Antarctic Ice shelf collapse – "worse than we thought"

“Melting Ice Sheets” Is Sheer Nonsense, says Prof. Cliff Ollier of the University of
Western Australia. His article Is worth to read, see http://ff.org/images/stories/sciencecenter/greenland_and_antarctic_in_danger_of_collapse.pdf , or http://icecap.us/images/uploads/PAPERIAGIce2.pdf

@- Gareth Phillips says:
July 27, 2011 at 4:31 am
“…why is the loss of ice not following a smooth curve and reflecting the increase in Co2? Currently ice loss has to an extent flattened off, though not recovered. It strikes me that basic concepts of cause and effect must indicate that other factors are at play.”
There are always MANY factors at play in climate cause and effect.
This is why the warming from winter to summer is not a smooth increase in temperature despite the increase in extra energy from the longer day length being a smooth even curve.
The most important factor that modulates HOW the smooth curve of extra energy received at the surface is expressed in temperature change or ice melt is the role of the oceans in storing, moving and releasing thermal energy. Along with the atmosphere there is a continual redistribution of energy from the equator to the poles. However this is not a smooth process it is chaotic and quasi-periodic with varying timescales of storage and release of energy.
The extra energy retained by CO2 at the surface is measurable. It is a fraction of the extra energy gained in mid latitudes as they tilt towards summer. That smooth addition of energy results in episodic and intermittent pattern of seasonal warming. It is inevitable that any warming (or ice melting) from the smaller, but global smooth addition of energy will also emerge as a noisy signal.

Ralph writes,
“That is probably the worst cherry-pick ever. We are looking at climate issues, not weather.
Yes, over the last TWO years antarctic sea ice has reduced, but since 1979 it has put on 0.5 million sq km.”
What numbers are you comparing, to get that 500,000 increase?
Arctic sea ice has unmistakeably declined. The summer minimum area went down by almost 70,000 square km per year 1979-2010, and faster than that recently. Even the WUWT poll just posted to SEARCH expects a faster than linear decline for 2011.
Antarctic summer mimimum shows no clear trend. The linear trend for 1979-2011 drifts upward just 5,000 square kilometers per year, which is not statistically significant and amounts to less than 1/13th of the arctic trend.
If you smooth the antarctic minimum instead of assuming a straight line, you see an uneven early increase, then decline since 2003. Whether the decline in recent years means anything, it’s too early to tell, but it emphasizes the problem with declaring an antarctic trend.

berple writes,
“Great paper.”
Cliff Ollier’s confident declaration,
“Indeed ‘collapse’ is impossible”
contrasts with much research over the past 15 years by scientists who, unlike Ollier, are experts on ice sheet dynamics. And their work is buttressed by evidence from coral reefs to caves showing that rapid sea level rises have indeed occurred, coincident with those “impossible” collapses.

@- klem says:
July 27, 2011 at 8:39 am
“Here’s a question I truly would like answered; The Greenland ice sheet is melting and the Antarcic ice sheet is melting. The amount of melting that is quoted in peer reviewed papers, are the amounts average, high or low?
It’s great to know that 10 cubic km of ice is melting every year but is that high, average or low?
It might seem high over the last 20 years, but over the last 5000 years is it within normal variation?”
For most of the last 10,000 years the Greenland and Antarctic ice-caps have been in relative mass balance. The amount melting every year was just about matched by the snowfall adding to the ice-cap.
The present best estimate for the loss of ice from Antarctica is more than 100Gt or cubic km of ice melting a year. This would cause around a metre of sea level rise over the last 2000 years, much more over 6000 if a similar rate of loss was happening in Greenland as it has recently.
Archaeological and eclipse records show there has NOT been a past rise in ocean levels that such a rate of ice melt would cause.
The present rate of mass loss from melting ice from Greenland would have reduced the Greenland ice cap to a fraction of its present size if it had been going on since the end of the last ice-age. If the present rate of melting had been happening since the Viking colony… then the Vikings would have had 10% more ice to deal with.
Geology of newly exposed regions around the ice-caps indicates that the ice now melting has been present for at least 8000 years, and probably in some cases since the Eemian.
The last time anything exceeding this scale and rate of ice-melt happened was probably the 1A pulse around 13000 years ago.
So despite Prof Ollier’s claims things could go faster yet….

