Changes

The theory that "greenhouse gases" have a greater warming effect than other gases goes back to the 19th century. The idea that carbon dioxide emissions might lead to catastrophic warming was introduced by Carl Sagan in the 1960s. He was inspired by research on the atmosphere of Venus. Around 1978, the environmental movement decided to promote Sagan's theory. The movement was already advocating energy conservation and renewables as a response to the "energy crisis." A desired political outcome was agreed upon, and then a scientific justification was developed.

The theory that "greenhouse gases" have a greater warming effect than other gases goes back to the 19th century. The idea that carbon dioxide emissions might lead to catastrophic warming was introduced by Carl Sagan in the 1960s. He was inspired by research on the atmosphere of Venus. Around 1978, the environmental movement decided to promote Sagan's theory. The movement was already advocating energy conservation and renewables as a response to the "energy crisis." A desired political outcome was agreed upon, and then a scientific justification was developed.

==Difficulties with the theory==

==Difficulties with the theory==