We, as individual consumers, need to reduce the carbon emissions ourselves as much as possible no matter what the politicians say. Deniers are going to be a problem until shit hits the fan for real, and waiting until everyone is convinced will simply be a waste of time.
So, in other words, focus less on what others do, more on what you do, and make sure to prepare as much as you can for whatever the future holds. Not saying everyone should become a prepper (although it's a fun hobby!), but the fact that people blindly believe that the future is a straight line is scarier, regardless of where they believe that line is pointing.