New Study Shows That as the Climate Warms, Melting of Alaskan Glaciers is Adding Significantly to Sea Level Rise

By Tom Yulsman | June 17, 2015 5:02 pm
Alaskan glaciers

An animation of Landsat satellite images showing dramatic shrinkage of the Columbia Glacier in Alaska. The animation pauses for extra time on the first image, acquired in 1986, and the last one from 2914. (Images: NASA Earth Observatory. Animation: Tom Yulsman)

As heat about global warming continues to emanate from the presidential campaign trail, new research published today shows that the melting of Alaskan glaciers is largely the result of a warming climate.

According to the study, accepted for publication in the peer-reviewed Geophysical Research Letters, Alaskan glaciers lost about 1.4 trillion tons of ice between 1994 and 2013. That works out to about 75 billion tons a year.

Given that rate of ice loss, we’re talking about enough water to cover the entire state of Alaska to a depth of one foot every seven years.

The melting is unlikely to stop any time soon.

SEE ALSO: As Republicans Criticize Pope’s Stance on Climate Change, NASA’s Monthly Update Shows Earth Continuing to Heat Up

I created the animation above using Landsat remote sensing imagery to help portray just how significant the melting of Alaskan glaciers has been. You’re looking at changes to the Columbia Glacier between 1986 and 2014. The glacier flows down the flanks of the Chugach Mountains and into an inlet that leads into Prince William Sound, about 90 miles west of Anchorage. (For a Google map locating the glacier, click here.)

As the animation shows, it has been shrinking dramatically. In fact, it is one of the most rapidly changing glaciers in the world. Since 1980, the glacier’s terminus has retreated more than 12 miles to the north, it has thinned by about 1,500 vertical feet, and has lost about half of its total volume.

Alaskan glaciers

Changes to glacial mass between 1994 and 2013 in the most densely glacierized subregion of Alaska. Black lines indicate survey flight lines. (Source: Chris Larsen/American Geophysical Union)

The Columbia is a tidewater glacier, meaning it is a mountain glacier that empties into the ocean. In the map above, which comes from the study, it’s one of the glaciers in the region marked “Chugach.” Wherever you see yellow, orange and red tones, glacial mass has been lost thanks to a warming climate. Blue is indicative of increased mass.

The new research published today has revealed at least one surprise: However fast Columbia and other Alaskan tidewater glaciers may be retreating and calving ice into the sea, they are not the region’s primary contributors to sea level rise. The biggest contributions are coming from melting of glaciers that end on land.  (Their melt runoff eventually finds its way to the sea through streams and rivers.)

Alaskan glaciers

Lidar survey over Alaskan glacier. (Source: Chris Larsen/AGU)

As part of their study, researchers from the University of Alaska, Fairbanks and the U.S. Geological Survey used data on 116 glaciers in the Alaska region. The data came from lidar altimetry collected during NASA’s Operation IceBridge, airborne surveys in the 1990s, and a new mountain glacier inventory of every glacier in the Alaska region. (This region includes the glaciers of Alaska, southwest Yukon Territory and coastal northern British Columbia.)

Click on the thumbnail image at right for a dramatic photo of a plane that conducted one of the lidar surveys, this one over the heavily crevassed Tana Glacier in Southcentral Alaska.

Alaskan glaciers

The Randolf Glacier Inventory. (Source: NASA Earth Observatory)

Although mountain glaciers hold less than 1 percent of Earth’s total glacial ice volume, their rapid shrinkage is responsible for nearly one-third of current sea level rise. The map above is the first global catalog of such glaciers. It was developed to help scientists working on assessments of the Intergovernmental Panel on Climate Change improve estimates of sea level rise.

Here are the details of what you’re looking at, from NASA’s Earth Observatory, which published the map in June of 2014:

The locations of glaciers are marked in blue. Glaciers outline the world’s major mountain ranges and fringe the ice sheets of Antarctica and Greenland. The map includes some 198,000 glaciers that cover approximately 726,800 square kilometers (280,600 square miles).

For a high resolution version of the map, which enables you to zoom in closely on specific areas, see the Earth Observatory post here.

