At this point, most green travelers know the basics of lowering your carbon emissions on the road. But there is one aspect you probably haven't thought much about--and it's likely to be one of the biggest contributions to your overall footprint. What am I talking about? Why your luggage, of course!

luggage

(Photo courtesy of IgoUgo member AmandaLyn)

When greening your luggage, you should consider three key factors: quality, materials, and weight. But first, let's consider if you really need new luggage, shall we?

As our friends at EbayGreen like to point out, the greenest product is the one that already exists. They did a comprehensive life-cycle study of a huge variety of products, and the vast majority of the time it's better for the earth to make do with something old instead of opting for something newer and greener. (The few exceptions to this rule involved major appliances.)

So the first question to ask yourself is,"Can I make do with my present luggage?" Or maybe, "Do my friends or family have an old bag I can use?" Even better, hop on Ebay or Freecycle and see if you can save a pre-owned bag from the landfill.

If the answer to the above question is no, then it's time to shop--but be smart about it. Paying a little extra money for a high-quality bag that will last you for years to come is one of the most important steps to lowering your luggage footprint. Sure, it's tempting to pick up a $10 bag at a local knock-off shop, but in just a few months, that bag is headed for the dump.

Look for companies offering a lifetime warranty--and be sure to take them up on their promises. ConsumerSearch has a nice breakdown of their top six luggage picks and the guarantees of each.

Another big factor when considering a bag is what it's made of. It's important to look for luggage that doesn't contain materials like PVC or chromium. Check out this awesome post from Green Living Ideas all about why certain chemicals are harmful to the earth. Then hop over to this post from Go Green Travel Green to learn about some of the best eco-bags around.

If it's a laptop bag you need, try the carbon-balanced bags from Brenthaven, the Timberland Earthkeepers messenger bag, or the Alchemy Goods Urban Messenger Bag.

Finally, the last thing to consider is weight. One of the easiest ways to reduce your carbon footprint is to bring less junk in a smaller bag. We've already blogged about how to pack like a pro, but don't forget that the bag's weight is important too. Look for bags that fit in the overhead bin so you can save money and the earth.

Need help shopping? LuggageOnline.com allows you to sort out the lightweight options. Bear in mind that anything in the 5-10 pound range is very light and brands like Rimowa specialize in feather-light options.