A Satellite Spots 11 New Emperor Penguin Colonies

[Karlston]

A Satellite Spots 11 New Emperor Penguin Colonies

Good news! An orbiter saw signs of almost a dozen previously uncounted colonies in Antarctica, boosting known numbers for a threatened species.

Photograph: Wolfgang Kaehler/Getty Images

 

 

This story originally appeared in The Guardian and is part of the Climate Desk collaboration.

 

Satellite images have revealed 11 previously unknown emperor penguin colonies in Antarctica, boosting the number of known colonies of the imperilled birds by 20 percent.

 

The discoveries were made by spotting the distinctive red-brown guano patches the birds leave on the ice. The finds were made possible by higher-resolution images from a new satellite, as previous scans were unable to pick up smaller colonies.

 

Two of the colonies were a particular surprise. They were found far from the coast, living on sea ice that is anchored to grounded icebergs, a location never seen before.

 

The new colonies are thought to number a few hundred penguins each, which is smaller than average, so the discoveries increase the total population of emperor penguins by a smaller proportion of about 5 to 10 percent.

 

Emperor penguins are the only penguins that breed on sea ice, rather than land, making them especially vulnerable to the climate crisis. All the new colonies are in areas that are at risk, and researchers say these will be the “canaries in the coal mine” as global heating increasingly affects Antarctica.

 

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  Great and Gorgeous Glaciers

  Seen from above, the beautiful abstraction reveals a looming threat—their retreat over time due to climate change. 

   

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  Thwaites Glacier

  A gigantic cavity photographed on November 7, 2016, growing at the bottom of Thwaites Glacier in West Antarctica. The huge cavity is under the main trunk of the glacier on its western side. In this region, as the tide rises and falls, the grounding line retreats and advances across a zone of about 2 to 3 miles. The glacier has been coming unstuck from a ridge in the bedrock at a steady rate of about 0.4 to 0.5 miles a year since 1992.

   

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  Larsen C Ice Shelf 

  This photograph shows a rift in the Larsen C Ice Shelf as observed from NASA’s DC-8 research aircraft on November 10, 2016. An iceberg the size of Delaware broke off from the ice shelf in 2017.

   

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  Tasman Glacier

  In the first image, captured on December 30, 1990, the Tasman Glacier in New Zealand stretched like a serpentine tongue. The second image was acquired on January 29, 2017. Both false-color images use white to show frozen snow or ice, and blue for water. Brown represents bare ground, while red areas are covered in vegetation. In the 27 years between images, the ice has retreated an average of 180 meters per year.

   

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  Excelsior Glacier

  These false-color images show Excelsior Glacier and Big Johnstone Lake. The left image was acquired on October 16, 1986. The right image was acquired on October 31, 2018. In these images, various visible and infrared wavelengths were combined to better differentiate areas of water that are frozen (light blue) from those that contain significant meltwater (dark blue). Rocks are brown, and vegetation is green. Note that by 2018 the glacier had retreated to a point where the eastern and western tributaries had separated: Over the past two decades, rising temperatures have rapidly transformed ice from Alaska’s Excelsior Glacier into a lake of meltwater.

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“The [new colonies] are an exciting discovery,” said Peter Fretwell, at the British Antarctic Survey (BAS), who led the research. “Whilst this is good news, the colonies are small and so only take the overall population count up to just over half a million penguins.”

 

Philip Trathan, also at BAS, said: “The new breeding sites are all in locations where recent model projections suggest emperor penguins will decline. These birds are therefore probably the canaries in the coal mine–we need to watch these sites carefully as climate change will affect this region.”

 

Fretwell said one of the colonies was 180 kilometers (112 miles) from the Antarctic continent: “Many of the penguin scientists we have talked to were disbelieving, as normally you expect them to be at the coast.” Emperor penguins need stable sea ice, usually attached to land, for nine months of the year to breed successfully.

 

There were only 30 colonies known a decade ago, as they are usually in remote and inaccessible locations, where temperatures can fall as low as -50 Celsius (-58 Fahrenheit) in winter. But then Landsat satellite images began to be used. These have a resolution of 30 meters, which is enough to spot the larger colonies.

 

The European Space Agency’s Sentinel-2 satellite was launched in June 2015 and has a resolution of 10 meters. This enabled a search for the smaller penguin colonies, as reported by the BAS scientists in the journal Remote Sensing in Ecology and Conservation.

Emperor penguins were expected to be present at fairly regular intervals around the coast of Antarctica, so the search was targeted in areas where none were known. “In every gap where we thought there might be a colony, we found one,” said Fretwell.

 

Three of the 11 colonies found had been suspected following ship or airplane sightings of penguins in the 1960s and 1980s, but Sentinel-2 images confirmed their presence. There are now 61 known emperor colonies around Antarctica. “There may be one or two very small colonies yet to be discovered, but I think we have filled in all the gaps now,” said Fretwell.

 

The next step is to direct satellites with very high, 30-centimeter-resolution cameras over the colonies to enable the penguins to be counted. “It is dark at the moment in Antarctica, so we can’t count them yet,” said Fretwell. “The sun will come up either later this month or next month in most of these locations, and then we will start.”

 

Previous studies have estimated that 90 percent of known colonies will be lost by the end of the century if no further action is taken to cut the greenhouse gas emissions that drive global heating. Even in the best-case scenario, where deep and fast cuts to carbon emissions limit the rise in global temperature to 1.5 Celsius (34.7 Fahrenheit), the population of emperor penguins is projected to fall by 30 percent.

 

 

A Satellite Spots 11 New Emperor Penguin Colonies