Here’s an Aerial View of a Massive Iceberg Shearing away from Antarctica

Located along the east coast of the Antarctic Peninsula is the Larsen Ice Shelf. Named after the Norwegian Captain who explored the ice front back in 1893, this ice shelf has been monitored for decades due to its close connection with rising global temperatures. Essentially, since the 1990s, the shelf has been breaking apart, causing collapses of considerable intensity.

According to the British Antarctic Survey (BAS), the section of the ice sheet known as the Larsen C Ice Shelf could be experiencing a collapse of its own soon enough. Based on video footage and satellite evidence of the sizeable rift (which is 457 m or 15oo ft across) in the shelf, it is believed that an ice berg that is roughly 5,000 km² (1930.5 mi²) in size could be breaking off and calving into the ocean in the near future.

An ice shelf is essentially a floating extension of a land-based glacier. In this case, the Larsen Ice Shelf is seaborne section of the larger Larsen Glacier, which flows southeast past Mount Larsen and enters the Ross Sea just south of Victoria Land. These shelves often act as buttresses, holding back glaciers that flow down to the coast, thus preventing them from entering the ocean and contributing to rising sea levels.

In the past twenty-two years, the Larsen A and B ice shelves (which were situated further north along the Antarctic Peninsula) both collapsed into the sea. This resulted in the dramatic acceleration of glaciers behind them, as larger volumes of ice were able to flow down the coast and drop into the ocean. While Larsen C appeared to still be stable, in November of 2016, NASA noted the presence of a large crack in its surface.

This crack was about 110 kilometers (68 mi) long and was more than 91 m (299 ft) wide, reaching a depth of about 500 m (1,600 ft). By December, the rift had extended another 21 km (13 mi), which raised concerns about calving. In February of 2017, satellite observations of the shelf noted that the crack appeared to have grown further, which confirmed what researches from the MIDAS project had previously reported.

This UK-based Antarctic research project – which is based at Swansea University and Aberystwyth University in Wales and supported by the BAS and various international partners – is dedicated to monitoring the Larsen C ice shelf in Antarctica. Through a combination of field work, satellite observations, and computer simulations, they have catalogued how recent warming trends has caused seasonal melts of the ice shelf and affected its structure.

And in recent years, they have been monitoring the large crack, which has been fast-moving, and noted the appearance of several elongations. It was during the current Antarctic field season that members of the project filmed what the crack looked like from the air. In previous surveys, the glaciology research team has conducted research on the ice shelf using seismic techniques to survey the seafloor beneath it.

However, this past season, they did not set up on the ice shelf itself for fear of a calving event. Instead, they made a series of trips to and from the UK’s Rothera Research Station aboard twin otter aircraft. During an outing to retrieve some of their science equipment, the crew noted how the crack looked from above and started filming. As you can see from the footage, the rift is very wide and extremely long.

What’s more, the team estimates that if an iceberg from this shelf breaks off and falls into the ocean, it will likely be over three times the size of cities like London or New York City. And while this sort of thing is common with glaciers, the collapse of a large section of Larsen C could speed the flow of the Larsen Glacier towards the Antarctic Ocean.

As Dr Paul Holland, an ice and ocean modeller at the British Antarctic Survey, said in a recent press release:

“Iceberg calving is a normal part of the glacier life cycle, and there is every chance that Larsen C will remain stable and this ice will regrow.  However, it is also possible that this iceberg calving will leave Larsen C in an unstable configuration.  If that happens, further iceberg calving could cause a retreat of Larsen C. We won’t be able to tell whether Larsen C is unstable until the iceberg has calved and we are able to understand the behavior of the remaining ice. The stability of ice shelves is important because they resist the flow of the grounded ice inland.  After the collapse of Larsen B, its tributary glaciers accelerated, contributing to sea-level rise.”

