With time environmental issues got much more complicated. It is pretty easy, if you know what you are doing, to stop a company from pouring poison into a lake where kids swim. It is much harder to address all the myriad greenhouse gases emitted by different sources - from petrochemical refineries to hundreds of millions of peasants cutting down trees for their incredibly inefficient cook stoves.

We've made some heroic efforts, but the Earth as a whole is in worse shape today than 30 years ago, ... There's been 30 more years of greenhouses gases, species extinctions and population growth.

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

Build high-speed, electrified trains over the most-traveled corridors. It'sreally hard to power carbon-free airplanes, but electrified trains are much easier. We'll be a half century behind the Japanese, but better late than never.

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.

Asbestos, EMFs, and CFCs have given us a degree of humility. When yesterday's "triumph of modern chemistry" turns out instead to be today's deadly threat to the global environment, it is legitimate to ask what else we don't know.

An aggressive building performance standard for all new buildings, and a set of performance requirements to be met by all buildings before they can be sold (when upgrades can be included in the new mortgage). These should encompass heating and cooling, lighting, and plug loads. Coupled with new efficiency standards for appliances, lights, and furnaces, this should reduce the energy consumption of new buildings by 50 percent, more or less immediately, and go on from there.