The contents below are paid advertisements. Their appearance does not imply an endorsement by The Oil Drum.
“For a successful technology, reality must take precedence over public relations, for Nature cannot be fooled.”
—Richard Feynman
Search The Oil Drum with Google
User login
Contact
- Content: editors at theoildrum dot com
- Tech support: support at theoildrum dot com
Personnel
- Editors: Prof. Goose, Heading Out, Stuart Staniford, Nate Hagens
- DrumBeat Editor: Leanan
- Contributors: ace, Engineer-Poet, Gail the Actuary, jeffvail, JoulesBurn, Khebab, Robert Rapier
- TOD:Local: Glenn
- TOD:Europe: Chris Vernon, Euan Mearns, Francois Cellier, Jerome a Paris, Luís de Sousa, Rembrandt, Rune Likvern, Ugo Bardi
- TOD:Canada: benk, Libelle
- TOD:ANZ: Big Gav, Phil Hart, aeldric
- Technician: Super G
Recently on TOD:World
TOD:Local
- Ask not what your next President can do, Ask what you can do for your tribe
- Summer Streets a Success!
- Plan for Hydro-Fracture Drilling for Unconventional Natural Gas in Upstate New York
TOD:Europe
- UK - Stansted Airport expansion gets go-ahead
- RAMseS: a new agricultural paradigm
- RAMseS: a new agricultural paradigm
TOD:Canada
- In this house, we obey the laws of thermodynamics!
- Compressed Air Energy Storage - How viable is it?
- Oil Megaproject Update (July 2008)
TOD:ANZ
Peak Oil Primers
Blogroll
Energy Sites
- The Coming Global Oil Crisis
- Die Off
- Dry Dipstick
- Energy Bulletin
- From the Wilderness
- Life After the Oil Crash
- Peak Oil Crisis
- Peak Oil News and Message Boards
- Powerswitch
- Rigzone
- Matthew Simmons
- Wolf at the Door
Environment & Sustainability Sites
- The Daily Green
- EcoGeek
- Eco Street
- Green Car Congress
- Green Options
- green.alltop.com
- Gristmill
- RealClimate
- Sustainablog
- Treehugger
- WorldChanging
Blogs
- The Big Picture
- Casaubon's Book
- Cleantech Blog
- Clusterf
k Nation (Jim Kunstler) - The Cost of Energy
- David Strahan
- The Energy Blog
- Entropy Production
- European Tribune
- GraphOilology
- jeffvail.net
- Mobjectivist
- Peak Energy (Australia)
- Peak Energy (USA)
- R-Squared
- Resource Insights
Finance & Economics Blogs
- Calculated Risk
- Ecological Economics
- Econbrowser
- Environmental Economics
- Infectious Greed
- The Mess That Greenspan Made
- Mish's Global Economic Trend Analysis
Organizations
License
This work is licensed under a Creative Commons Attribution-Share Alike 3.0 United States License.
GAIA Host Collective
I was going to post this up top, but what the heck, it kind of fits here....
The Year in Review: The planet
I've been watching the decline in sea-ice for a number of years now. This year's sudden loss of sea-ice, compared with previous years could be just a yearly fluctuation, with next year's sea-ice returning closer to the trend. But, the trend is strongly negative, such that one might expect to see more such instances of decline in extent in future years, as Global Warming is expected to strengthen.
As the loss of sea-ice increases, so will the flow of water and sea-ice between the Arctic Ocean and the Sub-Polar Gyre of the North Atlantic thru the Fram Strait. The Sub-Polar Gyre is where a portion of the Thermohaline Circulation (THC) has been found in years past. Adding the low salinity water and ice from the Arctic to that part of the North Atlantic could cap the THC in this area, preventing sinking there, which would have other impacts on climate, especially on Northern Europe. One other possible outcome could be that the THC location shifts from the North Atlantic into the Arctic, as the sea-ice cycle between maximum and minimum extent causes brine to be rejected, which can also sink. That's the mechanism for the THC that is found around Antarctica, which also has a large variation in sea-ice extent over the yearly cycle. Were this scenario to occur, the inflow of warmer water from the North Atlantic could further hasten the melt of the Arctic sea-ice.
My impression of the ACOGCM's used to model this part of the climate question is that they have been weak in the various representations of the THC. Whether this weakness is the cause of the difference between the model results and this summer's unexpected melt is beyond my knowledge.
E. Swanson
And yet the Antarctic ice sheet is growing.
And yet it has been losing mass.
http://www.jpl.nasa.gov/news/news.cfm?release=2006-028
So what?
The Antarctic Ice Cap is slumping, not growing.
So what? So if it keeps slumping, my brother's house will have a beach. He's above the 10 meter line for Greenland so he's not worried that much.