One of the greatest concerns about climate change is the feedback mechanisms it creates. In addition to increased warming trends caused by rising levels of CO² in the atmosphere, the melting of glaciers and the breakup of ice shelves can have a pronounced effect on sea levels. In the end, the depletion of glaciers in Antarctica could have dramatic consequences for the rest of the planet.

Further Reading: British Antarctic Survey

NASA: 2016 Was the Warmest Year on Record… Again!

The reality of Climate Change has become painfully apparent in recent years, thanks to extended droughts in places like California, diminishing water tables around the world, rising tides, and coastal storms of increasing intensity and frequency. But perhaps the most measurable trend is the way that average global temperatures have kept rising year after year.

And this has certainly been the case for the year of 2016. According to independent analyses provided by NASA’s Goddard Institute for Space Studies (GISS) and the National Oceanic and Atmospheric Agency (NOAA), 2016 was the warmest year since modern record keeping began in 1880. This represents a continuation of a most alarming trend, where 16 of the 17 warmest years on record have occurred since 2001.

Based in New York, GISS conducts space and Earth sciences research, in support of the Goddard Space Flight Center’s (GSFC) Sciences and Exploration Directorate. Since its establishment in 1961, the Institute has conducted valuable research on Earth’s structure and atmosphere, the Earth-Sun relationship, and the structure and atmospheres of other planets in the Solar System.

Monthly temperature anomalies with base 1980-2015, superimposed on a 1980-2015 mean seasonal cycle. Credit: NASA/GISS/Schmidt

Their early studies of Earth and other solar planets using data collected by satellites, space probes, and landers eventually led to GISS becoming a leading authority on atmospheric modeling. Similarly, the NOAA efforts to monitor atmospheric conditions and weather in the US since 1970s has led to them becoming a major scientific authority on Climate Change.

Together, the two organizations looked over global temperature data for the year of 2016 and came to the same conclusion. Based on their assessments, GISS determined that globally-averaged surface temperatures in 2016 were 0.99 °C (1.78 °F) warmer than the mid-20th century mean. As GISS Director Gavin Schmidt put it, these findings should silence any doubts about the ongoing nature of Global Warming:

“2016 is remarkably the third record year in a row in this series. We don’t expect record years every year, but the ongoing long-term warming trend is clear.”

The NOAA’s findings were similar, with an average temperature of 14.83 °C (58.69 °F) being reported for 2016. This surpassed last year’s record by about 0.004 °C (0.07 °F), and represents a change of around 0.94 °C (1.69 F) above the 20th century average. The year began with a boost, thanks to El Nino; and for the eight consecutive months that followed (January to August) the world experienced record temperatures.

This represents a consistent change since 2001, where average global temperatures have increased, leading to of the 16 warmest years on record since 1880 in a row. In addition, on five separate occasions during this period, the annual global temperature was record-breaking – in 2005, 2010, 2014, 2015, and 2016, respectively.

Land and ocean global temperatures in 2013 from both NASA and NOAA. Credit: NASA.

With regards to the long-term trend, average global temperatures have increased by about 1.1° Celsius (2° Fahrenheit) since 1880. This too represents a change, since the rate of increase was placed at 0.8° Celsius (1.4° Fahrenheit) back in 2014. Two-thirds of this warming has occurred since 1975, which coincides with a period of rapid population growth, industrialization, and increased consumption of fossil fuels.

And while there is always a degree of uncertainty when it comes to atmospheric and temperature modelling, owing to the fact that the location of measuring stations and practices change over time, NASA indicated that they were over 95% certain of these results. As such, there is little reason to doubt them, especially since they are consistent with what is at this point a very well-documented trend.

To see an animated graph of average global temperature increases since 1880, click here. To see the full data set and learn about the methods employed by GISS, click here.

And be sure to check out this NASA video that shows these changes on a global map:

Further Reading: NASA, NOAA

‘Global Warming Hiatus’ Not Good News For Planet Earth

A reprieve from Global Warming? A hiatus? That would be nice, wouldn’t it? But in this case, a hiatus is not quite what it seems.

