So one of the easiest things you can do to lesson your carbon footprint is to not use grocery store bags. I'm sure you've heard this by now and if you don't have your own bag to bring yet, I'll give you some easy ideas to get you on the boat. If you need to know why you should get on this boat, I suggest you check out this list here.
First, the bag I use is one from Ikea. They are the dimpa beach bags, which I searched their website and didn't find, but I did find these cuties. Anyway, I purchased them on a wim, and I'm really glad I did. I have three of these nifty bags. The only thing I find annoying about them is that because they're so big, I feel the need to fill them to the max when I'm shopping, and that can get really heavy.
If your a sewing type, I found these Morsbags. She gives us an easy tutorial on how to sew your own bags from fabric you already have around the house. I have issues even looking at my sewing machine right now, and one project that I've been procrastinating to get started. When I finally get brave enough to sit down and sew the bear, I'll make a bag and of course share the outcome.
Another link I found was at tipnut. They have all kinds of patterns out there from knitting, crochet, and sewing. So whatever you can do, I'm sure there's a pattern for you here.
If you need reasons to use, a place to search for kinds out there, Reusethisbag.com has a variety of things for you to look at. You can also check out Reusable Bags.com
I hope I've planted some ideas for you to try for Earth Day, it is coming soon!!