by Jordan Wilkerson
figures by Michael Gerhardt

When someone asks you to consider the impacts of climate change, what do you think of? There’s a good chance that melting ice sheets comes to mind pretty quickly. For that reason, a recent finding regarding the trend in Antarctic ice is quite perplexing; the ice sheet is reportedly increasing in size! This is according to a research study conducted by a NASA team and published in Journal of Glaciology in October 2015 [1].

What’s the Evidence that the Antarctic is Getting Larger?

Antarctica is a colossal landmass far from human civilization. How was this research team able to determine changes in the amount of ice each year? Well, they used a nifty device called a LIDAR altimeter (Figure 1). Using this, they were able to determine the ice trend by measuring the changes in surface height over time.

A LIDAR, a portmanteau of light and radar, altimeter is just like a radar. A RAdio Detection And Ranging (radar) device emits radio waves that then bounce back once they hit some sort of physical barrier – such as a big rock. Because we know how fast radio waves move, if we measure how long they take to bounce off that big rock and come back to us, we can determine how far away the rock is [2].

Placed on a satellite orbiting Earth, the LIDAR altimeter instead sends ultraviolet and visible light waves down to the Antarctic surface and patiently waits for their return. Using LIDAR measurements recorded over time, the research team determined that from 1992-2001, the Antarctic ice sheets gained an average of 112 billion tons of ice each year. From 2003-2008, this number decreased to 82 billion tons [1].

How can the planet be experiencing a warming trend and have regions that are accumulating ice? This is a fair question. Another tempting question to ask is this: is the planet even experiencing a warming trend if the Antarctic ice sheet is getting bigger? Let’s address that question first.

So is Climate Change Even Happening?

Yes, it is. But before we go over the evidence supporting climate change’s existence, we should keep something in mind: the notion that there’s net ice gain in the Antarctic is still being debated among top scientists. For example, many esteemed glaciologists, such as University of Washington’s Dr. Ben Smith, have pointed out that the LIDAR altimeter used in the study might register snowpack as increased surface height even though that’s not really a permanent component of the ice sheet (Figure 1). Across large swaths of land surface, this small contribution could propagate into an apparent enormous gain in ice mass that’s not really there [3]. But unlike this study’s conclusions, the notion that humans are causing climate change is well established by a portfolio of lab experiments, theoretical models, and observational data [4].

Figure 1: A satellite fires a laser at the Antarctic ice sheet and waits for the laser pulse to return to the satellite. The light from the laser pulse will take longer to return if it hits ocean than if it hits an ice sheet. Therefore, scientists can use this measurement to determine the topography of the ice sheet.
Figure 1: LIDAR. A satellite fires a laser at the Antarctic ice sheet and waits for the laser pulse to return to the satellite, measuring its speed of return and how the light is scattered upon returning. From these measurements, scientists can determine the topology of the region below the satellites. However, it is important to note that LIDAR can’t tell the difference between hitting ice and hitting snowpack, so scientists might think that the ice is thicker, when really there is just more snowpack.

First, there’s the rising temperature and its relationship with carbon dioxide. Gases in our atmosphere, particularly carbon dioxide (CO2), largely dictate the temperature of our planet. How this happens has been known for over a century – this is not recent stuff [5]. In short, CO2 acts as a heat-trapping blanket that envelops the planet. This blanket gets thicker and thicker as we emit more of this greenhouse gas into the atmosphere [6].

The effect of CO2 on Earth’s surface temperature isn’t just based on a collection of calculations and lab experiments (an extensive collection, mind you). Scientists have assessed hundreds of thousands of years of temperature and CO2 records. While there are some subtleties to the data, one clear trend emerges: the more CO2 there is in the air, the hotter our planet becomes [7,8,9]. This relationship is still true today. Temperature elevations over the past century match well with the rising CO2 levels since the Industrial Revolution [7].

Furthermore, while the Antarctic ice sheet is indeed increasing in size, this is not true for its northern counterpart, the Arctic. And the ice gain in the Antarctic doesn’t cancel out the ice loss in the Arctic. The Antarctic has gained about 7,300 square miles of ice each year since the late 1970s. The Arctic, on the other hand, has lost about 20,800 square miles of ice each year in that same period [10]. Global ice loss is still occurring on a significant scale.

