Wal-Mart lobbies against carbon-offset guidelines.

• What’s the climate impact of junk mail?

Reader support makes our work possible. Donate today to keep our site free. All donations TRIPLED!

Household PCs go on an energy diet.

California school buses will get cleaner.

Grist thanks its sponsors. Become one.

• Map shows how climate change affects biodiversity.

• Cuba scales back ethanol plans.