A useful general overview of the way technology has shaped human-environmental interactions is provided by David Kemp's Global Environmental Issues (Routledge, London, 1994). For a good introduction to the history of green thinking see David Pepper's seminal The Roots of Modern Environmentalism (Croom Helm, London, 1984) and Andy Dobson's Green Political Thought (Routledge, London, 1995).
You might also like to try to track down David Dickson's classic text Alternative Technology: the Politics of Technical Change (Fontana, London, 1974). Although this is out of print, it should still be available in libraries. The various strands of thinking that make up the 'deep green' or 'deep ecology' approach are explored in Bill Devall and George Sessions' classic text Deep Ecology (Peregrine Smith Books, Salt Lake City, 1985). Sessions' most recent book, Deep Ecology for the Twenty-First Century, is available from Schumacher Books, Foxhole, Dartington TQ9 6EB, UK, along with several other similar titles.
For a somewhat more conventional viewpoint on environmental problems and policies see the classic report Our Common Future by the Brundtland Commission on Environment and Development, which was published by Oxford University Press in 1987.
Moving up to the current debate on the environment, there is a vast and growing literature on sustainable development. For a good general introduction to the issues see, for example, Paul Ekins, Economic Growth and Environmental Sustainability (Routledge, London, 1999).
Finally, for an extensive and critical review of green thinking, see Bjorn Lomborg's The Skeptical Environmentalist (Cambridge University Press, Cambridge, 2001).