Wednesday, June 22, 2011

Climate change blamed in extreme shift from drought to flood in China



An extreme shift in weather in June across much of southern and eastern China has been put down to the effects of global warming and climate change. Usually light rains start in June in the middle and lower Yangtze valley leading in to the summer monsoonal rains and typhoon season, but this year torrential rains and storms struck on June 3 and have continued unleashing devastating floods, the worst in over 50 years.

Chen Zhenghong, senior engineer at the Meteorological Bureau of Central China's Hubei province, said the sharp shift between drought and flood in East and Central China was a result of global warming, according to a Xinhua News Agency report in China Daily on 17 June.


The floods follow the country's worst drought in half a century. From January to May, rainfall in the central and eastern provinces of Hubei, Hunan, Anhui, Jiangxi and Jiangsu was 40 to 60 percent lower than the seasonal average. Crops and vegetable production were down due to the drought producing inflated food prices. These floods will further damage many crops exacerbating food prices further.

During early June there has been torrential rains across 12 provinces in central and southern China. By June 8, floods had affected an estimated 4.81 million people. The heavy rains have continued in mid June forcing more than half a million people to evacuate in China’s central and eastern provinces. At least 175 people have now died from the floods with 86 more missing. The floods have affected 36.57 million people and left 1.64 million displaced in 510 counties in the provinces of Jiangsu, Zhejiang, Anhui, Fujian, Jiangxi, Hubei, Hunan, Guangdong, Sichuan, Guizhou, Yunnan, the Guangxi Zhuang autonomous region and the Chongqing municipality according to a Ministry of Civil Affairs statement from Monday reported the China Daily on 21st June.

For the city of Zhuji the torrential rain has produced the highest precipitation since meteorological data has been collected according to the city's deputy chief meteorologist Zhou Yongzhong reported in China Daily on 18th June. The Zhuji district has had 40.5cm of rain since the start of the month.

With 660 dams at capacity in East China's Anhui province, the Chinese Government has ordered sluice gates open sending floodwaters downstream to innundate farms, villages and cities. On June 17 the Chinese government upgraded it's emergency response to level 4, the highest level, sending disaster relief teams to the worst affected provinces of Zhejiang, Anhui and Jiangxi.

Chinese officials say the floods will only have a limited impact on rice production this year and will not threaten the country's food supply. But the prices of fruit, vegetables and other agricultural products are likely to surge because of the disastrous weather, according to Ma Wenfeng, a senior analyst at Beijing Orient Agribusiness Consultant Ltd, a major agricultural consulting company reported in China Daily.

At least 10 major rivers in the affected areas were threatening to burst their banks according to Water Resources Minister Chen Lei, "Severe floods triggered by heavy rains will continue to threaten parts of southern China," he said on Sunday on the ministry's website according to China Daily, "There is an increasing possibility that downpours with enhanced frequency and intensity will continue to lash regions in the south."

According to a report by German reinsurance company Munich Re the number of annual weather related disasters in China including violent storms, floods, extreme temperatures, droughts and forest fires has surged to about 48 by 2010 from around 11 in the early 1980s.

The Head of Munich Re's Georisk Research, Peter Hoeppe, outlined the long term trend and risk associated with climate change, "The devastating floods in China are of a dramatic dimension -- a phenomenon that has unfortunately occurred in China with increasing frequency over the last few decades. Every year, millions of Chinese are victims of weather-related natural catastrophes. And the risk is steadily growing, for climate change harbours the potential for torrential downpours while the risk of drought in certain regions is also on the rise." he said in an email reported by AFP on 21 June.

A report by the Chinese climate Centre two years ago provided to the Guardian warned of rainfall coming in shorter, fiercer bursts, interspersed by protracted periods of drought. The IPCC has warned that increasding global temperatures will see an increase in the frequency and intensity of floods, drought and storms.

A study - Detection of human influence on twentieth-century
precipitation trends
(PDF) - published in July 2007 in Nature, concluded "that anthropogenic forcing has had a detectable and attributable influence on the latitudinal pattern of large-scale precipitation change over the part of the twentieth century that we were able to analyse. Our best estimate of the response to anthropogenic forcing suggests (Fig. 1b) that anthropogenic forcing has contributed approximately 50–85% (5–95% uncertainty) of the observed 1925–1999 trend in annual total land precipitation between 40u N and 70u N (62 mm per century), 20–40% of the observed drying trend in the northern subtropics and tropics (0u to 30uN; a decrease of 98 mm per century) and most (75–120%) of the moistening trend in the southern tropics and subtropics (0u to 30u S; 82 mm per century)."

The floods in China follow significant rain and flood events in the US Midwest threatening 2 nuclear power plants, Brazil, Philippines, Queensland and Victoria and Pakistan. According to US National Oceanic and Atmospheric Administration (NOAA) 2010 was the wettest year globally.

Sources:

* NASA Earth Observatory June 13, 2011 - Heavy Rain in Southeast Asia
* NASA Earth Observatory June 22, 2011 - Heavy Rain in China
* China Daily, June 21, 2011 - Floods put strain on dikes
* China Daily, June 18, 2011 - When the levees broke . . .
* China Daily, June 17, 2011 - Dramatic climate shifts due to global warming
* PressTV, June 21, 2011 - China opens reservoir gates to prevent overflows
* Expatica.com, June 21, 2011 - Weather catastrophes in China soar: reinsurer
* Animated Gif made by Takver with GIMP from 2 NASA images acquired June 3 - 9, 2011 and June 13 - 19, 2011