Not enough people understand that Global Warming is a real scary thing. If we continue at our current rate, within a few decades we will potentially start seeing lowland cities (such as NY) underwater, lack of fresh water in major areas (Already happening in CA), even more massive hurricanes (Like Sandy), not to mention massive loss of life. This could be an apocalypse (Not an exaggeration).
But if within the next ten years, we start taxing small amounts on companies that produce lots of carbon, on people who drive "Gas Guzzling" cars and on companies who make vehicals that produce lots of carbon, it will help avoid it. This will encourage more people to buy hybrid vehicles (Which are relatively cheap nowadays), and encourage more companies to go green.