) that the odds are their current predictions are also wrong, and should be regarded as unreliable.