by Russel Norman
Where goes the antarctic ice sheet, there goes the world.
There has been a long and important debate about the state of the antarctic ice sheet. There have been models suggesting that increased precipitation over the East Antarctic ice sheet could increase the thickness of the ice as a result of climate change. The last IPCC report decided it was too hard to model what was happening and so decided to leave it out of its calculations of sea level rise.
Now, a new report in Nature suggests Antarctic ice sheet is losing mass at a fair rate and the rate is increasing:
In 2006 alone, Antarctica lost nearly 200 billion tonnes of ice, researchers say — the equivalent of a global sea level rise of more than half a millimetre. That’s 75% more than losses in 1996, they add.
A lot of the mass being lost through glaciers and their flow rates are increasing:
That trend — a 75% increase in losses since 1996 — is frightening Rignot [the study's author]. Once the glaciers are well lubricated by water, it’s hard to slow them down, even if global warming were to be arrested, he says. He estimates that the worst case scenario — a complete emptying of ice basins — would result in about a metre of sea level rise each from Greenland and Antarctica, as well as half a metre from remaining alpine glaciers.
It may be that other feedbacks slow the loss of water from Antarctica but this study is not good news from the frozen continent.
Published in Environment & Resource Management by Russel Norman on Tue, January 15th, 2008
More posts by Russel Norman | more about Russel Norman
on the trolls and those who are unable to keep on topic
Meanwhile, in other highly selective climate news, it snowed in Iraq
tinyurl.com/yu32p6
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BluePeter, not so selective! Nature is a pretty respectable source!
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Yup… measurements of the ice sheet over an entire continent for an entire year are just as selective as snow in one city on one day….
Not in the real world though….
BJ
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Why “there goes the world”?
“The report does not list simply the negatives that will come from a warmer world. It also says agriculture may become easier in some areas, there should be improved access to oil and gas deposits and new shipping lanes will open up. Some fisheries could become more productive.
The ACIA document is the work of more than 300 scientists and has taken four years to compile and has undergone a rigorous peer-review process. “
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Plenty more examples here…
“Year of Global Cooling”
http://www.washingtontimes.com/article/20071219/COMMENTARY/10575140
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BluePeter
Are you talking about this?
http://www.acia.uaf.edu/pages/scientific.html
respectfully
BJ
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Shock!..Horror!
Don’t worry guys, Russel is coming to the rescue, higher taxes and “social justice” will fix the melting ice caps.
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BluePeter,
This may sound pedantic, but an extreme event (e.g. snow in Iraq) is not climate news, it is weather news. It is possible that next week Wellington will have the coldest January day on record. This does not mean the climate is getting colder. The climate is essentially the average of many weather events. An extreme cold day will only contribute a very small cooling influence to the climate records.
People often confuse weather and climate, and then draw the wrong conclusion that an extreme weather event proves the climate is heading in one direction or the other. Indeed you will often see events such as strong tropical cyclones reported as “confirming” global warming is resulting in stronger or more frequent TCs. This is simply incorrect (although a warming climate may result in more frequent TCs, scientists are still divided on whether this is the case or not).
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I know, Samiuela
I’m having a dig at the extreme weather reports sometimes posted here.
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yes I agree Mouldwarp there are lots of examples of taking weather events and using them to say that the climate is changing, in that comment piece from mid December that you linked to.
However in the global mean figures, rather than cherry picked isolated events, 2007 was the second warmest on record.
http://www.celsias.com/2008/01/14/2007-second-warmest-on-record-despit e-la-nina/
http://www.earthpolicy.org/Indicators/Temp/2008_data.htm
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Also, real climate has a great illustration of how the year to year variability of the climate means that you shouldn’t take short term trends to argue for climate change (or not)
they show how 8 year trends are extremely variable depending on which year you start with.
