How glaciers really work and why Antarctica is just fine

Robert · Jul 2, 2017

I am privy to the works of Dr. Judith Curry who presents many scientists work. It gives the healthy mind plenty of data to work with. We don't get lectured this is that or that is this. We can see science evolve. I hope some of you appreciate this work.

Here she presents something from the Guardian. I think it is a fine analysis.

And what do you believe?
https://www.theguardian.com/science...ng-is-antarctica-falling-apart-climate-change

Once the ice is thick enough, it flows downhill towards the ocean, where it lifts off the ground and floats, forming an ice shelf. In contact with the ocean below and the atmosphere above, this is where the “rubber hits the road”: to maintain its size, the ice sheet must shed the extra ice it gains through snowfall, which it does through two processes that both occur at the ice shelves – calving of icebergs at the front, and melting underneath. Ice shelves also hold back the flow of the grounded ice; if shedding from ice shelves exceeds the gains from snowfall, they will shrink, and then glaciers feeding them will feel less resistance to flow and speed up, and sea level will rise.

There is plenty going on that merits concern: Antarctic ice shelves overall are seeing accelerated thinning, and the ice sheet is losing mass in key sectors of Antarctica. Continuing losses might soon lead to an irreversible decline. However, we do not need to press the panic button for Larsen C. Large calving events such as this are normal processes of a healthy ice sheet, ones that have occurred for decades, centuries, millennia – on cycles that are much longer than a human or satellite lifetime.

The Larsen C rift is like a dozen other rifts observed in Antarctica before. What looks like an enormous loss is just ordinary housekeeping for this part of Antarctica. An iceberg, even one as large as Delaware or a quarter of the size of Wales, is small compared to the whole ice sheet, which averages 1.4 miles thick and is larger in area than Australia. Think of it as one grain in a bag of rice. Similarly, waterfalls off the front of the ice shelf are not a catastrophe. Surface melt is common and occurs every summer as temperatures rise above 0C, as reported in papers published in the 1990s.

So, while ice fracturing and surface melting may sound like signs of climate change in action in Antarctica, they are really part of the background against which we must look for real change. Real changes are happening there, and when we report them they need to stand out. Previous collapse events involved large amounts of surface melt that forms ponds on an ice shelf that had already weakened. We have not observed this on Larsen C. We will continue to monitor Antarctica by satellites and from the ground, but we will not cry wolf about an imminent collapse of Larsen C.

Helen Amanda Fricker is a professor at the Scripps Institution of Oceanography

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Original source

https://judithcurry.com/2017/07/02/week-in-review-science-edition-68/#more-23164

OldManOnFire · Jul 3, 2017

I suppose when we consider Larsen C's behavior in a geological time scale huge hunks of ice shelves breaking off now and then are no big deal? But if this process at this point in time today is accelerating beyond the frequency of past events, we probably want to pay attention. Far into the past there was little to no worry about sea level rise, however, today we have billions of humans located near or at sea level across the globe, including businesses and economies and governments, so now we must begin to worry about the short and longer-term potential...

Robert · Jul 12, 2017

https://www.yahoo.com/news/iceberg-...e-island-breaks-off-antarctica-133158390.html

This is actual breaking news. Most of the time ordinary news is called breaking. But this break gave us a trillion tons of iceberg.

Iceberg nearly twice the size of Rhode Island breaks off Antarctica
Taylor Rogers 3 hours ago

Iceberg about twice the size of Rhode Island breaks away from Antartica
An iceberg about twice the size of Rhode Island has broke away from Antartica this week. It is one the biggest icebergs in recorded history.

A large portion of an ice shelf that was said to be “hanging by a thread” last month has broken off from the Antarctic mainland, creating one of the world’s largest icebergs, according to a Wednesday report by British Antarctic research group Project Midas.

The iceberg, which is estimated to have separated from the Larsen C ice shelf between Monday and Wednesday, will be named A68. It weighs 1 trillion tons and contains twice the volume of water held in Lake Erie, the report said. It is measured at 5,800 square kilometers, making it nearly twice the size of Rhode Island.

The ice shelf’s calving has been expected for some time. Project Midas wrote that it was “watching with bated breath” after the rift separating the iceberg from the main shelf grew 11 miles in six days in late May. At the time, Adrian Luckman, lead investigator of Project Midas, wrote that the separation of the ice shelf would “fundamentally change the landscape of the Antarctic Peninsula.”

