Fragmented sea ice, or pack ice, seen from the deck of the icebreaker, Nathaniel B. Palmer . Heavy sea ice in the Weddell Sea, on the east side of the Antarctic Peninsula, makes navigation extremely difficult even for large icebreakers....[More]
TREACHEROUS SEA:
Fragmented sea ice, or pack ice, seen from the deck of the icebreaker, Nathaniel B. Palmer. Heavy sea ice in the Weddell Sea, on the east side of the Antarctic Peninsula, makes navigation extremely difficult even for large icebreakers. Tidal currents can rapidly compress the ice floes together, trapping a ship—as happened to the Palmer for 24 hours on January 30-31, 2010, during the excursion when the photos in this slide show were taken.
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Douglas Fox
VANISHING ACT
Geologist Greg Balco from the Berkeley Geochronology Center collects rock samples from a mountain overlooking Sjögren Fjord on the Antarctic Peninsula....[More]
VANISHING ACT
Geologist Greg Balco from the Berkeley Geochronology Center collects rock samples from a mountain overlooking Sjögren Fjord on the Antarctic Peninsula. By measuring a rare isotope in the rock, Balco can determine how long the rock has been exposed to sunlight—and therefore how recent it was that thick Ice Age glaciers last covered this peak.
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Douglas Fox
ODDBALL:
This granite boulder does not match the surrounding bedrock. A glacier transported it to this location thousands of years ago, and later dropped it here as the ice receded....[More]
ODDBALL:
This granite boulder does not match the surrounding bedrock. A glacier transported it to this location thousands of years ago, and later dropped it here as the ice receded. These rocks, called glacial erratics, can be used to map the flow of ancient glaciers.
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Douglas Fox
GLACIAL SCARS:
The bedrock on a mountain overlooking Sjögren Glacier is covered in scrape marks left by the glacier when it was much thicker and skidded over the mountain long ago....[More]
GLACIAL SCARS:
The bedrock on a mountain overlooking Sjögren Glacier is covered in scrape marks left by the glacier when it was much thicker and skidded over the mountain long ago. The orientation of the scars reveals the direction that the glacier flowed.
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Douglas Fox
MELT UNDER WATER
A sensor is lowered through 700 meters of sea water filling a fjord on the Antarctic Peninsula. The sensor will measure temperature, salinity and the speed and direction of currents as it descends—allowing scientists to map the plumes of fresh meltwater bleeding off of coastal tidewater glaciers....[More]
MELT UNDER WATER
A sensor is lowered through 700 meters of sea water filling a fjord on the Antarctic Peninsula. The sensor will measure temperature, salinity and the speed and direction of currents as it descends—allowing scientists to map the plumes of fresh meltwater bleeding off of coastal tidewater glaciers.
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Douglas Fox
SEAFLOOR SAMPLE:
Workers on the rear deck of the Nathaniel B. Palmer haul in a four-meter-long core of sediment that was extracted from the seafloor 1,300 meters below....[More]
SEAFLOOR SAMPLE:
Workers on the rear deck of the Nathaniel B. Palmer haul in a four-meter-long core of sediment that was extracted from the seafloor 1,300 meters below. Sediment cores can provide a record of when the area was covered by a floating ice shelf or even by a gigantic, grounded glacier that rested on the seafloor.
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Douglas Fox
MICROSCOPIC SHELLS:
The shells of tiny organisms, called foraminifera, that lived thousands of years ago are found in sediment cores taken from the sea floor. Scott Ishman, a paleoecologist from Southern Illinois University, studies them as ancient environmental markers....[More]
MICROSCOPIC SHELLS:
The shells of tiny organisms, called foraminifera, that lived thousands of years ago are found in sediment cores taken from the sea floor. Scott Ishman, a paleoecologist from Southern Illinois University, studies them as ancient environmental markers. The shells shown here belong to the same species. But the robust form (on the left) occurs in areas with open water or moderate sea ice, whereas the “gracile” forms (center and right) occur in areas covered by heavy sea ice or thick ice shelves. These particular shells are about 0.2 millimeters across.
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Scott Ishman, Southern Illinois University
WARM DWELLER:
This silica shell of an ancient diatom found in a sediment core taken from the seafloor off the Antarctic Peninsula in only. Amy Leventer, a paleobiologist at Colgate University, uses diatoms as proxies of past environments in Antarctica....[More]
WARM DWELLER:
This silica shell of an ancient diatom found in a sediment core taken from the seafloor off the Antarctic Peninsula in only. Amy Leventer, a paleobiologist at Colgate University, uses diatoms as proxies of past environments in Antarctica. The existence of the species shown here, Thalassiosira antarctica, indicates a time of relatively warm surface waters—meaning a few degrees above freezing.
