Recycling and installing energy-efficient light bulbs are great things to do to help save the Earth, but what are the most important things?

A few years ago, I created a list of 10 things — the hard things — that will do the most to reduce your impact on the planet. They give a sense of the kinds of fundamental changes that will be required to create a sustainable society. And they can be goals toward which all of us can work.

Here are the first three things on the list:

• Stop at two: The birth of another excessively consuming American adds a tremendous burden to the earth's life support systems. So stop at two children, or one, or none.
• Live in a modest house: The super-sized American house consumes vast quantities of resources and energy. Think about what you really need for a satisfying life. Rehab an existing house before building new. And make your house as energy-efficient as possible.
• Live close to what you need: Choose to live a "lower-mileage lifestyle" in a community where the necessities of everyday life can be obtained by walking, bicycling, and using transit.

Go here for the entire list.