Earth Hour 2010 will start at 6:30 this evening. It's an hour to switch off our lights. But more than that, it's an hour to meditate about what we should and can do to reduce our carbon footprint.

Is global warming remote and that difficult to feel as some say? Maybe, it is when it comes to its direct and tangible impact on our lives. But we do feel its impact when it comes to environmental pollution. The air we breathe is not as clean as it used to be. We can see the smoke, the dust and the smog. And we can feel the difference that a strong wind or heavy rain makes to the quality of air.

Extreme weather conditions occur much more frequently nowadays than they used to. The much-longer-than-usual winter, which is still lingering in most parts of North China, is an abnormality, so is the worst drought in more than a century in Southwest China.