Everybody knows that global warming is partly caused by human activities, largely our use of fossil fuels. We understand how it works and we fear for the future. But there’s been a slowdown in the global mean surface temperature increase between 1998 to 2013. We haven’t lowered our emissions of greenhouse gases (GHGs) significantly during that time, so what happened?

Fossil fuels: we just can't get enough of them. Image: a petrochemical refinery in Scotland. Credit: User:John from wikipedia, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=2459867
Fossil fuels: we just can’t get enough of them. Image: a petrochemical refinery in Scotland. Credit: User:John from wikipedia, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=2459867

A new multi-institutional study involving NASA’s Jet Propulsion Laboratory (JPL), the National Oceanographic and Atmospheric Institute, and others, concludes that Earth’s oceans have absorbed the heat. So instead of the global mean surface temperature rising at a steady rate, the oceans have taken on the job as global heat sink. But what’s the significance of this?

“The hiatus period gives scientists an opportunity to understand uncertainties in how climate systems are measured, as well as to fill in the gap in what scientists know.” -Xiao-Hai Yan, University of Delaware, Newark

In terms of the on-going rise in the temperature of the globe, the hiatus is not that significant. But in terms of the science of global warming, and how well we understand it, the hiatus gives scientists an opportunity.

The new paper, titled “The Global Warming Hiatus: Slowdown or Redistribution?” grew out of the U.S. Climate Variability and Predictability Program (CLIVAR) panel session at the 2015 American Geophysical Union fall meeting. From those discussions, scientists reached consensus on three key points:

  • From 1998 to 2013, the rate of global mean surface warming slowed, which some call the “global warming hiatus.”
  • Natural variability plays a large role in the rate of global mean surface warming on decadal time scales.
  • Improved understanding of how the ocean distributes and redistributes heat will help the scientific community better monitor Earth’s energy budget. Earth’s energy budget is a complex calculation of how much energy enters our climate system from the sun and what happens to it: how much is stored by the land, ocean or atmosphere.
This graph shows the yearly global ocean heat content. The dashed line shows the 1958-65 average. Image: Balmaseda et al., 2013
This graph shows the yearly global ocean heat content. The dashed line shows the 1958-65 average. Image: Balmaseda et al., 2013

The paper is a reminder that climate science is complex, and that the oceans play a big part in global warming. As Yan says, “To better monitor Earth’s energy budget and its consequences, the ocean is most important to consider because the amount of heat it can store is extremely large when compared to the land or atmospheric capacity.”

“…”arguably, ocean heat content — from the surface to the seafloor — might be a more appropriate measure of how much our planet is warming.” – from the paper “The Global Warming Hiatus: Slowdown or Redistribution?”

The team behind this new research suggests that saying there’s been a hiatus in global warming is confusing. They suggest “global warming hiatus” be replaced with “global surface warming slowdown.”

There’s a danger in calling it a “global warming hiatus.” Those opposed to climate change and who think it’s a hoax can use that term to discredit climate science. They’ll claim that the “hiatus” shows we don’t understand climate change and the Earth may have stopped warming. But in any case, it’s the long-term trend—change over the course of a century or more—that defines “global warming,” not the change from year to year or even decade to decade.

There’s much more to learn about the oceans’ role in global warming. Research shows that some ocean areas absorb heat much faster than others. But whatever the fine detail of it is, there is broad agreement in the scientific community that the global surface warming slowdown was caused by an increased uptake of heat energy by the world’s oceans.

A screenshot from the "NASA's Eyes" app. The app allows anyone to check Earth's vital signs. Image: NASA/JPL
A screenshot from the “NASA’s Eyes” app. The app allows anyone to check Earth’s vital signs. Image: NASA/JPL

NASA uses a lot of tools to monitor the Earth’s temperature. For an interesting look at the Earth’s vital signs, check out Nasa’s Eyes. This easy to use visualization tool lets you take a closer look at the Earth’s temperature, CO2 levels, soil moisture levels, sea levels, and other things.

