Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

50% reduction in penguin population

  1. Apr 1, 2007 #1


    User Avatar

    I watched 60 minutes today and they used a new example of global warming in action! The journalist was talking to two arctic biologists, and the man said that there has been a 50% reduction in penguin population. That sure sounds like a big number! Is that true? I don't believe a mention of the time frame was there.
  2. jcsd
  3. Apr 1, 2007 #2


    User Avatar

    Staff: Mentor

    More global warming scare tactics which turns out to be bogus. There was a drop in the 70's and then the penguin population recovered in the 80's. :rolleyes:

    The decline in population was in the 1970's during a cyclical warming called the Antarctic circumpolar wave. In the early 1980s the winter air and sea surface temperatures dropped, and the emperor penguin population stabilized.


    They also failed to mention the 300% increase in the Antartic seal population in the last 20 years.

    The Antartic was once completely covered with vegetation and scientists believe that it may hold one of the last supergiant oil fields yet to be discovered.
    Last edited by a moderator: Apr 22, 2017
  4. Apr 2, 2007 #3

    Ivan Seeking

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member


    I saw that a number of other penguin populations are down by as much as 80%. Everything from climate change to overfishing is blamed, but most explanations seems to come back to declining krill populations.
    Last edited: Apr 2, 2007
  5. Apr 2, 2007 #4


    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    I was just watching the online version here:
    http://60minutes.yahoo.com/segment/54/the_age_of_warming [Broken]

    They talk about the problem with krill also.


    On the other hand, I saw the movie, "http://www2.warnerbros.com/happyfeet/"" last night. The main character, Mumble, discovered that fish stocks are declining due to overfishing... wonder who's right? :rolleyes:
    Last edited by a moderator: May 2, 2017
  6. Apr 2, 2007 #5
    I don't think anybody's worried about the Antarctic. Latest figures suggest the ice sheet there is growing!

    It's Greenland where the effects of global warming are being felt. These ecosystems rely heavily on upwelled nutrients, as the surface waters warm the ocean becomes more stable, a more stable ocean makes it harder for nutrients to upwell, so you get less upwelled nutrients, and less life. The ice is melting, less sea-ice is being produced in the winter, the planetary albedo drops... blah ..blah ..blah.. nutrients stay at bottom of ocean, krill die out, little fish die out, bigger fish die out, penguins die out.

    Considering bipolar glaciation is abnormal in earth's history I suspect the penguins are gonna have to adapt or die sooner or later.
  7. Apr 2, 2007 #6


    User Avatar

    Staff: Mentor

    And some penguin populations, such as the King Penguin have been steadily increasing.

    "With seven colonies known in 1992, the population has exhibited remarkable growth (>20% annually), doubling every five to seven years (see plot). Preliminary results from the current survey indicate that this rapid increase is continuing, and that the breeding population at Heard Island shows no sign of reaching its limit. All king penguin populations at other breeding localities in the subantarctic for which long term data are available also show this dramatic increase. The causes for this rapid, sustained and widespread increase remain unknown."


    From the Institute of Polar Environment, University of Science and Technology, China.

    "What has been responsible for the increase in Chinstrap penguin populations during the past 40 years in maritime Antarctica?"


    Adelie penguin population increases - "World population: estimated to 2 million couples.
    Archipelago's population: 29 182 couples in 84, 30 369 in 90.
    Threats: none. Population in slight increase (1% a year) almost everywhere


    So some are declining, some are increasing. A lot of it seems to be related to krill, the penguin's feeding territories overlap the krill fishing areas.
    Last edited: Apr 2, 2007
  8. Apr 3, 2007 #7
    Maybe you should look again at the latest comprehensive study.

    As far as I know, these are the latest figures using the state of the art technology. There is another study published about the same time, but it was of eastern Antarctica.

    The GRACE study is more comprehensive since it measures the mass of the entire continent.

  9. Apr 3, 2007 #8
    Maybe you should look again at the results of the latest radar altimetry study.

    http://bowfell.geol.ucl.ac.uk/~lidunka/EPSS-papers/djw3.pdf [Broken]
    Last edited by a moderator: May 2, 2017
  10. Apr 3, 2007 #9
    There are many conflicting studies based on satellite altimetry. It limited since it measures changes in altitude which then must be attributed to new snow or new melt. GRACE measures gravity, ie it is a direct measurement of mass. Empirical measurments tend to be more accurate than estimations, so i will stick with the conclusions of the GRACE project.

    Last edited by a moderator: May 2, 2017
  11. Apr 3, 2007 #10


    User Avatar

    Staff: Mentor

    The grace data is full of errors. It is supposed to measure gravity over land surfaces.

    "But there is another issue which needs resolving.

    Grace is unable to discriminate between ice and rock. And the rock surface of Antarctica, below the ice sheet, is rising.

    The new research paper attempts to correct for this by estimating the rate of rise through computer models of the Earth's interior.

    But uncertainties in the models produce uncertainties in the team's estimates of changes to the ice: the annual loss could be as low as 72 cubic km, or as high as 232 cubic km.

    Much better, said David Vaughan, would be to measure the rise directly, and eliminate the uncertainties.

    "The best way would be to go to rock outcrops on Antarctica, put GPS receivers on them and measure how rapidly they're rising," he told the BBC News website.

    "That is done at the moment in a few places, but not in enough, and a new programme is being planned."


    I have several other papers that go into more detail about the problems with GRACE data, but I don't have the time to get them together right now.
  12. Apr 3, 2007 #11
    Good point Evo.

    But it is still the state of the art. By 2009 the scheduled end of the mission, scientists will have a much clearer picture if what is going on with the Antarctic glaciers

    Even allowing for the wide margin of error the end result is still a net ice mass loss of 72-232 cubic km.
  13. Apr 3, 2007 #12


    User Avatar

    Staff: Mentor

    True. And how much of that is a normal reversal of the last ice age? The antartic used to be warm and coverd with vegetation. We may just be cycling back to how things were once.

    Pollution is adding a bit to normal warming, but is it really significant?

    The earth's climate has changed drastically throughout history. We are not to intervene, even if it means we can't adapt. As Moonbear said in a post, climate changes happen and species adapt or die and new species appear. Humans are only a blip on the timescale. We may not be meant to exist for long. It's the way it is. Although we act like it, this planet was not meant to exist for us. We may mess things up to some small extent, but climate change IS going to happen and we may not survive, but other species will.
  14. Apr 4, 2007 #13
    It's ashame that you can't put a gravity meter on a satellite. You have to very accurately measure slight changes in the probe's orbit. Although scientists have got this down to an art (only quite recently), I'm not sure they've got it fine enough for the I dunno, maybe 1 g.u. yr-1rate of change in the gravity field that would need to be detected.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook