Scientist devoted to measuring Earth's shrinking ice sheets

Sep 11, 2012 by Kathryn Bold
Isabella Velicogna, assistant professor of Earth system science, has shown that glaciers are losing mass at an increasing rate — a trend with dire implications for the planet. Credit: Nicole Del Castillo

(Phys.org)—Isabella Velicogna's office in UC Irvine's Croul Hall looks like it belongs to an artist instead of a university scientist. Her paintings and drawings—including charming sketches of mice—adorn the walls, and colorful, handcrafted mobiles dangle from the ceiling.

"In my next life, I will be a children's book illustrator," says Velicogna, who loves to paint, draw and sew. For now, though, she's too busy conducting pioneering research on global warming and publishing her less-than-rosy findings on the planet's shrinking ice sheets.

The assistant professor of Earth system science has been documenting the deterioration of the immense frozen masses in Greenland and Antarctica through data she's carefully culled via . Velicogna has shown that the ice sheets are thawing at an accelerating pace, and if the trend continues, the would-be children's book illustrator sees no happy ending. The will raise the sea level and have a major impact on worldwide.

A native of Italy, Velicogna began studying the Earth's ice masses a decade ago as a postdoctoral student at the University of Colorado, Boulder. Back then, she didn't realize her work would have the impact or urgency it does today. She wasn't a climate crusader—she simply loved research. "I ended up concentrating on something more meaningful than I initially thought," she says.

Still, there's more work to be done before she can devote time to her art. Velicogna continues to monitor the ice sheets to better understand what's happening on the Earth's surface. She recently discussed her research and concerns for the planet's future:

What's the main focus of your research?

I study the mass balance of ice sheets—how they are changing and why. I use 's GRACE [Gravity Recovery and ] mission technology to measure variations in the Earth's mass and . GRACE was launched in 2002 and is an amazing tool. With its twin satellites, it weighs the Earth from space and tells us every month how much ice Greenland and Antarctica are losing.

What do you consider to be your most important findings to date?

In 2006, we published a paper in Science showing that Antarctica was losing significant mass. It was the first time that we could weigh the entire ice sheet. When I started this work, most scientists assumed the in Antarctica would grow and Greenland's would shrink a little. We found that both ice sheets are rapidly shrinking. Greenland loses a huge amount of water every year: 230 gigatons. By comparison, Los Angeles County uses 1 gigaton [1 billion metric tons] of water a year. Antarctica is losing about 150 gigatons annually. We're seeing more loss every year; it's accelerating.

What has been the reaction to your findings?

They've contributed to increased awareness of changes taking place in the polar regions. The data brought new insights about Antarctica. Today, more scientists are convinced global warming is a serious issue. But there's a lot more we have to learn about our planet. In particular, it's not easy to predict what will happen to the ice sheets.

What will happen if the ice sheets continue melting at this rate?

By the end of the century, the melt-water flowing into the ocean will probably raise the sea level by 1 meter or so globally. It will affect people living in coastal areas and be especially devastating for low-lying, under-developed countries such as Bangladesh. The economic toll will be high. People will have to be relocated; building codes will have to be changed. There's a lot of resistance to act on global warming now, but if we don't do something, the costs will be higher down the line.

What can we do to mitigate climate change now?

There are a lot of things people can do to slow down our impact on the global climate, such as not running their air conditioning or heating so often, installing solar panels on their house, riding bikes or changing the kind of car they drive, and promoting the use of renewable energy. It's in everybody's interest to start making those changes.

You earned your doctorate in applied geophysics at the University of Trieste, in Italy. How did you end up in the U.S.?

I've always wanted to do research. I came to the U.S. as a postdoctoral fellow at the University of Colorado and started working on GRACE. I loved it so much that I'm still working here today.

Your husband, UCI professor Eric Rignot, also is an expert on polar ice sheets and . Do you collaborate on your research?

We've always talked about science, but we started collaborating only in recent years. Now we even write papers together.

What are your plans for the future?

A GRACE follow-on mission will be launched in 2017. I'll be involved in that. We'll combine the new data with other observations to better understand the evolution of ice sheets. The advent of satellites has given us the ability to observe Antarctica and Greenland with unprecedented accuracy. We're starting to develop models of changing ice sheets. We have a lot of data we didn't have even a few years ago, and we're really improving our understanding of the Earth. It's a magic time to be doing this research.