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Amy Leventer, Colgate University
SHAPE CHANGER:
A mishmosh of microscopic diatom shells, thousands of years old, was found in certain seafloor sediments off the coast of Antarctica. The big, angular, rod-like diatom at the center, Eucampia antarctica , grows in different shapes depending on the amount of sea ice....[More]
SHAPE CHANGER:
A mishmosh of microscopic diatom shells, thousands of years old, was found in certain seafloor sediments off the coast of Antarctica. The big, angular, rod-like diatom at the center, Eucampia antarctica, grows in different shapes depending on the amount of sea ice. Flat rods, like the one shown here, occur in waters covered with heavy sea ice, limiting access to sunlight. When sea ice wanes and sunlight is more plentiful, this species grows horns on either end of its shell. By analyzing the shapes of Eucampia diatoms found in the layers of a sediment core, Leventer can reconstruct how local conditions shifted over time.
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Amy Leventer, Colgate University
PARKED IN THE ICE:
A team of researchers disembarks from the icebreaker to take samples. The researchers will quantify pockets of melt water in the sea ice, and identify microscopic diatoms locked inside the ice....[More]
PARKED IN THE ICE:
A team of researchers disembarks from the icebreaker to take samples. The researchers will quantify pockets of melt water in the sea ice, and identify microscopic diatoms locked inside the ice.
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Douglas Fox
A MIDSUMMER'S NIGHT:
Scientists are lowered by the ship's crane. By studying the thickness and porosity of the sea ice, scientists can estimate its age (generally one to 10 years)....[More]
A MIDSUMMER'S NIGHT:
Scientists are lowered by the ship's crane. By studying the thickness and porosity of the sea ice, scientists can estimate its age (generally one to 10 years). Microscopic organisms called diatoms in the ice provide clues to the ecosystem in the ocean below.
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Douglas Fox
ANTARCTIC SEASCAPE:
The icebreaker Nathaniel B. Palmer plows a path through sea ice in the Prince Gustav Channel, just off the Antarctic Peninsula. Grounded by the dark bluffs of James Ross Island in the background, the scene is reminiscent of a sandy Utah desert—but the veneer of ice one meter thick conceals ocean water 700 to 1,000 meters deep....[More]
ANTARCTIC SEASCAPE:
The icebreaker Nathaniel B. Palmer plows a path through sea ice in the Prince Gustav Channel, just off the Antarctic Peninsula. Grounded by the dark bluffs of James Ross Island in the background, the scene is reminiscent of a sandy Utah desert—but the veneer of ice one meter thick conceals ocean water 700 to 1,000 meters deep.
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Douglas Fox
YES! Send me a free issue of Scientific American with no obligation to continue the subscription. If I like it, I will be billed for the one-year subscription.
"Cold clues reveal how fast ice is disappearing, and therefore how quickly sea level could rise" is an interesting notion. But systems resist change, which means that disappearing Artic, and Antarctic ice, is due to global cooling not warming. Global cooling reduces snowfall in the Artic since less moisture is transported. Less snow means that glaciers are shrinking. When global warming does occur then we will enter another ice age, which is the more normal condition for Earth. Global warming will cause greater snowfall and thus glacier expansion. Measuring average temperature at the Earth's surface does not include a measure of cloud cover. An average rising surface temperature, and a shrinking cloud cover, is actually a condition of global cooling!
"Cold clues reveal how fast ice is disappearing, and therefore how quickly sea level could rise"
Sea level has had a negative acceleration over the last 20 years or so.
Here's a screen shot: http://i39.tinypic.com/nr14bq.jpg From this Colorado University Presentation: Why has an acceleration of sea level rise not been observed during the altimeter era? Link: http://www.aviso.oceanobs.com/fileadmin/documents/OSTST/2011/oral/02_Thursday/Splinter%203%20SCI/04%20Nerem%20ostst_2011_nerem.pdf It shows that sea level has an acceleration of minus 0.06 MM/yr² since 1993.
4. R.Blakely
in reply to Eco_steve08:23 PM 6/25/12
Global dimming has been measured over India. Dimming is a more significant effect than any change that CO2 concentration can cause. Global cooling is not evident from temperature measurement since cloud cover reacts, like most systems, to counter change. Reduced cloud cover increases surface heating since sunlight can heat the surface more. CO2 already blocks all 15-micron photons, and so more CO2 cannot cause any more warming.
