Science

Given the climate (pun) of politics at the time he was alive and playing that role, and given that hindsight has taught us An Inconvenient Truth was more political than it was based in science, and given that Crichton's argument was that environmentalism had to be apolitical in order to ever be effective .... yeah I'm not a climate change denier but neither was Crichton.

Crichton was a Democrat. And he was right, Al Gore's movie was about fear-driven politics, not actionable goals and plans.

Go look at how climate scientists described that movie. "The basic truth and it's inconvenience remains" one researcher was quoted saying. Tacitly admitting everything beyond the basic truth of the film was inaccurate. Go on, check out what retrospectives have to say about it. There's a lot of em.

Again, Crichton was right, and he was absolutely not in denial of climate change. He was against using social problems with scientific solutions as political ammunition in the fear cannons.

Bottom line is any time someone insists a complex problem has a solution as simple and clear cut as "vote Democrat", they're wrong. More wrong than they are right, especially given any timeline longer than 4 years. And that's exactly what you're doing here. "Crichton deviated from the party line on the environment ergo he's just a 'denier'". There's far more nuance in this life than that.