Explore further: Global warming 'pause' since 1998 reflects natural fluctuation, study concludes

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Jitterbewegung
2.3 / 5 (13) Sep 11, 2012
400 billion tonnes over 400 million square kilometres of ocean is 1000 tonnes per square kilometre.
That's about a 1 mm rise in sea level every year.
Last time I saw a metre it had 1000mm in it not 88.
Jitterbewegung
2.3 / 5 (12) Sep 11, 2012
Ps. Don't forget to subtract an amount from this figure for years when the ice grows a bit.
VendicarD
3.8 / 5 (10) Sep 11, 2012
"We're seeing more loss every year; it's accelerating." - Article

Jitterbewequng presumes linearity when there is accelerating melt.

Foolish.
Lurker2358
3.2 / 5 (9) Sep 11, 2012
400 billion tonnes over 400 million square kilometres of ocean is 1000 tonnes per square kilometre.
That's about a 1 mm rise in sea level every year.
Last time I saw a metre it had 1000mm in it not 88.


1, You forgot to account for exponential growth in melt rate due to self-reinforcing positive albedo feedback.

2, You forgot to account for further exponential growth in melt rate due to increased GHG totals and emissions between now and then, as the Keeling Curve grows roughly parallel to the population curve growth rate.

3, you and the authors forgot to account for the fact that once all the Arctic Sea ice is melted, the excess heat budge continues to grow there as well, and will contribute to melting Greenland exponentially faster. It looks like we've lost another 900gigatons of annual minimum sea ice this year, so once the minimum hits zero, you can just add that to the losses from Greenland each year, which should just about quadruple annual rate, about 5 years from now.
Jitterbewegung
2.3 / 5 (6) Sep 11, 2012
I guess putting the brakes on is a form of acceleration but you have to deduct it not add it;-)
Do you have some numbers that you would like to post for people to check for themselves?
I don't mind crunching larger or smaller numbers.
I agree that my numbers are linear and I would love to see other people posting some numbers on yearly acceleration.
Jitterbewegung
2.5 / 5 (8) Sep 11, 2012
"We're seeing more loss every year; it's accelerating."

How can that be true if some years it grows? More ice loss per decade maybe but I don't have those figures to play with.
Jitterbewegung
1.8 / 5 (5) Sep 11, 2012
Does anyone know how many billion tons of ice are added to the ice sheet each year during winter?

Or do the figures in the article take that into account already?
VendicarD
3 / 5 (8) Sep 11, 2012
"Does anyone know how many billion tons of ice are added to the ice sheet each year during winter?" - Jitterbewegung.

And the article tells you who does.

You might try reading it.

"How can that be true if some years it grows?" - Jitterbewegung

Next you might ask yourself how a row boat can be moving away from you when it is in a fast moving river.

Then take the time derivative and grow in your comprehension.
ubavontuba
1.5 / 5 (15) Sep 11, 2012
"Scientist devoted to measuring Earth's shrinking ice sheets"

The title alone reveals the bias.

If she's "devoted to measuring shrinking ice sheets," I wonder if she has a counterpart who is equally "devoted" to measuring only the growing ice sheets. ...No? I didn't think so.

And they wonder why anyone might suppose there's a built in climate science bias. Go figure.

VendicarD
3.7 / 5 (9) Sep 11, 2012
How dare an article's title convey it's content.

"The title alone reveals the bias." - UbVonTard

How dare it!

Particularly when that content shows UbVonTard to be a congenital liar.

Caliban
3.7 / 5 (6) Sep 12, 2012
"Scientist devoted to measuring Earth's shrinking ice sheets"

The title alone reveals the bias.

If she's "devoted to measuring shrinking ice sheets," I wonder if she has a counterpart who is equally "devoted" to measuring only the growing ice sheets. ...No? I didn't think so.


uby,

There is inherent difficulty --in fact difficulty to the point of exclusion-- in devoting oneself to studying growth in a system which is in a trend of year-over-year loss. Even for a person of nominal intellect this is an obvious contradiction or "non-starter".

But don't give up hope --maybe you can apply for the job!!!

Jitterbewegung
2.6 / 5 (5) Sep 12, 2012
Well if nobody has any figures at hand then we wont let maths get in the way of a good story will we;-)
kochevnik
1.7 / 5 (6) Sep 12, 2012
@ubavontuba "Scientist devoted to measuring Earth's shrinking ice sheets"

The title alone reveals the bias.
Shrinking can be positive or negative. You failed again.
ubavontuba
1.7 / 5 (6) Sep 12, 2012
There is inherent difficulty --in fact difficulty to the point of exclusion-- in devoting oneself to studying growth in a system which is in a trend of year-over-year loss. Even for a person of nominal intellect this is an obvious contradiction or "non-starter".
What "year-over-year loss" are you talking about? Quantify it, please.

