We will never convince the deniers. Giant world wide conspiracy theories are fun and exciting to think about. Slowly changing climates, where the action happens over years or even decades, just can't compete with that for entertainment value.
Then there is the feeling of belonging these socially handicapped tRumpkins get from high-fiving each other every time they think they've scored some sort of point. For instance the all the screeching being done about the polar vortex disruptions last week. According to RWNJ pundits it was proof positive that global.warming was a hoax.
And finally there's the way these things are presented to them, as if they are some kinda privileged information that only a chosen few get to know. It makes them feel (falsely) superior to everyone else, even if only for a few minutes, and that can be a powerful thing if you suffer from low self esteem like the vast majority of these nut-bars do.