Yunnan’s worst drought for many years has been exacerbated by destruction of forest cover and a history of poor water management.
Since last September, the province has had 60% less rainfall than normal. According to the Ministry of Civil Affairs, 8.1 million people ” 18% of Yunnan’s population ” are short of drinking water, and US$2.5-billion worth of crops are expected to fail.
The drought in Yunnan province has left millions without water.
Scientists in China say that the crisis marks one of the strongest case studies so far of how climate change and poor environmental practice can combine to create a disaster. They are now scrambling to pin down exactly what caused the drought, and whether similar events are likely to hit the region more often in the future.
Indeed, the CAS report suggests that in previous strong El Niño years, the rainy season in Yunnan, which spans May to October, was delayed, with less rain in the summer and more rain in the autumn. But climate models are divided on how climate change will affect ENSO, with some showing increasing intensity and others decreasing intensity, says Bebber.
Climate change is not the only factor affecting the drought. Deforestation in mountainous Yunnan is also being blamed.
“Natural forests are a key regulator of climate and hydrological processes,” says Xu, who is also China’s representative at the World Agroforestry Centre, an international think tank headquartered in Nairobi, Kenya.
But in Xishuangbanna prefecture, renowned for the natural splendour of its tropical rainforests, forest clearance between 1976 and 2003 shrank the primary-forest cover to 3.6% of its 1976 value. The rainforest has been replaced by rubber trees — known as ‘water pumps’ by locals because of their insatiable thirst — which now cover 20% of the prefecture’s land.
In the Ailao mountains north of Xishuangbanna, where it is too cold to grow rubber trees, plantations of fast-growing but thirsty eucalyptus are replacing primary forest to feed the paper industry. In other parts of Yunnan, logging, mining, quarrying and increasing human settlement have cleared huge areas of forest. The results are an increase in soil erosion, landslides and flash floods.
“Such large-scale deforestation removes the valuable ecological services natural forests provide,” says Liu.
“The impact of deforestation on hydrological processes becomes particularly acute during prolonged droughts.”
The region could also be plagued by other natural hazards: with drought the risk of forest fire increases, whereas wetter monsoon seasons could see more floods wreaking havoc.
Source: China drought highlights future climate threats - nature news
Date: 11 May 2010