I tell them that new low-carbon technology is needed, but the scale of the challenge is such that it will be a long time before those technologies are developed. Before that happens we all wish to continue to drive to work, eat food shipped to our cities, and use computers, lights, AC and all the other conveniences of modern life. The day will come (I am guessing it will for a large part rely on nuclear, and hopefully fusion), but that is not here yet. In the mean time, you can help put me out of business: Drive a fuel efficient car, use air conditioning sparingly, eat local ... (even though in reality it will not make that much of a difference, you might feel better about your decadent ways). Except for those who moved into a mud hut and live by eating only grubs, everyone in the modern world has a very significant carbon footprint.