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29, Jun, 2011

Emperor Penguins threatened by climate change


Category: ECO Inc

While the prognosis improves for Happy Feet, all emperor penguins are at grave risk of extinction from climate change by the end of the century, the Environment and Conservation Organisations (ECO) said today.

ECO co-chair Barry Weeber said emperor penguins only breed in the Antarctic winter and their home is being increasingly impacted by climate change with the warmer temperatures and decline in and distribution of sea ice.

“Researchers are predicting that under current climate change trends the emperor penguin populations could decline by 95 percent by 2100.” [See footnote 5]

Mr Weeber said ice is fundamental to the existence of emperor penguins.  “The penguins breed on fast sea ice attached to ice shelves or coastlines over the winter so that the chicks are ready to leave the colony before the fast ice breaks up in summer.”

“If there is no ice or the ice forms late or breaks up early that is disastrous to emperor penguins.”

Mr Weeber said one monitored emperor penguin colony has disappeared in the last 60 years in the East Antarctic and area showing the greatest change due to global warming. [see footnote 6]

“The decline and loss of the Emperor Island colony was related to the rise in air temperature and decline in seasonal sea ice duration.”

Mr Weeber said emperor penguins were also being affected by the loss of their favourite krill food.

“Declining sea ice also reduces krill biomass which is the keystone species for much of the Antarctic sea web.”

“Declines in krill stocks as high as 80 percent in the south-west Atlantic region of the Southern Ocean have been reported by some researchers.” [See footnote 7]  “This raises concerns over the impact of krill fishing on krill stocks in the future.”

Mr Weeber said the Ross Sea could be the last refuge for emperor penguins as it is last part of Antarctica predicted to have retreating ice.  “The Ross Sea contains over a quarter of the Emperor Penguin population.”

ECO is working with colleagues throughout the world and the Antarctic and Southern Ocean Coalition to protect the Ross Sea as a marine reserve.

Notes:

  1. ECO – the Environment and Conservation Organisations was established in 1972 and represents 55 groups with a concern for the environment.
  2. Emperor penguins are largest penguin and can grow to 1.2 meters tall and can weigh as much as 38 kilograms and live for more than 20 years old.  They are the only bird that breeds around Antarctica during the winter. This penguin can stay underwater for up to 20 minutes and dive to 550m in depth.  They are found around Antarctica in the Weddell Sea and Dronning [Queen] Maud Land, Enderby Land, Princess Elizabeth Lands, and the Ross Sea.  Emperors do not build nests but instead use their warm body to incubate eggs tucked above their feet and raise their chicks.
  3. Adults are known to travel over 120 km over the ice to reach their colony and to return to the sea to feed during the winter.
  4. “Antarctic sea ice extent (SIE) is projected to shrink as concentrations of atmospheric greenhouse gases (GHGs) increase, and emperor penguins (Aptenodytes forsteri) are extremely sensitive to these changes because they use sea ice as a breeding, foraging and molting habitat.” - Jenouvrier et al. Demographic models and IPCC climate projections predict the decline of an emperor penguin population. Proceedings of the National Academy of Sciences, Jan 26, 2009; DOI: 10.1073/pnas.0806638106.
  5. Researchers have predicted that:   “the increased frequency of warm events associated with projected decreases in sea ice extent will reduce the population viability. The probability of quasi-extinction (a decline of 95% or more) is at least 36% by 2100. The median population size is projected to decline from ≈6,000 to ≈400 breeding pairs over this period. To avoid extinction, emperor penguins will have to adapt, migrate or change the timing of their growth stages. However, given the future projected increases in greenhouse gases and its effect on Antarctic climate, evolution or migration seem unlikely for such long lived species at the remote southern end of the Earth.” - Jenouvrier et al. Demographic models and IPCC climate projections predict the decline of an emperor penguin population. Proceedings of the National Academy of Sciences, Jan 26, 2009; DOI: 10.1073/pnas.0806638106.  See also Barbraud C, Weimerskirch H (2001) Emperor penguins and climate change. Nature 411:183–186. Ainley et al. 2010. Antarctic penguin response to habitat change as Earth's troposphere reaches 2°C above preindustrial levels. Ecological Monographs 80:49–66. [doi:10.1890/08-2289.
  6. One colony of emperor penguins at the Dion Islands, Eastern Antarctic peninsula, has disappeared in the last 60 years.  The researchers related “the decline and loss of the Emperor Island colony to a well-documented rise in local mean annual air temperature and coincident decline in seasonal sea ice duration.” - Trathan PN, Fretwell PT, Stonehouse B, 2011 First Recorded Loss of an Emperor Penguin Colony in the Recent Period of Antarctic Regional Warming: Implications for Other Colonies. PLoS ONE 6(2): e14738. doi:10.1371/journal.pone.0014738
  7. Antarctic krill is a key species in the Antarctic ecosystem. Decreases in sea ice extent due to warmer temperatures around the West Antarctic Peninsula have been well-documented and are thought to have contributed to a significant decline in the krill population since the 1970s.  Atkinson et al (2004) estimate that this decline may be as high as 80% in the southwest Atlantic region of the Southern Ocean.   See Atkinson et al 2004. Long-term decline in krill stock and increase in salps within the Southern Ocean. Nature 432:100–103; and Loeb VJ, et al. (1997) Effects of sea-ice extend and krill or salp dominance on the Antarctic food web. Nature 387:897–900; Ducklow et al 2007. Marine pelagic ecosystems: the West Antarctic Peninsula. Philosophical Transactions of the Royal Society B 362:67–94 doi:10.1098/rstb.2006.1955; Montes-Hugo et al. 2009. Recent Changes in Phytoplankton Communities Associated with Rapid Regional Climate Change Along the Western Antarctic Peninsula. Science 323: 1470-1473.  See also St. Clair C C and M S Boyce (2009) Icy insights from emperor penguins.  doi: 10.1073/pnas.0812940106 PNAS February 10, 2009 vol. 106 no. 6 1691-1692.
  8. Further information on protection proposals for the Ross Sea can be found at www.asoc.org.  A report on the proposal for the Ross Sea as a marine reserve can be found at http://www.asoc.org/storage/documents/MPAs/The_Ross_Sea.pdf and a report on the use of the Ross Sea as a climate change reference centre can be found at http://www.asoc.org/storage/documents/Meetings/ATCM/XXXIV/The_Ross_Sea-__A_Valuable_Reference_Area_to_Assess_the_Effects_of_Climate_Change.pdf

  9. The Antarctic and Southern Ocean Coalition is the global environmental coalition that has worked for protection of Antarctica and the Southern Ocean for over 30 years.  The Coalition is based in Washington and New Zealand members include ECO, Greenpeace and WWF.