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Thursday, July 30, 2009

F. Barringer, NYT, White roofs catch on as energy cost cutters

White roofs catch on as energy cost cutters

Link to Fahrenheit to centrigrade converter:

SAN FRANCISCO — Returning to their ranch-style house in Sacramento after a long summer workday, Jon and Kim Waldrep were routinely met by a wall of heat.

A Wal-Mart store in Chino, Calif., has both a cool roof and solar panels to cut its energy use. (J. Emilio Flores for The New York Times) Enlarge This Image

By Degrees

A Cool Shield

This is one in a series of articles about stopgap measures that could limit global warming.

A white roof has helped cool Jon Waldrep’s Sacramento home. (Jim Wilson/The New York Times) Enlarge This Image

“We’d come home in the summer, and the house would be 115 degrees, stifling,” said Mr. Waldrep, a regional manager for a national company.

He or his wife would race to the thermostat and turn on the air-conditioning as their four small children, just picked up from day care, awaited relief.

All that changed last month. “Now we come home on days when it’s over 100 degrees outside, and the house is at 80 degrees,” Mr. Waldrep said.

Their solution was a new roof: a shiny plasticized white covering that experts say is not only an energy saver but also a way to help cool the planet.

Relying on the centuries-old principle that white objects absorb less heat than dark ones, homeowners like the Waldreps are in the vanguard of a movement embracing “cool roofs” as one of the most affordable weapons against climate change.

Studies show that white roofs reduce air-conditioning costs by 20% or more in hot, sunny weather. Lower energy consumption also means fewer of the carbon dioxide emissions that contribute to global warming.

What is more, a white roof can cost as little as 15% more than its dark counterpart, depending on the materials used, while slashing electricity bills.

Energy Secretary Steven Chu, a Nobel laureate in physics, has proselytized for cool roofs at home and abroad. “Make it white,” he advised a television audience on Comedy Central’s “Daily Show” last week.

The scientist Mr. Chu calls his hero, Art Rosenfeld, a member of the California Energy Commission who has been campaigning for cool roofs since the 1980s, argues that turning all of the world’s roofs “light” over the next 20 years could save the equivalent of 24 billion metric tons in carbon dioxide emissions.

“That is what the whole world emitted last year,” Mr. Rosenfeld said. “So, in a sense, it’s like turning off the world for a year.”

This month the Waldreps’ three-bedroom house is consuming 10% less electricity than it did a year ago. (The savings would be greater if the family ran its central air during the workday.)

From Dubai to New Delhi to Osaka, Japan, reflective roofs have been embraced by local officials seeking to rein in energy costs. In the United States, they have been standard equipment for a decade at new Wal-Mart stores. More than 75% of the chain’s 4,268 outlets in the United States have them.

California, Florida and Georgia have adopted building codes that encourage white-roof installations for commercial buildings.

Drawing on federal stimulus dollars earmarked for energy-efficiency projects, state energy offices and local utilities often offer financing for cool roofs. The roofs can qualify for tax credits if the roofing materials pass muster with the Environmental Protection Agency’s Energy Star program.

Still, the ardor of the cool-roof advocates has prompted a bit of a backlash.

Some roofing specialists and architects argue that supporters fail to account for climate differences or the complexities of roof construction. In cooler climates, they say, reflective roofs can mean higher heating bills.

Scientists acknowledge that the extra heating costs may outweigh the air-conditioning savings in cities like Detroit or Minneapolis.

But for most types of construction, they say, light roofs yield significant net benefits as far north as New York or Chicago. Although those cities have cold winters, they are heat islands in the summer, with hundreds of thousands of square feet of roof surface absorbing energy.

The physics behind cool roofs is simple. Solar energy delivers both light and heat, and the heat from sunlight is readily absorbed by dark colors. (An asphalt roof in New York can rise to 180 degrees on a hot summer day.) Lighter colors, however, reflect back a sizable fraction of the radiation, helping to keep a building — and, more broadly, the city and Earth — cooler. They also re-emit some of the heat they absorb.

Unlike high-technology solutions to reducing energy use, like light-emitting diodes in lamp fixtures, white roofs have a long and humble history. Houses in hot climates have been whitewashed for centuries.

Before the advent of central air-conditioning in the mid-20th-century, white- and cream-colored houses with reflective tin roofs were the norm in South Florida, for example. Then central air-conditioning arrived, along with dark roofs whose basic ingredients were often asphalt, tar and bitumen, or asphalt-based shingles. These materials absorb as much as 90% of the sun’s heat energy — often useful in New England, but less so in Texas. By contrast, a white roof can absorb as little as 10% or 15%.

“Relative newcomers to the West and South brought a lot of habits and products from the Northeast,” said Joe Reilly, the president of American Rooftile Coatings, a supplier. “What you see happening now is common sense.”

Around the country, roof makers are racing to develop products in the hope of profiting as the movement spreads from the flat roofs of the country’s malls to the sloped roofs of its suburbs.

Years of detailed work by scientists at the Lawrence Berkeley Laboratory have provided the roof makers with a rainbow of colors — the equivalent of a table of the elements — showing the amount of light that each hue reflects and the amount of heat it re-emits.

White is not always a buyer’s first choice of color. So suppliers like American Rooftile Coatings have used federal color charts to create “cool” but traditional colors, like cream, sienna and gray, that yield savings, though less than dazzling white roofs do.

In an experiment, the National Laboratory in Oak Ridge, Tenn., had two kinds of terra-cotta-colored cement tiles from American Rooftile installed on four new homes at the Fort Irwin Army base in California. One kind was covered with a special paint and reflected 45% of the sun’s rays — nearly twice as much as the other kind. The two homes with roofs of highly reflective paint used 35% less electricity last summer than the two with less reflective paint.

Still, William Miller of the Oak Ridge laboratory, who organized the experiment, says he distrusts the margin of difference; he wants to figure out whether some of it resulted from different family habits.

Hashem Akbari, Dr. Rosenfeld’s colleague at the Lawrence Berkeley laboratory, says he is unsure how long it will take cool roofs to truly catch on. But he points out that most roofs, whether tile or asphalt-shingle, have a life span of 20-25 years.

If the roughly 5% of all roofs that are replaced each year were given cool colors, he said, the country’s transformation would be complete in two decades.


Jakobshavn Glacier's floating tongue breaking up, July 29, 2009
Nick Barnes said...

The southern half of the glacier front looks to have retreated about 4km since the 2006 line.
July 31, 2009 7:43 PM
Tenney said...

Yes, it looks like the 2006 line is the area of retreat -- wonder why that is.

I am still pretty much of a newbie, so I am still wondering if the tongue breaks up every year.
August 1, 2009 12:58 AM
Nick Barnes said...

Let me share some of my (limited) understanding of this glacier.

The main fjord, up to 10 km wide and maybe 50 km long, contains a lot of bergs from the glacier, with some sea ice between the bergs. The glacier is quite thick - 1-2 km - so the larger bergs are enormous and often ground on the fjord floor (a smaller berg will turn onto its side when it calves). This slows the outflow in the fjord - some bergs can spend years in the fjord - which is why the ice-filled fjord has this unusual look on satellite pictures: an ice finger poking out into Disko Bay and the Davis Strait. But it's important not to confuse this ice-filled fjord with the glacier itself.

Of course, the glacier used to occupy the fjord. It retreated out of most of the fjord in the late 19th and early 20th century. Then the front stayed in about the same place for 40 years, before retreating out of the rest of the fjord since 2000. The calving front continues to retreat (looking at these pictures).

