FLOODS AND DROUGHTS IN SOUTHEAST ASIA
A devastating drought hit Southeast Asia in the late 1990s and was particularly damaging in the Philippines, Indonesia, Malaysia, Thailand and Vietnam , where an estimated $20 billion of damage was caused most through lost crops. Plants withered in the heat, irrigation ditches dried up and cracked and The temperatures rose above 100°F for weeks on end.
Flooding has always been a problem but it has been exacerbated by man-made causes such as logging and slash and bun agriculture. One environmentalist with th World Watch Institute told the Los Angeles Times, “The forest that once absorbed and held huge quantities f monsoon rainfall, which could then percolate slowly into the ground, are now largely gone/ the result is much greater run-off into the rivers.”
In February 2007, Earthweek reported: Record low temperatures spread across many parts of Southeast Asia, causing crop damage as far south as the mountainous interior of the Philippines. Cambodia, Laos, Vietnam and northern Thailand experienced some of the coldest early February weather on record.The chill was caused by a Siberian high pressure area that sent the winter chill much farther south than normal. Vegetable crops in the Philippines' Benguet province were damaged when temperatures fell to 40 to 45 degrees Fahrenheit from the normal seasonal lows of 64 to 73 degrees. Provincial agriculturist Delina Juan told the French news agency that many areas of the province have been affected by the unusual weather.
Flood Risk Rampant Across Asia's Factory Zones
David Fogarty and Clare Baldwin of Reuters wrote: Global insurance companies are struggling to get a grip on their flood exposure in Asia nearly a year after one of the world's costliest disasters hit Thailand, with executives fearing an even worse event looms in the region.Some firms learnt from the Thai floods, with new defenses built to protect multi-billion dollar industrial estates in the country. Insurance premiums have also gone up, but factory construction in flood-prone areas remains rampant across Asia. Insurance executives say the industry is vulnerable to another major flood, with scientists identifying the coastal plains of southern China as one area at greatest risk. [Source: David Fogarty and Clare Baldwin, Reuter, July 22, 2012]
The Thai floods hit nearly 1,000 factories feeding global supply chains - particularly in the auto sector - costing insurers an estimated $20 billion. "When I go and look at these industrial parks and ports in some of the low-lying coastal areas, I just have to stand back and think: Who's insuring these things? Who's done the risk assessment?" said Adam Switzer, a coastal scientist at the Earth Observatory in Singapore. "What I consistently see on the coasts throughout Asia is that we're still making the same sorts of mistakes." [Source: David Fogarty and Clare Baldwin, Reuter, July 22, 2012]
In the rush for development that has lifted millions out of poverty in Asia, many factories have been built along coasts, especially in river deltas. According to insurance industry executives, most construction was done without long-term historical data on floods and storms.On top of that, rising sea levels, increasing rainfall and more intense storms - together with more people and infrastructure - mean the risks have multiplied. "We should be identifying these pockets of exposure earlier," said Scott Ryrie, Asia-Pacific vice chairman for Guy Carpenter, a global insurance industry services firm.
After the Thai floods, global reinsurer Swiss Re reassessed flood risk in emerging markets. The report's No. 1 risk was China, whose vast industrial estates are at the heart of global manufacturing, making everything from iPads to brake pads. Among other Asian countries listed, Malaysia was 5, Indonesia 7 and India 10. Thailand was ninth. Munich Re and Guy Carpenter have also reviewed flood risk models, particularly for industrial parks in Asia. "A new risk awareness has to set in along the entire value chain," said Tobias Farny, Munich Re's Asia-Pacific chief executive. "The exposures present need to be defined, described and ring-fenced in order to become insurable."
El Nino brings drought to Malaysia and Indonesia and elsewhere in the western Pacific. The devastating El Niño of 1997-98 produced a severe drought and heavy storms that more than 2,000 people and caused billions of dollars in damage to crops, infrastructure and mines in Australia and other parts of Asia. During the La Niña, Southeast Asia gets wetter.
El Niño is a periodic climate condition that occurs an average of every five years. It is strongest in the Pacific but has global ramifications. Caused when a dominate high pressure system over the Pacific collapses, it causes wind directions and ocean currents in the Pacific to change direction, throwing off prevailing winds and bringing drought to Indonesia, Southeast Asia, southern Africa and Australia, heavy rains and floods to Peru and east Africa, typhoons to Japan, stormy weather to the United States and disruptions to monsoons in India. [Source: Curt Suplee, National Geographic, March 1999
The name El Niño (Spanish for "the Christ Child") was coined by Peruvian fishermen in the port of Callao north of Lima in early 1970s because the warm air and water associated with change usually first appeared around Christmas. In the 20th century there were 23 El Niños and 15 La Niñas. During the 50 years period between 1950 and 200, El Nino condition existed 31 percent of the time and La Niña conditions existed 23 percent of the time.
