As China goes so does the World…. As Congress and Obama have decided the United States can afford unlimited immigration and a baby boom ( mostly of mexican anchor babies) and provide food for everyone , including China. China’s water shortages are due to China’s over-population ,which in the past was dealt with by massive famine and death. Think Locally Deport Nationally-
China drought highlights future climate threats
Yunnan’s worst drought for many years has been exacerbated by destruction of forest cover and a history of poor water management.
Born into a farming family in south Yunnan province, China, Zhu Youyong’s life has always been tied to the soil. At the age of 54, however, Zhu — now president of Yunnan Agricultural University in Kunming — says he “has never seen such severe drought in Yunnan”.
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.AP PHOTO
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.
Meanwhile, with most of the province’s winter crops ruined, local farmers need immediate help. Zhu has been going from county to county to persuade farmers to grow different crops together in the same field, rather than as a monoculture. Intercropping can boost yields by up to 30%, and could help to avoid food shortages in the region later this year1. This summer, 80% of the farmland in Yunnan — a staggering 2.9 million hectares — will use the technique. But success will depend on a break in the weather. “If it still doesn’t rain in late May, the consequences will be unthinkable,” says Zhu.
It is not news that China is seriously short of water, but its southwestern region — including the Yunnan, Guizhou, Guangxi and Sichuan provinces and Chongqing municipality — usually sees ample precipitation. This year, however, the rains did not come, and people there want to know why.
“Yunnan does experience droughts every few decades,” says Xu Jianchu, an ecologist at the Kunming Institute of Botany, an institute of the Chinese Academy of Sciences (CAS). But the severity of this year’s drought is unusual. Some say it is the worst in over a century. Xu is a contributor to a report on climate change in Yunnan and its myriad impacts2. Sponsored by CAS and the China Meteorological Administration, the report shows that Yunnan has got warmer and drier in the past half-century. Since 1960, the number of rainy days has decreased, whereas the number of extreme events, such as torrential rains and droughts, has increased.
“If it still doesn’t rain in late May, the consequences will be unthinkable.”
Some suggest that this year’s drought in Yunnan might be caused by the El Niño/Southern Oscillation (ENSO), an atmospheric circulation system that originates in the western Pacific Ocean and brings rainfall to Southeast Asia. During El Niño years the wind from the Pacific weakens, leading to droughts in the region.
“We’ve had a moderately strong El Niño event since October,” says Dan Bebber, a climate researcher at the Earthwatch Institute in Oxford, UK, a non-profit environmental group. Although Yunnan is not directly under the influence of ENSO, “there is a statistical relationship between El Niño and the monsoon system in southwestern China through mechanisms that are unclear”, he says.
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.
The forest’s thick litter layer of organic materials can absorb up to seven times its own weight in water, says Liu Wenyao, an ecologist at the Xishuangbanna Tropical Botanical Garden (XTBG), a research institute of CAS in Menglun in southwestern Yunnan. Natural forests also have an extensive network of roots that keep the ground moist, and the canopy can trap water vapour, creating a dense fog that keeps the myriad plant species alive during dry seasons.
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 value3. 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.
Many scientists are now worried that severe droughts, such as Yunnan’s, will become more common across southeast Asia. In addition to the effect on humans, “the impact on biodiversity could be huge,” says Jennifer Baltzer, an ecologist at Mount Allison University in Sackville, New Brunswick, Canada.
As existing plant species struggle to cope with the drought and die, they are replaced by hardier plants. Zhu Hua, an ecologist at XTBG, and his colleagues have already noted a 10% increase in the abundance of liana species over the past few decades in southwestern Yunnan’s tropical forests4. Cao Kunfang, also an XTBG ecologist, says that lianas have a deep root system that allows them to absorb water deep in the soil5. They can also minimize evaporation by closing the minute stomatal pores in their leaves. But without a large trunk, lianas are poor at absorbing carbon dioxide — and even worse once their stomata close. “Having more lianas in tropical forests could compromise their function as a carbon sink,” says Cao.
As government officials scramble to deal with the emergency in Yunnan, the province’s water management is being scrutinized. Most of its reservoirs were built more than 50 years ago, and half are either disused or do not function properly. Many of Yunnan’s natural lakes are severely polluted and unusable, says Ma Jun, director of the Institute of Public and Environmental Affairs, a non-governmental organization in Beijing. Xu says that the region has not enough small-scale infrastructure — ponds, small reservoirs and canals — to distribute clean water to the hardest-hit areas. “There is an urgent need to develop an effective hydrological network in the province,” he says.
In recent years the region has instead focused on building huge reservoirs and hydropower stations, Xu says, because of the economic and political capital that such projects offer. Overall, the central government has been reactive, tackling droughts when they come rather than preparing for the worst, adds Yu Chaoqing, a hydrologist at the Beijing-based China Institute of Water Resources and Hydropower Research, part of the government’s Ministry of Water Resources.
Throughout southwestern China, where 2,000 drought-relief workers are drilling wells around the clock, the location of groundwater remains elusive because few geological surveys have been done. “It’s a last-minute scramble because only 10% of the drought-ridden region has been surveyed,” says Hao Aibing, a geologist at the China Geological Survey in Beijing, who is helping to locate groundwater in Yunnan, Guizhou and Guangxi provinces. “Even if we get live water wells, the water quality remains an issue,” he says. “We just know so little about the groundwater in the region.”