http://www.realclimate.org/index.php/archives/2008/01/uncertainty-nois e-and-the-art-of-model-data-comparison/
“the longer the averaging time-period and the wider the spatial average, the smaller the weather noise and the greater chance to detect any particular signal”
The article says that in the global surface temperature record … trends longer than about 15 years average out the weather component. See how the 15 year trends rather than 8 year ones are smoothed out …
http://www.realclimate.org/images/giss-15yr.jpg
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check it out here Mouldwarp
http://gristmill.grist.org/skeptics
Welcome to Debatepedia!
http://wiki.idebate.org/index.php/Welcome_to_Debatepedia%21
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“In 2006 alone, Antarctica lost nearly 200 billion tonnes of ice, researchers say — the equivalent of a global sea level rise of more than half a millimetre.”
No wonder I cant see a rise in the high water mark every time I launch the boat. All that melted ice and only 0.5mm rise in sea level.
So 200 billion tons of ice is what percentage of the earths total ice store?
If we are to believe Al Gore and the total sea level rise is to be 20 metres. That means that 200 billion tons of ice already melted is only 1/40000’s of the total ice store comprising 8 million billion tons.
Pretty insignificant.
How does one measure mean high water mark? As the earth crust is constantly moving (it is why we have earthquakes) where is the datum point?
Recently a new retaining wall was built on the property next door to the factory. This being some 30 metres above the current sea level. They need extra long poles to get through a layer of sea bed sediment.
Indicating that either the sea level was once 30 metres higher then it is now or the land was lifted (did Maui not fish the North island up?).
So are we concerned about nothing or is the 20 metre sea level rise a myth and maybe realistically it is only 1 or two metres IF all the ice melted?
1 or two metres is easily manageable though the creation of levies, dykes and rain water pumping from low lying areas. The Dutch have been doing for over 500 years.
Be an interesting question for the environmental Greens to ponder. Would you allow the dredging of the sea bed to enable a sea wall to be built along side the Hutt Motorway? Transmission gully spoil could be used for this as well.
.
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Greenland and the West Antarctic have enough ice for about 6 m sea level each, and East Antarctica another 60 m. Estimates of mass balance suggest that Both Greenland and WA are strongly negative. See story and links here. IPCC AR4 gives current rate of SLR at 3.4 mm per year. Maximum rates seen in the paleo record are about 5 m per century. If you look at current ice melt rates, allow for future warming (inevitable, unavoidable), and you can see why there’s concern. In the last interglacial period, when temps were about 1.5C warmer than at present, sea level was 5 – 6 m higher than at present. The study of icesheet behaviour is one of the most interesting areas of climate research at the moment. It’s a hard problem.
I take issue with 1 or 2 metres being “easily manageable”. It might be possible to spend a lot of money defending cities, but large stretches of coast here and around the world will change beyond recognition. Ever wondered why India is building a fence on its border with Bangladesh?
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Chart of global ice coverage over time. We’re currently at a *high* level, despite what you alarmist cherry-pickers would have us believe:-
http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/global.daily.ice.area.w ithtrend.jpg
Stuey,
- “However in the global mean figures, rather than cherry picked isolated events, 2007 was the second warmest on record.”
You are quoting a surface temperature measurement, which is utterly worthless. Firstly, a great many of the measurement sites do not conform to even the *minimum* standards with regards to their location, so they exhibit a significant false warming trend as the surroundings get urbanised. Some examples can be seen at:-
http://www.coyoteblog.com/coyote_blog/2007/07/contributing-to.html
Secondly, even then this is *not* raw data you are quoting me – various “adjustments” have been applied to it. One government agency that does this says “the cumulative effect of all adjustments is approximately a one-half degree Fahrenheit warming in the annual time series over a 50-year period from the 1940’s until the last decade of the century.”
http://www.ncdc.noaa.gov/oa/climate/research/ushcn/ushcn.html
That’s right. They actually add a false warming trend to create the data-sets you find so alarming!
If you can hold your nose and go to a skeptic site, they subtract this false signal and, would you believe it, the alarming rising trend vanishes:
http://www.climate-skeptic.com/2007/11/signal-to-noise.html
Note that the figures you quoted are from Gavin Schmidt, a premier scaremonger. Like the agency above, he also subjects the data to a number of “adjustments” but – amazingly – he *refuses* to tell anyone what those adjustments are! It is quite staggering really. An absolute disgrace (but spookily reminiscent of Mann and his Hockeystick. Remember, Mann tried to obstruct efforts to audit his work, and was eventually shown to be not only completely incompetent, but also someone who did not hesitate to conceal data which contradicted his agenda).
I hope you can see how the surface temperature data you quote is completely worthless – especially after it has been through secret massaging processes. If you don’t agree, please explain why such surface temperature figures are valid.
Only satellite data has any hope of accuracy. The only problem (for alarmists), is that this data doesn’t show anything like the false warming that the modified surface data does.
http://wattsupwiththat.wordpress.com/2007/11/26/the-scoop-on-satellite -temperature-data/
Another spooky similarity you might enjoy is how the IPCC gets that alarming sea-level trend now being discussed here: “They entered a “correction factor,” …it was not a measured thing, but a figure introduced from outside. …It looks like it is measured from the satellite, but you don’t say what really happened. And they answered, that we had to do it, because otherwise we would not have gotten any trend!”
http://www.climate-skeptic.com/2007/12/a-brief-window.html
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Hi Mouldwarp, that is not a graph of global ice cover, that’s a graph of global sea ice. It doesn’t include land ice such as Antarctic and Greenland which is what is making the sea level rise as it melts.
As for the rest of your post, are you seriously suggesting that almost the entire scientific community is part of a conspiracy? Have you got a tin foil hat?
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Mouldwarp once again demonstrates the extent to which he allows his politics to distort reality.
Absolutely nothing he asserts above is true.
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Couple of things here.
1-2 meters is what we’re going to see by the end of the century, mouldwarp notwithstanding.
Bucolic Old Sir Henry has the numbers pretty much correct. I have seen 5 and 7 and I can’t remember which was WAIS and which was GIS today. The key point however, is that as far as anyone knows at this point EAIS (the 60 meter hit) has to actually melt to contribute. That makes it MUCH slower (thousands of years) than WAIS and GIS (100’s of years) which contribute faster by floating away from the land they were on.
I would be loathe to build seawalls along the Hutt… the process has a very good chance of accelerating in following centuries. By going for the wall you’ve locked yourself into a continuous war with the sea.
I have stated several times that there should be serious consideration to building new infrastructure at higher elevations…. at least 20 meters up. Anything else is going to lead to waste as the water rises… the countervailing consideration is of course, that not that much of what we build is kept for a hundred years.
OTOH, the routes created by the roads the Romans built are major roads even now.
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Gerrit,
If the land that is 30m above current sea level is in Wellington then the answer is very simple. The Great Wairarapa Fault is lifting Wellington at the rate of about 1m per millenium. The most recent uplift occured on 23 January 1855.
This extract from Te Ara – the Encyclopedia of New Zealand might help to answer your last question.
http://www.teara.govt.nz/EarthSeaAndSky/NaturalHazardsAndDisasters/His toricEarthquakes/3/en
“The uplift created a new fringe of beach and rock platforms along the Wellington coast. Many jetties in Wellington Harbour became unusable, but there were also beneficial effects. Blocks of the city’s central business district now occupy land that was below sea level before 1855. The newly exposed strip of shoreline between Wellington and the Hutt Valley offered a safe road and railway route – parts of the coastal road had previously been impassable at high tide. The uplift of the region helped drain the swampy lower reaches of the Hutt Valley. Commerce lost but sports gained when a low-lying area known as the Basin Reserve, originally proposed as a shipping basin, instead became Wellington’s cricket grounds.”
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BJ, The next Great Wellington quake should occur this century. After that it should be possible to build an elevated Hutt Rd using the technique used to keep the new Hong Kong Airport terminal sinking into it’s artificial island. Essentially the foundation piles are hydraulic acroprops, continuously adjusted by computer to keep the terminal level and at ground level. The same basic idea would allow an elevated motorway to be built on the ground and then be jacked up as and when needed.
For the uninitiated an acroprop is a simple type of screw jack used to prop up buildings during construction.
http://colouritgreen.wordpress.com/2008/01/12/acroprops-and-silver-lin ings/
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Kevyn,
The old sea bed I was refering to was in Auckland (On the Northcote ridge).
BJ,
Trying to get a time frame going in my mind. At the end of 2099 we will see a 1-2 metre rise in sea levels? So when will we have the 6 Metre rise? Around 2399?
Other questions to ponder
Is Al Gore scare mongering with his 20 metre claim in our lifetime?
How does one set the datum point for mean sea level when we have earth crust movement?
Is it possible that those low lying pacific islands are actually sinking back under the waves?
One can eaily see why there are “global warming causes sea level rises” skeptics when we follow the links provided by frog (in the Steve Irwin post) to Antartic ice melting where right at the end the scientist makes the statement
” This work suggests that the ice flow is accelerating,” Dr Allison said.
“It’s worrying because … the changes are happening due to processes we don’t understand.”
Because maybe, just maybe, melting ice is a natural occuring cycle in the earths evolution. And there is sweet nothing the human ant can do about it except adapt to the changes.
Unless you want to make money by selling carbon credits to appease the human ants need for the false believe that we can change the natural cycles the earth has.
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Mouldwarp,
Look at your sea ice graph, and see what is happening in the Arctic summer. No one suggested the sea ice would be gone all year, people are predicting the Arctic will be sea ice free during the summer within the next few decades.
You are correct that many surface temperature observations have various biases and uncertainties. People know this, and make efforts to quality control the data, to try and remove these biases. The quality control methods are not aimed at introducing some warm bias to fit someones theory on climate change.
To suggest the surface temperature data are worthless is ridiculous. Meteorological agencies around the world spend millions of dollars every year in order to make surface temperature observations. Are you suggesting that this money is wasted?
There is no scientific conspiracy concerning climate change. If you have evidence to suggest that global warming is not happening, you should submit a paper to an appropriate scientific journal. If your data are good, and you make a convincing argument, you will have no problem getting published.
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bj: The EAIS is roughly stable at the moment, but the concern arising from the study frog links to is that if, as it seems, it is glacier dynamics that determine mass balance, then warming at the fringes of the EAIS (which is happening) can destabilise the main sheet. That’s not to suggest that we’ll see the EAIS melting rapidly – it is very big, high and cold – but it could add to the GIS and WAIS melt and increase the rate of SLR.
I’d say 1-2 m by the end of the century is what current knowledge suggests is likely – but we’ll know a lot more after the IPY work is completed. Personally, I’d take a small bet on 5 m, and won’t be buying a seaside bach.
Gerrit: Al Gore didn’t claim “20m in his lifetime”. He said something like “if all the WAIS or GIS melts, sea level will rise by 20 ft” – which is true. He didn’t supply a time frame, but the graphic accompanying the words did show Manhattan being submerged, implying (if you really want to pick nits) it might be rapid.
And this is most certainly not “a natural occurring cycle”, because there are no instances of a rapid and sustained increase in CO2 levels in any prior interglacial period.
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because the surface is where we live, along with all the plants & animals & geological features which will be affected by the warming.
upper atmosphere warming is more relevant in terms of storms but not the biggest part of the problem
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Gerrit
Yes… that’s about the size of it on current form. I’d not bet on the 2 centuries after though, as I don’t know what we will do THIS century, which will certainly have an effect.
As I have mentioned in my darker moments… we may really not have to worry about AGW … we can always have a Nuclear Winter….
So 6 meters or more by 2399 on current form… but that is far less easy to nail down than the 1-2 meters by 2099.
respectfully
BJ
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