What if Earth Stopped Orbiting the Sun?

In a previous article I investigated what would happen if the Earth stopped turning entirely, either locking to the Sun or the background stars.

If it happened quickly, then results would be catastrophic, turning the whole planet into a blended slurry of mountains, oceans and trees, hurting past a hundreds of kilometers per hour. And if it happened slowly, it would still be unpleasant, as we stopped having a proper day/night cycle. But it wouldn’t be immediately lethal.

But would happen if the Earth somehow just stopped in its tracks as it was orbiting the Sun, as if it ran into an invisible wall? As with the Earth turning question, it’s completely and totally impossible; it’s not going to happen. And with the unspun Earth, it would be totally devastating and super interesting to imagine.

A view of Earth on October 24, 2014 from the Chinese Chang’e-5 T1 spacecraft. Credit: Xinhua News, via UnmannedSpaceflight.com.
Credit: Xinhua News, via UnmannedSpaceflight.com.

Before we begin to imagine the horrifying consequences of a total loss of orbital velocity, let’s examine the physics involved.

The Earth is traveling around the Sun with an orbital velocity of 30 kilometers per second. This is exactly the speed it needs to be going to counteract the force of gravity from the Sun pulling it inward. If the Sun were to suddenly disappear, Earth would travel in a perfectly straight line at 30 km/s. This is how orbits work.

If the Earth’s orbital velocity sped up, then it would go into a higher orbit to compensate. And if the Earth’s orbital velocity slowed down, then it fall into a lower orbit to compensate. And if the Earth’s orbital velocity was slowed all the way down to zero? Now we’re cooking, literally.

First, let’s imagine what would happen if the Earth just suddenly stopped.

As I mentioned above, the Earth’s orbital velocity is 30 km/s, which means that if it suddenly stopped, everything on it would still have 30 km/s worth of inertia. The escape velocity of the Earth is about 11 km/s.

In other words, anything on the Earth’s leading side would fly off into space, continuing along the Earth’s orbital path around the Sun. Anything on the trailing side would be pulverized against the Earth. It would be a horrible, gooey mess.

But even if the Earth slowed gently to a stop, it would still be a horrible mess. Without the outward centripetal force to counteract the inward pull of gravity, the Earth would begin falling towards the Sun.

How long would it take? My integral calculus is a little rusty, so I’ll draw upon the calculations of Dave Rothstein from Cornell’s Ask an Astronomer. According to Dr. Rothstein, the whole journey would take about 65 days. It would take 41 days to cross the orbit of Venus, and on day 57, we’d cross the orbit of Mercury.

As they days went by, the Earth would get hotter and hotter as it got closer to the Sun. Aatish Bhatia over at WIRED did some further calculations to figure out the temperature. A month into the freefall, and the average temperature on Earth would have risen to 50 degrees C. 50 days in and we’d be about 125 C. On the final day, we’d get up to 3,000 C… and then, that would be that.

Of course, this is completely and totally impossible. There’s no force that could just stop the Earth in its tracks like that. There is, however, a plausible scenario that might drag the Earth into the Sun.

In the far future, the Sun will turn into a red giant and expand outward, engulfing the orbits of Mercury and Venus. There’s still an argument among astronomers on whether it’s going to gobble up Earth as well.

Illustration of the red supergiant Betelgeuse, as seen from a fictional orbiting world. © Digital Drew.
Poor Earth. © Digital Drew.

Let’s say it does. In that case, the Earth will be inside the atmosphere of the Sun, and experience a friction from the solar material as it orbits around, and spiral inward. Of course, at this point you’re orbiting inside the Sun, so falling into the Sun already happened.

There you go. If the Earth happened to stop dead in its orbit, it would take about 65 days to plunge down into the Sun, disappearing in a puff of plasma.

What Causes Air Pollution?