It's important to remember that the glacier flows much more quickly than it retreats. Flow at the calving front is about 10 km/year. The current retreat is something like 1 km/year. Flow of the small bergs in the fjord is much quicker than the glacier flow (however, as noted above, the large bergs can get stuck).

Now the retreat has passed the confluence, where multiple ice streams in the interior of the ice sheet join to make the glacier at the head of the fjord. The confluence is roughly fan-shaped, but the ice sheet isn't homogeneous; roughly speaking here there's a northern ice stream and a southern ice stream, and the ice between them doesn't flow as fast as the streams themselves. The ice streams carve channels for themselves in the bedrock. The flow rates upstream from the confluence are lower, of course.
August 1, 2009 6:31 AM

Nick, that was a really helpful explanation. Please feel free to add to it, and I will post it up. Thanks, Tenney

Greenland Ice Sheet melt -- July 28, 2008, vs. July 30, 2009

July 28, 2008 (left); July 30, 2009 (right).

Be sure to click on the images to enlarge the details.

Joseph Romm: Climate change expected to sharply increase Western wildfire burn area — as much as 175% by the 2050s

Climate change expected to sharply increase Western wildfire burn area — as much as 175% by the 2050s

Joseph Romm, Climate Progress, posted 30 July 2009, 06:30 a.m. PDT

A major new study, “Impacts of climate change from 2000 to 2050 on wildfire activity and carbonaceous aerosol concentrations in the western United States” finds a staggering increase in “wildfire activity and carbonaceous aerosol concentrations in the western United States” by mid-century under a moderate warming scenario:

We show that increases in temperature cause annual mean area burned in the western United States to increase by 54% by the 2050s relative to the present-day … with the forests of the Pacific Northwest and Rocky Mountains experiencing the greatest increases of 78% and 175% respectively. Increased area burned results in near doubling of wildfire carbonaceous aerosol emissions by mid-century.

This graph shows the percentage increase in area burned by wildfires, from the present-day to the 2050s, as calculated by the model of Spracklen et al. [2009] for the May-October fire season. The model follows a scenario of moderately increasing emissions of greenhouse gas emissions and leads to average global warming of 1.6 degrees Celsius (3 degrees Fahrenheit) by 2050. Warmer temperatures can dry out underbrush, leading to more serious conflagrations in the future climate.”

And this is just the mid-century prediction for the IPCC’s “moderate” A1B scenario (CO2 at 522 ppm in 2050), which predicts “mean July temperatures to increase by 1.8 °C from 2000 to 2050.” This is not the worst-case emissions path, which we are currently on (see U.S. media largely ignores latest warning from climate scientists: “Recent observations confirm … the worst-case IPCC scenario trajectories (or even worse) are being realised” — 1000 ppm). What would happen by 2100 on our current emissions path, when the mean July temperature increase from 2000 is triple (or more) the 1.8 °C that the researchers modeled? Turns out someone did model that a few years ago.

Back in 2004, researchers at the U.S. Forest Services Pacific Wildland Fire Lab looked at past fires in the West to create a statistical model of how future climate change may affect wildfires. Their paper, “Climatic Change, Wildfire, and Conservation,” published in Conservation Biology, found that by century’s end, states like Montana, New Mexico, Washington, Utah, and Wyoming could see burn areas increase five times.

For completeness sake — and because I remain optimistic that someday the media will routinely make the connection between increased forest fires and global warming — let me note that back in 2006 Science magazine published a major article analyzing whether the recent soaring wildfire trend was due to a change in forest management practices or to climate change. The study, led by the Scripps Institute of Oceanography, concluded:

Robust statistical associations between wildfire and hydroclimate in western forests indicate that increased wildfire activity over recent decades reflects sub-regional responses to changes in climate. Historical wildfire observations exhibit an abrupt transition in the mid-1980s from a regime of infrequent large wildfires of short (average of 1 week) duration to one with much more frequent and longer burning (5 weeks) fires. This transition was marked by a shift toward unusually warm springs, longer summer dry seasons, drier vegetation (which provoked more and longer burning large wildfires), and longer fire seasons. Reduced winter precipitation and an early spring snowmelt played a role in this shift.

That 2006 study noted global warming (from human-caused emissions of greenhouse gases such as carbon dioxide) will further accelerate all of these trends during this century. Worse still, the increased wildfires will themselves release huge amounts of carbon dioxide, which will serve as a vicious circle, accelerating the very global warming that is helping to cause more wildfires.

For more on the new study, see here.

Related Posts:

Seattle hits 103 -- Welcome to the hottest day ever!

Seattle hits 103 -- Welcome to the hottest day ever!

Seattle hits 103 -- Welcome to the hottest day ever!

Wearing a bag of ice water on his head, baseball fan Kirk Schlemlein, of Snohomish, Wash., reacts as a friend sprays water in his ear while trying to keep cool during a baseball game between the Seattle Mariners and the Toronto Blue Jays, Wednesday, July 29, 2009, at Safeco Field in Seattle.

Story Published: Jul 29, 2009 at 5:00 PM PDT

by Scott Sistek

SEATTLE -- It's a day for the weather history books. For on July 29, 2009, Sea-Tac Airport hit 103 (39.44 °C) degrees just after 3:30 p.m. for the hottest day on record in Seattle, with records stretching back to 1891.

The previous records were 100 (37.78 °C) degrees set July 20, 1994, July 16, 1941, and June 9, 1955*.

Here are the preliminary high temperatures at 5 p.m. (Link to a good Fahrenheit to Celsius converter:

  • Vancouver, WA: 107 (41.67 °C)
  • Kelso: 106 (41.11 °C)
  • Portland: 106 (all-time record: 107)
  • Chehalis: 106
  • Renton: 105 (40.56 °C)
  • Tacoma: 104 (40 °C)
  • Olympia: 104 (ties all-time record)
  • Shelton: 104
  • Seattle (Sea-Tac): 103 (all-time record)
  • Seattle (Boeing Fld): 103
  • Gig Harbor: 103
  • Arlington: 102 (38.89 °C)
  • Bremerton: 102
  • North Bend: 102
  • Everett: 100
  • Friday Harbor: 97
  • Bellingham: 96
  • Port Angeles: 92
  • Forks: 83
  • Hoquiam: 77
It's the second all-time weather record set on Wednesday in Seattle. The lowest temperature recorded so far today was 71 degrees, and it's a safe bet we won't drop below that before midnight tonight. That means we have shattered the record for warmest low temperature which was set... Tuesday. (Well, tied last night at 69. The low was also 69 on Sept. 2, 1974). Put another way, this is the first day ever that the temperature failed to drop below 70 degrees at some point during the day. Miami would be so proud...

Too hot to play outside today!

(Incidentally, if you're wondering about the asterisk by the June 9, 1955 note above, technically speaking, that 100 doesn't count as an official 100 degree high. Why? Just like the 1941 reading, that was taken at the Downtown Federal Building. But in 1945, the official reporting station for Seattle was moved from the Federal Building to Sea-Tac Airport. So the 1955 Federal Building reading doesn't count as an official record.

It's sort of like pitching a no-hitter for 9 innings, then giving up a home run in the 10th. You accomplished the feat by usual standards, but the record books don't recognize it.)

