The world's worst El Nio in 100 years is slowly releasing its grip on the earth's climate.
The phenomenon has left its calling card across the globe - from severe droughts in Indonesia and South Africa to floods of biblical proportions in Peru and China. Other impacts were more bizarre: On Feb. 5, El Nio whipped up global winds so fast that they slowed the earth's rotation by 0.6 milliseconds, making it the longest day of the year.
Overall, it could inflict as much as $30 billion in damage by the time it ends and is now blamed with causing more than 2,000 deaths. Yet for all the mischief and casualties, the toll could have been far worse. One of the legacies of what could become history's costliest weather tantrum is the preparations countries took to blunt its impact - something scientists are now hoping to build on to cope with future El Nios.
In northern Peru, for instance, the government led an effort to clear channels and drainage canals filled with debris. And in flint-dry southern Africa, farmers were encouraged to plant fewer crops to save water.
"We're learning how to cope with changes in climate," says Nicholas Graham, director of the International Research Institute's (IRI) experimental forecast division at the Scripps Institution of Oceanography in La Jolla, Calif. The IRI, based near New York, was established in 1995 to develop tools for generating region-specific forecasts of climate events, such as El Nio.
First recorded by the Spanish as they colonized the West Coast of South America, El Nio refers to the accumulation of unusually warm water off the coast of Peru every five or six years. But El Nio is only half of what scientists call El Nio-Southern Oscillation (ENSO), which includes the phenomenon's effect on the atmosphere.
Ordinarily, cold water wells up along the South American coast. Heated at the tropics, the surface water is blown eastward by the trade winds toward Indonesia. Over time, the warm water reaches Indonesia accumulates, then backs up toward the Central Pacific. As it does, warm moist air rises to form intense thunderstorms. These storms weaken, and in some cases, reverse the trade winds, allowing the warm water to continue moving back toward South America. There it builds off the Peruvian coast, drenching the country with rain that would normally pelt Indonesia. The intense convection that generates the thunderstorms also sets up a train of events in the atmosphere that can alter weather patterns worldwide.
The phenomenon is part of the climate's normal pattern of change, researchers say. And the damage that altered weather patterns inflict in some regions is offset by benefits in others. During an El Nio year, for example, hurricane activity in the Atlantic is suppressed.
Strong El Nio events such as this year's occur at intervals ranging from 15 to 60 years, according to Henry Diaz, a research meteorologist at the National Oceanic and Atmospheric Administration's (NOAA) Climate Diagnostic Center in Boulder, Colo. The ENSO of 1877-78 "was a very big event, equal to this one," he says.
Until the 1997-98 ENSO, however, this century's record went to the El Nio of '82-83. Damage estimates for that event range from $8 billion to $13 billion. It also provided the stimulus for forecasting research, which helped blunt the impact of this year's event.
Some of that help came from El Nio itself. Although ENSOs produce changes in regional weather patterns, "there are a lot of localized differences" within a region, says Tim Rocke, foreign-grains-production chairman for the US Department of Agriculture's Foreign Agricultural Service. In key agricultural areas that often feel El Nio's touch, it didn't have the impact many worried it might.
Last June, the USDA estimated Australia's wheat harvest at 16 million metric tons. This past January, he says, the estimate had risen to 19 million metric tons, the fifth-largest ever for Australia. Last August, Argentina's corn harvest looked as if it would reach 13 million metric tons. Last month, the USDA revised its estimate to 16.5 million metric tons. Meanwhile, India is poised for a record rice harvest.
El Nio "really hasn't affected the countries that feed the world," Mr. Rocke notes. Despite drier-than-normal conditions, he says, rain fell at critical times during the growing season.
In other areas, the preparations based on climate forecasts appear to have softened El Nio's impact.
In Colombia, where hydroelectric dams supply most of the nation's electricity, the nation's public utilities got burned by the the 1991-92 ENSO. Prolonged drought and poorly managed reservoirs led to lengthy power shortages that cost the economy $1 billion. But this time, utilities have done a better job of using rainfall and stream-flow forecasts to regulate the flow of water from reservoirs, says German Poveda of the Water Resources Graduate Program at the National University of Colombia in Medelln. This event "is going to pass with no shortages," he notes, although electricity bills have increased.
Hardest hit economically among the South American countries, however, is Peru. Peruvian officials reportedly have estimated that this ENSO event has inflicted $600 million in damage so far, and that figure could rise to at least $750 million before the event ends.
Still, the program to clear canals choked by debris from the 1982 storms, started by President Alberto Fujimori last June, is being hailed as a success. It was an expensive project, notes Maxx Dilley, science adviser to the US Agency for International Development's (AID) Office of Foreign Disaster Assistance. But "if they hadn't made the effort, the damage could have been far worse," he says. "It probably saved a lot of lives."
Flooding also has pervaded eastern Africa, notes the IRI's Dr. Graham, who says rainfall in the region has reached five times its normal amount.
US AID has responded to flood-aid requests from five eastern African nations, Dilley adds. The agency has earmarked $10 million for Tanzania to help repair damaged roads, and that's only "the tip of the iceberg," he says.
If this ENSO event holds lessons on the benefits - however difficult to quantify - of mitigation efforts, it holds another lesson, specialists say. Namely, that in some cases, El Nio's adverse economic and social effects are partly self-inflicted.
In Brazil, Indonesia, and the Philippines, droughts have turned fecund rain forests into tinderboxes. Yet in the face of such conditions, subsistence farmers, commercial-plantation owners, and timber companies have set fires that rapidly roared out of control.
Fires in the Brazilian state of Roraima have charred 13,000 square miles of savanna and rain forest. Heavy rains last week doused 80 to 90 percent of the fires, which one UN representative referred to last week as "an environmental disaster without precedent on this planet."
In Indonesia, fires have blackened nearly 1,400 square miles of jungle, casting a pall of smoke over Southeast Asia that last year raised concerns about public health and threatens to do so again. The UN Environment Program and governments in Southeast Asia are said to be planning a coordinated attack on the region's fires, but that could cost between $2 billion and $3 billion, says Indonesia's environment minister.
Why weren't ENSO-related climate forecasts for these regions heeded? One reason may be the unproven track record of ENSO forecasts. This event marks the first time that such forecasts have become operational, says US AID's Dilley.
"The big problem is that we've just started making these forecasts," agrees Ants Leetmaa, director of the National Oceanic and Atmospheric Administration's Climate Prediction Center in Suitland, Md. "If you look at all the forecast models, there was no consensus at the outset that this would be a major event."
Yet by last June, he continues, NOAA announced that this would be one of the three strongest events this century. The climatology community's success in predicting this ENSO should go a long way to erasing doubts about the forecasts' credibility, he adds.
Janet Abramowitz, a senior researcher with the Worldwatch Institute in Washington, offers another explanation. "The barriers you encounter are twofold," she says. "Not everyone gets the forecasts information on these small farms on the Brazilian frontier. And the country's environmental agency is grossly understaffed."
In Indonesia, she continues, "the big actors knew full well that this was going to be a bad year. They knew the fires would keep burning. They were driven by personal profit."
Poor land management can also undercut attempts to heed ENSO warnings, some environmentalists say.
Extensive flooding and mudslides in countries such as Peru, Chile, and Kenya trace their intensity in part to poor land management, according to David Olson, a senior scientist at the World Wildlife Fund in Washington. In an ENSO year, these countries will experience floods, he says, "but the bad floods are due to the loss of hillside vegetation" through logging and fuel collection. "We have to recognize that natural features can help offset the damage" from climate variations.