There are various reasons why many people have come to be skeptical about climate change & warming. Part of it is just who they listen to and where they get their news. If they get 98% of what they process is from Faux News and related sources, they are gonna hear "it ain't true" 98% of the time.
There are also those who talk themselves into skepticism because *gasp*,,,Liberals DO mostly accept the climate change scenarios.
Some disbelieve because,like 9/11 conspiracy theories, there are SO many web sites claiming 'evidence' about the 'fraud'.

Now.... the reasons why there are so many ...mostly conservatives... who publish & post and talk and rant about their 'doubts' are quite different. The driving forces behind getting all those sheep to nod and baaaaahhhh in agreement are based on the serious financial inconvenience it will be to certain major corporations and investors IF the world in general takes the problem seriously.
There is WAY too much money tied up in preserving the status quo, or at least delaying action until they can get their cash cows into a different pasture. The trail of who is funding what in denial of climate change/warming is a scary labyrinth of vested interests paying ad agencies and lobbyists and funding 'experts' to do 'studies' which say what they want to hear.
(Remember the campaign to slow down and discredit the anti-tobacco movement? That pales in comparison to this!)

There was a 'rule' propounded about political issues a few years ago..."No matter what they're talking about, they're talking about MONEY!"

(naawwww...don't ask me to 'prove' this. But watch... once alternative energies are common, see who controls them.)