By definition, pollution refers to any matter that is “out of place”. In other words, it is what happens when toxins, contaminants, and other harmful products are introduced into an environment, disrupting its normal patterns and functions. When it comes to our atmosphere, pollution refers to the introduction of chemicals, particulates, and biological matter that can be harmful to humans, plants and animals, and cause damage to the natural environment.

Whereas some causes of pollution are entirely natural – being the result of sudden changes in temperature, seasonal changes, or regular cycles – others are the result of human impact (i.e. anthropogenic, or man-made). More and more, the effects of air pollution on our planet, especially those that result from human activity, are of great concern to developers, planners and environmental organizations, given the long-term effect they can have.

Continue reading “What Causes Air Pollution?”

Global Warming Watch: How Carbon Dioxide Bleeds Across The Earth

Red alert — the amount of carbon dioxide in the atmosphere is increasing year-by-year due to human activity. It’s leading to a warming Earth, but just how quickly — and how badly it will change the environment around us — is hard to say.

NASA released a new video showing how carbon dioxide — a product mainly of fossil fuels — shifts during a typical year. Billed as the most accurate model to date, the emissions shown in 2006 (tracked by ground-based sources) show how wind currents across the globe spread the gas across the globe. The red you see up there indicates high concentrations. The full video is below the jump.

In spring and summer, plants absorb carbon dioxide and the amount in the atmosphere above that hemisphere decreases. In fall and winter, carbon dioxide is not absorbed as well since the plants are dead or dormant. Also seen in the video is carbon monoxide that spreads out from forest fires, particularly in the southern hemisphere.

“Despite carbon dioxide’s significance, much remains unknown about the pathways it takes from emission source to the atmosphere or carbon reservoirs such as oceans and forests,” NASA stated.

“Combined with satellite observations such as those from NASA’s recently launched OCO-2 [Orbiting Carbon Observatory-2], computer models will help scientists better understand the processes that drive carbon dioxide concentrations.”

The model is called GEOS-5 and was made by scientists at the NASA Goddard Space Flight Center’s global modeling and assimilation office.

Source: NASA

Extreme Weather is Linked to Global Warming, a New Study Suggests

Extreme weather is becoming much more common. Heat waves and heavy rains are escalating, food crops are being damaged, human beings are being displaced due to flooding and animals are migrating toward the poles or going extinct.

Although it has been postulated that these extreme weather events may be due to climate change, a new study has found much better evidence.

The research shows blocking patterns — high-pressure systems that become immobile for days or even weeks, causing extreme heat waves and torrential rain — may have doubled in summers over the last decade.

“Since 2000, we have seen a cluster of these events,” lead author Dim Doumou told The Gaurdian earlier this month. “When these high-altitude waves become quasi-stationary, then we see more extreme weather at the surface. It is especially noticeable for heat extremes.”

It was a blocking pattern that led to the heat wave in Alaska in 2013, and to the devastating floods in Colorado last summer.

These blocking patterns are associated with the jet stream, the fast flowing winds high in Earth’s atmosphere at latitudes between 30 and 60 degrees. Sometimes the flow weakens, and the winds can dip down into more southern latitudes. These excursions lead to blocking patterns.

And the jet stream is becoming “wavier,” with steeper troughs and higher ridges.

The climatologists analyzed 35 years of wind data amassed from satellites, ships, weather stations, and meteorological balloons. They found that a warming Arctic creates and amplifies the conditions that lead to jet stream excursions, therefore raising the chances for long-duration extreme events, like droughts, floods, and heat waves.

That said the climatologists were unable to see a direct causal link between climate change and extreme weather. Ordinarily we think about “cause” in a simple sense in which one thing fully brings about another. But the Colorado floods, for example, were partially caused by moisture from the tropics, a blocking pattern, and past wildfires that increased the risk of runoff.

So there is a difference between “direct causation” and “systematic causation.” The latter is not direct, but it is no less real. In this study, the team noticed that the rise in blocking patterns correlates closely with the extra heating being delivered to the Arctic by climate change. Statistically speaking, the two seem to go hand in hand.

