WHEN it comes to finding someone to blame for global warming, the finger is usually pointed in the direction of the United States. In 2005, for instance, this nation produced 20 percent of the world’s emissions, the highest in the entire world. But the US has stubbornly refused to sign the Kyoto Protocol since it was conceived a decade ago.

The US government, it seems, doubts there is a link between economic activity and global warming. But