“So why are politicians and a few scientists like John Christy so adamantly denying climate change? One obvious reason lies in the resource that feeds the political machine: money. The Koch brothers, who made billions of dollars from oil refinery business, donated to Republican candidates like Marco Rubio and Carly Fiorina. They stated they are willing to spend up to $1 billion on the 2016 election.
Although money usually is the primary factor, the tendency to deny climate change may lie in human psychology. According to a study by Duke University, people evaluate scientific evidence based on the agreeability of its policy implications. If they do not agree with the proposed solutions to a problem (e.g. carbon tax to combat climate change), then they are more likely to deny that the problem exists in the first place to avoid dealing with the undesirable solutions.”
From The Odyssey Online Uncomfortable Truth: The Politicization Of Climate Change