Then What is Going On in Antarctica?

The measuring technique mentioned earlier gives us more than just what the ice gain is; it tells us where the ice is building up and where it’s receding. Using this insight, the NASA team concluded the culprit behind the net ice gain is East Antarctica. It is there and the interior of the West Antarctic ice sheet where gains are occurring. There is ice loss still occurring at the periphery of West Antarctica; it’s simply that the ice gains in the other regions are greater in magnitude [1] (Figure 2).

Figure 2: The data suggest an accelerating rate of ice loss in west Antarctica being balanced by a steady increase in the rate of ice gain in a wide area of east Antarctica.
Figure 2: Ice Gain and Loss in Antarctica. The data suggest an accelerating rate of ice loss in west Antarctica being balanced by a steady increase in the rate of ice gain in a wide area of east Antarctica.

According to the authors of the study, the ice loss and ice gain have different causes. The ice gains in the East Antarctic are not a new trend. Its cause is essentially the change in climate at the end of the last ice age – around 10,000 years ago. When the ice age ended, the planet overall became warmer. With increasing warmth comes increasing ability of air to retain moisture.

The warmer, thus wetter, air provided the Antarctic with additional snowfall. This snowpack has been accumulating and compacting for thousands of years on the East Antarctic Ice Sheet, causing a build up of ice [1]. The West Antarctic ice loss trend is new, abrupt, and began after the Industrial Revolution. Its tie to human activity has been demonstrated through a large number of both observations and theoretical models [11].

An important thing to note is that the ice gains in the East Antarctic have been constant. Every year, the region gains around 200 billion tons according to the NASA study [1]. This is a steady ice gain. Yet, if you recall, the net ice gain cited in that study went down from 112 billion tons to 82 billion tons per year. What’s causing the decrease? As the map of the Antarctic shows, while the East Antarctic ice gains have remained relatively steady, the ice loss in the West Antarctic is accelerating each year. By this, I mean the amount of ice lost each year is typically greater than the year before.

An important clarification to make: this trend in ice loss in the West Antarctic is one conclusion of the NASA study not being debated. “We’re essentially in agreement with other studies that show an increase in ice discharge in the Antarctic Peninsula and the Thwaites and Pine Island region of West Antarctica,” Jay Zwally, lead author of the study said. Therefore, if the increasing rates of ice loss in the West Antarctic continue, it’ll be only a few decades before they outweigh the ice gain in the East [12].

In this respect, there is no dispute. Antarctic ice is soon going to behave how we’d expect it to on a warming Earth – if it isn’t already. And when you’re considering how this study fits in with climate change, that is the important conclusion to keep in mind.

Jordan Wilkerson is a third year graduate student in the Department of Chemistry at Harvard University.


[1] Zwally, J., et. al., 2015. Mass gains of the Antarctic ice sheet exceed losses. Journal of Glaciology 61:1019-1036.

[2] Brit Lab. How does RADAR Work? (2013)

[3] Howard, Brian Clark. What Antarctica’s Incredible “Growing” Icepack Really Means. National Geographic. (2015).

[4] Scientific consensus: Earth’s climate is warming. NASA.

[5] The Carbon Dioxide Greenhouse Effect. The Discovery of Global Warming.

[6] A Blanket Around the Earth. NASA.

[7] Understanding Climate Change: A Primer. Woods Hole Research Center.

[8] Temperature Change and Carbon Dioxide Change. NOAA. (2008).

[9] CO2 lags temperature – what does it mean? Skeptical Science.

[10] Ramsayer, K. Antarctic Sea Ice Reaches New Record Maximum. NASA.

[11] Oppenheimer, M, Alley, RB. The West Antarctic Ice Sheet and Long Term Climate Policy. Climatic Change. 64: 1–10, 2004.

[12] Mass gains of Antarctic Ice Sheet greater than losses. Science Daily News.


Cover image from Andreas Kambanis and licensed under Creative Commons.

34 thoughts on “Why is Antarctica’s Ice Sheet Growing in a Warming World?

