Bill, Here is a chart demonstrating the salinity and temperature profile of the Arctic Ocean. The temperature of the deeper water is warmer than the surface layer, but the salinity gradient keeps the fresher surface water less dense. https://en.wikipedia.org/wiki/Halocline#/media/File:Arctic_sea_temperature_salinity_plot.svg

Bill, One thing I would point out is that due to the halocline, only the top 50 meters of the Arctic Ocean is near the freezing temperature; below that it the temperature rises. So only the top 50 meters of water needs to be warmed, giving a difference in the thermal inertia of about a factor of 3 rather than 40.

Hans, after reading the entire article, I became skeptical of the writer's interpretation. The writer is a global warming denier, and enters conspiracy theory territory in discounting the original PNAS article's connection of the event to global warming. Apparently, events of this sort are episodic and have occurred several times during the period of observation. This latest event is the largest seen, but previous events have been comparable, and the PNAS article attributes increasing size and frequency of these events to global warming. Here is the original PNAS abstract: http://www.pnas.org/content/early/2013/11/05/1315447110

A Facebook User, As far as I can see, the Guardian article does not mention the Antarctic at all. This did not strike me as dismissive, but rather the simple fact that the article is about the Arctic, and one cannot put everything into a single article. I don't see folks here dismissing the Antarctic, either. There is a whole section devoted to the Antarctic over in the Forum. But again, the primary subject of the blog and forum is the Arctic. Yes, there are some similarities between the two poles. They are both warming up faster than the lower latitudes, and both Greenland and Antarctica are losing hundreds of cubic kilometers of ice every year. Both are the subject of scientific study, measuring and understanding the effects of the warming. However, the dominant geographical factor in the Antarctic is the continent itself, while in the Arctic the dominant geographical factor is the semi-enclosed sea at the pole. This sea is undergoing the most dramatic change, as millions of square kilometers of sea change from perennially ice-covered to seasonally ice-free. This can greatly affect the climate of the Northern Hemisphere, where more than 90% of the human race lives. In the Antarctic, starting from a much colder state, has displayed the effects of warming quite differently. It has been warming up to where there can be sufficient water vapor in the air to increase snowfall. The fresher meltwater from the continent has counterintuitively caused the Antarctic sea ice to increase. However, this increase occurs in the winter, when it does not cause much albedo change in the polar winter, unlike the sea ice changes in the Arctic summer.

Scientists aren't in the business of making predictions; their goal is understanding the mechanics of how the physics operates in the system. Putting in statistical fudge factors without a theoretical basis may make models more closely reflect observational results, but add nothing to the goal of understanding the system, and the usefulness of any projections into the future becomes speculative. Real world concerns may push them into issuing warnings based on their educated judgment, but they should not be forced to give them the imprimatur of science if the theoretical basis is not there.

I think that we need a system that lets us use a name while the storm is going on. It is at that time that people most want to talk about it, and when a name would become established. A name given after the fact would not be connected to the references and discussion during the event, and so would not be a useful search term. Thus duration is not a useful naming requirement, because much of the storm would be over before the name would be given. Similarly, names of deniers would not be useful because a search on the name would find too many references irrelevant to the storm.

2.4 Mkm^2 Based on my feeling that the sea ice volume trend is a better measure of the physical reality of the situation in the Arctic, and that trend is strongly downward. https://sites.google.com/site/arctischepinguin/home/piomas

This is off-topic and Antarctic, but I saw this article: http://www.nature.com/news/polar-research-trouble-bares-its-claws-1.12015 about how crabs, excluded from the Antarctic seas for 30 million years by the cold, are now invading due to the incursion of warming ocean waters. The ecology had been free from crushing predators, and many species are vulnerable to being wiped out.

Ah, that made the next page icon appear.

No new comments are visible to me since November 3, although I see from the recent comments sidebar that more are being posted.

Here is an article about recent research aboard the Polarstern. http://www.redorbit.com/news/science/1112711909/polarstern-arctic-sea-ice-101112/

The NOAA article about the research: http://www.noaanews.noaa.gov/stories2012/20121010_arcticwinds.html

Sam, I am interested in learning more about the shifting north cold pole. Can you provide some links to discussions and research?