Other all time records are poised to fall as well. Bellingham hit 95 after 1 p.m. breaking their all-time record high of 94 degrees. Others in jeopardy: Olympia's is 104 (they hit 101 Tuesday) and Portland's is 107 (they hit 106 on Tuesday)

Hot Weather News:

The heat is causing a myriad of problems across the Puget Sound area, aside from people scrambling to keep cool.

  • Snohomish PUD says three substations went out near Monroe, knocking out power to about 14,000 people in the Monroe area.

    Officials say the heat caused transmission lines to sag into trees, causing brush fires. It also knocked out three substations.

    They were able to get all but 2,500 back online by 2:15, and then everyone else a short time later, but as power was coming back on, several transformers were reported on fire and torching the power poles, keeping firefighters busy across the city.

    Power outages were an issue in other parts of Western Washington as well. Some 10,000 people in Tacoma were without power for several hours during the record-breaking day, as were 700 others on Vashon Island. In Renton 2,800 residents were also left in the heat for an hour.

    Some 3,300 customers of Seattle City Light spent a few hours in the dark and without the relief of their fans on Wednesday night. And 300 Bellingham residents were forced to turn in for the night without power as crews were repairing an underground cable.

  • A flicked cigarette butt sparked a brush fire in the median of I-5 near Tukwila, the state patrol says.

    Flames were seen shooting up from the trees between the north and southbound lanes near S. 200 Street. The fire was put out a short time later, with the help of a foaming truck from Sea-Tac Airport, but traffic was backed up as far as eight miles through the afternoon as firefighting vehicles were blocking lanes to fight the fire.

  • Firefighters were also busy in West Seattle and Auburn battling house fires. The West Seattle one broke out around 1 p.m. in the 5200 block of 45th Ave. SW. People were inside when the fire started, but all got out safely. Two firefighters reportedly required treatment for heat exhaustion.

    About an hour later, a fire broke out in a home in the 600 block of 24th Street SE in Auburn. A neighbor called 911 after seeing smoke and flames coming from the back of the home.

    Firefighters rescued two dogs from the home, but one didn't survive. No word yet what caused that fire.

    Later in the evening, brush fires kept firefighter busy. A brush fire near the University of Washington's horticulture center scorched several acres. Firefighters had to stretch their hoses to the length of four football fields just to reach the flames.

    And at Lake Ballenger in Snohomish, flames shot more than 10 feet into the air, and a helicopter was called in to douse them.

    Want to buy an air conditioner or fan? Good luck!

    Now that the region has suffered through the warmest night on record, thousands went in search of air conditioning and fans.

    Lines were very long at several hardware and department stores -- including this line at the SoDo Sears store.

    Why over 100 today?

    We have the perfect heat scenario of an incredibly strong ridge of high pressure. That alone has been baking the Northwest into the 90s of late.

    But Wednesday, we finally have the icing on the cake to make this the "perfect storm" of a heat wave -- the hot, east wind.

    It took a while, but a thermal trough has finally developed that is drawing in the hot, dry east wind. Put the two together, and it's like mixing fire and oxygen.

    Locally, the east wind makes it hotter for a few reasons. One, that air is coming from Eastern Washington, where is hot to begin with. Second, as that air crosses over the Cascades and then sinks down, it warms further. For those living along the foothills, this is akin to living at the end of a blow dryer and why your highs are among the hottest.

    Now, as to why it's sticking around so long, the weather pattern over North America has two big features -- a big, big ridge of high pressure anchored along the western third (stretching from Baja to almost the Arctic Circle) and a big, big area of low pressure anchored over Hudson Bay.

    Not only has that ridge baked the West Coast, but on the other end of the scale, that low has made life miserable for the rest of the nation east of Denver. There, summer has gone into hiding, with relentless rain and thunderstorms. New York City is on pace for one of their coldest July's ever.

    With such exaggerated patterns, it's hard for them to budge because they are so strong they get stubborn. Incoming weather systems, typically weaker around here in summer anyway, are no match to move a ridge of this size, and then in turn, this ridge doesn't move to push the eastern low out of the way. It's like having a disabled semi jackknifed on the 520 bridge -- there's just not much room to move.

    That ridge, in turn, keeps the thermal trough over our area. Heat waves usually don't go longer than two or three days because the ridge gets nudged east by the westerly flow of the planet, and once the thermal trough moves east of the Cascades, it opens the door for the cool west wind to kick up. But with the ridge so strong, it's able to hold back the ocean breezes and maintain the thermal trough right over Western Washington.

    The last time we saw this pattern was 1977 and 1981, our two current heat wave champs. 1981 is notable for 5 days in a row over 90, including a 99 and 98, while 1977 had an 18 day period where it was over 79 every day (15 in a row over 80), 13 days over 85 (9 consecutive) and six days over 90 (4 consecutive).

    The east wind should also at least eat away at some of this lingering humidity, but it'll still be a bit muggier than a normal heat wave - not that anything else is much normal about this heat anyway.

    Record Check:

    A quick list of other records that might fall this week:

    • Consecutive days at or over 90: 5 (Aug. 7-11, 1981). Current forecast: 4, Potential: 6
    • Consecutive days at or over 85: 9 (Aug. 5-13, 1977). Current forecast: 9. Potential: 11
    • Consecutive days at or over 80: 15 (July 30-Aug 13, 1977) -- Current forecast: 11, which stretches through the end of the extended forecast. Potential: ??? (Incidentally in the '77 streak, the 14th was 79, there were three more 80s afterward.
    • Number of 90 degree days in a month: 7 (July 1958)
    • . Current forecast: 6. Potential: 7
    • Number of 90 degree days in a year: 9 (1958)
    • . Through Tuesday: 5 with two more a slam dunk, and potential for a few more by next Monday. And there's still August and early Sept. yet.
    • Hottest July on record (high temperature): 81.4 degrees in 1958. (If current 7 day forecast verifies exactly, our avg. this month will be 81.25)
    • Seattle daily records: Wednesday: 95, Thursday: 94. Friday: 93

    When Does It End?!?

    As I mentioned earlier, this pattern has the makings of the 1977 heat wave that stretched 18 days. We should begin some gradual cooling as we get into Friday, and by the weekend, highs should be into the upper 80s as this ridge slowly weakens. But a new area of low pressure developing off the California coast, it will keep pressures lower offshore and could keep the surge of marine air from rolling in until the middle of next week, meaning several more days of above normal temperatures, although not to these extreme levels.

    BUT! Cool weather fans, I present this to you:

    That may seem like squiggles and blobs, but what it represents, is bliss: At face value, that's a mostly cloudy day with a few showers and highs in the upper 60s or so.

    Only one slight problem -- that's not until next Thursday. It's circled on my calendar anyway.

  • Link:
  • Wednesday, July 29, 2009

    Subglacial hydrology, basal lubrification, glacier acceleration

    Basal Lubrication - Just Use Water

    by Graham Cogley,, July 27, 2009

    It sounds like something they might do to you at a health spa, doesn’t it? But to students of glaciers, basal lubrication is the key that unlocks a long list of puzzles.

    Why do precise measurements of glacier motion often show stick-slip behaviour, that is, hours and hours of near motionlessness punctuated by half-hours of rapid movement? Why do some glaciers surge, that is, accelerate suddenly every few decades, flowing rapidly for a year or two before returning, sometimes suddenly but more often gradually, to normal? Why does the landscape of southern Ontario, which I can see from my window, undulate? Why, in the sediment of the northern Atlantic Ocean, are there occasional layers of sand, interrupting the blanket of ultra-fine-grained mud?