Researchers are adamant that lessons must be learned from this year’s drought in Yunnan. “Extreme weather events are likely to happen more frequently in the future,” says Xu, referring to the findings of the CAS report. “I hope we will be better prepared when the next natural disaster strikes.”
Li, H., Ma, Y., Aide, T. M. & Liu, W. Forest Ecol. Manag. 255, 16-24 (2008). | Article
Zhu, H., Xu, Z.-F., Wang, H. & Li, B.-G. Biodivers. Conserv. 13, 1355-1372 (2004). | Article
Zhu, S.-D. & Cao, K.-F. Plant Ecol. 204, 295-304 (2009). | Article
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This news emphasized the problem of Yunnan’s drought and the author attributed the problem to the climate threat. However, this was no piece of data showing that how much Yunan’s water cycle system depended on rain precipitation and the solution they attempted for the observed short of rain due to “climate change”. Without a scientific approach, it will be a problem for the next natural disaster strikes.
2010-05-12 03:35:06 PM
Posted by: Bing Ye
National Drought Mitigation Center (NDMC) based in the School of Natural Resources at the University of Nebraska-Lincolnhas interesting report on DROUGHT AND CLIMATE CHANGE:
We know with certainty that the concentrations of CO2, CH4, N2O, and CFCs have increased as a result of recent human activity. Carbon dioxide is responsible for approximately half of the increase. Concentrations of CO2 have been systematically monitored at the Mauna Loa Observatory in Hawaii since 1958. Scientists can determine the CO2 concentrations from before 1958 using data collected from air bubbles within ice cores around the world. In 1750, levels of CO2 were around 270 parts per million (ppm). By 1999, these levels were at 367 ppm, and they are increasing at 0.4% per year (IPCC, 2001). According to the congressional Office of Technology Assessment (OTA, 1993), 70â€“90% of the CO2 added to the atmosphere is due to the burning of fossil fuels, and the rest is from deforestation. Methane, N2O, and CFCs are also increasing at a similar rate. But because CFCs destroy ozone, the net warming effect from CFCs is approximately zero (but that leads to an entirely different problem: depletion of stratospheric ozone). At these rates, it is estimated that the concentration of CO2 will double preindustrial concentrations by at least 2100 (IPCC, 2001).
Scientists can use this information within large-scale models of the atmosphere called General Circulation Models (GCMs). These models are composed of mathematical equations and relationships designed to simulate global atmospheric conditions and make projections of the future climate. Although there are differences between the GCM projections, the models are in general agreement that, as a result of increasing greenhouse gas concentrations, the average global temperature will increase 1.4â€“5.8Â°C (2.52â€“10.44Â°F) by 2100 (IPCC, 2001). In the past 100 years, the global average surface temperature has increased 0.60Â°C (1.08Â°F). This increase by itself is within the normal variability and, although it may be a result of climate change, it cannot be used as definitive proof that recent human activities have caused a global warming. Between 1860 and 2000, however, the nine warmest years for the global temperature have occurred since 1980 (IPCC, 2001).
With the projected global temperature increase, some scientists think that the global hydrological cycle will also intensify. GCMs indicate that global precipitation could increase 7â€“15%. Meanwhile, global evapotranspiration could increase 5â€“10% (OTA, 1993). Thus, the combined impacts of increased temperature, precipitation, and evapotranspiration will affect snowmelt, runoff, and soil moisture conditions. The models generally show that precipitation will increase at high latitudes and decrease at low and mid-latitudes. Therefore, in mid-continent regions, evapotranspiration will be greater than precipitation and there will exist the potential for more severe, longer-lasting droughts in these areas. In addition, the increased temperatures alone will cause the water in the oceans to expand, causing an estimated sea level rise of 20 cm (8 in) by 2030 (OTA, 1993).
Water Resources and Climate Change
Although we donâ€™t know how climate change will affect regional water resources, it is clear that water resources are already stressed, independent of climate change, and any additional stress from climate change or increased variability will only intensify the competition for water resources. Current stresses on water resources around the globe include:
â€¢ growing populations
â€¢ increased competition for available water
â€¢ poor water quality
â€¢ environmental claims
â€¢ uncertain reserved water rights
â€¢ groundwater overdraft
â€¢ outmoded institutions
â€¢ aging urban water infrastructure
In all likelihood, the direct impacts of climate change on water resources will be hidden beneath natural climate variability. With a warmer climate, droughts and floods could become more frequent, severe, and longer-lasting. The potential increase in these hazards is a great concern given the stresses being placed on water resources and the high costs resulting from recent hazards. The drought of the late 1980s showed what the impacts might be if climate change leads to a change in the frequency and intensity of droughts across the United States. From 1987 to 1989, losses from drought in the United States totaled $39 billion (OTA, 1993). More frequent extreme events such as droughts and floods could end up being more cause for concern than the long-term change in temperature and precipitation averages.
The best advice to water resource managers regarding climate change is to start addressing current stresses on water supplies and build flexibility and robustness into any system. Flexibility helps to ensure a quick response to changing conditions, while robustness helps people prepare for and survive the worst conditions. With this approach to planning, water system managers will be better able to adapt to the impacts of climate change, whatever they may be, and will also be better equipped for the climate variability we have now.