Despite popular, largely politically-based claims to the contrary, global warming is a scientific observation explained by an accepted, well-defined scientific theory. Most debate over whether global warming exists and how it is caused occurs not among scientists who study climate change, but among the general public, mostly due to a lack of understanding and what is called the politicization of science.
Lobbyists for corporations and other entities often twist, cherry-pick, and/or simply lie about scientific studies for the purpose of achieving their own political or ideological ends—often, turning a profit. Since politicians (who listen to the lobbying) regularly interact with the public, but the scientists who have actually studied the subject in great detail usually don’t, the politicized science is what the general public hears far more often. And, because different lobbies twist science in different ways, conflicting “facts” become common beliefs, and the debate is generated.
While those who know the most about global warming (climate change scientists) have moved past any doubts about the existence and general causes of global warming, national policies are shaped by a public opinion informed by a varying mix of some actual science and a lot of conflicting politicized science. And for this, the process of saving the climate that we know how to survive in is slowed drastically.