Why Beijing makes it snow

Photo by "eye of wolf" on Flickr.

Record levels of snow hit the Chinese capital this week causing road, school and airport closures. Most Beijingers assumed the authorities were to blame, after they instigated snowfall using weather manipulation techniques in October.

China, which spends an estimated $100 million each year on trying to make it rain and snow, is easily the world's biggest fan of man-made precipitation. On Oct. 31 last year the authorities fired 186 doses of silver iodide into the sky using "weather guns". The next day, 16mm of snow fell on the capital.

Can you tell the difference between real and fake?

Above, snow in Beijing on Monday, after it snowed naturally. Photos by BB Wang; sent to us by one of our Observers in Beijing, Roseann Lake.

Fake:

Above, snow in November, after iodide was fired into the air on Oct. 31. Photos by Roseann Lake.

“Rain and snow helps give the city a good washing, but the effect is only a temporary one”

Alex Pasterneck is an environment-specialised writer for treehugger.com and editor of motherboard.tv who has spent three years living in Beijing.

As soon as I heard of the record-breaking snowfall, I expected that this was again prompted by cloud seeding.

For years Beijing has been undergoing a severe drought; the city has less water per citizen than Israel, which sits in a desert. Demand for water (for washing up and cooling down) is higher in summer, but because precipitation is rare in Beijing's winters, snow- or rain-making might be more enticing than usual during the winter months.

Precipitation helps Beijing increase its water tables, clear the air of pollution and give the city a good washing. Without as much rain, the city would, temporarily at least, be drier and dirtier.

In winter, Beijing experiences the Siberian anticyclone, which ferries in cold, dry and often cloudless air from the north. By cycling pollution out of the skies, that can be a relief from the summer, when hot air from the south gets trapped in the basin in which Beijing sits, keeping smog over the city. But the high pressure system in the winter can also trap Beijing's air, leaving pollution sitting over the city and leaving those with breathing difficulties with abnormal problems.

Rain, snow (and wind) can act have a ‘scrubber' effect on air pollution, washing particulates and other pollutants out of the air. [For a few days leading up to the big snowfall on January 3rd, the Beijing US Embassy air monitor that provides hourly reports via Twitter was reporting conditions as ‘very unhealthy'. After the snow, air conditions were reported as ‘unhealthy' and eventually as ‘moderate']. But the effect is only a temporary one. As with other ‘geo-engineering' schemes, rain-making is not a solution to environmental problems. It's a band-aid, providing temporary relief from the symptoms. And I think it also has a masking effect, making it harder to recognise the actual pollution problem and obviously relieving pressure on the authorities to tackle the real source of the problem, from automobiles to factories to agricultural burning.

Witness the relative general satisfaction with Beijing's air during the Olympics, which was in part the result of rain-making and temporary bans on vehicles and industry. Did Beijing improve its environmental controls and monitoring in the lead up to and after the Olympics? Yes. Did it become even better at controlling its environmental image and creating the impression of clear skies and healthy water? Yes."