One world.

You've heard about global warming, now get ready for global dimming...

It would seem that one way to muck up the planet just wasn't enough. While our gaseous pollution is heating the place up, at the same time particle pollution (soot, smog, whatever you want to call it) has resulted in more reflective clouds and less sunlight reaching the Earth's surface - something like 10% less over the space of a few decades in many parts of the world.

The dreadful irony is that the dimming has actually been protecting us from the full effects of the warming. Now that we've starting to clean up the visible pollution (over the last couple of decades in Europe, for example), the rate of warming is likely to accelerate if we don't clean up the greenhouse gases at the same time.

The thing that REALLY got me about the documentary discussing all this, however, was the cataclysmic effects that happen to people who aren't doing the polluting in the first place.

Remember the massive drought in Ethiopia in the mid-80s? The one that inspired Live Aid and songs like "We Are The World"?

They were right, but not for the warm-hearted mushy reasons. It's now thought that the drought (which lasted for about a decade, we only heard about the end part of it) was caused by the polluted clouds streaming across from North America and Europe. Basically the temperature changes caused by the dimming meant that the monsoon rains never reached Ethiopia's latitude - they were pushed further south, away from the pollution.

Anyone who thinks their actions are their own business and they're not hurting anyone else is probably kidding themselves.