Subscribe free to our newsletters via your
. 24/7 Space News .


Subscribe free to our newsletters via your




















ICE WORLD
A perfect storm of fire and ice may have led to snowball Earth
by Staff Writers
Boston MA (SPX) Mar 15, 2017


About 700 million years ago, runaway glaciers covered the entire planet in ice. Harvard researchers modeled the conditions that may have led to this so-called 'snowball Earth'. Image courtesy NASA.

What caused the largest glaciation event in Earth's history, known as 'snowball Earth'? Geologists and climate scientists have been searching for the answer for years but the root cause of the phenomenon remains elusive. Now, Harvard University researchers have a new hypothesis about what caused the runaway glaciation that covered the Earth pole-to-pole in ice.

The research is published in Geophysical Research Letters. Researchers have pinpointed the start of what's known as the Sturtian snowball Earth event to about 717 million years ago - give or take a few 100,000 years. At around that time, a huge volcanic event devastated an area from present-day Alaska to Greenland. Coincidence?

Harvard professors Francis Macdonald and Robin Wordsworth thought not. "We know that volcanic activity can have a major effect on the environment, so the big question was, how are these two events related," said Macdonald, the John L. Loeb Associate Professor of the Natural Sciences.

At first, Macdonald's team thought basaltic rock - which breaks down into magnesium and calcium - interacted with CO2 in the atmosphere and caused cooling. However, if that were the case, cooling would have happened over millions of years and radio-isotopic dating from volcanic rocks in Arctic Canada suggest a far more precise coincidence with cooling.

Macdonald turned to Wordsworth, who models climates of non-Earth planets, and asked: could aerosols emitted from these volcanos have rapidly cooled Earth? The answer: yes, under the right conditions.

"It is not unique to have large volcanic provinces erupting," said Wordsworth, assistant professor of Environmental Science and Engineering at the Harvard John A. Paulson School of Engineering and Applied Science. "These types of eruptions have happened over and over again throughout geological time but they're not always associated with cooling events. So, the question is, what made this event different?"

Geological and chemical studies of this region, known as the Franklin large igneous province, showed that volcanic rocks erupted through sulfur-rich sediments, which would have been pushed into the atmosphere during eruption as sulfur dioxide. When sulfur dioxide gets into the upper layers of the atmosphere, it's very good at blocking solar radiation. The 1991 eruption of Mount Pinatubo in the Philippines, which shot about 10 million metric tons of sulfur into the air, reduced global temperatures about 1 degree Fahrenheit for a year.

Sulfur dioxide is most effective at blocking solar radiation if it gets past the tropopause, the boundary separating the troposphere and stratosphere. If it reaches this height, it's less likely to be brought back down to earth in precipitation or mixed with other particles, extending its presence in the atmosphere from about a week to about a year. The height of the tropopause barrier all depends on the background climate of the planet - the cooler the planet, the lower the tropopause.

"In periods of Earth's history when it was very warm, volcanic cooling would not have been very important because the Earth would have been shielded by this warm, high tropopause," said Wordsworth. "In cooler conditions, Earth becomes uniquely vulnerable to having these kinds of volcanic perturbations to climate."

"What our models have shown is that context and background really matters," said Macdonald.

Another important aspect is where the sulfur dioxide plumes reach the stratosphere. Due to continental drift, 717 million years ago, the Franklin large igneous province where these eruptions took place was situated near the equator, the entry point for most of the solar radiation that keeps the Earth warm.

So, an effective light-reflecting gas entered the atmosphere at just the right location and height to cause cooling. But another element was needed to form the perfect storm scenario. After all, the Pinatubo eruption had similar qualities but its cooling effect only lasted about a year.

The eruptions throwing sulfur into the air 717 million years ago weren't one-off explosions of single volcanoes like Pinatubo. The volcanoes in question spanned almost 2,000 miles across Canada and Greenland. Instead of singularly explosive eruptions, these volcanoes can erupt more continuously like those in Hawaii and Iceland today. The researchers demonstrated that a decade or so of continual eruptions from this type of volcanoes could have poured enough aerosols into the atmosphere to rapidly destabilize the climate.

