//
you're reading...

Glaciers

We’re In Deep Heat: trouble boils over in West Antarctica

Article

Schmidtko S, Heywood K J, Thompson A F, Aoki S (2014) Multidecadal warming of Antarctic waters. Science 346, 1227-1231. DOI: 10.1126/science.1256117

Background

What would happen if all of Antarctic’s ice sheets were to suddenly melt? This is very unlikely, but if it did, we would experience some of the most dramatic changes in weather and an intrusion of seawater in almost every coastal community. Antarctica is the world’s largest reservoir of freshwater, storing nearly 70 percent and making up its own continent. If all the glaciers and ice sheets on Antarctica melted, global sea level would be 60 meters higher than it is today. Findings from a recent study reveal alerting trends that may make this unlikely scenario a brutal reality over the next century or two. Schmidtko and co-authors examine the spatial distribution of long-term and large-scale temperature trends over Antarctica’s continental shelf. They show that different water types around Antarctica have not been warming uniformly, but rather in distinct regional patterns.

Figure 1. Continent of Antarctica comprising of West and East domains and numerous seas. [Source: Wikipedia.en]

Figure 1. Continent of Antarctica comprising of West and East domains and numerous seas. [Source: Wikipedia.en]

Flowing clock-wise around Antarctica is a warm, salty deep-ocean current known as Circumpolar Deep Water (CDW). Water masses from the Atlantic, Pacific and Indian Oceans mix together to form CDW. Understanding how the temperature of this water is changing is critical, and if it warms, can undermine glaciers with melt water and reduce ice thickness. CDW has shown significant warming around Antarctica, which has raised temperatures beneath ice shelves at shallower depths through changes in easterly wind strength over the Antarctic shelf break.

Findings

Researchers examined data from oceanographic observations in and around Antarctica collected from the 1960s onward. Their research points to startling findings that West Antarctica shelf waters in the Bellingshausen Sea and Amundsen Sea have warmed considerably more over the past 5 decades than previously thought. Meanwhile, the Ross Sea and Weddell Sea are cooling slightly. However, the trends in shelf-water temperatures are highly sensitive to the time period of data being analyzed. This is one challenge the authors attribute to conflicting findings of warming patterns in past studies. Observations from the 1990s onward are more reliable than older measurements dating back to the 1970s due to poor sampling frequency.

The authors categorize CDW temperature properties into two flow regimes: (1) sloping upward or (2) sloping downwards. These two regimes are primarily caused by differences in wind patterns blowing east to west around the South Pole. The changes in the strength of these winds modify seawater temperatures across the continental shelf under the sea ice.

Figure 2.  Schematic of an upward sloping CDW flow regime showing weak easterly winds, warmer shelf water temperatures and increased melt from ice shelves.

Figure 2. Schematic of an upward sloping CDW flow regime showing weak easterly winds, warmer shelf water temperatures and increased melt from ice shelves.

Figure 3. Schematic of a downward sloping CDW flow regime with strong easterly winds and cold shelf water.

Figure 3. Schematic of a downward sloping CDW flow regime with strong easterly winds and cold shelf water.

Shelf water temperatures are rising in regions where CDW slopes upward toward the shelf break. These changes in CDW are most pronounced in the warming Bellingshausen and Amundsen seas. In regions where CDW slopes downward towards the shelf break, offshore trends in CDW show no correlation with bottom water masses on continental shelves, and therefore have no correlation with warming.

Significance

Ice shelf melting and ice sheet collapse depends on delivery of warm water by ocean currents. Therefore, it is important to have accurate estimates of oceanic heat transport. Surfacing CDW has the potential to increase heat transport and must be represented in climate models for future ice shelf predictions.

Observed trends in water mass properties may influence Southern Ocean ecosystems through the redistribution of salps and krill due to their complex life cycles and spawning preferences. Salps and krill play a critical role in Antarctic ecosystems and a change in abundance could impact their predators.

The melting occurring under the West Antarctic ice shelves is considered irreversible, and there are no indications that this warming trend will stop anytime soon. The good news is that scientists have not yet seen other Antarctic regions beginning to melt as intensely as in the west, but they agree that a change may be looming with significant consequences for sea level rise.

Discussion

3 Responses to “We’re In Deep Heat: trouble boils over in West Antarctica”

  1. The weather there is terrible then. We are hoping people will be all okay.

    Posted by Glaiza | July 20, 2016, 9:54 am
  2. Oceanbites should put a link to each article you discuss that will take you directly to the article in its journal. That would make getting it a lot easier.

    Posted by Ross Robertson | January 19, 2015, 9:56 am
    • Hi Ross – The article is hyperlinked at the above citation “DOI: xx”. Forgive me if the link was added as an edit in response to your comment, as I only came across your comment today. The above link will bring you to the abstract. If you are not affiliated with a university or institution with a subscription to the journal, or if you yourself do not have an online subscription, you may not be able to access the full article.