And while doing so, please explain where the water went, 'cause it sure doesn't seem to be doing anything unusual to the oceans, as the sea level rise remains below the long term trend:

http://sealevel.colorado.edu/

Is it just disappearing into space?

News: Even the famous Jay Zwally (predicted "ice free Arctic by the end of summer 2012″) admits Antarctic ice is growing:

http://vimeo.com/46429608

http://ntrs.nasa....=twitter

So, are we simply measuring the ice mass, or are we (from a subjective bias) specifically looking for ice mass loss?

ubavontuba
1.9 / 5 (7) Sep 12, 2012
More actual science:

"Increased ice loading in the Antarctic Peninsula since the 1850s and its effect on Glacial Isostatic Adjustment"

http://www.agu.or...59.shtml

Which seemingly contradicts the often heard claims the Antarctic Penninsula is rapidly losing ice.

So, which scientists are telling the truth? Is it the scientists that are simply reporting their observations (whatever they may be), or the scientists "devoted to measuring Earth's shrinking ice sheets?" Or more specifically, which are the real scientists?

Caliban
2.7 / 5 (3) Sep 12, 2012
More actual science:
"Increased ice loading in the Antarctic Peninsula since the 1850s and its effect on Glacial Isostatic Adjustment"

http://www.agu.or...59.shtml

Which seemingly contradicts the often heard claims the Antarctic Penninsula is rapidly losing ice.

So, which scientists are telling the truth? Is it the scientists that are simply reporting their observations (whatever they may be), or the scientists "devoted to measuring Earth's shrinking ice sheets?" Or more specifically, which are the real scientists?


First, why don't you supply the actual thing itself, instead of a LETTER from these authoritieson Antarctic ice mass balance of yours.

In the meantime, here's the research from Dr. Velicogna et al, via skeptical science:

http://www.skepti...iate.htm

Also, it should be noted that "Antarctic Peninsula" is such a broad term as to be nearly meaningless in the context of this debate.

Caliban
3 / 5 (4) Sep 12, 2012

A few additional citations:

http://www.nature...race.pdf

Combined NASA missions:http://www.nasa.g...308.html

An explicit treatment of uncertainties involved in calculating ice balance. Note that it still supports a trending loss:

http://www.scienc...l_07.pdf

Read more at: http://phys.org/n...html#jCp
rubberman
4 / 5 (4) Sep 12, 2012
Ironically not the only observed evidence of the mass loss either...

http://www.newsci...ial.html

This one actually explains the mechanism:

http://www.scienc...0353.htm

Queue the obligatory data smear and accompanying drivel....
ubavontuba
1.8 / 5 (5) Sep 13, 2012
Caliban:

So you weren't able to quantify the supposed ice mass loss and describe where it went?

Seriously, it has to go somewhere, right?

First, why don't you supply the actual thing itself, instead of a LETTER
That's not just a "letter." That's the abstract from a scholarly, peer reviewed paper. It's a new paper so you have to buy it to see it. If I provided it, I'd likely be liable for a copyright infringement. Suffice it to say, the paper concludes by suggesting there's been up to 45m of ice-sheet thickening in the Antarctic Peninsula since 1855.

The important information is in regards to the Glacial Isostatic Adjustment caused as a result of this ice accumulation (more on this later).

from these authoritieson Antarctic ice mass balance of yours.
This paper is from the School of Civil Engineering and Geosciences, Newcastle University, and the Department of Geography, Durham University.

ubavontuba
1 / 5 (5) Sep 13, 2012
Also, it should be noted that "Antarctic Peninsula" is such a broad term as to be nearly meaningless in the context of this debate.
Even the free abstract specifies the greatest thickening is in the northern and western Antarctic Peninsula.

And it's important to note this is based on empirical measurements of actual ice cores, verses purely inferred measurement methodologies (like GRACE).

In the meantime, here's the research from Dr. Velicogna et al, via skeptical science:
Now we get to the heart of the matter. My reference generally contends that GRACE underestimates ice mass as a result of Glacial Isostatic Adjustment (GIA).

