I don't think there has ever been a time when the argument was that there is no such thing as global warming. This is just something leftist say to make themselves feel superior.
Absolute bullshit. Of course, in proper scientific circles, there has never been a reasonable argument that global warming isn't happening, but in the world of scientists bought and paid for by the fossil fuel companies, particularly in the 80s and 90s in America, there absolutely was rampant denial of global warming. And consequently, in the media, politics and the general public, where decisions actually get affected/made, complete denial of global warming was widespread.
We all have memories mate. You can't try and argue against what we saw with our own eyes. People arguing that the ice wasn't actually melting. People showing graphs that show that the earth is 'actually cooling' (which was later modified to show that it was a 'natural cycle of warming and cooling'). They were literally hiring people who were part of a similar campaign for the tobacco industry years earlier (The Advancement of Sound Science Center, for example). The operated a campaign similar to what you're trying to do here, by presenting your side as 'healthy skepticism' that will naturally delay any action rather than denial of a clear set of facts with mountains of data to back it up.
As for the left vs right debate, it's only a right-wing issue because the right, since Reagan and Thatcher at least, intrinsically prioritise the interests of big corporations over the interests of the general population. So when a fossil fuel funded think tank comes out with a non peer reviewed 'study' that they've sent directly to the media rather than academic journals, the right wing politicians, journalists, columnists, etc, will be happy to eat it up and amplify it. When it came to the overwhelming consensus on proper academic journals, however, well we all know the right wing have 'had enough of experts' by now.
The right wing has always been the protector of the established power structures, be it religion, monarchy, aristocracy, or in modern times, the corporate powers, which is why they've fought tooth and nail to maintain the power of all of those groups throughout history and attack anything that threatens them. This is just the latest chapter in a long line of failures to be on the right side of evidence from the right wing establishment.