Mountains, Whitecaps Change Weather Models

What do the tallest mountains in the world have in common with whitecaps on a roiling sea?

Both, it turns out, have a far greater impact on global weather patterns than had been thought.

Two separate international teams of scientists have come up with evidence showing the majestic Himalayan Mountains can influence weather all over the Earth, and whitecaps on a wind-blown sea can reflect so much solar energy back into space that the entire climate system is altered.

Himalayas Contributed to Dust Storms

Scientists have known for a long time that the Himalayas have a dramatic impact on local weather patterns in Asia, but the latest research shows the impact is global in scale, and may even have precipitated the beginning of the ice age 2.5 million years ago.

And whitecaps have generally been left out of most computer models for global climate, because their effect was thought to be minimal, but the latest research will probably force scientists to remodel their models.

What it all adds up to is this: The Earth's climate is so complex, and subject to such wide reaching influences, that it's nearly impossible to comprehend it. Little wonder that meteorologists have trouble predicting the next day's weather, not to mention the long range impact of burning fossil fuel.

The Himalayas, it turns out, contributed to storms that carried dust from China and Mongolia's Gobi Desert to the United States last month, as I reported in a recent column. Even more important, that desert wouldn't even be there if it weren't for the mountains to the south.

That story is, quite literally, written in the sands of the desert, according to climatologist John E. Kutzbach of the University of Wisconsin-Madison, who returned to China this week to resume his research. Kutzbach, a member of an international research team, has been arguing for more than a decade now that the uplifting of mountain ranges has a profound impact on weather, and now, he says, he has the data to prove it.

The scientists collected ancient dust deposits in China, and deep ocean sediments from the North Pacific and Indian Oceans, to reconstruct the story of the Himalayas over the past eight million years.

The mighty range, which includes the world's tallest mountains and the Tibetan Plateau, actually began to form more than 50 million years ago when the tectonic plate that carried India crashed into Asia. The two huge land masses ground together, causing giant chunks of Earth to be thrust upward, giving rise to the Himalayas.

Digging in the Desert

Mountain building is a slow process, marked by occasional earthquakes, but about eight million years ago the Himalayas went through a dramatic growth process, according to geologists who have studied the region.

According to computer-driven models developed by Kutzbach, the growth of the mountains should have had two dramatic effects. "The Himalayas and the Tibetan Plateau form a barrier for moisture getting into the interior [of Asia,]" Kutzbach says. Just as the Rockies and the Sierras trap moisture on the seaward side of western North America, the Himalayas cause torrential rains to fall on the southern and eastern side of the plateau.

That heavy rainfall comes at the expense of inland regions and Kutzbach and his colleagues suspected that the relatively sudden growth of the Himalayas eight million years ago caused the deserts of Mongolia and interior China to form.

So they went to the deserts and dug deep into the sand.

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