- Jonathan Patz / Marjorie Share
EcoHealth101 – www.ecohealth101.org
Every few years, a weather pattern called El Niño appears off the coast of Peru. It turns the world’s climate topsy-turvy. El Niño may be a sneak preview of our future. Why? Because global warming also brings extreme weather changes.
El Niño is an abnormal warming of the ocean’s surface. It’s caused by an unusually warm current flowing eastward across the Pacific Ocean. Because the Pacific is so large, this current is huge too. Sometimes, in fact, it’s wider than the U.S.!
This surge of warm water has a tremendous impact. The extra heat within the water interacts with the atmosphere above, shaking up weather patterns. Dry places get drenched, and wet places turn arid. These dramatic changes can cause significant health and environmental effects.
Written records about El Niño date back to 1525, and geological evidence shows that the phenomenon is at least 13,000 years old. Yet El Niño didn’t attract serious scientific attention until about 30 years ago.
Something Strange in South America
In the 1970s, fishermen found that their catches off the west coast of South America had turned from great to bad. This seemed to occur every few years around Christmas, so the fishermen connected it with the birth of Christ. They named the event El Niño ("little boy" in Spanish). El Niño’s full name is El Niño Southern Oscillation (ENSO).
Things heated up in 1982-83. Peru’s rainfall nearly doubled. The southwestern United States also got far more rain than usual. The extra moisture meant more plants. That, in turn, meant more food for mice and rats – plus outbreaks of disease carried by the rodents. At the same time, droughts, dust storms, and forest fires swept ordinarily wet Northern Australia, Indonesia, and parts of Africa. Altogether, El Niño was blamed for 2,000 deaths and $13 billion in losses worldwide.
Many factors in the ocean and atmosphere combine to cause El Niño. It seems to be coming more frequently, which has climate experts worried.
Learn more about El Niño:
The National Oceanic and Atmospheric Administration (NOAA) – www.noaa.gov
How can El Niño affect human health?
El Niño significantly alters rainfall patterns. Those changes can have big impacts on human health:
Dry areas (such as southern California and the west coast of Central America and Mexico) are sloshed by torrential rains that can lead to flooding. All that extra water creates homes for mosquitoes, which spread malaria, dengue fever, and other diseases.
Places west of the Pacific Ocean become arid, or dry. Instead of getting their annual monsoon rains, areas like Indonesia, northern Australia, and the Pacific islands experience droughts. The change can give rise to crop shortages, starvation, illness, and economic problems.
Can we predict El Niño Events?
Forecasting the weather is always tricky. But scientists are increasingly adept at predicting El Niño events. These early warnings save millions of dollars – and many lives.
One of the key steps toward predicting El Niño was a data-gathering project begun in 1985. Researchers placed 70 buoys, or floating markers, in the Pacific Ocean. Cables and anchors held the buoys in place along the equator. Each buoy was equipped with devices that monitored air and water temperatures, wind, and relative humidity (the amount of water vapor in the air).
Over the next nine years, the buoys amassed a huge amount of information. Analyzing the data, researchers paid close attention to what happened before each El Niño event. Detecting patterns enabled scientists to identify the warning signs of future El Niño events.
Knowing those warning signs, weather experts successfully predicted the 1997-98 El Niño event. They warned officials to prepare for flooding, droughts, and other problems. Once warned, governments responded. Peru, for instance, built storm drains and stockpiled emergency supplies. Papua New Guinea received international aid that prevented starvation.
Some American farmers planted rice and beans in areas normally too dry to support them; they were rewarded with great harvests. Fishing crews adjusted their routes, catching shrimp in waters generally too cold for shellfish. Expecting a warmer winter, one big company reportedly saved millions by not stocking up on de-icing fluids.