Gone with the wind? Gustier future in China may ease smog in big cities says Tibetan Plateau study
Team says wind patterns have become more aggressive in mountainous western region, which suggests a reversal of weakening gusts nationwide may be on the cards.
China’s notoriously bad air quality may improve naturally over time because smog can be dispersed by just a gentle breeze, and such gusts are expected to grow in frequency in Beijing and other landlocked Chinese cities in the future, according to a new study by local scientists.
While the rate of efficacy remains up for debate, a team led by Professor Yang Kun found in their latest study that gusts moving at speeds of 3.5 metres per second (12.6 kph) can have a significant effect in cleaning the air.
Such winds classify as a gentle breeze on the Beaufort scale, with only enough strength to move flags, leaves or twigs.
The researchers based their findings on the relationship between wind speed and the dimming effect of air pollutants on sunlight over the last half a century.
They also drew on their previous research in Tibet after picking up an important signal at a remote monitoring station in the western Chinese province two years ago, which they reported in an earlier paper.
They found that surface wind speeds at high altitudes across the mountainous region had increased steadily for more than a decade.
And while wind speeds are known to have declined across China from the 1960s to the early 2000s, they said this suggested another reversal may be in the pipeline with more gusts expected across the mainland in the coming years.
The team published their latest findings last week in the journal Scientific Reports.
“With potential wind speed reversals and strict controls on aerosol emissions, the current solar dimming may be alleviated and polluted regions may experience brightening in the future,” they wrote.
This could “be a useful reference for [government bodies] managing industrial activities and vehicle emissions in large cities, such as Beijing,” they added.
Yang worked on the paper with other colleagues from the Chinese Academy of Sciences’ Institute of Tibetan Plateau Research in Beijing.
Air pollution remains one of the biggest headaches for the Chinese government, with a number of Chinese cities in the top 10 index of the world’s unhealthiest metropolises.
A 2013 study of northern China, where coal burning creates massive amounts of smog in winter, by an international team found that people living in this broad swathe of land could expect to have their life expectancy shortened by five years on average due to illnesses related to air pollution. The research was published in the Proceedings of the National Academy of Sciences journal in July of that year.
Moreover, as China embraces a healthier outlook in line with the government’s latest five-year plan, more wealthy Chinese are moving their money and families overseas to minimise the risk of contracting heart disease, lung cancer or some over ailment linked to pollution.
To tackle the issue of chronic smog, the government has launched its most stringent environmental laws and policies to date in recent years.
Measures include shuttering factories that don’t meet the required guidelines, or relocating them away from urban city centres, and regularly banning automobiles from the roads depending on their registration plate.
While these measures have been welcomed by the majority of Chinese society, negative side effects include inconveniencing commuters, impeding economic output and ramping up pollution levels in less developed areas.
“The mainstream view [about pollution in China] is still quite grim,” said one environmental science researcher who was asked to comment on the new study. He declined to give his name.
“Global warming will lead to weaker winds across China, and that is the estimate of many research teams over the last few decades,” he said, adding that he was surprised at Yang’s claims.
“To overthrow other people’s forecasts, they need to come up with stronger evidence [than this].”
However, more scientists in China have come up with findings to challenge the generally accepted status quo in recent years.
Another research team with the Chinese Academy of Sciences reported recently that global warming will actually benefit China by increasing rainfall in its dry northern regions, while reducing flooding in the southern areas.
Although this contradicts previous studies, the argument was supported by evidence based on climate patterns repeated in plants dating back as far as 20,000 years.