    The layers of sand beneath the Atlantic are spaced irregularly, 10,000-15,000 years apart, according to the Principle of Superposition, at depths below the sea floor that correspond to the last ice age. They are thin on the European side, thicker towards the northwest, and thickest of all in the neighbourhood of Hudson Strait, which separates Quebec from Baffin Island. The simplest explanation of this pattern is that every so often the bed of the Laurentide Ice Sheet, that covered most of Canada, became much more slippery. Much of its interior was drained by the Hudson Strait Ice Stream, which accelerated occasionally and discharged icebergs in huge numbers. With the icebergs came the sand. All of the plausible accounts of this instability have variations in basal meltwater supply, or possibly just its behaviour, as a critical ingredient.

    Around where I live, we are rather proud of our drumlin field. Somebody counted these egg-shaped hills and got up to about four thousand. But geomorphologists now reckon that the tunnel channels are even more interesting. Tunnel channels are drainage networks shaped by subglacial meltwater at the end of the last ice age, after the ice had shaped the drumlins and indeed not long before the ice disappeared altogether. For a long time I simply could not see these things, and I still suspect that the geomorphologists are asking for more meltwater than is probable, but recent evidence from beneath the modern ice sheets is vindicating their interpretations. Now I can see the ancient tunnel valleys in the light of modern ones, apparently hard at work, beneath the Antarctic Ice Sheet.

    I don’t know why most glaciers do not surge but a few do. Nor does anyone else. Surging is a phenomenon that has eluded explanation over several decades of concentrated observation and analysis. But we are all positive that subglacial hydrology contains the answer if we can only put together the pieces of the puzzle. The most recent instance of a surging glacier, detected by the U.S. Geological Survey on 3 July 2009, happens also to be a famous glacier -- Malaspina Glacier in Alaska.

    Many glaciers go faster in summer, suggesting that meltwater supply has something to do with glacier speed. Where the ice is observed to move in short bursts, there is usually also a suggestion, from one line of evidence or another, that it spends most of the time frozen -- that is, stuck -- to its bed. Slip happens when that immobile state is disturbed, in other words when the bed is lubricated upon the arrival of meltwater. But where does the meltwater come from? And go to?

    It might not go anywhere, if the stuff that is moving around is not water but heat. That is, stick-slip may be telling us not about patterns of meltwater flow but about patterns of thawing and freezing. In fact, there may not be any heat moving around either. The melting temperature depends, slightly but measurably, on the confining pressure. So the thaw-freeze patterns could actually be patterns of subtle fluctuations of pressure, not just squeezing the water from one place to another but determining which of the two states, solid or liquid, it is stable in.

    It is all very complicated, at scales from sticky patches up to the width of the north Atlantic and beyond. Great fun for glaciologists, but not without consequences for society -- for example, if the Antarctic or Greenland Ice Sheet should decide to do what, according to the lesson from the sand under the Atlantic, the Laurentide Ice Sheet did repeatedly.


    Hank Roberts said...

    A while back, I dumped a collection of quotes, references, and links on drumlins, subglacial channels, and jokulhapts here (with a pointer to an earlier thread at the late Prometheus blog):

    Thanks Hank! That's great stuff!


    Comments on stoat:

    Curious -- I read this:
    " ...The research team found that the Recovery stream accelerates significantly as it passes over the lakes.

    "Upstream of the lakes, it flows at two to three metres per year; after passing them, at about 50 metres per year.

    "Whether there is a link to climate change is another question. The lakes lie in the eastern portion of Antarctica, where evidence suggests the icecap may be gaining mass rather than losing it.
    "As this research team puts it: 'The Recovery sub-glacial lakes and the associated Recovery ice stream tributaries have the potential greatly to affect the drainage of the East Antarctic ice sheet, and its influence on sea level rise in the near future.'"

    and read the abstract for this:

    "Rapid Sediment Erosion and Drumlin Formation Observed Beneath a Fast-Flowing Antarctic Ice Stream - AM Smith, T Murray, KW Nicholls, K Makinson, G ... - American Geophysical Union, Fall Meeting 2005

    Couple questions: at the bottom of the icecap (everywhere, I think) there's enough ice thickness that it's grounded. How close are any areas of the ice to neutral? I realise the water pressure at the bottom of the ice is ---- whatever it is, at a mile or two below sea level.

    [There are bits of W Antarctica that are fairly close to neutral - part of its possible instability -W]

    Does water under pressure carry more silt than water at 1 atmosphere pressure?
    I ask because the rapid drumlin article says, yes, they looked through the ice and saw one form, really fast -- these had been thought to be slow creatures.

    But -- given that liquid water is flowing along the interface between ice and ground, whatever that ground is (presumably rock) --- how much of what kind of rock flour can that stream carry?

    I know it's possible to "fill up" a moving stream's capacity to carry a load -- any time the flow becomes turbulent it drops some and then when it gets laminar it can and will pick up more again. It's one of the conundrums of restoration: if I take a nasty eroding stretch of stream and methodically make check dams and secure eroding banks and plant willow, and otherwise do everything I can to make that stretch of streambed turbulate the flow and be dropping rather than carrying all the sediment it can.

    Anytime you turbulate a flow, whatever's flowing drops some of what it's carrying.

    If there's a dead air spot on the interface, anyplace a vortex or ripple consistently leaves undisturbed, whatever silt (for a stream), leaves and dust and seeds (for a breeze), or household lint (for a fan).

    So --- we're at the bottom of a glacial ice cap. There's a lot of melting way above but we're two miles down and it's been dark and quiet for a while. But every now and then the ice does flow far enough to cause the contact plane to shift downstream a bit.

    There will be some flow, where there's excess heat or friction or impurities in the water if anything can change its melting point in those conditions.

    We get flows of water; some of them are carrying silt.

    That passes through a space where there's a bit of a void, the stream spreads out and slows down and drops what it's carrying.

    So, finally, a question -- isn't a drumlin seen happening so fast, likely to be built up by silt filling a void that's melted a bit, on the bottom of the ice, and so going to get silted up as fast as the flowing water going by can provide the silt?

    How else could they be happening, under the ice and so fast? And doesn't this lead to some ideas about streamflow rate?

    And, has anyone had a look at the Channeled Scablands recently? They were an icecap letting go --- are we sure the water was on top of or behind that ice, or could it have been building up underneath the ice like this?

    Because there's one other thing a very silty fast strong flow will do going downhill --- cut away what's in front of it and just rearrange it if it's so full of silt it can't keep any more suspended. A topside melt lake will be mostly water; an under-ice-cap flow must be quite a bit of silt.

    Done handwaving; I'll go catch up on the drumlin stories. Turns out they're seen on Mars, resembling those in the Scablands. Hmmmm.

    [Ah, I know nothing of drumlins - sorry -W]

    Posted by: Hank Roberts | February 23, 2007 10:06 PM


    Well, drumlins were thought to be long slow streamflow processes, til that snapshot of fast formation under the ice. Perhaps nobody knows yet. Got grad students? (grin)

    Does this make sense?
    "... Martin Siegert, a glaciologist at the University of Bristol in England. "\...

    The melting point of ice in environments such as Lake Vostok is related to the thickness of the ice above the water. The melting point is colder under thicker ice, as it is at the northern end of the lake.

