“The models have gotten better and better, there is no question about that.” However, El Niño is a “chaotic system”, says Cane, who is now a professor at the Lamont-Doherty Earth Observatory of Columbia University in the United States. “Sometimes it’s just not very predictable, no matter how great you are at making predictions.”
El Niño, a mass of warm water moving eastwards across the Pacific Ocean every few years, is on track to reach its peak in the next few months off the Central American coast (see chart). The phenomenon alters global weather — causing altered monsoon patterns over Asia, droughts in Central America and flooding in South America. Despite ongoing research, it remains difficult to forecast the precise impacts of each individual El Niño event. But the stronger the El Niño, the easier it is to read and predict. “At the moment, we have a good-sized El Niño going, so we’re more confident about our predictions,” Cane explains.
This means governments have more reliable information to prepare for the floods, droughts and other disasters that are more likely in an El Niño year. This has improved significantly with better models, Cane points out.
“In the late 1980s, the level of awareness of what El Niño could do was much lower than it is now,” he says. But, he adds, “the ability to do anything about it varies quite a lot from country to country”, especially in the developing world.
Cane says it takes time to build trust between governments and scientists. “You tell people: ‘There’s a forecast’ — why should they believe you?”
To deal with this problem, Cane helped set up the International Research Institute for Climate and Society (IRI) at Columbia University. The institute has been working at this for 20 years and has built a good deal of trust in many places in the world, he says.
For example, “in the early days”, Cane worked with politicians in Peru, where El Niño causes droughts in the Altiplano, the Andean high plateau, and rain in desert areas along the coast.
“I worked initially through the IRI to make that information available,” Cane recalls. Now, “governments are used to getting this information and try to act on it,” he explains, for instance by limiting fishing in their territorial waters when El Niño hits, as overfished stocks take longer to recover in an El Niño year than in other years.
Another example is Indonesia, where people burn down forests to clear land for oil palm plantations, causing forest fires that El Niño aggravates. “When things are so abnormally dry, [fires] can get out of hand,” Cane says. “We know this happens in an El Niño year and governments have made some efforts to restrict it.”
But scientists must remain cautious with their assertions, as predictions that do not come true can be harmful. For example, during the 1997-98 El Niño, the drought in some parts of Africa was less dire than expected, Cane explains, yet some banks “withdrew credit from farmers because they expected it was a bad year to farm” and they thought their clients would have reduced incomes.
In more recent years, Cane has also studied the link between El Niño and war. “It turns out there is more conflict worldwide in an El Niño year,” he says, but admits that preventing that is very complex. “You can look at places with poor governance and poverty [where El Niño is predicted to have a strong effect], and make a special effort to alleviate problems in those places,” he suggests.
This article was produced by SciDev.Net's Global Edition.