But the team does hypothesize a direct causal link. The jet streams are driven by the difference in temperature between the poles and the equator. So because the Arctic is warming more quickly than lower latitudes, the temperature difference is declining, providing less energy for the jet stream and causing it to meander.

Although the study shows a correlation — not causation — between more frequent blocking patterns (and therefore extreme weather) and Arctic warming, it is a solid step forward in understanding how the two are related.

The article has been published in the journal Proceedings of the National Academies of Science (PNAS).

To see why Universe Today writes about climate change, please read a past article on the subject.

What Created This Huge Crater In Siberia?

What is it with Russia and explosive events of cosmic origins? The 1908 Tunguska Explosion, the Chelyabinsk bolide of February 2013, and now this: an enormous 80-meter 60-meter wide crater discovered in the Yamal peninsula in northern Siberia!

To be fair, this crater is not currently thought to be from a meteorite impact but rather an eruption from below, possibly the result of a rapid release of gas trapped in what was once frozen permafrost. The Yamal region is rich in oil and natural gas, and the crater is located 30 km away from its largest gas field. Still, a team of researchers are en route to investigate the mysterious hole further.

Watch a video captured by engineer Konstantin Nikolaev during a helicopter flyover below:

In the video the Yamal crater/hole has what appear to be streams of dry material falling into it. Its depth has not yet been determined. (Update: latest measurements estimate the depth of the hole to be 50-70 meters. Source.)

Bill Chappell writes on NPR’s “The Two-Way”:

“The list of possible natural explanations for the giant hole includes a meteorite strike and a gas explosion, or possibly an eruption of underground ice.”

Dark material around the inner edge of the hole seems to suggest high temperatures during its formation. But rather than the remains of a violent impact by a space rock — or the crash-landing of a UFO, as some have already speculated — this crater may be a particularly explosive result of global warming.

According to The Siberian Times:

“Anna Kurchatova from Sub-Arctic Scientific Research Centre thinks the crater was formed by a water, salt and gas mixture igniting an underground explosion, the result of global warming. She postulates that gas accumulated in ice mixed with sand beneath the surface, and that this was mixed with salt – some 10,000 years ago this area was a sea.”

The crater is thought to have formed sometime in 2012.

Read more at The Siberian Times and NPR.

UPDATE July 17: A new video (in Russian) of the hole from the research team has come out, and apparently it’s been made clear that it’s not the result of a meteorite. Exactly what process did produce it is still unknown, but rising temperatures are still thought to be a factor. Watch below (via Sploid).

(If any Russian-speaking UT readers would like to translate what’s being said, feel free to share in the comments below.)

Also check out the latest photos from the research expedition at The Siberian Times here.

UPDATE Nov. 13: Once the water in these holes froze solid scientists were able to enter and explore the bottoms. According to an article published on The Guardian, “eighty percent of the crater appears to be made up of ice and there are no traces of a meteorite strike.”

Researchers descend into an ice-covered Yamal Crater in Siberia. Credit: Vladimir Pushkarev/Russian Centre of Arctic Exploration (via Siberian Times) 
Researchers descend into an ice-covered Yamal Crater in Siberia. Credit: Vladimir Pushkarev/Russian Centre of Arctic Exploration (via Siberian Times)

“As of now we don’t see anything dangerous in the sudden appearance of such holes, but we’ve got to study them properly to make absolutely sure we understand the nature of their appearance and don’t need to be afraid about them.”

– Vladimir Pushkarev, Director, Russian Center of Arctic Exploration

See more photos from inside the crater from the Russian Center of Arctic Exploration on The Siberian Times here.

Scientists Now Suspect More Sea Level Rise from Greenland’s Glaciers

Greenland’s glaciers may contribute more to future sea level rise than once thought, despite earlier reports that their steady seaward advance is a bit slower than expected. This is just more sobering news on the current state of Earth’s ice from the same researchers that recently announced the “unstoppable” retreat of West Antarctic glaciers.

