Yes and no, I think. Obviously one single person can't make a tangible difference all by themselves, but to stop the thought process there does a massive disservice to the importance of collective action. It doesn't take all that many people to affect change, both politically and culturally. Join CCL (US focus here), vote and advocate for carbon fee and dividend and other beneficial policies, buy less shit you don't need, ride a bike if you can, and if you have the means electrify your home/vehicle and support more ethical companies. Basically, don't blame BP if you're putting 20 gallons of their shit in your 4runner every week so you can commute to an office job with a permanent rooftop tent and a "save our winters" sticker on the back (yes I live in the front range). You're not responsible for all of humanity, but you are responsible for your own actions when you have the means to choose a less carbon intensive option.