Some people say global warming isn't occurring. Or it's not caused by humans, and is just natural climate variation. A small number of scientists and academics appear periodically in the mass media expressing such views. Sociologists, journalists, science writers and scientists have done some research on these 'global warming sceptics'. Here is what they have found.
First, most of them are not active climate researchers and have published little or nothing in peer-reviewed scientific journals about climates past or present. In a few instances where they have published work that disputes claims about global warming or its causes, their work was later shown to contain critical errors. Typically, they have little or no influence on the views of active climate scientists.
Second, many are affiliated with a 'conservative think tank', which are typically funded by corporations or billionaire industrialists.
Their common mission is to promote free-market ideology. They are typically libertarian: government regulation is viewed as a threat to freedom, and regulation of the economy must be resisted or rolled back. Many people affiliated with these organisations believe environmentalists are not much different from socialists, because they want to regulate business and impose constraints on the economy.
Most think tanks that promote scepticism about climate change have received funds from fossil-fuel corporations and industry associations. They know that one way to prevent regulation or special taxes on their product is to convince the public that there is legitimate scientific doubt about global warming.
If a group of scientists could demonstrate that global warming is not occurring, or is the result of natural processes rather than human activities, those scientists would be world-famous. But no scientists have been able to provide convincing evidence in peer-reviewed scientific journals for either of these claims. Instead, almost all active climate scientists agree that global warming is occurring, and that human activities are contributing to it.