Using data collected by several international radar-mapping satellites and NASA’s airborne Operation IceBridge surveys, scientists at NASA and the University of California, Irvine have discovered deep canyons below the ice sheet along Greenland’s western coast. These canyons cut far inland, and are likely to drive ocean-feeding glaciers into the sea faster and for longer periods of time as Earth’s climate continues to warm.

Some previous models of Greenland’s glaciers expected their retreat to slow once they receded to higher altitudes, making their overall contribution to sea level increase uncertain. But with this new map of the terrain far below the ice, modeled with radar soundings and high-resolution ice motion data, it doesn’t seem that the ice sheets’ recession will halt any time soon.

According to the team’s paper, the findings “imply that the outlet glaciers of Greenland, and the ice sheet as a whole, are probably more vulnerable to ocean thermal forcing and peripheral thinning than inferred previously from existing numerical ice-sheet models.”

Read more: Scientists Set Their Sights on Arctic Ice Loss

Watch a video of the new topography map below:

“The glaciers of Greenland are likely to retreat faster and farther inland than anticipated, and for much longer, according to this very different topography we have discovered. This has major implications, because the glacier melt will contribute much more to rising seas around the globe.

– Mathieu Morlighem, project scientist, University of California, Irving

Many of the newly-discovered canyons descend below sea level and extend over 65 miles (100 kilometers) inland, making them vulnerable — like the glaciers in West Antarctica — to undercutting by warmer ocean currents.

The team’s findings were published on May 18 in a report titled Deeply Incised Submarine Glacial Valleys Beneath the Greenland Ice Sheet in the journal Nature Geoscience.

Source: NASA/JPL press release & University of California,Irvine News

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What would happen if all the ice on land melted into the ocean? Find out what the world would look like here.

NASA West Antarctic Ice Sheet Findings: Glacier Loss Appears Unstoppable

It’s a key piece of the climate change puzzle. For years, researchers have been eyeing the stability of the Western Antarctic Ice Sheet as global temperatures rise. Melting of the ice sheet could have dire consequences for sea level rise.

And though not unexpected, news from today’s NASA press conference delivered by Tom Wagner, a cryosphere program scientist with the Earth Science Division of NASA’s Science Mission Directorate in Washington D.C., Sridhar Anandakrishnan, a professor of geosciences at Pennsylvania University, and Eric Rignot, JPL glaciologist and professor of Earth system science at the University of California Irvine was certainly troubling.

Credit: NASA
The key region targeted in the study (arrowed) Credit: NASA

The Western Antarctic Ice Sheet is a marine-based ice sheet below sea level that is bounded by the Ronne and Ross Ice Shelf and contains glaciers that drain into the Amundsen Sea. The study announced today incorporates 40 years of data citing multiple lines of observational evidence measuring movement and thickness of Antarctic ice sheets. A key factor to this loss is a thinning along the grounding line of the glaciers from underneath. The grounding line for an ice sheet is the crucial boundary where ice becomes detached from ground underneath and stretches out to become free floating. A slow degradation of the Western Antarctic Ice Sheet has been observed, one that can be attributed to increased stratospheric circulation along with the advection of ocean heat coupled with anthropogenic global warming.

Credit: Eric Rignot
A closeup of the region: red indicates regions where flow speeds have accelerated in the past 40 years. Credit: Eric Rignot

“This sector will be a major contributor to sea level rise in the decades and centuries to come,” Rignot said in today’s press release. “A conservative estimate is it would take several centuries for all of the ice to flow into the sea.”

Thickness contributes to the driving stress of a glacier. Accelerating flow speeds stretch these glaciers out, reducing their weight and lifting them off of the bedrock below in a continuous feedback process.

A key concern for years has been the possible collapse of western Antarctica’s glaciers, leading to a drastic acceleration in sea-level rise worldwide. Such a catastrophic glacial retreat would dump millions of tons of ice into the sea over a relatively short span of time. And while it’s true that ice calves off of the Western Antarctic ice sheet every summer, the annual overall rate is increasing.

