One of the things you might try to do is to observe a "green" Shabbat, wherein you try to minimize your detrimental impact on the earth.  Some ideas:

• do errands by bicycle, rather than by car (when practical)
•  go for a hike, or a walk in the woods, or in a park
• eat vegitarian rather than meat meals on Shabbat
• engage in "passive", rather than "active" activities on that special day
• refrain from using appliances (washing machines, dishwashers, etc.)

 
For other ideas and more information on Judaism and the environment check out what groups like the Teva Learning Center and The Adamah Community are doing.