Who stopped the rain?

Apparently, it rained pretty heavily almost everywhere in China over the weekend. Everywhere.... except in Beijing, where we had only a couple of light showers overnight. Beijing is still pretty damned parched. At least the laying of the dust across much of north China has restored our blue skies (the air in Beijing is still fairly poisonous, especially anywhere near the huge construction sites around Sanlitun; but at least it's transparent again, which it wasn't for much of the preceding fortnight).

Quite a few times recently, it's looked like it might rain here in the capital, it's felt like rain.... but it hasn't rained. This is quite remarkable, since ordinarily any and every cloud that approaches the city is promptly shot full of silver iodide by artillery batteries stationed to the south and west - and, sure enough, rain comes. A sour-tasting, chemical-rich rain that tints the sky green.

But I don't think we've seen any of that since the Olympics last year.

There are two (non-exclusive) 'conspiracy theories' to explain this curious circumstance. Or three, if you believe in karma or divine retribution or....

1) OK, so, the Hand-of-God, reap-what-you-sow, don't-mess-with-Dame-Nature explanation is simply that the powers-that-be here in Beijing are being punished for all the meddling they did with the weather last year to try and ensure a reasonably well-watered and non-polluted Olympics. There doesn't have to be any mechanism; it's simply right and just that we are now suffering month after month of rain-free, cloud-free drought and inexorably turning into a desert.

But me, I like to try and find a mechanism always.

2) The drought currently afflicting north central China is at least partly caused by the massive re-routing of water supplies to the capital last summer. Beijing demanded so much water from the provinces to the west that their water-tables were dangerously depleted, and still haven't recovered. Beijing's not getting any rain because there's now very little groundwater to evaporate from the areas immediately upwind.

3) Even when clouds do appear over the capital, we don't seem to be trying the silver iodide trick any more. Did we use up all our stocks last year? No, I think it's more possible, more likely that we're having to observe some kind of quota system. I noted last year that Beijing's rampant cloud-seeding must effectively be robbing areas further east - notably the sprawling municipality of Tianjin - of rainfall, and that this probably couldn't continue completely unregulated. I suspect that Beijing used up all of its cloud-seeding allowance and then some last summer, and is now being forced to refrain from the practice for a while.

Just idle speculation, of course. But I think these ideas merit some investigation.