  1. JFC, it is baffling to read all these comments. I love how people think scientists are against humanity.
    It is cute, and all, but the amount of comments seems to point to the fact that the majority of people actually don’t believe the planet is warming up. And this is a very dangerous realisation.
    When the education system fails to such a degree, then we cannot really have democracy. Because that would mean we are ruled by the uneducated (pretty much what is happening today). Sadly, if this continues, I predict that the USA will soon lose its “democracy” status. It was virtual to begin with, but it might just become official.
    P.S. good work with the article. Nice points.

    1. I honestly think that the US has already lost their democracy. It is so hilarious that people think that they are smarter than the scientists who went to college to study for this. These people did a very nice job on this and it helped me learn a lot more and get a good grade on a geography essay. Thank you.

  2. Does all of your science indicate big bang or planned existence? Man will not cause the earth to disintegrate. God will cause it when Jesus comes. Then you will have real catastrophic occurrences. Stand watch and be alert for the Day of the Lord.

  3. I’m sorry if this isn’t where I’m supposed to do this, but it seems like the links aren’t working for footnote 11:

    Oppenheimer, M, Alley, RB. The West Antarctic Ice Sheet and Long Term Climate Policy. Climatic Change. 64: 1–10, 2004.

    I also had trouble navigating through princeton’s website, so I think it’s on their end, but figured you would want to know.

  4. Hey, Dennis!

    Thanks for the comment. I first want to respond to your comment, “it seems to that sea level change should be negligible or falling.” This is actually not the case. Sea levels have been rising. This is according to satellite data you can view on NASA’s website.

    While you do mention sea level change as being dependent on the amount of ice in the Antarctic and Greenland, there is another factor: as water gets warmer, it expands. This is important because it brings us to the broader point: globally averaged air temperatures have been rising. Rising sea levels are very likely a direct consequence of these increasing temperatures, and rising temperatures are very likely a consequence of the CO2 humans have been emitting post-Industrial Revolution. I appreciate that discussing the past 5 years of sea ice extent is interesting. However, it’s important not to ignore the long-term trends we’ve been seeing in air temperature, sea level change, and CO2 concentrations just because 5 years of Arctic sea ice extent observations don’t contain a record low. That being said, I’d still like to respond to the individual points you make in your comment.

    In regards to Arctic Sea Ice Extent in recent years, you’re referring specifically to the change over the years in late-summer Arctic sea ice extent. The story is different for winter Arctic sea ice extent. According to National Snow & Ice Data Center, the Arctic winter sea ice extent actually hit a record low just last year.

    For late-summer sea ice extent, I agree that we didn’t hit a record low last year. However, there’s some additional information necessary to give your statements more context. 2012 was the lowest year record, and 2016 was the second lowest (being somewhat tied with 2007). In fact, the 10 lowest summer Arctic sea ice extents observed have occurred 2007 onward.

    Regardless, you do point out looking at just a couple years isn’t the best strategy, and I completely agree. I think what would be most useful is to zoom out and look at the historical trend of Arctic sea ice extent over the past 1000 years or so. Since around 550 AD, the late-summer Arctic sea ice extent has been estimated to be between 9-10 million square km until the last 20 years:

    Today, the area is more like 5 million square kilometers. While we haven’t observed a record low in the past 5 years, we’ve observed around 5 million square km of sea ice extent every one of those years, which is historically unprecedented.

    In regards to the Greenland ice sheet, I appreciate that the mass of ice sheet does increase in short periods. However, I think you make a very good point when you say that ‘this is just one year.’ If you look at the mass of Greenland’s ice sheet since 2002, the trend looks like a pretty clear decline over time. I agree, though, there is some variability on smaller time scales.

    1. Is it possible to explain how is it plausible for a GHG as diluted and scarce (0.04% of the total atmosphere) as CO2 is, with a man-made contribution to this tiny percentage an even tinier single digit percentage (or at best in the low teens), to be the main driver for whatever climate change occurs (when most of CO2 comes from the oceans, biomass and volcanoes)? That’s the first question.

