Key to predicting climate change could be blowing in the wind

A reconstruction of the Anglian ice sheet in Precambrian North London (credit: BBC / The Natural History Museum, London)

This isn’t the first time a dust-related theory of long-term climate change has been put forward. But this one looks at what could have caused the Earth to go into cycles of glacial and interglacial periods in the first place.

Dust that blew into the North Pacific Ocean could help explain why the Earth’s climate cooled 2.7 million years ago, according to a new study, reports ScienceDaily.

One of the co-authors was Alex Pullen, an assistant professor of environmental engineering and earth sciences at Clemson University.

“Why study the past? It’s a great predictor of the future,” he said. “The findings of this study were both interesting and very unexpected.”

Researchers were interested in dust because when it blows off land and into the ocean, the iron in it fertilizes the water like farmers do their fields. Through photosynthesis, tiny organisms that live in the ocean surface waters pull carbon-dioxide out of the atmosphere, which usually means cooler temperatures.

The biggest surprise in the study was that precipitation, rather than dryness, was the most important factor for adding East Asian dust to the atmosphere and oceans leading up to the ancient climate change, Pullen said.

It may seem counterintuitive, he said, because “most people associate dust emission with aridity and deserts, not with precipitation.”

But researchers believe they have an idea of what happened.

The monsoon precipitation intensified, and the increase caused erosion along the Tibetan Plateau and lower elevation areas nearby in what today is China, researchers found. Wind carried the relatively loose sediment into the North Pacific Ocean, where it likely helped spur photosynthesis.

The research focused on a time that marked a change between a period of high carbon-dioxide levels in the atmosphere similar to modern day and much lower levels similar to the period before the industrial revolution, Pullen said.

The research helps explain what caused the Earth to go into the glacial and interglacial periods that have dominated ever since, he said.

Continued here.
– – –
Yes, how many years can a mountain exist
Before it is washed to the sea?

– Bob Dylan
“I wrote ‘Blowin’ in the Wind’ in 10 minutes”

via Tallbloke’s Talkshop

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February 15, 2018 at 01:30PM

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