Severe El Niños are though to contributed to the decline and fall of the Moche civilization in Peru around A.D. 500. It also probably created smooth sailing across the Pacific for Magellan in 1520, In 1630, 5 million people died in India from an El Niño-induced drought and famine. During an El Niño that lasted from 1789 to 1793 the flow of the Nile was greatly reduced and 600,000 people died in India.
Scientist have said that El Niños have been getting progressively worse. More powerful and far-reaching than originally suggested, the El Niño 0f 1982-83 was the strongest of century. It was still creating havoc in 1990s. After that El Niños have been more frequent. The 1997-98 El Niño was the worst on record.
Normal Trade Wind Conditions
Under normal conditions the trade winds blow from east to west across the equatorial Pacific. They are generated by a low pressure system around Indonesia and Australia caused by warm that rises thousands of feet upwards. As it rises and cools it produces rain. High in the atmosphere the air moves from west to east---the opposite direction of the trade winds--- pushed by up upper atmosphere winds. The air becomes cooler and heavier as it moves eastward, When the air reaches the Americas it is cold and heavy enough so that it sinks, creating a high pressure system there.
As the trade winds blow from east to west the wind pushes the ocean surface along with them. As a result of this the sea level in Asia is about 18 inches higher than seas along the coast of South America. Because the ocean is lower along the South American coast than it is further to the west, water from deep in the ocean rises up and displaces the missing water. The cooler water is full of nutrients that feed plankton, which in turn feed some of the world's richest fisheries. The thermocline (the depth where surface water and cold deep water meet) also rises bringing even more nutrients.
The trade winds create a balance between the warm waters of the western Pacific and the cool water of the eastern Pacific. Sun heats the waters in the eastern Pacific but the thermocline is only about 40 meters below the surface. Storm clouds form over warm water surfaces in the western Pacific. The winds pick up moisture as they blow across the ocean and releases in the form of south-west monsoon rains in Indonesia, Papua New Guinea, northern Australia and parts of Southeast Asia and the Philippines.
The coastal regions of northern Chile and Peru are among the driest regions on earth because the trade winds blow Pacific moisture away and the Andes block moisture from the Amazon region. Oceans are the largest sources of atmospheric heat. Water vapor produced by transpiration of heat and evaporation produces more clouds and heat that disrupts patterns around the globe in ways still not completely understood.
El Niño Development
El Niños generally occur an average of once every five years within a three to seven year period. Still there are great fluctuations and El Ninos are difficult to predict. Each El Niño is different and local conditions can change dramatically in single place over a few days.
El Niño are caused when a dominate high pressure system over the Pacific collapses, causing wind directions and ocean currents in the Pacific to change direction. Instead of coming from the east the winds start comings from the west, thrown offing all kinds of things.
El Niños start when prevailing easterly trade winds slacken as air pressure become abnormally low around Tahiti and an unusually high pressure develops over Australia. Warm water from the western Pacific starts flowing eastward, creating a band of warm water that spans the equatorial Pacific. Oceans begin warming up in March or so and then slacken off and gain momentum in September and reach their peak around December.
p><As the trade winds weaken seawater and moisture-laden clouds don’t move westward. This means that areas that rely on southwest monsoon experience drought. Warner waters in equatorial Pacific cause a low pressure system to form there and dry air descends over Australia and Indonesia, causing drought.
Why a low pressure forms over Tahiti and a high pressure forms over Australia and trade winds slacken is still kind of a mystery. Among the variable that play a part in the complex mechanisms are the Earth’s orbit, strength of ocean currents and possibly global warming.
El Niños contains the seeds for their own destruction. They brings drier, hotter air to the south and wetter, colder air to the north, which eventually lead to their demise.
Meteorologists at the Research Institute for Global Change in Yokohama, Japan have found that the presence of a weather condition in the Indian Ocean---the negative phase of the so-called Indian Ocean Dipole, when warn water occurs in the east and cold water in the east---often occurs a year before El Nino events in the Pacific.
Effects of El Niño
El Niño throws off weather patterns worldwide. In Tahiti, which normally sits under a fair weather high pressure system, waves of typhoon start rolling in. Pacific storm lash the northwest United States and drought descends on Australia, Indonesia, Southeast Asia and as far west as Southeast Africa.
El Niño brings: 1) drought to Indonesia, Southeast Asia, the Philippines and Australia; 2) heavy rains to the west coast of South America; 3) stormy wether and milder winters to western United States; 4) droughts to southern Africa; 5) fewer hurricanes to the Atlantic; 6) heavy rains to eastern Africa; and 7) disruptions to the monsoon cycle in India.
The effects can be far-reaching. During El Niño years temperatures are usually warmer in Japan, India, Alaska. The eastern United States has a warmer-than-normal winters and there are droughts in northeast Brazil. Drought-stricken areas in Indonesia, Southeast Asia, Australia, Papua New Guinea and Brazil often times experience ravaging forest fires.
During the 1997-98 El Nino, Smoke from fires caused by droughts in Indonesia reduced air visibility to less than half a mile hundreds of miles away in the Maldives. In Mongolia an unusually high temperature of 108 degrees F was recorded.
Asia Faces Threat to Crops From El Nino
In May 2012, Naveen Thukral and Lewa Pardomuan of Reuters wrote: “A return of the El Nino weather pattern may threaten food output in Asia, the world's top producer of rice and palm oil, but drier conditions in some areas could also benefit crops such as coffee and cocoa and keep global prices in check. Malaysia and Indonesia account for almost 90 percent of the world's palm oil supplies, while most of the world's rice is exported from Asia. The region also accounts for nearly 40 percent of wheat production and the bulk of natural rubber output. Thailand, the world's biggest rice exporter, is also the world's second-largest sugar exporter after Brazil. [Source: Naveen Thukral and Lewa Pardomuan, Reuters, May 10, 2012]
Coffee and cocoa could thrive this year after being hit by heavy rains last year. Vietnam and Indonesia, the world's top robusta producers, account for nearly a fifth of the world's coffee crop. Indonesia accounts for 10 percent of global cocoa output. Malaysia, the world's second-largest palm oil producer, could see lower production in 2013 if the El Nino results in poor rainfall.
Chinese authorities are keeping their fingers crossed as farmers gear up to plant the world's second-largest corn crop. In India, where farmers are banking on another near-record rice crop to keep the momentum of exports, forecasters are predicting a normal monsoon season. "An absence of El Nino in the first half of the monsoon season helps planting of summer crops and also aids initial growth stages," said S. Raghuraman, a New Delhi-based analyst.
El Niña refers to a cooling of the mid-Pacific equatorial region as seawater there cools to temperatures below normal. It often occurs in years following El Nino. The effects are often opposite those of El Niño: floods occurring in places where droughts occurred under El Niño and cold winters occurring where mild winters occurred under El Nino.
La Niñas are like El Niños in reverse. They start when prevailing easterly trade winds intensify as air pressure become abnormally high around Tahiti and an unusually low pressure develops over Australia. The strong trade winds push the water westward. Warm waters flow towards Asia. Cold, deep water upwells to the surface along the Americans. The cool water dilutes the warmer liquid at the surface, causing the temperatures to drop. Nutrients become more plentiful and evaporation decreases, reducing rain and cloud formation in the eastern Pacific. With more warm water pushed to the western Pacific, storm clouds intensify there and bring more rain to Indonesia and Southeast Asia.
La Niñas tend to develop from March to June and reach the peak of their intensity at the end of the year. The phenomena is linked to fewer typhoons in the Pacific but more in the Atlantic. In the Pacific a “cold water tongue” stretches along the Equator from Ecuador to Samoa. The equatorial cloud formation there becomes split, separated by the Tahiti high. The Pacific subtropical jet stream is similarly split and weakened, allowing Atlantic hurricanes to move westward and gain strength.
La Niña brings higher temperatures and more rainfall to Australia, Indonesia and Southeast Asia and causes heavier rainfalls in the monsoon season in India and wetter than normal condition as far west as Africa. In the Western hemisphere, the polar jet stream moves southward bringing cold temperatures to the northern United States. The weak subtropical jet stream weakens causing less ran in the Gulf of Mexico and the southeast United States.
La Niña and El Niño are like a pendulum that goes back and forth. There were La Niñas after the El Niños in 1982-83 and 1986-87 A La Niña occurred in late 2005 and early 2006 and occurred after the El Niño ended in 2007.
Image Sources: Wikimedia Commons
Text Sources: New York Times, Washington Post, Los Angeles Times, Times of London, The Guardian, National Geographic, Smithsonian magazine, The New Yorker, Time, Newsweek, Reuters, AP, AFP, Wall Street Journal, The Atlantic Monthly, The Economist, Global Viewpoint (Christian Science Monitor), Foreign Policy, Wikipedia, BBC, CNN, NBC News, Fox News and various books and other publications.
© 2008 Jeffrey Hays
Last updated April 2014