      The second question is what are we to do with your answer? What does that “solve”? What do the 5 trillion $ of “climate change” subsidies actually solve? Are we seeing a decline in “global warming”, sorry, I meant to say “climate change”? Are we to reduce our per capita daily energy needs in the developed world (about 100Kwh/daily per person) to stone age levels? Will that solve the problem?

      Most of them are rhetoric questions but feel free to answer.

      1. That’s a long first question. Yes, most of the CO2 in the atmosphere is natural. You mention the natural ways CO2 is emitted. This is misleading because you don’t state the natural ways by which CO2 is pulled back out of the air. The natural emissions and sinks balance out. The human emissions do not. Consequently, CO2 levels have increased from around 0.03% (pre-industrial) to around 0.04% now (and expected to continue rising). That increase is due to fossil fuel emissions and, to a lesser extent, deforestation. I agree it’s a very small component of the total atmospheric mix. But considering only 0.03% of the air was CO2 before, 0.01% is a significant relative increase.
        Also, we’re talking about an increase of around 0.8 Kelvin over the past 50 years. One the Kelvin scale, which is the appropriate temperature scale for looking as percent change, we’ve only seen an average temperature increase of less than 1%. In that sense, the small amount of CO2 is only causing a small increase in temperature. Unfortunately due to global circulation patterns among other complex factors, the temperature changes are not uniform. The climate system is therefore changing in more ways than mere global warming. You can ask Alaska Senator Lisa Murkowski, a Republican, how she and her constituents feel about climate change, considering the frozen ground much of their infrastructure rests on is thawing. Hint: they’re concerned,

        Your second question (or series of questions rather), really more delves into policy. I don’t want any reader to conflate my political opinions with scientific fact, so I’m going to abstain from addressing Question 2.

  5. It snowed in Florida today. New Year’s Eve in NYC almost set an all-time record LOW temperature record. They are now forecasting one of the coldest and most snow-bound winters in the UK.

    “More than 3,800 flights were canceled and all public schools in New York City, Boston and Philadelphia were closed Thursday as about 50 million people braced for a nasty nor’easter that could dump a foot of snow or more — the largest so far this season.”

    Oh, I forgot: Colder and more severe winters are also proof of the AGW theory…. Temps keep rising and the Earth gets hotter, because of rising levels of CO2. Temps keep going lower and the Earth gets colder, because of rising CO2. So goes the liturgical chanting of the devout AGW acolytes. No contradictions there, right?

    They still won’t discuss the very active Gakkel volcanic ridge below the North Pole (1,100 miles long, that adds heat and chemically charged fluid flows — loaded with CO2 and methane gas) to the sea water below the North Pole sea ice. That has to be of great significance when it comes to cause-effect analysis of the accelerated melting rate of Arctic sea ice.

    Yet, in spite of that Natural factor, the net ice sheet total for both poles is now larger, not smaller. Greenland must have heard about that and decided to join the growing ice crowd. Wasn’t Greenland supposed to be totally melted by now?

    What will be their next argument to support AGW theory? That when Canada is totally covered with glacial ice, that too will be evidence to support the AGW cult?

  6. While we can argue nuances all we want, there are 3 key factors that cannot be ignored when discussing the future of our ice sheets. The first is that we have not set a new record minimum sea ice extent in the arctic in 5 years. Being a numbers guy, I understand that in a trend there can be variations from year to year. I can entertain this argument when one, two, maybe even 3 years go by without setting a new record. But 5 years without a new low (or even close), and with the ice sheet currently 400,000 KM2 larger than it was 10 years ago in 2007, there is no longer evidence of a pervasive, and certainly not an accelerating trend. Someone without such an emotional investment in the existence of man made climate change would call these numbers either a significant pause or even a trend reversal.
    Second, the Greenland ice sheet volume grew this year. This was supposed to be the ice sheet that was melting so fast that everyone was speculating what would happen when Greenland is ice-free. Yes this was one year, but this was not supposed to happen. How fast can thousands of feet of ice melt into the sea when there is no guarantee that it will even melt at all year on year? The answer is probably thousands of years, if ever.
    Third, the topic of your article, which is that the Antarctic ice sheet is growing by billions of tons every year. So when you factor in stable sea ice extent, a Greenland ice sheet that has grown, and billions of net tons added to the Antarctic, it seems to me that sea level change should be negligible or falling. There simply aren’t enough alpine glaciers in Italy to make up that difference.
    Given that academics have invested their entire reputations and emotional well being in man-made global warming being true, I expect many more trivial discussions over the next 10 years about whether snow pack is interfering with Lidar measurements etc as a way to avoid uncomfortable truth facing. However, the raw aggregate numbers are not adding up for your theory over the last 10 years and it will begin to affect the long run averages. It seems you may be worshiping a false god, and it will take time to come to grips with that.