    The water that melts at the northern end will thus be colder and less dense than water at the southern end. "The density contrast between these waters will cause the circulation," said Siegert.
    I wonder why the melting point would be colder under thicker ice, and if that relationship is linear, or describes only the Lake Vostok depth conditions.
    (Clipped from a BBC story, lost the cite, sorry).

    [Because of the pressure effect. Pressure will melt ice, you know that; ie the melt point gets lower under pressure -W]

    Here's another source for the "20 feet in 100 years" sea level rise possibility:

    " ... the WAIS is considered unstable because a large portion of it floats on water above the sea floor. For this reason, scientists suspect that the WAIS is particularly sensitive to global climate change, and they have long debated whether global warming would cause the WAIS to collapse. ...

    "If so much ice melted into the oceans at once, sea levels could rise as high as 20 feet all over the world, within a single century. ..."

    [Ermm, OK, but its still *if* -W]


    I'd speculate the whole idea of meltwater lakes sitting on top of icecaps and spilling over is due for a revision --- and that we'll be looking at things like drumlins completely differently now that we know they can form rapidly under ice. It still has to be happening from deposition by flowing water --- but it's not surface water.

    Looking at the radar maps of the ground under the ice, what I see is the major areas below sea level looking like places not pushed down dramatically by the overlying ice, but like river drainage channels. As the ice accumulated and moved, now that we know about under ice flows, the icecap would push whatever rock flour and warm-epoch silt out toward the edges, carrying it along with meltwater.

    What do you see looking at the radar maps? Looks to me like --- clear shapes toward the middle; less and less clear out to the edges along each likely river course, and big smooth rounded banks of what I'd expect to be extruded silt/rock flour along the edges.

    I think under the ice caps water is flowing 'uphill' from the basins around the center, radially, and as it spreads out it flows slower, so the farther it goes toward the circumference the more silt it drops.

    Fill a deep bowl with peanut butter, put a shallower bowl on the top, push down ....

    Okay, enough speculation from the uninformed and uneducated moi. Just wondering.

    Posted by: Hank Roberts | February 24, 2007 11:46 AM


    Belatedly, I find New Scientist covered all these ideas (except they haven't quoted anyone anticipating my Channeled Scablands speculation, you read that first here) in their special December 2-8, 2006, special issue: "Hidden World Beneath Antarctica's Ice."

    It's really quite good. Other than being quietly overwhelming.

    "Water moves in mysterious ways. The weight of the ice squeezing downwards counts for much more than local hills and valleys in telling water where to go. 'You can have lakes sloping down the sides of mountains, you can have uphill waterfalls, it's wacky' [Don Blankenship, geophysicist at U. Texas] ....Blankenship fears that warming since the end of the last ice age has melted the base of the ice, and this may already be priming some parts of the ice sheet to slip. East Antarctica could be ready to open its floodgates.

    "David Marchant from Boston University believes this may have happened before. .... one place in particular, a tortured landscape of channels and pits known as the Labyrinth .... sinuous .... often potholes .... channels that stop abruptly .... what you'd expect if they had been made by water that then flowed off down a different path, ... or plunged [that's in an upward direction --hr] into the overlying ice.

    "He became convinced that the Labyrinth had been carved by a massive under-ice flood, and he published his ideas in July (Geology, v34, p. 513). .... potholes that are 200 metres across and 50 metres deep,' says Marchant. 'They are just enormous features. They're the largest potholes in the world. The water quickly stripped away all sedimentary rocks, and then lifted blocks of granite bedrock more than 2 metres wide ..."

    Okay, I think this is serious stuff. Anyone found any more about it?

    Posted by: Hank Roberts | March 1, 2007 12:22 AM


    Ok, it's been covered. Good references, including the Antarctic

    "... By about 1990 the way that glaciologists envisaged
    basal water flow had greatly changed, largely owing to
    the realization that R channels could not form the basis
    for an explanation of observations from surging Varie-
    gated Glacier [Kamb et al., 1985] and rapidly moving ice
    stream B in Antarctica [Blankenship et al., 1987]. Theo-
    ries were developed to elucidate the hydraulics of water
    flow through linked cavities [Walder, 1986; Kamb, 1987],
    deformable till [Alley et al., 1987], and till-floored chan-
    nels [Walder and Fowler, 1994]....

    To summarize, the drainage system under any given
    glacier comprises several or all of the morphologically
    distinct components described in this section. A slow,
    nonarborescent drainage system, comprising a mixture
    of elements including cavities, permeable till, and
    conduits incised into the bed (i.e., Nye channels and canals),
    probably covers most of the glacier bed and is nearly
    fixed relative to the bed. The water pressure in the slow
    drainage system is commonly close to the ice-overburden pressure.

    Posted by: Hank Roberts | March 1, 2007 6:20 AM


    Say what? Has this story showed up as science yet?

    ------ begin snippet -----

    ... early conclusions drawn by geologists at Andrill (Antarctic Geological Drilling), the multinational consortium leading the project, which recently released preliminary data from the drilling on its Web site. ...

    A first look at conditions that prevailed five million years ago

    "This time we were able to drill into layers representing the period between five and 12 million years ago," Andrill team member and geologist Lothar Viereck-Götte told SPIEGEL ONLINE. What these unique ice cores revealed about temperature changes in the last 5 million years was both surprising and new, says Viereck-Götte, who calls the results "horrifying." The data suggests "the ice caps are substantially more mobile and sensitive than we had assumed.",1518,469495,00.html

    Posted by: Hank Roberts | March 10, 2007 10:12 AM


    BAS liked the "Drumlin" paper:

    Paper of the Month
    30 Mar 2007

    Rapid erosion, drumlin formation, and changing hydrology beneath an Antarctic ice stream

    Posted by: Hank Roberts | April 2, 2007 5:06 PM


    found here:

    Re the latest release from the IPCC:
    ---- quote----
    Change 3: Deleting a threat:
    The scientists originally included this statement about changes caused by retreating glaciers:
    enlargement and increased numbers of glacial lakes, with increased risk of outburst floods

    The final draft wound up reading:
    enlargement and increased numbers of glacial lakes
    ---- end quote -----

    Anyone got anything new on drumlins?

    Posted by: Hank Roberts | April 10, 2007 6:49 PM


    Jökulhlaups. With an umlaut.

    Having learned that the whole issue is handled by this single word, I can let the subject rest.

    Subglacial floods beneath ice sheets
    Issue Volume 364, Number 1844 / July 15, 2006
    Pages 1769-1794
    Article Type Research-Article
    DOI 10.1098/rsta.2006.1798

    G.W. Evatt1, A.C. Fowler 1, C.D. Clark 2, N.R.J. Hulton 3

    1 Oxford University Mathematical Institute 24-29 St Giles', Oxford OX1 3LB, UK
    2 University of Sheffield Department of Geography Winter Street, Sheffield S10 2TN, UK
    3 University of Edinburgh School of Geosciences Drummond Street, Edinburgh EH8 9XP, UK


    Subglacial floods (jökulhlaups) are well documented as occurring beneath present day glaciers and ice caps. In addition, it is known that massive floods have occurred from ice-dammed lakes proximal to the Laurentide ice sheet during the last ice age, and it has been suggested that at least one such flood below the waning ice sheet was responsible for a dramatic cooling event some 8000 years ago. We propose that drainage of lakes from beneath ice sheets will generally occur in a time-periodic fashion, and that such floods can be of severe magnitude. Such hydraulic eruptions are likely to have caused severe climatic disturbances in the past, and may well do so in the future.

    Posted by: Hank Roberts | June 14, 2007 9:03 PM


    Lo! It's News! (Well, it's about Greenland, so I'm still just speculating that it's happening in Antarctica too, and happened underneath the continental glaciers elsewhere like in Idaho instead of water pooling on top of them as often pictured.)

    Note per last line of the abstract that nobody has thought about this possibility til now :-)

    (P.S., William, search on your blog page is still or again broken. Google for stoat scienceblog jokulhlaup
    found the dusty old topic to add this. Good thing I remembered how to spell jokulhlaup.

    GEOPHYSICAL RESEARCH LETTERS, VOL. 35, L02503, doi:10.1029/2007GL031765, 2008

    Channelized bottom melting and stability of floating ice shelves

    E. Rignot

    Earth System Science, University of California, Irvine, California, USA
    Jet Propulsion Laboratory, Pasadena, California, USA

    K. Steffen

    Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado, USA


    The floating ice shelf in front of Petermann Glacier, in northwest Greenland, experiences massive bottom melting that removes 80% of its ice before calving into the Arctic Ocean. Detailed surveys of the ice shelf reveal the presence of 1-2 km wide, 200-400 m deep, sub-ice shelf channels, aligned with the flow direction and spaced by 5 km. We attribute their formation to the bottom melting of ice from warm ocean waters underneath. Drilling at the center of one of channel, only 8 m above sea level, confirms the presence of ice-shelf melt water in the channel. These deep incisions in ice-shelf thickness imply a vulnerability to mechanical break up and climate warming of ice shelves that has not been considered previously. ....

    [Interesting, true, but losing 80% is an awful lot. It hardly matters if they break up after that :-) nb this can only apply to ice shelves, not the main ice sheet -W]

    Posted by: Hank Roberts | January 19, 2008 9:40 PM


    William, which 'this'?

    > this can only apply to ice shelves, not the main ice sheet

    "this" -- the channels under the ice? Or the breakup?

    [The channels. They are from oceanic heat: "We attribute their formation to the bottom melting of ice from warm ocean waters underneath" -W]

    I'd think the channels observed out at the edges of the Greenland ice would likely have counterparts under the Antarctic -- the shape would seem to be from meltwater flowing out rather than melting along the edge from warm seawater.

    I recall (maybe left links earlier above or in the old Prometheus thread) that liquid water has been described there from cameras lowered into boreholes to the base of the ice, in surprising large voids, and flows of water observed under the ice sheets would, I'd think, create similar channels.

    Admittedly they won't be as easy to observe; I recall one unmanned sub was lost,

    but don't see much new reported, though there are mentions of several new ones planned

    Posted by: Hank Roberts | January 21, 2008 2:46 PM



    Robotic Telescope Installed on Antarctica Plateau
    Posted by Zonk on Wednesday February 06, @03:44PM

    Robotics Space Science

    Reservoir Hill writes "Antarctica claims some of the best astronomical sky conditions in the world -- devoid of clouds with steady air that makes for clear viewing. The very best conditions unfortunately lie deep in the interior on a high-altitude plateau called Dome A. With an elevation of up to 4,093m, it's known as the most unapproachable point in the earth's southernmost region. Now astronomers in a Chinese scientific expedition have set up an experimental observatory at Dome A after lugging their equipment across Antarctica with the help of Australia and the US. The observatory will hunt for alien planets, while also measuring the observing conditions at the site to see if it is worth trying to build bigger observatories there. The observatory is automated, pointing its telescopes on its own while astronomers monitor its progress from other locations around the world via satellite link. PLATO is powered by a gas generator, and has a 4000-litre tank of jet fuel to keep it running through the winter. The observatory will search for planets around other stars using an array of four 14.5-centimetre telescopes called the Chinese Small Telescope Array (CSTAR). Astronomers hope to return in 2009 with new instruments, including the Antarctica Schmidt Telescopes (AST-3), a trio of telescopes with 0.5-metre mirrors, which will be more sensitive to planets than CSTAR."

    Posted by: Hank Roberts | February 7, 2008 2:00 AM


    So, given that we know this:

    and have reports about surface melting in Antarctica,

    and now this:

    ... The paired surface temperature and gravity data confirm a strong connection between melting on ice sheet surfaces in areas below 6,500 feet in elevation, and ice loss throughout the ice sheet's giant mass. The result led Hall's team to conclude that the start of surface melting triggers mass loss of ice over large areas of the ice sheet.

    The beginning of mass loss is highly sensitive to even minor amounts of surface melt. Hall and her colleagues showed that when less than two percent of the lower reaches of the ice sheet begins to melt at the surface, mass loss of ice can result. For example, in 2004 and 2005, the GRACE satellites recorded the onset of rapid subsurface ice loss less than 15 days after surface melting was captured by the Terra satellite.

    The MODIS instrument acquired this image of melt ponds on Greenland's western coast in June, 2006. The MODIS instrument acquired this image of melt ponds on Greenland's western coast in June, 2006. The ponds appear as dark blue dots on the aqua blue background.

    "We're seeing a close correspondence between the date that surface melting begins, and the date that mass loss of ice begins beneath the surface," Hall said. "This indicates that the meltwater from the surface must be traveling down to the base of the ice sheet -- through over a mile of ice -- very rapidly, where its presence allows the ice at the base to slide forward, speeding the flow of outlet glaciers that discharge icebergs and water into the surrounding ocean."

    How will the modelers handle this behavior?

    I recall this:

    [Response: Dynamics are as important as thermodynamics here. Recent evidence (e.g. as reviewed by us a few months back) suggests that the demise of large parts of the major ice sheets could potentially take place far faster-on timescales of perhaps several centuries-due to the influence of ice sheet dynamics. For example, crevices at the surface of the ice sheet are now known to sometimes penetrate all the way down to the bottom of the ice sheet forming channels ("moulins") that allow surface meltwater to reach the bottom of the ice sheet, where it lubricates the ice, allowing it to stream into the ocean at velocities potentially far greater than once envisioned. These processes are still far from perfectly understood, because they require a representation of the fairly complicated rheology involved in ice sheet dynamics. But it appears far more likely that a better understanding of these processes will act to revised our estimates of ice sheet collapse timescales downward, rather than upward. - mike]


    Posted by: Hank Roberts | February 23, 2008 8:08 PM


    Sunday, 24 February 2008, 00:24 GMT

    Antarctic glaciers surge to ocean
    By Martin Redfern
    Rothera Research Station, Antarctica

    ---excerpts follow------

    ... the researchers spent most of their time driving skidoos across the flat, featureless ice.

    "We drove skidoos over it for something like 2,500km each and we didn't see a single piece of topography."

    Rob Bingham was towing a radar on a 100m-long line and detecting reflections from within the ice using a receiver another 100m behind that.

    The signals are revealing ancient flow lines in the ice. The hope is to reconstruct how it moved in the past.
    Throughout the 1990s, according to satellite measurements, the glacier was accelerating by around 1% a year. Julian Scott's sensational finding this season is that it now seems to have accelerated by 7% in a single season, sending more and more ice into the ocean.

    "The measurements from last season seem to show an incredible acceleration, a rate of up to 7%. That is far greater than the accelerations they were getting excited about in the 1990s."

    The reason does not seem to be warming in the surrounding air. ...

