I'm remodeling my office right now and I want everything being added to be green. I have heard that carpet tiles is a green option for flooring? Why is that?

Shaw Carpet tile is a good options. It can be 100% recycled. It can also be replaced/repaired as the tiles are 2' tiles. Somoeone spills coffee and stains a tile, pop it out and replace it. There are a few things to keep in mind when considering "gree" carpet. The first one is what material is the carpet made from. I would recommend wool carpet since it is renewable and not petroleum based. In addition, look for a carpet that has a non-PVC backing. The last thing to look for is low VOC adhesives. The "greenest" carpets on the market is Natures Carpet, and Earthweave (undyed, not treated with moth repellant). Unique Carpet LTD just came out with a new line that is undyed and untreated. As for a bang for the buck I would look at Unique Carpet LTD dealer near you and ask about their Mill Promotions. These are end runs from mills, 100% wool and many are priced below $20/yd. Godfrey Hirst is another great option: their Torquay and Drysdale line are around $20-25/yd.