One of the big problems with climate change is that carbon dioxide is invisible. It's hard to notice something you can't see. Because if carbon dioxide were visible, the eastern U.S. and western Europe would be choking on the stuff worse than Londoners choked on coal soot in the 1800s.

You're probably aware that western countries account for most of the world's greenhouse gas emissions. But actually seeing it, as in the map below, makes that notion perfectly clear. The map shows the world's carbon emissions from 1997 to 2010, say the scientists who made it. The data came from satellite measurements and reported emissions rates from factories and power plants, among other sources.

Lest you think this carbon dioxide emissions map is really just a population map in disguise, look at this map (albeit from 1994) of the global population distribution: