A Day In The Life Of Mother Earth : What’s is ‘Sustainable’? : sus*TAIN (v), 1) to keep in existence; keep up; maintain or prolong.

Sustainable development. The sustainable society. An environmentally sustainable global economy.

They’re the hot environmental terms of the 90s, and will no doubt pepper virtually every speech and corridor conversation at next week’s Earth Summit in Rio. But what do they mean, really?

To be “sustainable,” development must meet the needs of today without compromising the ability of future generations to do the same. The term implicitly concedes limits to what the planet can handle. But it also rejects the position that any economic growth is irresponsible.

What does it all mean in terms of everyday life? Here’s a sampling of products and technologies that promote the goal of a sustainable world . . . and some that don’t:

Thumbs up * Compact fluorescent light bulbs * Electric cars * Reusable glass containers * Reusable canvas tote bags * Solar energy * Recycling * Cogeneration (combined production of heat and power) * Family planning * “Green taxes” on emissions of pollutants or other harmful practices * Utility rates that encourage conservation

Thumbs down * Incandescent light bulbs * Gasoline or diesel powered vehicles * Plastic “yokes” for six packs * Throwaway plastic grocery bags * Oil or coal-fired generating plants * Landfills * Sprawling suburbs * “Planned obsolescence” * Government subsidies for road building * Utility rates that link profits to rising sales of power