The European nations take climate change very seriously.

A good leader sets the right goals, gets things moving, and helps us to discover that we already know what to do.

There are no separate systems. The world is a continuum. Where to draw a boundary around a system depends on the purpose of the discussion.

A knowledgeable and courageous U.S. president could help enormously in leading the world's nations toward saving the climate.

Biodiversity can't be maintained by protecting a few species in a zoo, or by preserving greenbelts or national parks. To function properly, nature needs more room than that. It can maintain itself, however, without human expense, without zookeepers, park rangers, foresters or gene banks. All it needs is to be left alone.

The world is a complex, interconnected, finite, ecological - social - psychological - economic system. We treat it as if it were not, as if it were divisible, separable, simple, and infinite. Our persistent, intractable global problems arise directly from this mismatch.

How do we appreciate the good without letting it be the enemy of the perfect? How do we keep a step in the right direction from becoming a stopping point? How do we get beyond shades of insipid light green?