Peru studies climate riddle as the world heats up

LIMA (Reuters) - Scientists are using everything from a yellow submarine to weather balloons and special airplanes to solve a climate conundrum: why is Peru getting colder while the rest of the world heats up?

Researchers from Europe, the United States and South America started collecting reams of data this week from clouds, the shoreline and deep underwater to try to figure out the dynamics of the southeastern Pacific.

The area, home to a fifth of the world's fish stocks, plays a crucial part in global weather patterns and scientists want to discover why temperatures have dropped on the desert coast.

"Peru has a very important role in global climate," said Alexis Chaigneau, a French scientist leading experiments in Peru. "Over the past 50 years, the Peruvian coast has gotten colder, mainly because of stronger winds that have pulled up the deep cold waters of the ocean current."

The Humboldt current, which flows north to Peru from the frigid southern waters off Chile, is considered the world's most productive marine ecosystem, in part because deep cold waters rich in nutrients interact with the sun's energy to create life.

For the next three months, everything from a small satellite-controlled submarine to cloud-hugging airplanes will feed computers with information on oxygen levels in the water, temperature, salinity, wind speeds and current.

Along the way, they also hope to solve the riddles of the famous El Nino and La Nina weather phenomenon that occur in the southeastern Pacific -- the periodic oscillations in surface water temperatures that are linked to floods and droughts.

El Nino has also been blamed for interrupting the upswelling of the current, causing fish stocks to crash in an area where up to 20 percent of the world's fish are caught.

"We need to know more to understand how this will impact fisheries," said Hector Soldi, chairman of Peru's marine biology institute.

(Editing by Pav Jordan and Patrick Markey)