In 70's, the great warning on all covers of national geographic and scientific American was "ice age alert! Coming ice age!" Temperatures were going down and we ere supposed to prefect prepare for certain disaster a freezing temperatures and coming ice age.
In 80's, trumpets work blown that we had 20 years left and that major cities would be under the water by 2000.
Earth is 4.5 billion years old God knows how many times the temperature went up and down and up and down and up and down stop. A really the hot and other periods of freezing cold.
Doesn't it seem presumable to blame the current one or two degrees of rise of temperature on human race?