Global warming weakens vast Pacific climate system

WASHINGTON (Reuters) - Climate scientists identified a likely new victim of global warming on Wednesday: the vast looping system of air currents that fuels Pacific trade winds and climate from South America to Indonesia.

This could mean more El Nino-like weather patterns in the United States, more rain in the western Pacific and less nourishment for marine life along the Equator and off the South American coast.

Known as the Walker Circulation, this system of currents functions as a huge belt stretching across the tropical Pacific, with dry air moving eastward at high altitude from Asia to South America and moist air flowing westward along the ocean's surface, pushing the prevailing trade winds.

When the moist air gets to Asia, it triggers massive rains in Indonesia. Then it dries out, rises and starts the cycle again, heading east.

This important system has weakened by 3.5 percent over the last 140 years, and the culprit is probably human-induced global warming, scientists reported in the current edition of the journal Nature.