You could pick a solution area you feel attracted to from the Drawdown book (http://www.drawdown.org) and see how you can contribute. The Drawdown team has spent several years computing and ranking the impact of over 100 solution areas that can combine to reduce CO2 while also providing other benefits (so called no-regret solutions)

You may find that high impact solutions are in areas you may not be thinking about but that energize you, like the fact that educating girls beats out rooftop solar power (which is also a very high ranking solution).