Lewis, I agree that renewable energy is only a partial mitigation of the global warming problem. However, my concern about geoengineering is that we don't yet know enough to be confident we wouldn't create more problems than we solve. The recent failure of the models to predict the magnitude of the sea ice melt is just the latest demonstration that we don't have a good grasp of the feedbacks and the magnitude of their effects. I don't like the idea of intentionally mucking about with our climate, but if geoengineering is found to be necessary, then so be it.

Ggelsring, My amateur understanding is that after freezing out some ice from the seawater, you would have to get rid of the remaining salt water by some means, as brine inclusions would make the ice weak and "rotten". Rinsing it away would mean pumping at least 4 times as much seawater as the final amount of ice formed. I think the scale of the undertaking would make it impossible. A cubic kilometer of ice masses a billion tons, and with annual melts being 16,000-18,000 cubic kilometers, you would need to freeze 1000 km^3 to even be visible above measurement uncertainties. If you pump the seawater up 10 meters in making manmade MYI, the energy required would be 10^15 Joules per km^3, or 270 million kw-hr. If you pump 4 times as much (per above), you would need a 500 MW installation to pump that much in 3 months of winter. Multiply that by 1000 km^3 and it would be 10 times the total US windpower installed capacity, or more than a third of total power capacity. Considering the difficulty of operating in open ocean in the Arctic winter, switching us to all renewable energy would be cheaper and easier.

Speaking toward Yuha's two proposed negative feedbacks: 1. How much warming can the Arctic Ocean waters take before the halocline breaks down, and the warmer deep waters mix with the surface? When that happens, wouldn't that be a huge positive feedback toward melting sea ice in the central basin? Could the shallow seas on the periphery still freeze seasonally? 2. Do the climate models offer any guidance about how much the heat flow would reduce with a warmer Arctic? How would the slowdown of heat flow be divided between the atmosphere and the water? What would that look like in terms of changes in weather patterns? Would the change be gradual or would there be wild oscillations? I pose these thoughts as questions, as I am a novice at this. I confess I had not paid enough attention to climate change until this summer's amazing melt. That came like a kick in the teeth, and I realized we were falling off a climate change cliff right now. I thank Neven and all of you for the wealth of information, discussion, and speculation provided by this site.

The link to Tamino's article in Thereoncewasawindmill's post makes me wish for a graph combining the insolation information with the sea ice coverage data, showing the energy absorbed by the Arctic Ocean through the year. I imagine the limits would be a bell-shaped curve representing a completely ice-free ocean centered on the summer solstice, and a much shorter but similar curve representing complete ice cover. The curve for the year's data would be a curve in between, skewed toward later in the summer due to the timing of the melt. Does such a graphical representation exist?

Kris, it doesn't seem to me that he thinks he is discovering new organisms, but interested in the the extent and albedo change, in much the same spirit as the NSIDC tracks the extent of sea ice. One of the photos shows a colleague measuring how varying microbe concentration affects the rate of ice melt.

I have a hard time imagining that a single collapse event could involve all or most of Greenland. Its 2655 north-south length is farther than the distance between Halifax and Miami.

Hello; thanks to Neven for this site and to everyone for their informative contributions. Since the GIS is being discussed, I would like to ask if the spreading microbial staining of the ice is known and discussed. http://ajw.asahi.com/article/behind_news/social_affairs/AJ201209280006

Jim Williams, 1) The question was raised in terms of melting, 2) Ice sheet collapse would not occur as incremental doubling in quantity, but as one or a small number of large catastrophic events. That would be a whole different discussion.

Oops, looked at my back-of-the-envelope calculation again; dropped a decimal place. It's only 400 W/m^2, only several times the solar energy falling on Greenland.

If I might jump into the discussion of the Greenland melt and sea level rise: For a rate doubling every decade, the quantity for any decade is just over the total of all the preceding decades. So for a 5 meter rise, the final decade would have a 2.5 meter rise. Globally, this amounts to 900,000 km^3 of melt. The energy to melt this much ice on Greenland would require 4000 W/m^2, applied 24/365. This is equivalent to putting every square meter of Greenland under an oven broiler element continuously. There isn't that much energy available.