El Nino assisted early explorer

2008-05-16 18:56

Washington - The El Nino phenomenon that has puzzled climate scientists in recent decades may have assisted the first trip around the world nearly 500 years ago.

Explorer Ferdinand Magellan encountered fair weather on November 28 1520, after days of battle through the rough waters south of South America. From there the calming effects of El Nino may have eased his passage across the Pacific Ocean, researchers speculate in a new study.

When an El Nino occurs, the waters of the Equatorial Pacific become warmer than normal, creating rising air that changes wind and weather patterns.

Tree ring data indicate that an El Nino was occurring in 1519 and 1520 and may even have begun in 1518.

After passing through the strait later named for him, Magellan sailed north along the South American coast and then turned northwest, crossing the equator and eventually arriving at the Philippines, where he was killed in a battle with natives.

Magellan was seeking the so-called spice islands, now part of Indonesia, and his course took him north of that goal.

But the route may have been dictated by mild conditions and favourable winds during an El Nino, anthropologists Scott M Fitzpatrick of North Carolina State University and Richard Callaghan of the University of Calgary, Canada, propose in a new study of his trip.

Early exploration trips

Their research is summarised in Friday's edition of the journal Science and is scheduled to be published in full in the August edition of the Journal of Pacific History.

They were studying early exploration trips and were struck by the fact that Magellan sailed unusually far north, Fitzpatrick explained in a telephone interview.

"We had not considered El Nino until afterward, when we were trying to account for why the winds were so calm when he came into the Pacific," he said. "We knew it was unusual."

The researchers used a computer to model wind and weather conditions across the Pacific during an El Nino and then compared that to Magellan's route.

Crew died of scurvy

Magellan's journals show that many of the crew had died or were sick with scurvy, so he may simply have chosen to sail with the existing winds and currents, reducing the number of crew needed to operate his ships, Fitzgerald said.

"It could have been an adept manoeuvre," the researchers wrote, allowing him to move west along the past of least resistance.

In his writings, Magellan said he chose the northerly route because of reports of a famine in the spice islands. This also could be accurate, Callaghan and Fitzpatrick say, as El Nino conditions often result in drought in that region.

Magellan had received correspondence from a friend in the spice islands before setting out and so may have known about a famine there, Fitzgerald said. But that cannot be determined for certain, because the correspondence was destroyed in the great Lisbon earthquake of 1755.

- SAPA