Laboratorij za fiziku mora , Laboratoriji , News

El Nino

The vast landscape of the Pacific region. Not a thing around, only blue sea and blue skies. Just, here and there, some lost island paradise. Such as Hawaii, Tahiti and Samoa. These islands are hundreds, thousands of miles from each other. And yet they are inhabited, and for so long that the people no longer remember who put them there or when. Memories of old people long ago became mixed with mythology.

But history still provides the answers. Islands of the Pacific region are inhabited by descendants of the Lapita civilization. Their civilization developed around 3000 BC in the Bismarck Islands. The Lapitans were fearless sailors. By 900 BC, these brave sailors inhabited Fiji, Tonga and Samoa, the paradise islands rich with life with food. On these islands Lapitans stayed for several centuries, and then, around 300 BC, they went further east. This time they reached Cook Islands and Tahiti. Then followed a rest before the final trips. In the sixth century, the descendants of the Lapita sailors settled in Hawaii and the Easter Islands. There are even some evidence that, a hundred years before the Europeans, these brave sailors managed to reach even South America.


How could these sailors come so far? On fragile boats, with their families, with women and children? Without a compass or an engine? It’s not quite sure. Most knowledge about their long journeys is lost. Memories of settling the region have long ago became mixed with myths about creation. What is it that drove the seafarers to these long journeys? Far from all that they knew? No trace of the lands on the horizon where they would go to?

They were excellent sailors, for sure. They knew the stars and were guided by them. They knew the fish that lived in deep seas and the fish that lived in shallow seas. When they saw certain birds, they knew land was nearby. They knew how the currents changed and the waves broke on the reefs. And yet… Storms, waves, the endless sea! And still, that was not all! Direction of migration of these brave sailors was opposite to the winds that blew over the equatorial Pacific, as was opposite to it’s currents. How, then?

Well, maybe these sailors simply got lucky. Or unlucky, if you like. Perhaps theywent on a fishing trip, and currents and winds unexpectedly changed direction, and took them away East. Maybe they met El Niño. Because, during El Niño, Pacific winds change direction and blow west to east, from Australia and Indonesia towards South America. Only during El Niño it is easier to travel from west to east. In the direction oppositeo to all the great geographical discoveries.


But El Niño does not affect only the ease of travel. During El Niño, extreme droughts were reported in Indonesia and Australia. Droughts help fires spread faster and easier. During El Niño in 1997./98.Indonesia was overrun by extreme fires. As a result of fires, smog developed over many cities. Reportedly, spending just a day in the city of Kuching in neighboring Malaysia was like smoking 40 cigarettes! On the other side of the Pacific region, in the South and North America, El Niño is responsible for many storms and floods. And even for the massive disappearance of fish. In fact, that’s how El Niño got it’s name. Peruvian fishermen noticed that every few years, at Christmas time, along the coast of Peru, the fish disappears. At the same time, instead of a cold one, by the shores of Peru there is a warm sea current. As this usually occured at the time of Christmas, this warm current was called El Niño (Spanish: baby, Baby Jesus). But the impact of El Niño is not limited to the Pacific. El Niño causes the changes in weather even in the Indic and the Atlantic.

With such a large impact on weather in the world, great efforts are invested in forecasting and understanding of El Niño. After a catastrophic El Niño in 1982./83., there began the systematic measurements in the Equatorial Pacific. During the next 10 years, as much as 70 buoys were set up to measure sea temperature and speed of sea currents ( Buoys measure air temperature as well as humidity, and wind speed. El Niño is a complex phenomenon which occurs due to interactions between the atmosphere and the sea, and the situation in the sea is changing much more slowly than in the atmosphere, and so measurements of the sea provide forecast of El Niño as much as a few months in advance.Thus, the El Nino in 1997./98. was successfuly forecast and the damage that it caused was greatly reduced. Authorities in Peru, expecting a number of floods associated with El Niño, ensured sufficient supplies of food and drinking water. And when the floods of that year really happened, many villages remained cut off, and the sources of drinking water polluted, but Peruvians were ready.

And so, El Niño helped the brave sailors from the beginning of our story to inhabit the Pacific, but every time El Niño shows up it inflicts huge damage. So is El Niño good or bad? The best answer to this question may be provided by the Galapagos Islands. On the Galapagos Islands, one of the most diverse plant-animal communities has developed. A community special in many ways. On the Galapagos penguins and iguanas live just next to eachother. Penguins enjoy the cold seas and iguanas enjoy the infinite lying in the sun. These two species can live juxtapose because of El Niño. During the normal years, a cold current goes by the Galapagos, full of fish, and the air is colder. Then the Penguins enjoy themselves, and reproduce. And the number of iguanas decreases. But then comes a year of El Niño. And along the coast of Galapagos now flows a warm current. There is less fish. The air is warmer. And now the number of penguins declines. But now the iguanas enjoy and reproduce. And so on, alternating. Years with El Niño, years without El Niño. The Galapagos diversity blooms.

(Jadranka Šepić)


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