The taxing problem

First up, taxes. There's a new carbon tax in Boulder, Colorado. Also: Britain isn't meeting its biofuel targets, so the House of Lords is recommending tax incentives. Their new report attacks the practice of importing Brazilian bioethanol, which is often made on rainforest land that's been cleared for agriculture.
Let's ask: what's tax for? To fund the goverment, which will spend money on schools, roads, hospitals, that sort of thing, right? Well, no - maybe now taxation is a social lever in itself - a tool to directly affect the market rather than to redress imbalances (green or otherwise) after the collection and redistribution is all done.