I think that climate change is the most important issue facing humanity. I think we will all have to see lower economic growth if our civilisation is to survive. However, I think slapping a straight tax on would be quite disastrous. There are some high carbon industries that going to be vital in the short and medium term, and simply closing them over night, as a flat rate tax is likely to do, is not the way to get our economy to adjust.
Lower economic growth, better try your bets elsewhere because unless you can suddenly remove a third of the population from the planet we ain't going anywhere but up.
Energy production will simply shift to what is the most affordable and don't expect it to ever become less than today. If anything our energy expenditures will continue to climb. The only change will be how we create it. When cheaper energy becomes available expect usage to dramatically spike, if anything our biggest threat won't be carbon, it will be heat; waste heat.
Carbon tax can be vary effective while having minimal impact. The important point is it causes conservation in the most economically efficient way possible, carbon credits even with a significantly lower tax rate are far more harmful. The real issue is there is less to lobby about just rate and what to do about imports /exports.