Research provides new theory on cause of ice age 2.6 million years ago

Jun 27, 2014
Credit: NASA

New research published today in the journal Nature Scientific Reports has provided a major new theory on the cause of the ice age that covered large parts of the Northern Hemisphere 2.6 million years ago.

The study, co-authored by Dr Thomas Stevens, from the Department of Geography at Royal Holloway, University of London, found a previously unknown mechanism by which the joining of North and South America changed the salinity of the Pacific Ocean and caused major ice sheet growth across the Northern Hemisphere.

The change in salinity encouraged to form which in turn created a change in wind patterns, leading to intensified monsoons. These provided moisture that caused an increase in snowfall and the growth of major ice sheets, some of which reached 3km thick.

The team of researchers analysed deposits of wind-blown dust called red clay that accumulated between six million and two and a half million years ago in north central China, adjacent to the Tibetan plateau, and used them to reconstruct changing monsoon precipitation and temperature.

"Until now, the cause of the Quaternary had been a hotly debated topic", said Dr Stevens. "Our findings suggest a significant link between ice sheet growth, the monsoon and the closing of the Panama Seaway, as North and South America drifted closer together. This provides us with a major new theory on the origins of the ice age, and ultimately our current climate system."

Surprisingly, the researchers found there was a strengthening of the monsoon during global cooling, instead of the intense rainfall normally associated with warmer climates.

Dr Stevens added: "This led us to discover a previously unknown interaction between plate tectonic movements in the Americas and dramatic changes in global temperature. The intensified monsoons created a positive feedback cycle, promoting more global cooling, more sea ice and even stronger precipitation, culminating in the spread of huge glaciers across the Northern Hemisphere."

Explore further: Large sea ice changes North of Swalbard

More information: Pacific freshening drives Pliocene cooling and Asian monsoon intensification, Scientific Reports, 2014.

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Whydening Gyre
5 / 5 (1) Jun 27, 2014
Don't ya just love it when researchers bring valid new variables to the equation?
jonekat
3 / 5 (2) Jun 27, 2014
This isnt a new theory, its at least 30 years old, I was in school when I first heard about it
The Alchemist
1 / 5 (1) Jun 27, 2014
@jonekat, it is disturbing: I started noticing science was recycling a while ago. I thought I was going crazy at first: How could I know something science has just discovered? It is as pervasive as I can tell, quantum, climate, chemistry, and even alot of nano was old science repackaged.
Whydening Gyre
5 / 5 (1) Jun 27, 2014
@jonekat, it is disturbing: I started noticing science was recycling a while ago. I thought I was going crazy at first: How could I know something science has just discovered? It is as pervasive as I can tell, quantum, climate, chemistry, and even alot of nano was old science repackaged.

Nature of the Universe, Alchy, nature of the universe....
Rustybolts
2 / 5 (4) Jun 28, 2014
"the joining of North and South America changed the salinity of the Pacific Ocean"

and that would happen how? two land masses slowly touching each other over a very long period of time, changed the entire salt content of the pacific ocean? That's about as funny as the Big Bang theory.
Burnerjack
5 / 5 (1) Jun 29, 2014
Big Bang Theory, IMHO, is a pretty funny show...

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