These are not exhortations from overwrought extremists, but carefully phrased warnings from some of the world's finest scientists.

I suppose I'd characterize myself as having a faith-based optimism. My faith is parental and Darwinian.

Sustainability requires that we demand enduring quality. Steve Strong has a slide presentation pointing out that much of Oxford was built 800 years ago. What are we building today that will be here 800 years from now? If something like that emerged from this recession, it would help justify the hardship so many people are currently experiencing.

When we held the first Earth Day, everyone said it was a success because of the huge turnout. It was probably the largest planned event across the country.

America has the technology and resources to meet all its energy needs while safeguarding the earth's climate. The urgent question now is, 'Do we have the will?' At least one city does, and I'm proud to live in it.

Under communism, prices were not allowed to reflect economic reality. Under capitalism, prices don't reflect ecological reality. In the long run, the capitalist flaw -- if uncorrected -- may prove to be the more catastrophic.

By the year 2000, such renewable energy sources could provide 40 percent of the global energy budget; by 2025, humanity could obtain 75 percent of its energy from solar resources.