Modern day scourge helped ancient Earth escape a deathly deep freeze

Dec 01, 2008
Modern day scourge helped ancient Earth escape a deathly deep freeze
Ancient glaciers may have been stalled by greenhouse gas

( -- 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

Explore further: Frontier science in ocean-going lab

Related Stories

Rising carbon dioxide levels stunt sea shell growth

3 hours ago

Scientists have discovered that stunted growth can be a genetic response to ocean acidification, enabling some sea creatures to survive high carbon dioxide levels, both in the future and during past mass ...

Frontier science in ocean-going lab

2 hours ago

Oceanographer Dr Martina Doblin is preparing for one of the most significant explorations of her career. In early June, a mobile laboratory known as the Micro-CSI will leave from Brisbane aboard Australia's ...

Climate connections

Apr 14, 2015

In common parlance, the phrase "global climate change" is often used to describe how present-day climate is changing in response to human activities. But climate has also varied naturally and sometimes quite ...

Recommended for you

Extending climate predictability beyond El Nino

5 hours ago

Tropical Pacific climate variations and their global weather impacts may be predicted much further in advance than previously thought, according to research by an international team of climate scientists ...

Ocean currents impact methane consumption

22 hours ago

Large amounts of methane - whether as free gas or as solid gas hydrates - can be found in the sea floor along the ocean shores. When the hydrates dissolve or when the gas finds pathways in the sea floor to ...

Study shines new light on the source of diamonds

Apr 20, 2015

A team of specialists from four Australian universities, including the University of Western Australia, has established the exact source of a diamond-bearing rock for the first time.

User comments : 9

Adjust slider to filter visible comments by rank

Display comments: newest first

2.7 / 5 (7) 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.
2.4 / 5 (7) Dec 03, 2008
learn in a video presentation

how and why this global warming scam propaganda
is done

1.8 / 5 (5) Dec 03, 2008
To the two commenters above. Let's stick to science here, please. Too much religion in this world already.
3 / 5 (4) Dec 05, 2008
I can't help but agree with the poster who noted we should "stick to science", but I'm still looking for evidence of REAL science. And I'm not some conspiracy nut or in denial of supposed facts, I just don't trust computer modeling of complex systems like global climate and how it is related to levels of one compound made up of two of the most common elements.

How many of you reading this, and all the projections of global warming, would be willing to make expensive, life-altering, or otherwise critical decisions based on the weather forecast you see on the evening news? My estimate, probably high because I know and like the meteorologist for the local NBC affiliate, is that he is right about 33% of the time. Not a real impressive performance, unless you're a major league hitter, especially when you consider that weather forecasting basically has to deal with only three factors; temperature, relative humidity, and 'time' (i.e. seasonal orientation of the planet itself and length of day vs. night). With only three factors to consider, projections are accurate about 1/3 of the time, and many of those predictions are expressed in understandably indefinite terms like 'a 60% chance of precipitation".

With a track record like that, it cracks me up that millions of no-doubt well-intentioned idiots don't think twice about accepting as factual global warming projections based on models that should be several orders of magnitude more complex than weather forecasting, with hundreds of complicating factors and a myriad of interactions that could affect the results. So let's stick to science when we find evidence of it, but don't preach rationality when you're selling politics at best, and quackery as the basis of your so called science.

Before you bozos start ranting that global warming can't be denied, I realize you can't read and comprehend very well, so let me point out that I have not made any statement or comment to the effect that the global climate is not changing, and in most cases seems to be getting warmer. I am happy to state however, and emphatically, that absolutely no link between human activity and global warming has every been clearly established, much less proven. Even the statistical correlations that I've studied are flawed because with the single-minded intent of proving a point typical of politics, they don't even factor in things like particulates and gases released through natural events like volcanic eruptions, much less the more complex issues of how carbon balance is affected by practices like no-till farming.

So I'm not losing any sleep about my 'carbon footprint', but I do lose sleep wondering what is the political agenda by the persons driving this latest 'crisis awareness campaign'. It seems to me that whenever I'm being urged to change my lifestyle based on pseudo-science, what's really going on is that I'm expected to not notice that what's really happening is that I am being conned into giving up my ability to choose - called Freedom by those of us who value it. That's why the Kyoto accord is such a threat and not just a farce; Europeans and North Americans are expected to drastically change our lives, with associated economic disadvantages, while Asians and Aficans would be generally exempt. So I'm selfish about wanting to keep at least some manufacturing here in the states? Fine, call me selfish; I'd rather be selfish than stupid.

Even if you are one of the idiots who buys into the whole 'We're cooking the earth' scam, why bother worrying about it now? Every so-called global warming expert I've read says even if we cut our CO2 output by 90%, temperatures will still rise to the point that coastlines will be altered and climate changes will make widespread crop failures likely. Talk about wishfull thinking!
3 / 5 (2) Dec 05, 2008
I don't think I've ever agreed with a guy named Guido before. This is a first.
1 / 5 (3) 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.
3.7 / 5 (3) 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.
3 / 5 (2) Dec 07, 2008
The IPCC report insinuates that humans are responsible with no evidence linking temperature increase to any human activity.

Here's your materials for reference.

2.3 / 5 (3) 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


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.