    Posted by: Hank Roberts | February 23, 2008 10:14 PM


    A useful expert summary here:

    Quoting in full, because it answers a lot of my questions in simple clear language of few syllables:

    # Mauri Pelto Says:
    28 April 2008 at 2:52 PM

    Lakes form at the bottom of a glacier or on the surface. Because ice crystals deform under pressure, and pressure is substantial within a glacier or ice sheet it is not possible to have substantial void volumes. Ice under pressure would deform and flow into this void. This happens to much of the seasonal hydrology system each winter. Without water flow to keep tunnels open, they close, then in spring maximum water pressures often occur befor the conduit system redevelops. Once opened the flowing meltwater can maintain these narrow conduits. However, the meltwater does not have enough heat to melt much. At the base of the glaciers even in the summer next to these streams, you will see new ice coating the bedrock in places. The moulin ice riddling is science fiction. No ice sheet or glacier collapses due to riddling by moulins. I still see a persistent misconception about the ability of meltwater to melt glacier ice and riddle the glacier with holes. I work on glaciers with lots of melt and they are not weakened by all the meltwater drainage. The meltwater is not a very capable melter of ice. Ice is unlike rock which does not deform under the pressure and temperatures observed on glaciers.

    Posted by: Hank Roberts | April 28, 2008 5:56 PM


    The ANDRILL ice cores should have been farmed out to researchers who should be writing and publishing papers on them Has anyone seen mention of these?

    I found this:


    in late 2006, the Andrill team discovered undisturbed deposits 15 kilometers (9 miles) outside the research station near the Mount Erebus volcano.

    A first look at conditions that prevailed five million years ago

    "This time we were able to drill into layers representing the period between five and 12 million years ago," Andrill team member and geologist Lothar Viereck-Götte told SPIEGEL ONLINE.

    What these unique ice cores revealed about temperature changes in the last 5 million years was both surprising and new, says Viereck-Götte, who calls the results "horrifying." The data suggests "the ice caps are substantially more mobile and sensitive than we had assumed."

    "The idea that the ocean here was ice-free for almost a million years is completely new," says Viereck-Götte. Besides, he adds, the melting that occurred about 5 million years ago can be seen in the context of a prehistoric climate shift.

    According to Viereck-Götte, "massive melting" must have occurred in the Antarctic during the so-called Miocene-Pliocene warming. The cause sounds anything but massive. Based on isotope analyses from various locations worldwide, paleoclimatologists know that the average global temperature in the oceans increased by only two to three degrees Celsius (3.6-5.4 degrees Fahrenheit) -- a seemingly minor change. Nevertheless this change in temperature, according to the new Andrill ice core, led to an ice-free Ross Sea.

    For researchers the clue lies in tiny microorganisms known as diatoms, which cannot survive in water that is covered by ice. But they were found in the core representing an uninterrupted period of 1 million years.

    "We would never have thought that this system is so sensitive," says Viereck-Götte. The consequences of an ice-free Ross Sea would be far-reaching, not just for sea levels.

    -----end excerpt--------

    Posted by: Hank Roberts | April 29, 2008 7:28 PM


    "The Antarctic Geological Drilling (ANDRILL) programme has astonished scientists recently with evidence for periodic warm open waters in the Ross Sea up until as recently as 1 million years ago...."

    Nature 451, 284-285 (17 January 2008) | doi:10.1038/nature06589; Published online 16 January 2008
    Unlocking the mysteries of the ice ages
    Maureen E. Raymo & Peter Huybers

    Posted by: Hank Roberts | April 29, 2008 7:50 PM


    Actual science (abstract only)

    Palaeogeography, Palaeoclimatology, Palaeoecology
    Volume 260, Issues 1-2, 7 April 2008, Pages 245-261
    Antarctic cryosphere and Southern Ocean climate evolution (Cenozoic-Holocene), 1) EGU Meeting, 2) XXIX SCAR Meeting

    Retreat history of the Ross Ice Sheet (Shelf) since the Last Glacial Maximum from deep-basin sediment cores around Ross Island

    R.M. McKay, G.B. Dunbar, T.R. Naish, P.J. Barrett, L. Carter and M. Harper

    Posted by: Hank Roberts | April 29, 2008 8:07 PM


    Increasing Antarctic sea ice under warming atmospheric and oceanic conditions

    Author(s): Zhang JL (Zhang, Jinlun)
    Source: JOURNAL OF CLIMATE Volume: 20 Issue: 11 Pages: 2515-2529 JUN 1 2007 Times Cited: 1 References: 34
    IDS Number: 177NH
    ISSN: 0894-8755
    DOI: 10.1175/JCLI4136.1

    Abstract: Estimates of sea ice extent based on satellite observations show an increasing Antarctic sea ice cover from 1979 to 2004 even though in situ observations show a prevailing warming trend in both the atmosphere and the ocean. This riddle is explored here using a global multicategory thickness and enthalpy distribution sea ice model coupled to an ocean model. Forced by the NCEP-NCAR reanalysis data, the model simulates an increase of 0.20 x 10(12) m(3) yr(-1) (1.0% yr(-1)) in total Antarctic sea ice volume and 0.084 x 10(12) m(2) yr(-1) (0.6% yr(-1)) in sea ice extent from 1979 to 2004 when the satellite observations show an increase of 0.027 x 10(12) m(2) yr(-1) (0.2% yr(-1)) in sea ice extent during the same period. The model shows that an increase in surface air temperature and downward longwave radiation results in an increase in the upper-ocean temperature and a decrease in sea ice growth, leading to a decrease in salt rejection from ice, in the upper-ocean salinity, and in the upper-ocean density. The reduced salt rejection and upper-ocean density and the enhanced thermohaline stratification tend to suppress convective overturning, leading to a decrease in the upward ocean heat transport and the ocean heat flux available to melt sea ice. The ice melting from ocean heat flux decreases faster than the ice growth does in the weakly stratified Southern Ocean, leading to an increase in the net ice production and hence an increase in ice mass. This mechanism is the main reason why the Antarctic sea ice has increased in spite of warming conditions both above and below during the period 1979-2004 and the extended period 1948-2004.

    [Yeah. Not sure I believe it though -W]

    Posted by: Hank Roberts | September 22, 2008 2:13 PM


    More from the old workplace:

    Posted by: Hank Roberts | November 17, 2008 8:42 PM

    Michael Cunliffe, Peter Liss, Oliver Wurl: Sea-surface microlayer habitant is distinct phytoplankton ecosystem, ocean-atmosphere interface

    Scientists Find a Microbe Haven at Ocean’s Surface

    A LITTLE OFF THE TOP Little Kilo Moana skims thin layers from the ocean’s surface near its namesake, a University of Hawaii research vessel. Scientists have learned that the top hundredth-inch of the ocean is an ecosystem all its own. (Photo: Masaya Shinki)

    The world’s oceans are like an alien world. The National Oceanic and Atmospheric Administration estimates that 95% of them remain unexplored. But the mysteries do not start a mile below the surface of the sea. They start with the surface itself.

    Scientists are now discovering that the top hundredth-inch of the ocean is somewhat like a sheet of jelly. And this odd habitat, thinner than a human hair, is home to an unusual menagerie of microbes. “It’s really a distinct ecosystem of its own,” said Oliver Wurl, of Canada’s Institute of Ocean Sciences.

    This so-called sea-surface microlayer is important, scientists say, in part because it influences the chemistry of the ocean and the atmosphere. “One of the most significant things that happens on our planet is the transport of gases in and out of the ocean,” said Michael Cunliffe, a marine biologist at the University of Warwick in England. The ocean stores a large fraction of the global-warming gases we produce; at the microlayer, the gases are pulled down.

