50% reduction in penguin population

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  • #1
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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.
 

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  • #2
Evo
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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.

Using the longest series of data available, reseachers have shown that an abnormally long warm spell in the Southern Ocean during the late 1970s contributed to a decline in the population of emperor penguins at Terre Adelie, Antarctica.

The warm spell of the late 1970s is related to the Antarctic circumpolar wave—huge masses of warm and cold water that circle Antarctica about once every eight years. In response to this cycle, Terre Adelie experiences a warming period every four or five years that generally lasts about a year.

In the late 1970s, however, the warming continued for several years. Whether it was the result of natural climate variability in the Antarctic circumpolar wave cycle or an anomaly related to global warming is not possible to determine because air and sea surface temperature data from many years ago are not available.

In the early 1980s the winter air and sea surface temperatures dropped, and the emperor penguin population stabilized.
http://news.nationalgeographic.com/news/2001/05/0509_penguindecline.html

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.
 
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  • #3
Ivan Seeking
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...But, after millions of years of endurance, many Chinstrap and Adelie penguins aren’t surviving anymore.

“We knew something was drastically wrong. Something had changed in the ocean,” Wayne Trivelpiece tells Pelley.

What do they think was happening?

“We didn’t really know. We knew it had to be something that was going on once they left land and went out to sea,” Sue Trivelpiece explains.

“We love working with the Chinstraps. They are far and away the most cooperative,” says Sue’s husband Wayne.

“But you know what, Wayne, I’m not sure they like working with you,” Pelley remarks.

Getting manhandled may ruffle their feathers, but it was key to discovering their fate.

There were some grown penguin chicks, chasing their mothers for food which she delivers beak to beak. Soon, the chicks will go to sea to hunt a shrimp-like crustacean called krill.

Krill grow beneath the sea ice, but in the warming ocean, the sea ice is melting away.

“So the penguins have been going to sea and starving to death?” Pelley asks.

“The chicks are declining and we think they just can’t find the krill,” Sue Trivelpiece says.

“When you can link a change in warming in air temperature to ice to krill to penguins and show a 50 percent reduction in the penguin population here and connect all the dots you really can’t make it any clearer than that,” her husband adds. [continued]
http://www.cbsnews.com/stories/2007/03/30/60minutes/main2631210.shtml

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.
 
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  • #4
Q_Goest
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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:
 
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  • #5
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They also failed to mention the 300% increase in the Antartic seal population in the last 20 years.
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.
 
  • #6
Evo
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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.
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."

http://www.aad.gov.au/default.asp?casid=2021

Ivan said:
many Chinstrap and Adelie penguins aren’t surviving anymore, from a CBS tv show
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?"

http://www.ncbi.nlm.nih.gov/entrez/...ve&db=PubMed&list_uids=11382136&dopt=Abstract

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

http://www.gdargaud.net/Antarctica/Penguins.html

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.
 
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  • #7
Skyhunter
I don't think anybody's worried about the Antarctic. Latest figures suggest the ice sheet there is growing!
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.

Measuring variations in Antarctica's ice sheet mass is difficult because of its size and complexity. Grace is able to overcome these issues, surveying the entire ice sheet, and tracking the balance between mass changes in the interior and coastal areas.

Previous estimates have used various techniques, each with limitations and uncertainties and an inherent inability to monitor the entire ice sheet mass as a whole. Even studies that synthesized results from several techniques, such as the assessment by the Intergovernmental Panel on Climate Change, suffered from a lack of data in critical regions.

"Combining Grace data with data from other instruments such as NASA's Ice, Cloud and Land Elevation Satellite; radar; and altimeters that are more effective for studying individual glaciers is expected to substantially improve our understanding of the processes controlling ice sheet mass variations," Velicogna said.

The Antarctic mass loss findings were enabled by the ability of the identical twin Grace satellites to track minute changes in Earth's gravity field resulting from regional changes in planet mass distribution. Mass movement of ice, air, water and solid earth reflect weather patterns, climate change and even earthquakes. To track these changes, Grace measures micron-scale variations in the 220-kilometer (137-mile) separation between the two satellites, which fly in formation.
 
  • #8
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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]
 
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  • #9
Skyhunter
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]
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.

Finally, in a very nice bit of work Velicogna and Wahr use data from the "Gravity Recovery and Climate Experiment" (GRACE) satellites to show that the Antarctic ice sheet has been losing mass at a rate of 150 +/- 80 km3 each year since 2002. That's equivalent to about 0.4 mm of sea level rise each year. This is about twice other recent estimates, while IPCC 2001 actually gives negative 0.1 mm/yr. What is especially nice about Velicogna and Wahr's study is that by using gravity measurements they have measured mass changes directly, avoiding the problem of virtually all previous measurements of ice sheet mass change, which usually measure either input (snowfall) or loss (calving, melting, or thinning of the ice), but not both at once.
http://www.realclimate.org/index.ph...level-rise-more-evidence-from-the-ice-sheets/
 
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  • #10
Evo
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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."

http://news.bbc.co.uk/2/hi/science/nature/4767296.stm

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.
 
  • #11
Skyhunter
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.
 
  • #12
Evo
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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.
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.
 
  • #13
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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.
 

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