The study is backed up by satellite, airborne and ground observations looking at thickness of ice layers over decades.

Researchers stated that the Amundsen Sea Embayment sector alone contains enough ice to increase global sea level by 1.2 metres.  A strengthening of wind circulation around the South Pole region since the 1980s has accelerated this process, along with the loss of ozone. This circulation also makes the process more complex than similar types of ice loss seen in Greenland in the Arctic.

The research paper, titled Widespread, rapid grounding line retreat of Pine Island, Thwaites, Smith and Kohler glaciers, West Antarctica from 1992 to 2011 has been accepted for publication in the American Geophysical Union’s journal Geophysical Research Letters. The American Association for the Advancement of Science will also be releasing a related study on the instability of the West Antarctic ice sheet today in the journal Science.

The most spectacular retreat referenced in the study was seen occurring at the Smith/Kohler glaciers, which migrated about 35 kilometres and became ungrounded over a 500 kilometre square region during the span of 1992 to 2011.

Another telling factor cited in the study was the large scale synchronous ungrounding of several glaciers, suggesting a common trigger mechanism — such as ocean heat flux — is at play.

On the ice shelf proper, the key points that anchor or pin the glaciers to the bedrock below are swiftly vanishing, further destabilizing the ice in the region.

Assets that were used in the study included interferometry data from the Earth Remote Sensing (ERS-1/2) satellites’ InSAR (Interferormetry Synthetic Aperture Radar) instruments, ground team observations and data collected from NASA’s Operation IceBridge overflights of the Antarctic. IceBridge uses a converted U.S. Navy P-3 Orion submarine hunting aircraft equipped with radar experiment packages used to take measurements of the thickness of the ice sheet.

Possible follow up studies targeting the region are upcoming, including five Earth science and observation missions scheduled to be launched this year, which include the Soil Moisture and Passive (SMAP) mission, The Orbiting Carbon Observatory (OCO-2) and the Global Precipitation Measurement (GPM) Core Observatory, launched this past February.

Along with these future NASA missions, there are also two missions — RapidScat and the Cloud-Aerosol Transport System or CATS — slated to study climate headed for the International Space Station this year.

This comes as recent United Nations and United States reports have also announced the reality of climate change and anthropogenic global warming.

“The collapse of this sector of West Antarctica appears to be unstoppable,” Rignot said. “The fact that the retreat is happening simultaneously over a large sector suggests it was triggered by a common cause, such as an increase in the amount of ocean heat beneath the floating sections of the glaciers.”

Of course, the solar cycle, volcanic activity, global dimming (via changes in reflectivity, known as albedo) and human activity all play a role in the riddle that is climate change. The bad news is, taking only natural factors into account, we should be in a cooling period right now.

And yes, reflective ice cover also plays a role in the albedo of the Earth, but researchers told Universe Today that no significant overall seasonal variations in the extent of surface layer of ice will change, as the key loss comes from the ungrounding of ice from below. Thus, this ice loss does not present a significant contribution to changes in overall global albedo, though of course, much of this additional moisture will eventually be available for circulation in the atmosphere. And the same was noted in the press conference for those pinning their hopes on the 2014 ice extent being greater than previous years, a season that was a mere blip on the overall trend. The change and retreat in the grounding line below seen in the study was irrespective of the ice extent above.

NASA’s Operation IceBridge will continue to monitor the ice flow when the next Antarctic deployment cycle resumes in October of this year.

And in the meantime, the true discussion is turning to the challenges of living with a warmer planet. Insurance companies, the Department of Defense and residents of low-lying coastal regions such as Miami’s South Beach already know that the reality of global warming and sea level rise is here. Perhaps the very fact that naysayers have at least backed up their positions a bit in recent years from “global warming isn’t happening” to “Its happening, but there are natural cycles” can at least give us a starting point for true intelligent science-based dialogue  to begin.

– Social media questions from today’s conference can be reviewed at the #AskNASA hastag.