El Niño is the name given to the warming of the equatorial Pacific Ocean that takes place every two to seven years. Climatologists regard it as a weather "safety valve", redistributing heat across the globe when localised circulation systems can no longer contain it. The normal flow of water across the Pacific from the Americas in the east to Indonesia in the west is reversed and the "warm pool" formed over several years in the west flows towards the American coastline. Consequently, Indonesia and Australia dry out, while the American coastal deserts are buffeted by rainstorms.
The last El Niño struck in 1997-1998, causing flooding, fires, drought, monsoons and cyclones worldwide — not to mention famine and disease. It is believed to have claimed 22,000 lives and to have resulted in around US$34 billion in material losses. Nobody knows what triggers the phenomenon. But recent meteorological records suggest that it has been returning with greater frequency and intensity since the mid-1970s — every three or four years versus every two to seven. That could represent a natural shift in its evolution, or it could mean something more ominous — that the safety valve has to be released more often to compensate for human-induced global warming.
Assessing El Niño
To find out how much man has influenced El Niño by pumping greenhouse gases into the atmosphere, scientists need to put together a reliable record of its historical fluctuations. They have begun to do so by studying the growth rings of ancient corals, as well as sediment from the beds of Ecuadorian lakes. The idea behind this is that cyclical changes in climate affect the chemical and isotopic composition of the water in both lakes and oceans, and therefore of the plants and animals that grow in it. The same principle applies to the precipitation that falls on the Andes — snow that never melts because of its high altitude. According to Dr Bernard Francou, a 51-year-old French glaciologist and mountaineer who has been studying Andean glaciers for a decade, those glaciers promise the best record yet of El Niño’s fluctuations over millennia.
"The properties of ice offer much higher resolution over much longer periods of time for this type of investigation and reconstruction," says Francou. Based in Quito, Ecuador, he has been responsible for the glacier-monitoring programme of the French Institute for Research and Development since 1998. His latest project is to drill a 70-metre ice core from a glacier at the top of Ecuador’s highest peak — Chimborazo, an extinct volcano that stands at 6,268 metres and only 140 kilometres from the Gulf of Guayaquil on the Ecuadorian coast.
The Ice of the Andes
Several ice cores have already been extracted from other Andean peaks — Francou has been involved with some of these expeditions himself — but the Chimborazo project is unique because of its proximity to the Pacific. Since Chimborazo receives precipitation on its Pacific-facing slopes during warm, wet El Niño years, and precipitation on its Atlantic-facing slopes during the cold, La Niña phases of the cycle, it is ideally placed to provide a reliable archive of the phenomenon. It is for this pioneering experiment to extract and study the ice core that Francou was chosen as an Associate Laureate of the Rolex Awards 2000.
Claude Lorius, director of the French Polar Institute and a specialist in the field, says, "The information that this drilling could provide is of the greatest importance. By understanding El Niño evolution over a long stretch of time, we will be able to improve our understanding of the mechanisms that cause these events."
Testing the Technique
An accomplished mountaineer, Francou has already made several successful attempts to scale Chimborazo with his team. In December 1999, in the first-ever demonstration of the feasibility of deep ice-core drilling in the Ecuadorian Andes, they successfully extracted a 16-metre test plug. Analysis of that ice has shown that its composition tells the same story as meteorological records for the last 10 years, which means that the technique is reliable.
Francou intends to use his Rolex Award to fund the main expedition at the end of 2000, when around 600 kilograms of ice will be extracted from two boreholes using a specially designed solar-powered drill. It will then be packed in dry ice and transported from the summit of Chimborazo, to Quito, and on to laboratories in Grenoble and Bern for analysis.
Hope for the future
"The success of this project will have great repercussions at an international level," contends Francou. If it were possible to accurately predict El Niño events, as it may be in the near future, the lives of those inhabiting the entire tropics — half the world’s population —could be improved immeasurably.
Published in 2000