    “It’s the ocean breathing through its skin,” Dr. Cunliffe said.

    Sailors have long known that the surface can be covered with oily slicks (hence the phrase “pouring oil on troubled waters”). But when scientists began studying the surface in the mid-20th century they found it vexing. A scientist cannot just dunk a bucket into the ocean without dredging up deeper water as well. “Even defining the surface is hard, since it’s moving up and down,” said Peter Liss, a professor of environmental sciences at the University of East Anglia in England.

    So scientists had to invent some tools to skim the surface. Dr. Liss and his colleagues, for example, chill a piece of glass with liquid nitrogen and lower it into the sea, freezing water it contacts.

    These tools have allowed scientists to discover that the top hundredth of an inch is chemically distinct. It is loaded with molecules carried up by air bubbles and concentrated at the surface.

    Recent surveys carried out by Dr. Wurl and his colleagues have revealed that the microlayer has a rich supply of sticky clumps of carbohydrates. These carbohydrates are made by single-cell organisms called phytoplankton that live lower in the ocean to stick together in colonies. Eventually the carbohydrates break off the phytoplankton and clump together. Dr. Wurl’s studies indicate that many of them rise to the microlayer, forming a film.

    “I really imagine it as tiny pieces of jelly floating on the ocean,” Dr. Wurl said.

    It may be hard to imagine such a fine coat of slime holding together for long on top of the heaving ocean. But Dr. Wurl has found that it is quite durable. “We have collected microlayer samples with wind conditions of 16 to 18 knots,” he said. “It’s not pleasant to be in a small boat at that wind speed. That tells us the microlayer is pretty stable.”

    Dr. Wurl and his colleagues report the findings in a paper to be published in the journal Marine Chemistry. He suspects that when waves disrupt the jellylike microlayer, air bubbles deliver sticky material back to the surface.

    Dr. Cunliffe, who has replicated Dr. Wurl’s results, argues that these studies mean that the microlayer is a special kind of habitat for microbes. The gelatinous film calms the turbulence in the microlayer, which may make it easier for bacteria to attach to the particles and feed on the molecules flowing past.

    To document the sort of microbes that live in the microlayer, Dr. Cunliffe and other researchers are collecting surface water, breaking open the cells it contains, and sequencing the genes they hold. They compare the microlayer residents to the microbes that live a few inches deeper.

    “We’re finding consistently different communities,” Dr. Cunliffe said. The microlayer communities are dominated by groups of microbes well known for forming biofilms on more familiar surfaces, like rocks in streams, our teeth and the insides of sewer pipes.

    “They’re always the usual suspects,” Dr. Cunliffe went on. “If our hypothesis is correct, it makes complete sense.”

    Dr. Liss called the finding “a really interesting result, because it shows that the microlayer is a really different environment.”

    Scientists say it is important to become better acquainted with this mysterious ocean skin, because it may play a critical role in the environmental well-being of the planet. Studies have shown, for example, that pollutants like pesticides and flame retardants can be trapped in the microlayer.

    Dr. Cunliffe and his colleagues have identified bacteria in the microlayer that devour important chemicals like methane and carbon monoxide. The microlayer is also crucial to the ocean’s ability to absorb carbon dioxide, a potent greenhouse gas.

    “It’s actually sucking the carbon dioxide down into the water column,” Dr. Cunliffe said.

    Dr. Liss said the microlayer was “clearly important, because it’s where the ocean and the atmosphere interact.”

    “But it’s difficult to study,” he added, “so it hasn’t received as much attention as it ought to.”


    Sharon Begley, Newsweek: Climate-change calculus -- Why it's even worse than we feared

    Climate-Change Calculus

    Why it's even worse than we feared

    M. A. Kelly & T. V. Lowell, Quart. Sci. Rev., Fluctuations of local glaciers in Greenland during latest Pleistocene and Holocene time

    Quarternary Science Reviews, 2008, doi:10.1016/j.quascirev.2008.12.008
    Elsevier Science Publishers

    Fluctuations of local glaciers in Greenland during latest Pleistocene and Holocene time

    Meredith A. Kelly (Geochemistry Division, Lamont-Doherty Earth Observatory, Palisades, NY 10964, U.S.A.)*, E-mail The Corresponding Author and Thomas V. Lowell (Department of Geology, University of Cincinnati, Cincinnati, OH 45221, U.S.A.)

    Received 22 May 2008, revised 4 December 2008,
    accepted 4 December 2008.
    Available online 29 January 2009.


    This paper is the first to summarize research on fluctuations of local glaciers in Greenland (e.g. ice caps and mountain glaciers independent of the Greenland Ice Sheet) during latest Pleistocene and Holocene time. In contrast to the extensive data available for fluctuations of the Greenland Ice Sheet, surprisingly little data exist to constrain local glacier extents. Much of the available research was conducted prior to wide-spread use of AMS radiocarbon dating and the advent of surface-exposure and luminescence dating. Although there is a paucity of data, generally similar patterns of local glacier fluctuations are observed in all regions of Greenland and likely reflect changes in paleoclimate, which must have influenced at least the margins of the Inland Ice. Absolute-age data for late-glacial and early Holocene advances of local glaciers are reported from only two locations: Disko (island) and the Scoresby Sund region. Subsequent to late-glacial or early Holocene time, most local glaciers were smaller than at present or may have disappeared completely during the Holocene Thermal Maximum. In general, local glacier advances that occurred during Historical time (1200–1940 AD) are the most extensive since late-glacial or early Holocene time. Historical documents and more recent aerial photographs provide useful information about local glacier fluctuations during the last not, vert, similar100 yrs. In all but one area (North Greenland), local glaciers are currently receding from Historical extents.

    *Corresponding author. Present address: Department of Earth Sciences, Dartmouth College, Hanover, NH,03755, U.S.A Tel.: +1 (603) 646-9647; fax: +1 (603) 646-3922.

    Article Outline

    1. Introduction
    2. Western Greenland
    2.1. Overview
    2.2. South and South-West Greenland
    2.3. Southern West Greenland
    2.4. Central West Greenland
    2.4.1. Disko (island)
    2.4.2. Nûgssuaq (peninsula)
    2.4.3. Svartenhuk Halvø (peninsula)
    2.5. North-West Greenland
    2.5.1. Upernavik to Melville Bugt
    2.5.2. Thule area to Inglefield Land
    3. Southeastern Greenland
    3.1. Overview
    3.2. Tasiilaq region
    3.3. Kangerlussuaq region
    4. Northeastern Greenland
    4.1. Overview
    4.2. Scoresby Sund region (not, vert, similar70–72°N)
    4.3. Mesters Vig region (not, vert, similar72–74°N)
    4.4. Hochstetter Foreland to Germania Land (not, vert, similar74–78°N)
    4.5. Jøkelbugten to Ingolf Fjord
    5. North Greenland
    5.1. Overview
    5.2. Eastern North Greenland
    5.3. Central North Greenland
    5.4. Western North Greenland
    6. Discussion
    6.1. Existence of local glaciers during the LGM
    6.2. Existence of local glaciers during late-glacial to early Holocene time
    6.3. Existence of local glaciers during the Holocene ‘thermal maximum’
    6.4. Existence of local glaciers during Neoglacial time, prior to Historical time
    6.5. Existence of local glaciers during Historical time
    6.6. Summary
    7. Conclusions and recommendations for future work

    Link to abstract: