First, that starts off with a false premise. You don't know that the government is going to regulate carbon.
Second, ignoring the "climate change is a myth" crowd, there are those that believe that we are, at this point, past the point of helping and that we might as well just get on with it and adapt to whatever changes await. That attempts at regulation will just destroy the economy, and thus their place in it, and that ruining the economy and thus untold (b|m)illions of lives that way is not worth the unknown outcome of attempting to save the current state of climate.
This isn't even a "not my problem" situation. I've heard this from folks leaving in a coastal region that already suffers some amount of regular nuisance flooding. It's not as if rising tides will skip over them.
Failing to understand that viewpoint is going to result in two sides yelling past each other. One side thinks we must do everything in our power to preserve nature's status-quo, the other is firmly of the mind that it is an impossibility and to try would be wasted effort with much risk and unclear gain.
Your first task is convincing them of the horrors that await for them.