      Posted by Brian Caccioppoli | January 30, 2015, 11:35 am

Leave a Comment on Ross Robertson Click here to cancel reply

Instagram

  • by oceanbites 2 weeks ago
    Happy Earth Day! Take some time today to do something for the planet and appreciate the ocean, which covers 71% of the Earth’s surface.  #EarthDay   #OceanAppreciation   #Oceanbites   #CoastalVibes   #CoastalRI 
  • by oceanbites 2 months ago
    Not all outdoor science is fieldwork. Some of the best days in the lab can be setting up experiments, especially when you get to do it outdoors. It’s an exciting mix of problem solving, precision, preparation, and teamwork. Here is
  • by oceanbites 2 months ago
    Being on a research cruise is a unique experience with the open water, 12-hour working shifts, and close quarters, but there are some familiar practices too. Here Diana is filtering seawater to gather chlorophyll for analysis, the same process on
  • by oceanbites 3 months ago
    This week for  #WriterWednesday  on  #oceanbites  we are featuring Hannah Collins  @hannahh_irene  Hannah works with marine suspension feeding bivalves and microplastics, investigating whether ingesting microplastics causes changes to the gut microbial community or gut tissues. She hopes to keep working
  • by oceanbites 4 months ago
    Leveling up - did you know that crabs have a larval phase? These are both porcelain crabs, but the one on the right is the earlier stage. It’s massive spine makes it both difficult to eat and quite conspicuous in
  • by oceanbites 4 months ago
    This week for  #WriterWednesday  on  #Oceanbites  we are featuring Cierra Braga. Cierra works ultraviolet c (UVC) to discover how this light can be used to combat biofouling, or the growth of living things, on the hulls of ships. Here, you
  • by oceanbites 4 months ago
    This week for  #WriterWednesday  at  #Oceanbites  we are featuring Elena Gadoutsis  @haysailor  These photos feature her “favorite marine research so far: From surveying tropical coral reefs, photographing dolphins and whales, and growing my own algae to expose it to different
  • by oceanbites 5 months ago
    This week for  #WriterWednesday  on Oceanbites we are featuring Eliza Oldach. According to Ellie, “I study coastal communities, and try to understand the policies and decisions and interactions and adaptations that communities use to navigate an ever-changing world. Most of
  • by oceanbites 5 months ago
    This week for  #WriterWednesday  at  #Oceanbites  we are featuring Jiwoon Park with a little photographic help from Ryan Tabata at the University of Hawaii. When asked about her research, Jiwoon wrote “Just like we need vitamins and minerals to stay
  • by oceanbites 5 months ago
    This week for  #WriterWednesday  on  #Oceanbites  we are featuring  @riley_henning  According to Riley, ”I am interested in studying small things that make a big impact in the ocean. Right now for my master's research at the University of San Diego,
  • by oceanbites 6 months ago
    This week for  #WriterWednesday  at  #Oceanbites  we are featuring Gabby Stedman. Gabby is interested in interested in understanding how many species of small-bodied animals there are in the deep-sea and where they live so we can better protect them from
  • by oceanbites 6 months ago
    This week for  #WriterWednesday  at  #Oceanbites  we are featuring Shawn Wang! Shawn is “an oceanographer that studies ocean conditions of the past. I use everything from microfossils to complex computer models to understand how climate has changed in the past
  • by oceanbites 6 months ago
    Today we are highlighting some of our awesome new authors for  #WriterWednesday  Today we have Daniel Speer! He says, “I am driven to investigate the interface of biology, chemistry, and physics, asking questions about how organisms or biological systems respond
  • by oceanbites 7 months ago
    Here at Oceanbites we love long-term datasets. So much happens in the ocean that sometimes it can be hard to tell if a trend is a part of a natural cycle or actually an anomaly, but as we gather more
  • by oceanbites 7 months ago
    Have you ever seen a lobster molt? Because lobsters have exoskeletons, every time they grow they have to climb out of their old shell, leaving them soft and vulnerable for a few days until their new shell hardens. Young, small
  • by oceanbites 8 months ago
    A lot of zooplankton are translucent, making it much easier to hide from predators. This juvenile mantis shrimp was almost impossible to spot floating in the water, but under a dissecting scope it’s features really come into view. See the
  • by oceanbites 8 months ago
    This is a clump of Dead Man’s Fingers, scientific name Codium fragile. It’s native to the Pacific Ocean and is invasive where I found it on the east coast of the US. It’s a bit velvety, and the coolest thing
  • by oceanbites 9 months ago
    You’ve probably heard of jellyfish, but have you heard of salps? These gelatinous sea creatures band together to form long chains, but they can also fall apart and will wash up onshore like tiny gemstones that squish. Have you seen
  • by oceanbites 9 months ago
    Check out what’s happening on a cool summer research cruise! On the  #neslter  summer transect cruise, we deployed a tow sled called the In Situ Icthyoplankton Imaging System. This can take pictures of gelatinous zooplankton (like jellyfish) that would be
  • by oceanbites 10 months ago
    Did you know horseshoe crabs have more than just two eyes? In these juveniles you can see another set in the middle of the shell. Check out our website to learn about some awesome horseshoe crab research.  #oceanbites   #plankton   #horseshoecrabs 
WP2Social Auto Publish Powered By : XYZScripts.com