How has El Niño affected your life?

El Niño Southern Oscillation (ENSO)

Oceans are able to store a lot of heat energy, but whereas the weather can change rapidly, it takes the ocean hundreds of years to warm up throughout its depths. Because the oceans can store heat, they slow down the rate of global warming and are therefore a major influence on the climate system. Individual oceans have their own circulation patterns; some of them region or local, and unusually cold or warm patches can persist for years. Some areas regularly oscillate between a warmer and a cooler state every few years. The best known of these is the El Niño Southern Oscillation (ENSO), in the eastern Equatorial Pacific, where the warm state is called El Niño and the cooler state is called La Niña. The El Niño straddles the equator; broad along the coasts of Ecuador and Peru, and getting narrower as it stretches west.

South America gave El Niño its name, calling it after the boy child (the Christ child) because it appears somewhere around Christmas. La Niña means the girl child. ENSO effects many weather systems, causing floods for some and droughts for others, in a pattern lasting 2 to 8 years. The severity of El Niños varies. There was a very large area of warm water for the El Niño which appeared in 1972, and it upset the pattern of rainfall around the world. Africa, Australia, India and the former Soviet Union suffered major droughts. The Mediterranean and the South American coast had heavy rainfall and extensive flooding.

The warm area can arise because the pattern of winds in the southwestern Pacific Ocean changes, allowing warm water to move to a different part of the ocean. During a strong El Niño event, the prevailing trade winds that blow from east to west across the equatorial Pacific weaken or blow in the opposite direction and the warmer surface water is forced eastwards. The warmer water means the atmosphere can pick up more moisture into the clouds, which is followed by heavier rain for parts of South America and less for others such as Indonesia. During La Niña the south east trade winds strengthen instead, pushing warmer water into the west Pacific, and causing more rain in the west and less in the east Pacific.

ENSO can also affect the pattern of monsoons, particularly where their peaks or troughs overlap (monsoons follow a different cycle). There were very strong ENSOs in 1877, 1884, 1891, 1899, 1911, 1918, 1925, 1941, 1957, 1972 and 1982. In 1877, 1899, 1918 and 1972 they coincided with monsoon phases and caused major droughts in Asia. 1997/98 was the second strongest El Niño in the past century; 2,000 people died. It was followed by a moderate La Niña.

Whilst the impact of El Niños is felt most strongly by the countries bordering the Pacific, in strong years the effects can spread further afield. for example a strong ENSO leads to a wetter than average spring in central Europe and southern England. This is because the atmospheric patterns over the Pacific can affect the strength and position of jet streams, which tend to be tracked by storms. Strong El Niños also cause more hurricanes and tropical storms to make landfall over the Gulf of Mexico and the Caribbean.

El Niño can also affect fish stocks and coral reefs (there was a record bleaching in 1997-1998 because of the elevated temperatures). El Niño droughts can lead to an increase in forest fires and loss of crops. El Niño rains can lead to extra soil erosion and destruction and loss of crops.

El Niños and La Niñas are known to have been happening for at least 15,000 years judging by archaeological evidence. Thanks to climate change, El Niño has been more frequent, intense and persistent since the 1970's. Climate modellers are unsure what will happen in the future, however. It could change rain and drought patterns, and could change the distribution of tropical cyclones, which get their energy from warm surface water.

ENSO is not the only oscillation; The North Atlantic Oscillation (NAO) is the next best known, affecting the westerly winds across western and northern Europe, affecting weather there and in the Mediterranean. The oscillations are not the only aspect of the climate that can flip-flop between states; another is the Ocean Conveyor Belt.

Forecasts Help Farmers Improve Harvest

Better access to and improvements to weather forecasting are helping farmers in Zimbabwe plan better and achieve higher harvests in what turned out to be better seasons. The El Nino weather phenomenon causes variation in the weather, so farmers not aware of what it is doing tend to either gamble and risk losing crops or hedge their bets.

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Hong Kong people despair over China food scares

Hong Kong is reeling under a wave of food scandals recently; pig disease, cancer-causing malachite green in fish and eels, and excessive pesticides on fruit and vegetables. There are also concerns about bird flu and SARS. People in Hong Kong are calling for better food standards in China. Singapore and Japan are also concerned about the fish and eels.

China's south on high alert as pig disease spreads, China reports pig disease death after giving all clear

One person who handled meat has died of the pig disease Streptococcus suis in Shenzhen, which is a special economic zone just across the border from Hong Kong, and 3 butchers from Guangdong have been taken ill.

Satellite tracks "Sputnik", the croc

A transmitter has been attached to a saltwater crocodile called Sputnik in Australia's Northern Territory near Darwin. New Zealand researchers will be tracking him for a year by satellite. You can watch his progress at http://www.croctrack.org.nz/.

Cameroon scientist denies dam about to collapse

Geologists differ on how soon the eroding natural dam holding back Lake Nyos will collapse, threatening 10,000 people downstream in Cameroon and Nigeria. A start has been made to extracting the carbon dioxide behind the dam; a cloud of the gas escaped in 1986 and killed 1,800 people.

Two new bird species identified in Colombia

Two new species of birds have been discovered in the Finca Merenberg mountains of Colombia. The existence of one, the Upper Magdalena Tapaculo (Scytalopus rodriguezi) had been suspected since the 1980s. The other is called Stiles' Tapaculo (Scytalopus stilesi). Their songs differ from other tapaculos, though their appearance is similar.

Antarctic ozone hole grows from last year-WMO

The World Meteorological Organization (WMO) says that the winter Antarctica ozone hole is larger than last year's, but smaller than the record hole of 2003.

European aircraft help battle Portugal forest fires

France, Germany, Italy, the Netherlands and Spain are helping Portugal fight its wildfires with the loan of helicopters or planes.

High-Tech Spy Planes Might Fight Fires

The U.S. Forest Service has been experimenting with using unmanned aerial vehicles (UAVs) to fly over fires with special heat-sensing cameras that can see through smoke and spot fires both day and night, enabling their operators to plot fires and plan responses. It will be some time before they can replace firefighting planes, however, and the Federal Aviation Administration will need to approve their use.

Local strategies crucial to save Asia's mangroves

Many countries affected by the December 26 2004 tsunami are now planting and protecting mangroves along their coasts. Experts meeting in Kuala Lumpur warn that they need to involve the local communities, however, giving them a financial stake in the projects. This is just one example of how things need to be done right in the aftermath of the tsunami if the solutions are to be sustainable.

Bangladeshis Flee Homes Submerged by Tides

Particularly high tides have inundated Sandwip Island and Kutubdia Island off Bangladesh, but the locals had time to escape.

600M Asian Children in Poverty, Group Says

The "Growing up in Asia" report from the child humanitarian organization Plan says that more than 47% of children in Asia live in poverty, lacking at least one of food, health, safe drinking water or shelter. More than 27% lack two or more of these basic necessities.

Georgians Claim to Unearth Ancient Skull

Archaeologists say they have found a 1.8-million-year-old skull of the genus Homo near Tbilisi in the former Soviet republic of Georgia. The remains are a million years older than Western European pre-human remains, but younger than African ones.

How has El Niño affected your life?

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