The environmental movement's midlife crisis.

The major changes roiling today's environmental movement necessarily add layers of complexity to the "Save the Earth" and "Stop Pollution" messages of the first Earth Day 35 years ago. One measure of maturity is the ability to think with complexity while also acting effectively. Environmentalists must figure out how better to do that, both to emerge from their midlife crisis and to make everyone else care about the threats to the future that they see so clearly. In celebration of Earth Day Friday, let's get cracking.