  7. Hey, David!
    Author here. I don’t really discuss most of the effects of climate change in this article, so I take it your comment is somewhat independent of the content I cover. (Unless you’re asserting that global temperatures have not risen due to increases in atmospheric carbon dioxide) That being said, I do mention that climate change has induced measurable loss in Arctic sea ice. Polar Science Center discusses this and shows graphically that Arctic ice volume is showing a pretty clear decline over recent years:

    Here, I’m not discussing the future. I’m merely describing measured data. Now, I’m not calling it ‘doom,’ but I am saying it’s already come true. In regards to the sources you provide, they appear to largely quote claims made by a single scientist or a news media outlet. This quite a different situation than what we’re dealing with regarding man-made climate change: there’s a scientific consensus man-made climate change is happening.

    Let’s just put some numbers on this. NASA, which has around 18,000 employees, accepts anthropogenic climate change as true and is an active research center on the topic. American Geophysical Union, which has around 60,000 members, also accepts this. So does American Chemical Society, which has almost 157,000 members. These are only a handful of mainstream American scientific communities who support this theory. I do think it’s useful to talk about how we know climate change is happening. But I just wanted to first clarify that this theory is accepted by tens of thousands of experts – not just one or two scientists being quoted by news media outlets.

    Next, I’d like to focus on the 1922 article published by Associated Press that is quoted at the start of one of your sources. First, note that this is a press release for a research finding – not the research finding itself. As discussed in the original research article, the scientists were only evaluating a specific Arctic island in Norway, Spitzbergen. It turned out this was a warming event specific to that island, not the Arctic region at large. This makes sense because climate change wasn’t particularly an issue in 1922. Looking at the temperature anomaly graph by NOAA, you can see it’s not really until after 1950 that you start seeing noticeable changes in globally averaged temperature:

    Also, if you read the Associated Press passage, you’ll notice there’s no discussion of carbon dioxide being emitted by humans at all, so it’s not even commenting on man-made climate change. This is merely a news article that got a little carried away by one research finding on a warming Arctic island. For sure, the article was ultimately mistaken about its broader conclusions. However, incorporating this article into the discussion of man-made climate change is pretty misleading.

  8. Never have so many claimed so much was going to happen without A SINGLE CLAIM of doom coming true. For almost three decades we’ve been told the end of the world is nigh. I’m old enough to remember when we were told that the world would be completely destroyed BEFORE the 21st century due to over population… and the beat goes on…. and the beat goes on.
    Here is a novel idea…. re-examine the computer models AGAIN

  9. Hello, Mitch!
    Thanks for your comment. When I said ‘largely dictates,’ I didn’t mean to suggest our atmosphere is the largest contributor to temperature. Let me clarify what I’m saying. Without our atmosphere, the Earth would be around 0 degrees Fahrenheit (deg F). Now, without our Sun, the Earth would be closer to -450 deg F, so you’re right that the Sun does most of the work. But what gets us from 0 deg F to the temperatures we experience now? It’s actually the greenhouse gases in our atmosphere. This is similar to when we wrap ourselves in a blanket. Our bodies constantly give off heat. A blanket will absorb some of that heat and send it right back to us (thicker blankets make us warmer). The Earth constantly gives off heat, too. Like a blanket, the greenhouse gases in our atmosphere absorb some of that heat and send it back to Earth. Those gases bring the Earth from 0 deg F to the temperatures that allow us to survive. In that sense, calling greenhouse gases a large dictator of Earth’s temperature feels appropriate – though I agree they are not the largest.

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