Ditto my sister. She's going to sell in May, after the school year is out. They are moving above the 100 meter line.
If the shelf lifts off the terminal moraine we don't know what's going to happen, but it could happen over the course of a few years, or months, or weeks. How many holes have we drilled in the ice of Antarctica? How fluid is the ice at the bottom? At temperatures near freezing the flow rate is nonlinear. And a house is a thirty year investment. The resale value is what people are thinking about global warming in 2038, not 2008.
Just be sure to be far enough away from shore so that salt water doesn't get into the well.
It was 37 degrees F there last week.
A woman was standing naked on the pebble strewn beach.
You got any evidence to back up that claim?
Do a Google image search on "Nekoharbour Antarctica". Obviously the resulting image is not work safe... and it doesn't appear to be from last week.
Carefull you are poking around in a hill of fire ants.
The interesting thing is about 10 days ago some one had gone in and ajusted the data to provide a plot of less than 16 million.
The artic ice had also been adjusted but was obviously screwed up, but I see now both north and south plots are back to provide what appears to be accurate data plots.
Ants? On Fire? In Antarctica? Well -- there's your problem right there!
I can't stand going thru another conversation this year like the one I had today at another site.
Neo...isn't that worse than clean carbon dioxide?
The Rat
" clean carbon dioxide?"
What's that?
Neo
It is transparent and doesn't leave an ugly mess. Trees love the stuff
TR,working real hard to help out
I think you mean clean carbon, as in clean coal tech.
Or maybe CO2 what doesn't absorb IR? Good luck.
Neo
No, I mean clean as it is not pollution and even much higher levels will not kill us, but make trees grow.
Time to flee the country. Gonna take my daughter and her guest on a Caribbean cruise. On to Barbados. Arr, buckos..
Happy New Year
Mike da Rat
Math people...I could use a little help.
I've been trying to figure out why America is so far behind the world in understanding GW; best I can figure,
N=M(Tv + B)1/R
where N =# who get it
M = median IQ
Tv = (Ai +Lw)Fv, where Ai = total votes on American Idle, Lw = total lbs lost on the fat show, and Fv =faux viewers
B = % who think the Bible is The science book
R = world rank, scientific literacy (17th)
I'm thinking it may be 1/M; makes a big difference. Please help the poor Rat out.
Thanks
That's a pretty good analogy.
And the Winner is...?
http://www.controlfireants.com/fire-ant-fights.htm
The trend looks flat to me.
I would not expect, a priori, that all metrics of global ice to retreat uniformly as the earth warms.
Alan
Yes, in area. Not in mass according to the data from the GRACE Satellites.
Mass has been decreasing rather dramatically.
NOTE: Sea ice is not the same as ice sheets, ice shelves or
glaciers. The chart says nothing about the growth (or shrinkage) of the Antarctic ice sheets.
Ice sheets are layers of ice that are on land. See "West Antarctic Ice Sheet (WAIS)" at Wikipedia or the online Encyclopedia Britannica for information. Ice sheets can be hundreds or even thousands of feet thick.
Ice shelves are layers of ice that flow from land and are anchored at one end on that land but otherwise mostly floating on the ocean. See "Ross Ice Shelf" for example. Ice shelves can be hundreds, or even a few thousand feet thick. The Ross Ice Shelf reaches a thickness of about 3,000 feet in some areas.
Sea ice is ice that forms, spreads and melts on ocean water. This is in contrast to ice shelves, ice sheets and glaciers, all of which form over land. Most sea ice is annual, forming and melting in the same year. Some survives for more than a year, becoming thicker. This happens more readily in the Arctic than the Antarctic. Typical average sea ice thickness in the Arctic is 6 to 9 feet, which it is only 3 to 6 feet in the Antarctic. Multiyear sea ice in both areas can achieve thicknesses of 12 to 15 feet.
At least for the past 30 plus years of detailed records, Antarctic sea ice normally grows in the winter to cover about 18 million square kilometers before shrinking in the summer to only about 3 million square kilometers. Arctic sea ice grows to about 15 million square kilometers before melting back (until recently) to about 7 million square kilometers.
One could probably write a pretty good SciFi thriller around the scenario of the Ross Ice Shelf breaking off from Antarctica, becoming the world's largest iceberg, and causing all sorts of havoc as it drifts around the globe.
Maybe someday it will really happen, too, which is more than can be said for most SciFi thrillers.
Yeah, the Ross Ice Shelf is about 600 miles wide at the widest. It could definitely block some straits or force ocean traffic to reroute around it. It would also probably create its own weather pattern over itself and over nearby waters.
Some really big icebergs have broken off the Ross shelf in the past. B-15 back in 2000 was roughly 180 miles long and 25 miles wide. It ended up grounding itself near Ross Island, where it was a real nuisance to penguins and the handful of ships that visit the science bases on Ross Island each year. Finally broke up into smaller pieces which drifted off.
Linearity and proof of how muich CO2 is needed is precisely not ht epoint. We need just enought o make the slip off of some big ice bargs happen by melt down of water to the base of the ice sheets then it is too late. So the 350 ppm level is likely enough. I have given up on the arctic ice and am now concetrating on the data from Grace satellite. Once the arctic sheet is disspated then Greenland will be going over to break up quickly I presume.
Since you are following it, is there any more recent published Grace data for Antarctica than that linked to above from March 2006? It would be interesting to see what has been happening in the past 18 months since this graph was published:
http://www.jpl.nasa.gov/images/grace/grace-20060302-browse.jpg
I don't grok the data flow at the tech sites but here's a forum link maybe they can interpret it.
http://isdc.gfz-potsdam.de/index.php?name=PNphpBB2
But seriously I think Grace is the only place to figure aóut what is the net minus on Greenland ice mass so we have to figure out how to get the latest data set and interpret it.
can you provide any reference for this statement - especially the "mostly floating" part?
He is right on this one, nh3 - "ice shelf" is a bit of a contraction, with the full name being "floating ice shelf". Ice that is over land is referred to as "grounded ice". There are some situations where the weight of the ice has pushed rock that was originally above sea level down to the point where it is below sea level. I believe large portions of the land under the West Antarctic Ice Sheet are this way.
And when all or part of the ice shelf lets go? Then you've got ice bergs.
i am not so sure. there is a ground line beneath an ice shelf which could be way beyond the normal coast line and way below normal sea level. my believe that ice shelf can stay in place for a long time is mostly because that the large part of it is grounded on the continental shelf - without that, the ice shelf would break away as ice burger quickly and the ice sheets on land would flow away much faster. i view ice shelves as the "retaining walls" of the ice sheets.
You're right about the ice shelf being a protection for the grounded ice. When the Jakobshavn ice tongue broke up in Greenland the drainage of grounded ice through the area sped up dramatically. It was an ice tongue rather than an ice shelf due to the fact that it was constantly calving on the ocean end and constantly being refreshed on the grounded ice side. The whole structure just went away during 2002/2003. Prior to that its presence moderated ice flows. The shelves serve a similar purpose, but without the dynamic nature of an ice tongue.
"An ice shelf is a thick, floating platform of ice that forms where a glacier or ice sheet flows down to a coastline and onto the ocean surface."
First hit on googling "ice shelf".
Here is a link to Earth and Space Research, an Institute devoted to oceanographic research.
You might also want to check "The Physics of Glaciers," by W. Paterson. It is a principal text for glaciology. It says the following about ice shelves:
"An ice shelf is a body of ice originating as part of the ice sheet that has flowed off the land and is floating on ocean. The zone between ice that is in contact with land (grounded ice) and ice that is supported by water (floating ice) is known as the “grounding zone,” or “grounding line.” Grounded ice can also occur in small areas seaward of the grounding line over locally high points in the bedrock."
In my post I referred to an ice shelf being "anchored" on land. The technical term is obviously "grounded." However, it still remains a fact that an extended part of an ice shelf floats on sea water.
A quick check on Google will locate several papers by scientists researching the marine biota, fresh water flows and ice structure below the Ross Ice Shelf.
Finally, the Britannica Online states that the Ross Ice Shelf is the worlds largest body of floating ice, with an area of roughly 185,000 square miles, about the size of the Yukon Territory in Canada.
Regarding Leanan's post:
This was because the land-based ice-sheets were melting in a "non-linear" way – not just melting at a steady rate, but dynamically breaking up as well...
Will the sea level rise be reflected by a bell curve or more of a hockey stick type of graph? I think either way that a rise of 20 feet will occur mostly by 2050. IMO We certainly won't get a slow linear rise over the next 90 years. The general population is so ignorant or naive about GW happenings. And PO knowledge is even less so.
Thanks to all at TOD and those who post
breaking up on land? any reference?
Google "greenland moulins" for 35,000.
Or try "accelerating glaciers" or...
When something is very well reported some
posters do not see a need for a link. Yes, this
can ruffle feathers.
My admittedly incomplete understanding is that ice doesn't have to melt to raise sea level - floating ice raises it just as effectively as melted ice. So if a major body of ice slides off a continent, or if glacier flow abruptly speeds up, thinning continental ice caps, sea level should rise immediately, even if that ice is floating, unmelted, as part of an ice shelf. In other words, I'd guess hocky stick.
It's Nature's Way of telling you something's wrong
http://www.youtube.com/watch?v=4kknbg7xquQ&feature=related