Modern day scourge helped ancient Earth escape a deathly deep freeze

Modern day scourge helped ancient Earth escape a deathly deep freeze
Ancient glaciers may have been stalled by greenhouse gas

(PhysOrg.com) -- The planet’s present day greenhouse scourge, carbon dioxide, may have played a vital role in helping ancient Earth to escape from complete glaciation, say scientists in a paper published online today.

In their review for Nature Geoscience, UK scientists claim that the Earth never froze over completely during the Cryogenian Period, about 840 to 635 million years ago.

This is contrary to the Snowball Earth hypothesis, which envisages a fully frozen Earth that was locked in ice for many millions of years as a result of a runaway chain reaction that caused the planet to cool.

What enabled the Earth to escape from a complete freeze is not certain, but the UK scientists in their review point to recent research carried out at the University of Toronto. This speculates that the advancing ice was stalled by the interaction of the physical climate system and the carbon cycle of the ocean, with carbon dioxide playing a key role in insulating the planet.

The Toronto scientists say that as Earth’s temperatures cooled, oxygen was drawn into the ocean, where it oxidized organic matter, releasing the greenhouse gas carbon dioxide into the atmosphere.

The review’s lead author, Professor Phillip Allen, from Imperial College London’s Department of Earth Science and Engineering, says that something must have kept the planet’s equatorial oceans from freezing over. He adds:

“In the climate change game, carbon dioxide can be both saint and sinner. These days we are so concerned about global warming and the harm that carbon dioxide is doing to our planet. However, approximately 600 million years ago, this greenhouse gas probably saved ancient Earth and its basic life forms from an icy extinction.”

Professor Allen, whose previous research has found evidence demonstrating hot and cold cycles in the Cryogenian period, says a plethora of papers has been published and much debate has been devoted to the Snowball Earth theory since it was originally proposed. He says:

“Sedimentary rocks deposited during these cold intervals indicate that dynamic glaciers and ice streams continued to deliver large amounts of sediment to open oceans. This evidence contradicts the Snowball Earth theory, which suggests the oceans were frozen over. Yet, many scientists still believe Snowball Earth to be correct.”

Professor Allen hopes his review in Nature will prompt climate modellers to realign their thinking about the Cryogenian period and review their models to reflect a warmer Earth during this time. He adds:

“There is so much about Earth’s ancient past that we don’t know enough about. So it is really important that climate modellers get their targets right. They need to build into their calculations a warmer planet, with open oceans, despite lower levels of solar radiation at this time. Otherwise, climate models about the Earth’s distant past are aiming for a target that never existed.”

Provided by Imperial College London


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Citation: Modern day scourge helped ancient Earth escape a deathly deep freeze (2008, December 1) retrieved 23 July 2019 from https://phys.org/news/2008-12-modern-day-scourge-ancient-earth.html
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Dec 02, 2008
I don't consider CO2 to be a "scourge" (it is after all a beneficial gas required by plants.)

I think this is more like the witch hunts of the dark to middle ages.

Dec 03, 2008
learn in a video presentation

how and why this global warming scam propaganda
is done

http://www.youtub...PV01uyRs

Dec 06, 2008
Yeah, put one Guido against tens and hundreds of IPC scientists that have stated that by 90% probability the warming of earth is caused by human CO2 pollution. Just look at the measured levels of CO2 during say last 500 years and try to find non-human reason for the doubling of the amount of CO2 in the atmosphere in the last 100 years. I bet there is none. And each year we, the people on earth, put more than previously CO2 to skies. And the results are visible in environment and therefore in the news. Remember ozone hole? This CO2 problem is not so easy to contain and will escalate to further problems before change happens, if we can find the ways and will to curb the emissions.

Dec 06, 2008
Yeah, put one Guido against tens and hundreds of IPC scientists that have stated that by 90% probability the warming of earth is caused by human CO2 pollution. Just look at the measured levels of CO2 during say last 500 years and try to find non-human reason for the doubling of the amount of CO2 in the atmosphere in the last 100 years...


1) So what if the CO2 levels doubled in the last 500 years? They have been nearly 20 times higher.

2) The IPCC reports were written by a small group of scientists, reviewed by a larger group of scientists (some with agendas) and the turned over to politicians for a final rewrite that was NOT reviewed by scientists. The Summary for Policymakers was written BEFORE the chapters were which is impossible in a truly scientific document.

Dec 08, 2008
science religion facts or fiction

if u dont understand its a elite out there
the powerrs that may be

than run the show from the ap news feed witch relfects here ur name maybe alrbert ainstein

yet u have no clue

watch little sheep u might learn somthing today

http://www.youtub...SB59DT34

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