Thank you Mr Blakely. An average rising temperature is an indication of Global cooling? Global cooling not evident from temperature measurements? Cloud cover needs to be taken into account when measuring temperature. Certainly gives one an insight into the problems one faces when dealing with these issues.
NSIDC data shows the Antarctic is *gaining* sea ice, not losing it: http://nsidc.org/data/seaice_index/archives/index.html
In the last decade (i.e. 120 months), there has been 1.4% more Antarctic sea ice than the decade before. In fact, for the most recent month (June), Antarctic sea ice is 9.6% higher than 10 years before. Over the NSIDC's total record, starting in Nov 1978, the linear trend of Antarctic sea ice implies a total increase of 4.2%, or 1.3% per decade.
So why is Fox writing as if Antarctic sea ice is disappearing?
7. Denny0789
in reply to Steve Case12:38 PM 7/8/12
Your graph is out of date. AVISO now shows sea level back on its previous trend: http://www.aviso.oceanobs.com/en/news/ocean-indicators/mean-sea-level/index.html
(It dipped because of the strong La Nina, which moved a lot of water from the oceans onto land. That water has not drained back to the oceans.)
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8 Comments
Add Comment"Cold clues reveal how fast ice is disappearing, and therefore how quickly sea level could rise" is an interesting notion. But systems resist change, which means that disappearing Artic, and Antarctic ice, is due to global cooling not warming.
Reply | Report Abuse | Link to thisGlobal cooling reduces snowfall in the Artic since less moisture is transported. Less snow means that glaciers are shrinking.
When global warming does occur then we will enter another ice age, which is the more normal condition for Earth. Global warming will cause greater snowfall and thus glacier expansion.
Measuring average temperature at the Earth's surface does not include a measure of cloud cover. An average rising surface temperature, and a shrinking cloud cover, is actually a condition of global cooling!
Mr. Blakeley : Can you provide validated and refereed proof of your statements?
Reply | Report Abuse | Link to thisThe head line says:
Reply | Report Abuse | Link to this"Cold clues reveal how fast ice is disappearing, and therefore how quickly sea level could rise"
Sea level has had a negative acceleration over the last 20 years or so.
Here's a screen shot:
http://i39.tinypic.com/nr14bq.jpg
From this Colorado University Presentation:
Why has an acceleration of sea level rise not been observed during the altimeter era?
Link:
http://www.aviso.oceanobs.com/fileadmin/documents/OSTST/2011/oral/02_Thursday/Splinter%203%20SCI/04%20Nerem%20ostst_2011_nerem.pdf
It shows that sea level has an acceleration of minus 0.06 MM/yr² since 1993.
Global dimming has been measured over India. Dimming is a more significant effect than any change that CO2 concentration can cause. Global cooling is not evident from temperature measurement since cloud cover reacts, like most systems, to counter change. Reduced cloud cover increases surface heating since sunlight can heat the surface more.
Reply | Report Abuse | Link to thisCO2 already blocks all 15-micron photons, and so more CO2 cannot cause any more warming.
Thank you Mr Blakely. An average rising temperature is an indication of Global cooling? Global cooling not evident from temperature measurements? Cloud cover needs to be taken into account when measuring temperature. Certainly gives one an insight into the problems one faces when dealing with these issues.
Reply | Report Abuse | Link to thisNSIDC data shows the Antarctic is *gaining* sea ice, not losing it:
Reply | Report Abuse | Link to thishttp://nsidc.org/data/seaice_index/archives/index.html
In the last decade (i.e. 120 months), there has been 1.4% more Antarctic sea ice than the decade before. In fact, for the most recent month (June), Antarctic sea ice is 9.6% higher than 10 years before. Over the NSIDC's total record, starting in Nov 1978, the linear trend of Antarctic sea ice implies a total increase of 4.2%, or 1.3% per decade.
So why is Fox writing as if Antarctic sea ice is disappearing?
Your graph is out of date. AVISO now shows sea level back on its previous trend:
Reply | Report Abuse | Link to thishttp://www.aviso.oceanobs.com/en/news/ocean-indicators/mean-sea-level/index.html
(It dipped because of the strong La Nina, which moved a lot of water from the oceans onto land. That water has not drained back to the oceans.)
One interesting detail: On Google Maps most of the areas described in article as "Former Ice Shelves" seem to be PhotoShopped.
Reply | Report Abuse | Link to this