From here, I'm going to stray from the paper a bit and expand on and extrapolate on the concept:

GIA is the result of the weight of the ice crushing the Antarctic land mass downward, into the Earth's mantle. That is, as the ice mass piles up on the continent, the land mass sinks toward the center of the earth.

cont...

ubavontuba
1 / 5 (4) Sep 13, 2012
GRACE essentially measures Earth's mass variances over time. So ask yourself: Which is denser, ice or granite?

Obviously, Grace isn't simply measuring a linear accumulation of ice.

Worse, as Antarctica sinks into the mantle, what do you think happens to the rest of the earth? It expands (ever so slightly) to compensate, thereby exaggerating the appearance that mass is leaving the Antarctic relative to the mass of the rest of the world.

Of course the amount of this effect is all relative to and dependent on the upper mantle viscosity. But all in all, it paints a negative image of GRACE as a continental ice sheet measuring tool.

As mentioned above, Dr. Zwally realized a net gain in Antarctic ice accumulation using ICESat laser interferometry. Even this would suffer problems with accuracy due to continental subsidence. However, at least it's a direct measurement of the height of the ice and shows a substantial net gain.

ubavontuba
2.3 / 5 (3) Sep 13, 2012
A few additional citations:

http://www.nature...race.pdf

Combined NASA missions:http://www.nasa.g...308.html

An explicit treatment of uncertainties involved in calculating ice balance. Note that it still supports a trending loss:

http://www.scienc...l_07.pdf
It looks like you did a copy and paste edit. All of these links are truncated (inoperable).

Can you correct them and repost them, please?

ubavontuba
1 / 5 (5) Sep 13, 2012
Ironically not the only observed evidence of the mass loss either...

http://www.newsci...ial.html

This one actually explains the mechanism:

http://www.scienc...0353.htm
Well then, it's a good thing the ice isn't melting, but rather expanding then, isn't it?

Did you also know the Antarctic air has been unusually cold? They recently set a record:

http://amrc.ssec....hp?id=41

Queue the obligatory data smear and accompanying drivel....
What, so you don't believe the scientists? You did know Dr. Zwally was the one who famously predicted "ice free Arctic by the end of summer 2012,″ didn't you? Are you saying now he's full of drivel?
rubberman
4.3 / 5 (6) Sep 13, 2012
Your record is for that location only, vostok has recorded colder.

http://www.antarc...cts.html

Fyi, the high temp record was set last december, less than 12 months apart...although I am not sure of the relevance of either in this discussion.

It isn't a good thing if accelerated inland glacial movement is causing the increase sea ice...hence the measured mass loss from the continental sheet. Clearly Zwally was incorrect, as all we did was observe a new record low..which can apparently be done from a catamaran now.

If Velicogna isn't factoring isostatic compression and rebound into her calculations for mass loss, I'll lay in the middle of one of your denialist circle jerks.
You actually believe someone who makes a career in this field would miss this factor, and the individuals who are responsible for the peer review process would also miss it? That is a notparkeresque assumption.
Caliban
3.4 / 5 (5) Sep 13, 2012

Fixed, uby:

Veligogna, GRL, 2009:

http://ess.uci.ed...race.pdf

Combined NASA. Guess what --also published in GRL.

http://www.nasa.g...308.html

Rignot, et al -Note isostatic rebound specifically accounted for:

http://igitur-arc...2011.pdf

Meta-analysis of research that specifically treats error and uncertainty:

http://www.scienc...l_07.pdf

All account for isostatic rebound. All find increasing ice balance loss.

I am not going to spend money to pay for your citation, so you'll need to find a free version, wait for community review, or wait until it's available for free before citing it, as the citation of an invisible paper --even one published in GRL-- is no better than a citation that god told you it was so.

Of course you understand.
ubavontuba
1 / 5 (4) Sep 13, 2012
It isn't a good thing if accelerated inland glacial movement is causing the increase sea ice
Who says it is?

hence the measured mass loss from the continental sheet.
What mass loss? Can you quantify it? Where is the mass going?

If Velicogna isn't factoring isostatic compression and rebound into her calculations for mass loss, I'll lay in the middle of one of your denialist circle jerks.
I never said she wasn't. The argument is the "standard" adjustment is insufficient.

ubavontuba
1 / 5 (3) Sep 14, 2012
Veligogna, GRL, 2009:

From the paper:

The combined contribution of Greenland and Antarctica to global sea level rise is accelerating at a rate of 56 ± 17 Gt/yr2 during April 2002–February 2009, which corresponds to an equivalent acceleration in sea level rise of 0.17 ± 0.05 mm/yr2 during this time.

