Aside from having children - Driving and eating red meat are the biggest contributors that an individual can easily control. Cutting these out of your life can help and might make you feel better about the situation.

If you have an electric car the driving point is slightly less of a concern, and even reducing your red meat intake to a couple times a week will help.

Ultimate, the vast vast majority of greenhouse gas emissions come from giant corporations, Boycotting as many of the major pollutors as you can and encouraging others to do so is perhaps harder than the above but would be the best thing an individual can do.

Rally for systemic change, protest, firebomb an oil companies headquarters. Contact your local representative and ask them what they're doing to fight climate change. Volumteer with an environmental group.

There's a lot you can do. Will any of it work? Probably not, but if will help the cause