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  • Mike Richardson

    Unlike floating sea ice, which would actually displace less water if melted, any land-based ice is naturally going to raise the sea level as it melts. The only counter to this that I’ve heard of is that large glacial landmasses, such as Antarctica or Greenland, might rebound somewhat as billions of tons of ice melt off of them. Of course, this wouldn’t help the coastlines of more temperate areas, which would be dealing with sea level rise caused by melting ice and possible displacement caused by rising formerly ice-covered landmasses. More on point to the Alaskan glaciers, I do recall seeing photos of some of the retreating ice from earlier in the 20th century to more recently, and it’s a pretty obvious change. It’s good, though unsettling, to see the actual amount of melting quantified.

    • ronaldmsonntag

      Small correction-floating ice displaces exactly as much water as when it is melted. Archimedian principle guarantees this.

      • Mike Richardson

        Thanks for pointing that out. I was thinking in terms of ice expanding in volume, but you’re right — which is why there’s always going to be some part of an iceberg sticking up out of the water. Getting your facts right is important, though. Looks like you’ve got that well in hand from this and some of your other posts.

  • OWilson

    “”…. new research published today shows that the melting of Alaskan glaciers is largely the result of a warming climate””

    I hope they weren’t spending taxpayer money to find the obvious, but knowing how they spend other people’s money, I wouldn’t be surprised.
    Here’s my “Study”, for free!

    We are in an inter glacial period.

    A couple thousand years ago lots of glaciers around then, not so many now.

    Manhattan was under ice kilometers thick.

    The ice is retreating, now they have cute sidewalk cafes and a nice park.

    Lol

    • ronaldmsonntag

      Your “free” study is complete hogwash consisting of nothing more than your ignorance. Read “The Two Mile Time Machine” and then get back to me with some opinions backed by scientific facts. The current trend is, in fact, going counter to what the normal naturally driven cycles should be doing.

      • OWilson

        Another low info true believer who cannot distinguish truth from lies.

        Lol

        • ronaldmsonntag

          Again, your purposeful ignorance is appalling. Fossil fuels are not just Earth’s energy. They represent millions of years of stored sunlight. And, we are using them all up in a few hundred years. Saying we are a normal part of the fauna is ignoring both the scientific nature of our uniqueness as well as our spiritual responsibility to take care of our home. No other species has developed nuclear energy with the capability of truly wiping out life as we know it. Stop justifying your and your kind’s bad and selfish behavior with the excuse that you are just part of the natural cycle!

          • OWilson

            So, how do you think you got your magazines, computers, cable TV, telephones, electricity, gas?

            All conveniently brought into your home by pipelines, waterlines, electricity transmission corridors, wires and pipes. Unless you are a farmer, how are you getting your eggs, milk bread and vegetables?

            They are not part of “the natural cycle”. That stuff just doesn’t grow on trees.

            For selfish, and even obscene behavior, look no further than the spiraling debt which can never be repaid, that left wing governments are passing along to my grandchildren, so you can have yours, NOW!

          • ronaldmsonntag

            Your memory also appears hampered by your ignorance. It has been the right-wing conservatives that drove up the debt through illegal wars (Bush) and dismantling oversight of Wallstreet resulting in the worst economic collapse since the great depression and the multi-trillion dollar bailout of those same banks that the GOP have been protecting.

          • OWilson

            Ook! :)

  • http://blogdredd.blogspot.com/ Dredd Blog

    You need to do some research on sea level fall.

    That is what is happening in S.E. Alaska as the glaciers melt (Proof of Concept – 3).

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ImaGeo

ImaGeo is a visual blog focusing on the intersection of imagery, imagination and Earth. It focuses on spectacular visuals related to the science of our planet, with an emphasis (although not an exclusive one) on the unfolding Anthropocene Epoch.

About Tom Yulsman

Tom Yulsman is Director of the Center for Environmental Journalism and a Professor of Journalism at the University of Colorado, Boulder. He also continues to work as a science and environmental journalist with more than 30 years of experience producing content for major publications. His work has appeared in the New York Times, Washington Post, Audubon, Climate Central, Columbia Journalism Review, Discover, Nieman Reports, and many other publications. He has held a variety of editorial positions over the years, including a stint as editor-in-chief of Earth magazine. Yulsman has written one book: Origins: the Quest for Our Cosmic Roots, published by the Institute of Physics in 2003.

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