The initial rift branched off several times, but only one iceberg can be seen at this time, Luckman told the Guardian.
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JDliberal · Jul 13, 2017

The large iceberg that broke off today was not clearly due to climate change according to:
http://www.npr.org/sections/thetwo-...782/massive-iceberg-breaks-free-in-antarctica

WillReadmore · Jul 13, 2017

JDliberal said: ↑

The large iceberg that broke off today was not clearly due to climate change according to:
http://www.npr.org/sections/thetwo-...782/massive-iceberg-breaks-free-in-antarctica
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Very few single events are ever going to be stated by science as being "caused" by climate change. A warming earth will simply make these events more likely or more frequent.

It's really easy to ask (or answer) the wrong questions here.

Gradual warming of average temperature is more like the toad on a hot plate. Like the toad, we need to be smart enough to take action on the basis of trends, some of which require serious science to detect.

JDliberal · Jul 14, 2017

WillReadmore said: ↑

Very few single events are ever going to be stated by science as being "caused" by climate change. A warming earth will simply make these events more likely or more frequent.

It's really easy to ask (or answer) the wrong questions here.

Gradual warming of average temperature is more like the toad on a hot plate. Like the toad, we need to be smart enough to take action on the basis of trends, some of which require serious science to detect.
Click to expand...

Very true. Climate changes probably are mostly indirect causes of these events.

waltky · Sep 13, 2017

Granny says, "Dat's right - gonna be just like Noah's flood...

Study: Asia's Glaciers Face Massive Melt from Global Warming
Thursday 14th September, 2017 - Scientists say one-third of the ice stored in Asia's glaciers will be lost by the end of the century even if the world manages to meet its ambitious goal of keeping global warming below 1.5 C, affecting water supplies for millions of people on the continent.

In a paper published Wednesday in the journal Nature, researchers in the Netherlands also examined what would happen if average global temperatures rise beyond 1.5 C(2.7 F) by the end of the century. They concluded that almost two-thirds of the ice in Asia's glaciers could vanish, if no effort is made to curb climate change. "In regions where glacier melt water is an important part of the river flow, the retreating glaciers can become a problem," Philip Kraaijenbrink, a University of Utrecht geographer who led the study, said. "There are many people living in basins that have their rivers originating in Asia's high mountains, such as the Indus, Ganges and Brahmaputra," Kraaijenbrink said. "In these basins, the river water is used for irrigation of cropland, drinking water and for hydropower dams."

The 1.5-degree target was set at the international climate conference in Paris two years ago, but experts say it would require a massive shift to the world economy. In total, the researchers compared 110 climate simulations and found that high mountain glaciers in Asia tended to experience greater levels of warming than the global average. All glaciers analyzed already are losing mass except those in the Kunlun Mountains of western China. Taking into account the effect on melting levels of rubble covering some of the glaciers, they concluded that the amount of ice lost from Asian glaciers is almost proportional to the amount of warming they experience, though with some regional variations. "Even if temperatures stabilize at their current level, mass loss will continue for decades to come until a new equilibrium is reached," the researchers said.

Kraaijenbrink acknowledged that a scenario in which global warming remains under 1.5 C is optimistic. "We are aware that more extreme, business-as-usual scenarios are possibly a more likely future," he said. In a comment published along with the study, J. Graham Cogley of Trent University in Canada said the researchers' glacier model "has some innovative features that might raise eyebrows among glaciologists, but it is difficult to find fault with it as a pioneering effort." "The authors have shown that achieving the 1.5 C target will conserve a substantial fraction of Asia's water resources and that, if we fail in this regard, we will pay in direct proportion to the extent of the failure," Cogley said.

http://www.bignewsnetwork.com/news/...laciers-face-massive-melt-from-global-warming
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tecoyah · Sep 13, 2017

If Antarctic glacial ice is melting or the northeast passage is free of ice, or Greenland is melting faster than ever...all we can do is watch and complain. Atmospheric changes already in place will take a good century to fully interact and then even longer to dissipate, The damage is already done folks and all we will do is continue making it even worse while we biatch or deny it.

Fortunately I will be dead before the excrement truly becomes fan plastered....my kids are pretty well screwed however.

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