Adelaidewonderer wrote:You got huge carriers (and millions of small leisure craft) being added to oceans each year (displacement). Permanent stutures like breakwaters etc being added. Volcanic fallout.
I wonder if the models and projections figure in melting going on right into the winter? I'm guessing NOT. Couldn't this accelerate the time for three meter rise considerably?
by dissident » Tue Feb 01, 2011 1:15 pm
It looks to me like Hansen et al. are taking this into account in the 5 meter estimate since they identify a 10 year e-folding melt rate increase based on observations rather than models. But note that there will not be much ice loss by 2050
by dissident » Sun Aug 01, 2010 7:35 pmIt does not all need to all melt to be a big deal for at some point during the melting process you can bet that a big chunk (thousands of cubic miles) will suddenly slide into the ocean. [sorry for not citing the original poster here]
Exactly. .... The story of the last few years is that ice sheet dynamics is poorly understood. The default mode for human thinking be it scientific or not is implicit linearization. There is no sense of the rapid nonlinear processes that can develop in natural systems. .... Do they really have detailed finite volume codes that follow every crack in the Greenland ice sheet and are able to respond properly to the propagation of new cracks along with water flow from the surface? .
12:36 24 March 2006
A rapid increase in "glacial earthquakes" - caused by sudden large movements of glaciers - over the past few years indicates that warmer temperatures will destroy the Greenland ice sheet faster than expected, a new study warns.
Surface meltwater is not dribbling away, as if from a giant ice block melting slowly, but is seeping through cracks to the bottom of the glacier. Once there it forms a layer that "helps lift the glacier up from the rock" so it flows faster to the sea, says seismologist Göran Ekström at Harvard University, US, who led the study.
He discovered the glacial quakes three years ago, when looking for unusual earthquakes, and traced them to slips within the ice. And the quakes can be substantial: a 10-metre slip of an ice slab roughly the size of Manhattan Island, and as tall as the Empire State building, causes a magnitude-5 quake on the Richter scale.
When the team analysed glacial seismic records back to 1993, they found a striking increase in the number of quakes recorded in recent years. All 136 of the best-documented slips were traced to glaciated valleys draining the main Greenland ice sheet. A handful of others occurred in Alaskan glaciers or on Antarctica.
Dissident, I guess I'm posing this as a question to you: I would anticipate that you feel that there is a real possibility that there could be a significant break up (20% or more) of the Greenland ice sheet within the next 20 years.
An iceberg expert says there's a slim chance two gigantic islands of ice drifting south from the Arctic could reach Newfoundland's Grand Banks as early as August.
Luc Desjardins, a senior forecaster with the Canadian Ice Service, says the icebergs have a long way to go and they could break up or get stuck in some Arctic bay in the months ahead.
However, he says the unusually large bergs have a shallow draft, which means they could float over the Grand Banks.
He says there's a one-in-a-million chance one of the frozen slabs could hit the Hibernia offshore oil platform, but it's anybody's guess what path they will take.
One of the icebergs is 84 square kilometres, the other 65, making it about the size of Manhattan.
Both were once part of a gigantic slab that calved from a glacier in northwestern Greenland last August.
Read more: http://www.cbc.ca/canada/newfoundland-l ... z1Cq9NZp00
Arctic climatologist Konrad Steffen has spent 18 consecutive springs on the Greenland ice cap, personally building and installing the weather stations that help the world's scientists understand what's happening up there. And what's happening may be much worse than anyone thought possible
In the annals of polar science, Konrad Steffen will go down as one of the legends. Koni, as he is known by his friends and colleagues, oversees an annual budget of $50 million and a staff of 550 at the Cooperative Institute for Research in Environmental Sciences (CIRES) in Boulder, Colorado, a research center that is jointly funded by the National Oceanic and Atmospheric Administration and agencies like NASA.
But Steffen has had the most influence not as an administrator but as an icy-boots explorer. He has spent the past 32 summers in the high Arctic, working in Alaska and Canada before settling on Greenland, where his Greenland Climate Network serves as the eyes and ears for climate scientists worldwide. I
n this extreme environment, the on-the-ground reality was invisible until Steffen personally customized and deployed much of the instrumentation that tells the scientific world, hour by hour and year by year, the conditions on the Greenland ice sheet and how they're changing.
dolanbaker wrote:You do realize that this thread is seven years old!
meemoe_uk wrote:Still looks to be plenty of ice. Just what you'd expect for 12 million years into the current ice age, with at least another 40 million years to go.
Iceberg bigger than Manhattan breaks from Greenland glacier
A massive iceberg larger than Manhattan has broken away from the floating end of a Greenland glacier this week, an event scientists predicted last autumn.
The giant ice island is 46 square miles, and separated from the terminus of the Petermann Glacier, one of Greenland's largest.
The Petermann Glacier last birthed — or "calved" — a massive iceberg two years ago, in August 2010. The iceberg that broke off and floated away was nearly four times the size of Manhattan, and one of the largest ever recorded in Greenland. …
"The Greenland ice sheet as a whole is shrinking, melting and reducing in size as the result of globally changing air and ocean temperatures and associated changes in circulation patterns in both the ocean and atmosphere," Muenchow said.
“The freshwater stored in this ice island could keep the Delaware or Hudson rivers flowing for more than two years. It could also keep all U.S. public tap water flowing for 120 days,” Muenchow said.
Return to Environment, Weather & Climate
Users browsing this forum: No registered users and 8 guests