Climate Science Glossary

Term Lookup

Enter a term in the search box to find its definition.

Settings

Use the controls in the far right panel to increase or decrease the number of terms automatically displayed (or to completely turn that feature off).

Term Lookup

Settings


All IPCC definitions taken from Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Annex I, Glossary, pp. 941-954. Cambridge University Press.

Home Arguments Software Resources Comments The Consensus Project Translations About Support

Twitter Facebook YouTube Mastodon MeWe

RSS Posts RSS Comments Email Subscribe


Climate's changed before
It's the sun
It's not bad
There is no consensus
It's cooling
Models are unreliable
Temp record is unreliable
Animals and plants can adapt
It hasn't warmed since 1998
Antarctica is gaining ice
View All Arguments...



Username
Password
New? Register here
Forgot your password?

Latest Posts

Archives

New research shows the world’s ice is doing something not seen before

Posted on 26 September 2018 by John Abraham

In this warming world, some parts of the planet are warming much faster than others.  The warming is causing large ice bodies to start to melt and move rapidly, in some cases sliding into the ocean. 

This movement is the topic of a very new scientific study that was just published in the journal Earth and Planetary Science Letters.  The Arctic is warming much faster than other parts of the planet and the ice there is showing the signs of rapid warming.  This fact has serious consequences. First, melting ice can cause sea levels to rise and inundate coastal areas – it also makes storms like hurricanes and typhoons more destructive.  Melting ice also causes a feedback loop, which can cause more future warming and then more ice loss.

It should be noted that there are different types of ice.  Some ice floats on water and is called sea ice.  When it melts, the ocean water level hardly budges because the ice is already in the sea displacing liquid water.  But, sea ice is really important for this feedback loop I mentioned above.

Other ice is on land and may be a large ice sheet or a smaller glacier.  These ice bodies sit atop the land and “rest” there.  In some cases, they extend out off the land and into the ocean where they partly float on liquid water.  When this land ice melts, the liquid flows into the oceans and can cause significant ocean level rising.

So, the importance of ice depends on what type it is, where it is located, and how fast it is melting. And this brings us to the new paper.

The researchers looked at a type of high latitude glacier in their study.  These glaciers hold enough water to cause about 1 foot (about a third of a meter) in sea level rise. Typically, they exist in cold and dry areas, where snowfall is limited. 

How do glaciers move?  Well really by either sliding over the underlying bedrock or surface that they sit on, or by deforming and stretching under their weight. The colder glaciers tend to move by the deforming and stretching process.  Glaciers that have wetter and more temperate regions involve more sliding.  But regardless of how they move, these glaciers, particularly the glaciers that have both cold and temperate parts, experience surges in their motion.  These surges are short duration times where the glacier moves a lot.  During a surge, ice is redistributed from one part of the glacier to another region.

The authors in this study observed such a glacier surge.  It happened at an outlet glacier that is mainly of the “cold” type in Russia.  At the Vavilov Ice Cap on October Revolution Island, the authors find it “is undergoing extraordinary acceleration and thinning but displays no previous evidence of surging.”  The authors write,

the 300-600 meter thick 1820 square kilometer Vavilov Ice Cap is frozen to its bed over the majority of its area, apart from a region along its western margin where basal sliding is potentially important for faster flow.

In 2010 the ice in the region began to accelerate and the next year, crevasses were observed that matched the patterns of ice acceleration. The researchers were able to watch this surge in ice motion in real-time using satellite images. They could track the motion and show the incredible speed of flow. 

What caused the rapid motion? This is an important question because if the motion is caused by human warming, we can expect the behavior to be repeated elsewhere as temperatures rise.  Importantly both air and ocean-water temperatures could be a factor.  One potential cause is surface meltwater.  The top of the ice can melt, and liquid water then can flow downwards, into the ice through cracks and holes.  This flowing water can precondition the ice for rapid motion.

This fact may be a contributing cause to the motion.  Basically, the melted water lubricated the ice/ground interface causing more sliding and more friction.  The friction caused some of the bottom ice to melt and released more liquid water, and a cycle had begun.

The researchers also took measurements of elevation to better understand areas where ice was becoming thicker or thinner.  In addition, they studied the forces that exist within the ice itself to help elucidate the cause of the increased speed. Obviously, this is an evolving area of study and all of the questions have not yet been answered.  However, I was impressed when I read that even though these types of surges are becoming more common, what the researchers observed in Russia was still unique.  They describe the rate of ice loss at Vavilov as “extreme.” The authors also point out,

Click here to read the rest

0 0

Printable Version  |  Link to this page

Comments

Comments 1 to 3:

  1. The article states:

    "The Arctic is warming much faster than other parts of the planet and the ice there is showing the signs of rapid warming. This fact has serious consequences. First, melting ice can cause sea levels to rise and inundate coastal areas"

    This is NOT a helpful statement and is, in fact, providing a (valid) target to deniers.

    As readers of this site should know, _Artic_ sea ice melting will NOT 'cause sea levels to rise.' Including the statement only serves to (a) misinform the ignorant, and (b) offer fodder for those who will (not 'might') claim that SkepticalScience is 'fake'.

    There is no need to make false statements; the facts speak for themselves.

    0 0
    Moderator Response:

    [JH] A readers of this site well know, it is always best to carefully read an entire article before commenting on it. You obviously did no do so. Therefore your critique of Abraham's article has no foundation and is entirely unwarranted.

    BTW, the use of "all caps" is prohibited by the SkS Comments Policy.

  2. "As readers of this site should know, _Artic_ sea ice melting will NOT 'cause sea levels to rise.'"

    Readers of this site usually read the entire article for clarity, and most read the linked sources given.  Further, the quote you object to doesn't refer to sea ice, a point that the author then makes clear pains to clarify.

    0 0
  3. #1

    "The Arctic" as well is not just the Arctic Ocean.  If one includes only that part of the Earth above the Arctic Circle, it also includes most of Greenland as well as the large Islands of Northern Canada, Victoria, Baffin and others.  There is a LOT of land ice there.

    0 0

You need to be logged in to post a comment. Login via the left margin or if you're new, register here.



The Consensus Project Website

THE ESCALATOR

(free to republish)


© Copyright 2024 John Cook
Home | Translations | About Us | Privacy | Contact Us