@- Smokey says:
July 27, 2011 at 10:22 am
“The Arctic is going through one of its natural cycles, as it has repeatedly in the past…. This puts the current pseudo-science alarmism in perspective. -(link to animation of last 500,000 years of climate derived from a Greenland ice core)
You are quite right that much bigger warmings and melts have happened in the past. The end of the last ice age was a faster, bigger warming with more ice melting. (despite Prof Ollier!)
Past glacial cycles may have been even more extreme.
But then as roaming tribes of hunter-gatherers humans managed under these conditions to walk to every continent and establish populations.
Its only since all these big climate events, and during the very stable climate of the last 8000 years that humans started using agriculture to support vast populations living in urban societies.
Not many of those early civilizations have coped well with small climate change in the past, whatever the cause and whichever the direction. Making our present society sufficiently adaptable requires some knowledge of what is possible in climate change.
I am not convinced that the last 500,000 years of big changes,melts and sea level rise is particularly reassuring.

Adriana Ortiz says:
July 27, 2011 at 5:13 am
“…thank god for r gates…”
_____________
We can leave it at that.

ferd berple says:
July 27, 2011 at 6:58 am
Dave Wendt says:
July 26, 2011 at 2:31 pm
However the real telling comparison is to the volume of the world’s oceans which is generally given as approx. 1.5 BiILLION km3. Given the 3800m avg depth of the the oceans, the extra vol. generated by the claimed losses would amount to a couple of tenths of a millimeter of GMSL.
Even then we have no idea of how much water lies below the oceans within the earth itself. No one knows how far water extends into the earths crust and mantle. It could well be that the oceans are simply the tip of iceberg, the spots where the global water table rises above the level of the land.
“Scientists scanning the deep interior of Earth have found evidence of a vast water reservoir beneath eastern Asia that is at least the volume of the Arctic Ocean.”
“Although they appear solid, the composition of some ocean floor rocks is up to 15 percent water.”
There are so many elements in the attempted calculation of GMSL which are either unknown, inadequately modeled or neglected that the whole project is an exercise in statistical folly. Even if we could magically determine an accurate number for GMSL, it would still be entirely meaningless information because the underlying and mostly unacknowledged fact is that the seas are never “level” and any change in GMSL will not necessarily be reflected directly at any particular local piece of coastline.
The geoid, which along with the reference ellipsoid, are abstract and artificial constructs which purport to show the ocean surface as it would be if every variable except variations in the planet’s gravitational strength were removed and land masses were 100% permeable to the oceans, and a mathematically smoothed and perfect approximation of the shape of the Earth, respectively. Neither is more than loosely connected to the underlying physical reality of the planet, yet they provide the basis for all the satellite derived sea level data, which are actually anomalies from the undulations of the geoid, which is the calculated difference between the geoid and the reference ellipsoid. BTW, if you look at a map of the undulations of the geoid, you will find an equipotential surface for the world’s oceans that varies by 200 meters, which provides some indication of just how far from “level” the seas really are, bearing in mind that there are a multitudes of other variabilities that are removed from that projection.
The deployment of the GRACE and GOCE satellites has allowed the geoid to be much more accurately plotted, but has also demonstrated that is not that stable over even a relatively short term. That suggests that trying to combine the records from earlier generation satellites, which used a geoid model which was significantly erroneous to figure its anomalies, with the present improved model will be very difficult to impossible because we have no means of deriving what a similar geoid model of the past would look like.
Personally I feel that all these endless arguments about whose millimeter level SWAG about the rate of rise in GMSL is correct are entirely analogous to those legendary arguments from the Middle Ages about how many angels would fit on the head of a pin.