People seem to be obsessed with sustainability and eco-friendly living these days, but do you think that we'll actually make a difference to the environment? If not, why not?

I dont think we alone can make a huge difference. I think its entirely on the goverments shoulders to make the changes and then inforce them to prevent violation.

I think that we can make a difference, particularly by re-cycling waste products.
Re-cycled products obviously save on extracting new raw materials from the earth; but it also saves an enourmous ammount of landfill space. Landfill sites generate large ammounts of methane (which is a greenhouse gas) and not many landfill sites actually tap in to this surplus energy. It is merely vented to the atmosphere.
Whatever re-cycling or energy saving methods we use they will never be enough; but at least we can maintain a balance so that things don't get worse.
The developing nations are going to want all the things that we have, and this will require large resources and energy consumption. For this reason alone, we need to be more economic with the resources we use. We should not try to deprive others of what we have.
Enforced legislation may be required in the future to combat waste, and save energy and water; but for now everybody doing a little will make a big difference.

Regards

Ralph.