I have no children or pets, these are the biggest things you can do to save the planet. I also don't drive, I eat very little meat, I look at food miles when choosing my shopping, my energy suppliers are as green as I can get them. I get as much use out of my furniture as possible, my wardrobe is 17yrs old, the doors are nearly falling off but I won't replace it till they actually fall off. However, I don't do nearly enough, I could recycle more, take fewer baths, put the heating on less.
I sometimes feel like it's futile and there's nothing we can do to save the planet, due to rampant consumerism and unfettered capitalism but I hope something will be done by world leaders to make huge changes that are beyond the control of folks like us