Personally I'm not much a player of computer games but maybe they can be used for environmental education. In a first investigation I found Lincity and Real Life, please check their usefulness by yourself.
Lincity - Build & maintain a city/country. You are required to build and maintain a city. You must feed, house, provide jobs and goods for your residents. You can build a sustainable economy with the help of renewable energy and recycling, or you can go for broke and build rockets to escape from a pollution ridden and resource starved planet, it's up to you. Due to the finite resources available in any one place, this is not a game that you can leave for long periods of time. This game is similar to the commercial simulation game with a similar name. This package provides files common to both the X and SVGALIB versions of the game.
Real Life - "In Conway's Game of Life every cell is either fully alive (has the value of 1) or completely dead (has the value 0). In Real Life this restriction to bivalence is lifted to countenance -real-valued- degrees of life and death. Real Life contains Conway's Game of Life as a special case; however, Real Life, in contrast to Conway's Game of Life, exhibits sensitive dependence on initial conditions which is characteristic of chaotic systems."
Sierra has produced (some time ago) Eco Quest 1 - Lost in Rainforest and Eco Quest 2 - The Search for Cetus. The EcoQuest games were for MS-DOS and Windows 3.x. These were targeted at younger players.
SimEarth, 1988, Maxis (DOS, Win3.x, Mac) Simulates the development of a planet from the forming of the crust to the spread of civilization. Based on James Lovelock's Gaia theory. Somewhat dull and difficult to learn, but there's a good amount of educational value to be gotten out of fiddling around with the models, particularly greenhouse effect.
Balance of the Planet, 1991, Chris Crawford (DOS, Mac): You take the role of a government policy-maker who must try to balance industry and ecology. Remarkably complicated and drab (even moreso than SimEarth), but certain to be educational and thought-provoking if time is spent with the manual. The Mac version can now be downloaded for free from Crawford's website.
Global Effect, 1992, Millennium (DOS, Amiga): An early real-time strategy game where you must try to conquer your opponent while dealing with the ecological ramifications of your weapons and industry upon your population. Clunky interface, not a lot of fun compared to current Warcraft-type games.
SimIsle, 1995, Maxis (DOS, ???) Develop a tropical island without destroying the rainforest ecology. Large learning curve but supposedly a lot of fun.
SimPark, 1997, Maxis (Win 95, ???) Sort of a children's version of SimIsle, which is simpler and more education-focused.
I suspect the older games should run just fine on dosemu.