Extremes of Climate - Droughts

Global warming results in more frequent and more severe droughts

There are strong implications from scientific climate models that global warming due to increased greenhouse gas emissions has been associated with the more frequent occurrence of extreme climatic events, and  that humankind is the cause of global warming.

Warming is expected to pose serious challenges to global security and stability. Sub-Saharan Africa will be worst hit by impacts of climate change. In the Sahelian region of African, warmer and drier conditions have led to shorter growing season, reduced crop harvests and crop failure. Longer dry seasons and more uncertain rainfall are prompting urgent adaption measures in Africa.

Fires to Follow Floods as Wild Weather Hits Australia: Feb 06 2009 AFP
Eastern Australia braced for more fires and floods; as the south faced extreme heat and heavy rain threatened to swell floodwaters ravaging the north. A once-in-a-century heatwave was forecast to intensify over the weekend with high temperatures and dry winds producing the worst wildfire conditions in 25 years, authorities said.

Data collected shows widespread drying from the 1970s to the early 2000s over much of Europe and Asia, Canada, western and southern Africa, and eastern Australia. Severe droughts too, occurred in southern England in 1976, as a result of 18 months of below average rainfall concurrent with temperatures of 4° C above average. The heat-stress caused numerous daily fire break outs. In Surrey alone, the fire service answered 11,000 calls within a period of five months. Just crop failure alone resulted in an estimated loss of £500m.

The United States and many coastal regions had on the other hand, become wetter overall during the last 50 years.

Extremes may also occur at a particular place, but at different times. For example the summer of 2002 in Europe brought widespread floods but was followed a year later in 2003 by record-breaking heat waves and drought. Over recent years within China (for example 2008), droughts occur in the north while floods occur frequently in the south.

Chinese soldiers use washbasins to help irrigate crops
Chinese soldiers use washbasins to help irrigate crops in a field at Hejie village in Xuchang in China's Henan province Friday, Feb. 6, 2009. The People's Liberation Army deployed over 1,000 soldiers to help irrigate crops in Xuchang.

China has declared the highest-level emergency for the first time to combat the country's worst drought in five decades that has hit eight wheat-growing northern provinces and left more than 4 million people without proper drinking water. AP - Hier,

 

Effects of these extremes will bring costly consequences

Frequent droughts will adversely affect sea and land ecosystems, coastal systems,  freshwater security, food security and land degradation.

The impacts incurred on environmental and ecological systems during the 1999 drought in the United States may provide a clearer picture of  the probable drought effects. Shortage of fresh water increased the salinity of river waters posing risks to river habitats. It also created stress on fresh water supplies for consumption and agriculture. As future sea level rise shifts the saltwater-freshwater boundary farther inland, droughts will exacerbate the geographic extent and impacts of saltwater encroachment into coastal aquifers.

According to the U.S. Drought Monitor (USDM), nearly 8% of the United States (including Alaska, Hawaii, and Puerto Rico) was experiencing moderate to severe drought as of March, 2010. Drought affected 57% of Hawaii's land, with certain part of the Big Island moving into exceptional drought for the first time since 1999.

In 1997 and 1998 unprecedented forest fires broke out in Indonesia. 24.1 million acres of forest were destroyed, releasing 0.81 - 2.57 Gt of carbon dioxide into the atmosphere. This is equivalent to 13-40% of the mean annual global carbon emissions from fossil fuels, and contributed greatly to the largest annual increase in atmospheric CO₂ concentration detected since records began in 1957.

The accompanying underground peat fires made it almost impossible to put off the fire. Consequential haze covered the neighboring countries of Singapore, Malaysia, Sumatra, Sabah and Sarawak, creating health hazards for months before the fires were finally put off  with international help and efforts. There were many other forest fires in Java and Sulawesi on the same year. Nature: Forest Fires in Indonesia 1997  

A report, Global Warming Contributes to Australia's Worst Drought by WWF-Australia and leading meteorologists has shown that human-induced global warming was a key factor in the severity of the 2002 drought. Comparison with other major droughts found higher temperatures caused a marked increase in evaporation rates from soil, watercourses and vegetation.

Syrians head for cities amid severe drought/ June 2010
A severe four-year drought is devastating Syria’s rural communities, forcing them to head for urban centers to seek for employment. The UN estimates the mass exodus of migration amounts to more than a million people, who simply were not cultivating enough food or earning enough money to sustain themselves. Prolonged drought has caused the spread of a wheat crop disease and disappointing wheat and cotton harvests.

Worst drought in Thailand since years /June 2010
Thailand too is experiencing probably the worst drought in the last 10 years. The drought is affecting 9.6 million Thai farmers very badly as more than 60% of the population depends on agriculture. The drought is affecting 66 of Thailand's 76 provinces, forcing local authorities to stop supplying water for irrigation. Alarmingly, the current water supplies are not sufficient to have a second dry-season crop cultivation this year.

The drought is affecting other countries in South-east Asia.

Drought adds to Vietnam's Power Woes /June 2010
Vietnam is confronted with its worst water shortage in decades, with the dry spell pushing temperatures to a near 40°C, making the drought the worst in a century. Water levels at the reservoir was just above the “dead point”. This had severely restricted output of power much needed in Vietnam which is undergoing robust economic development.

Cambodia has called for international assistance.
Cambodia is suffering its second year of drought, with the Mekong River water levels dropping below normal levels, and many farmers expect to lose their crops.

 

References and related news:

China Struggles With Drought - Feb 05 2009 Beijing (AFP)
Los Angeles: Worst Drought Ever Recorded - Climate Progress
Brutal Drought Where It’s Normally We - Climate Progress
Warming Will Worsen Water Wars - Climate Progress

 

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