Again, what "accelerating" sea level rise? Sea level remains below the long term trend, and barely maintained the trend during the period she's discussing (and this is with an already included .3mm/yr GIA bias). Did she even LOOK at the sea level trends to verify her claim? Apparently not. This is BAD SCIENCE.

http://sealevel.colorado.edu/

And of course, as I've shown previously, both physical measurements of and modeling of the ice sheet also falsify her claims.

And just how do you think the ice might be "disappearing" when the average temperature in the Antarctic interior during the Antarctic summer isn't even close to being above freezing?

Caliban
5 / 5 (1) Sep 14, 2012
From your beloved CU:

http://sealevel.colorado.edu/

~3.1mm per annum mean sea level increase, of which mass loss from Antarctica/Greenland --combined-- comprise from as little as 1/3 to as much as about 2/3.

As to just how the ice might be disappearing, well, probably the usual ways: sublimation, compression melt/gravitational transport, reduced snowfall, and terminal contact with with warmer coastal air and finally water.

And yes, I am aware that not all of the snow/ice is in glaciers.
And the "stationary snow/ice is just as subject as glacial to reduction via sublimation and wind transport, if not more so.

I think you may be laboring under the assumption that this snow/ice is just sitting there, piling up, as if it were behind a dam, or something...

The meta-analysis

http://www.scienc...l_07.pdf

addresses the rest of your questions.
ubavontuba
1 / 5 (2) Sep 14, 2012
All account for isostatic rebound. All find increasing ice balance loss.
Um, not really. You need to carefully read your references again.

One even admits incorrectly applied isostatic modeling can cause large discrepancies in the results:

"...and the East Antarctic anomaly as being an error in the isostatic adjustment modeling."

I am not going to spend money to pay for your citation, so you'll need to find a free version, wait for community review, or wait until it's available for free before citing it, as the citation of an invisible paper --even one published in GRL-- is no better than a citation that god told you it was so.

Of course you understand.
That you're unaware of the current science doesn't invalidate it. And most of the claims are easily accessible in the free abstract, anyway.

The problem is GRACE studies essentially "guess" at an isostatic adjustment essentially based on presupposing there is an ice mass loss, leading to an inborn ice mass loss bias.
ubavontuba
1 / 5 (2) Sep 14, 2012
From your beloved CU:

http://sealevel.colorado.edu/

~3.1mm per annum mean sea level increase, of which mass loss from Antarctica/Greenland --combined-- comprise from as little as 1/3 to as much as about 2/3.
Where, exactly, did you get that from the homepage link you provided?

"current estimates indicate that mass balance for the Antarctic ice sheet is in approximate equilibrium and may represent only about 10 percent of the current contribution to sea level rise coming from glaciers."

http://nsidc.org/...vel.html

As to just how the ice might be disappearing, well, probably the usual ways: sublimation, compression melt/gravitational transport, reduced snowfall, and terminal contact with with warmer coastal air and finally water.
This is nothing but hand-waving nonsense. Where's the science?

cont...
ubavontuba
1 / 5 (3) Sep 14, 2012
And yes, I am aware that not all of the snow/ice is in glaciers. And the "stationary snow/ice is just as subject as glacial to reduction via sublimation and wind transport, if not more so.
More hand-waving nonsense.

Again, you're going to have to quantify it and show where it's going, as it certainly isn't contributing to an "acceleration" in sea level rise.

I think you may be laboring under the assumption that this snow/ice is just sitting there, piling up, as if it were behind a dam, or something...
No, I think it's piled up on a continent and an island chain. Some of it has been there for more than 1.5 million years.

And, it's accumulating...

http://ntrs.nasa....3235.pdf

ScooterG
1 / 5 (1) Sep 17, 2012
So, are we simply measuring the ice mass, or are we (from a subjective bias) specifically looking for ice mass loss?


Neither.

AGW is simply a financial shakedown of corporate America. It's all part of the shell game designed to keep people working, paying taxes, all the while distracting them with mindless entertainment eg pro football. Create strife and fear, cast blame, start wars, "pull" buildings, usurp American freedoms, anything to keep dumb f**ks off balance and confused.

You have to understand that the vast majority of people in America no comprende the operation of business. They do not understand that if a $1.00 tax is imposed on say, an oil company, that they (the consumer) will pay an extra $1.35 at the pump.

Create a crisis, then use that crisis to extoll money from the masses in order to resolve the crisis. In a sick and perverted sort of way, it's economic stimulus...and corporate America (the original villain) reaps handsome profits.

Slick!