Key Facts & Analysis

Scientists agree that the world’s CO2 concentration should stabilize around 450ppm. It is now around 387ppm, and increasing by 2ppm per year.

In China’s Icy North, Outfitting Buildings to Save Energy

Written by Te-Ping Chen For National Geographic News

Harbin, in China's northeast, plays up its "Ice City" reputation with its annual Harbin International Ice and Snow Festival, where ice sculptures were on display January 4. But in its real buildings, officials are making renovations that they predict will increase energy efficiency by 50 percent.