"Cooling from aerosols doesn't have to freeze the whole planet; it just has to drive the ice to a critical latitude. Then the ice does the rest," said Macdonald.

The more ice, the more sunlight is reflected and the cooler the planet becomes. Once the ice reaches latitudes around present-day California, the positive feedback loop takes over and the runaway snowball effect is pretty much unstoppable.

"It's easy to think of climate as this immense system that is very difficult to change and in many ways that's true. But there have been very dramatic changes in the past and there's every possibility that as sudden of a change could happen in the future as well," said Wordsworth.

Understanding how these dramatic changes occur could help researchers better understand how extinctions occurred, how proposed geoengineering approaches may impact climate and how climates change on other planets.

"This research shows that we need to get away from a simple paradigm of exoplanets, just thinking about stable equilibrium conditions and habitable zones," said Wordsworth. "We know that Earth is a dynamic and active place that has had sharp transitions. There is every reason to believe that rapid climate transitions of this type are the norm on planets, rather than the exception."

ICE WORLD
World's first museum of polar lands opens in France
Prémanon, France (AFP) March 11, 2017
As global warming reshapes the Arctic and Antarctic, a new museum built by the son of a renowned French explorer aims to show "the beauty of polar landscapes" and illustrate the consequences of climate change. The centre in eastern France is "the only permanent museum devoted to the Arctic and Antarctic in the world," said communications director Anthony Renou. Built in the shape of a ju ... read more

Related Links
Harvard School of Engineering and Applied Sciences
Beyond the Ice Age

Thanks for being here;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.

SpaceDaily Contributor
$5 Billed Once


credit card or paypal
SpaceDaily Monthly Supporter
$5 Billed Monthly


paypal only

Comment on this article using your Disqus, Facebook, Google or Twitter login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle

ICE WORLD
New Plant Habitat Will Increase Harvest on International Space Station

NASA Releases Free Software Catalog

India has capability to develop space station, says top official

Orion spacecraft achieves key safety milestone

ICE WORLD
Space squadron supports record-breaking satellites launch

Europe launches fourth Earth monitoring satellite

Elon Musk: tech dreamer reaching for sun, moon and stars

Blue Origin shares video of New Glenn rocket

ICE WORLD
New evidence for a water-rich history on Mars

Humans May Quickly Evolve on Mars, Biologist Claims

NASA Orbiter Steers Clear of Mars Moon Phobos

Remnants of a mega-flood on Mars

ICE WORLD
Riding an asteroid: China's next space goal

China launches experiment satellite "TK-1"

China Plans to Launch 1st Probe to Mars in Summer 2020

China to launch space station core module in 2018

ICE WORLD
How low can you go? New project to bring satellites nearer to Earth

Teal Group Pegs Value of Space Payloads Through 2036 at Over $250 Billion

Iridium Safety Voice Communications Installs Surge Past 500 Aircraft

Eutelsat Signs up for Blue Origin's New Glenn Launcher

ICE WORLD
MIPT physicists predict the existence of unusual optical composites

Sandia creates 3-D metasurfaces with optical possibilities

First exact model for diffusion in magnesium alloys

New application of the selective laser melting method

ICE WORLD
Kepler Provides Another Peek at Ultra-cool Neighbor

Hunting for giant planet analogs in our own backyard

Faraway Planet Systems Are Shaped Like the Solar System

Biochemical 'fossil' shows how life may have emerged without phosphate

ICE WORLD
Juno to remain in current orbit at Jupiter

Europa Flyby Mission Moves into Design Phase

NASA receives science report on Europa lander concept

New Horizons Refines Course for Next Flyby




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News








The content herein, unless otherwise known to be public domain, are Copyright 1995-2017 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement