[Tanada]

Solar insolation data

Thanx Cid, from that data it looks as though about 65 to 70% of Greenland as a whole, and all of the southern third, is above threshold as of the date of the graphic.

[Tanada]

For those following this thread I highly recommend the brief paper on Glaciation and climate change you can find HERE.

Please pay close attention to the graph on page 11, it shows continental type glacier formation begins when summer insolation falls below a critical value of about 455 or 457 W/m^s, and every time the critical insolation exceeds 470 W/m^2 or so the ice sheets melt. Depending on how large the ice sheet is the lag between exceeding 470 and onset of melt changes, the greater the glaciation the more time it takes.

Zooming in on Greenland in the link Cid_Yama supplied above it appears that from June 26 to July 3 most of the island ranged from 410 to 550 W/m^2. If you now turn to page 13 of the document I linked too above and look at our current CO2 levels you will see that the critical value has decreased from 457 to 440, which places a lot more of the island in the deglaciation range than it would be without the CO2 forcing we already have in place today. If we add another 50% to our current CO2 levels which would place us around 550 ppm then the critical insolation value falls below 410, and ice on all of Greenland would become a melt situation. If you add in the forcing from other GHG components we are already past 450 ppm equivalent. That lowers the critical insolation threshold down to about 430 W/m^2

I think Greenland is at or above threshold now, or it will be in the very near future. How fast can it all melt? Nobody knows.

[katkinkate]

... Climate change may just make Greenland may be one of the best locations to be for peak oil, ever increasing growing season and land area from melted glaciers. ...

No really. No soil. Just rock, gravel and sand if you're lucky. All the silt and clay suspended in the ice gets washed into the sea. Sterile.

[dohboi]

Thanks for the link, tanada. I'll look into it more deeply when I have some time.

The dynamic that seems to be playing a large role in the melt is black carbon (soot).

Here as elsewhere, it turns out that GHG caused warming is acting as a trigger setting off powerful feedbacks.

As I understand it, the warming from AGW makes it likely that at least all of last year's snow/ice melt. This brings to the surface of the snow all the soot that was mixed in from the last year (at least). Now the albedo of the surface has changed to something darker that it would have been with out the initial melt. This increase in heat retention from the added surface darkness further accelerates the melting, bringing yet more soot to the surface as the snow melts around it...so you have an accelerating dynamic.

A recent study reviewed over at realclimate concluded that this change in albedo from soot accumulating at the surface (once AGW kicks off the process) accounts for most of the current melting.

Another thing affecting the lower altitudes that will accelerate as the Arctic sea ice melts is increased rain. On the other hand, increased snow may have a dampening effect.

[Tanada]

New video report here. It now seems that the ice sheet is shrinking 1.5 meters per year in altitude around the southern periphery.

[Homesteader]

When viewing the video it was a bit of a shock to see the layer of black particulates on the ice.

[Cid_Yama]

The quote, "just 10 years ago, the ice sheet was 45 feet higher than it is today." says all that needs to be said.

[Lore]

I don't get it? The climate was suppose to be cooling for the last 10-years. Why the ice-sheet melt... go figure?

[dissident]

The ice sheet melt should be drilled into the public mind at every opportunity. The denialist idiots like to bleat about 1998 being the warmest year and that there has been cooling ever since. Well, the melting ice cube picture is something simple enough for people to visualize and understand. Can't have melt without warmer temperatures and there is no way around this (forget about soot since air quality has been improving quite a bit). The ice is a great indicator that filters out the meaningless variability that is endlessly cited as explaining everything by the denialists.

[rangerone314]

I kind of wish the ice sheets would undergo a rapid melt that would actually start seriously flooding a few coastal areas, like Shanghai and New York. It might serve to elevate people's thinking a little.

[eXpat]

NASA data: Greenland, Antarctic ice melt worsening

WASHINGTON – New satellite information shows that ice sheets in Greenland and western Antarctica continue to shrink faster than scientists thought and in some places are already in runaway melt mode.

British scientists for the first time calculated changes in the height of the vulnerable but massive ice sheets and found them especially worse at their edges. That's where warmer water eats away from below. In some parts of Antarctica, ice sheets have been losing 30 feet a year in thickness since 2003, according to a paper published online Thursday in the journal Nature.

Some of those areas are about a mile thick, so they've still got plenty of ice to burn through. But the drop in thickness is speeding up. In parts of Antarctica, the yearly rate of thinning from 2003 to 2007 is 50 percent higher than it was from 1995 to 2003.

These new measurements, based on 50 million laser readings from a NASA satellite, confirm what some of the more pessimistic scientists thought: The melting along the crucial edges of the two major ice sheets is accelerating and is in a self-feeding loop. The more the ice melts, the more water surrounds and eats away at the remaining ice.

"To some extent it's a runaway effect. The question is how far will it run?" said the study's lead author, Hamish Pritchard of the British Antarctic Survey. "It's more widespread than we previously thought."

http://news.yahoo.com/s/ap/20090923/ap_on_sc/us_sci_big_melt

[VZR1800]

I kind of wish the ice sheets would undergo a rapid melt that would actually start seriously flooding a few coastal areas, like Shanghai and New York. It might serve to elevate people's thinking a little.

What exactly do you hope to have happen once their thinking is elevated? According to Cid and others, this is a done deal, nothing we can do to change it now. It took what, a hundred and fifty years of us burning fossil fuels to get to this point. How many will it take to reverse the damage?

As for myself, I am not going to change a thing I do. Going to keep on driving the old gas-hog pick-up truck, because it is payed for in full. I am not going to put myself in debt to buy some POS hybrid, so some future generation may have things a "little better".

Most people out there simply do not give a crap about the things that concern you, me being one of them. Nothing we can do about it, so why care?

Kind of like the boneheads that discuss 09/11 "Truth". It is the same people talking about it, no new participants. I simply do not care! There will be no new investigation, so why bother?

Back to your regularly scheduled programming.

[dissident]

And the lemmings keep on running to the cliff....

[VZR1800]

And the lemmings keep on running to the cliff....

Maybe so!
But since we outnumber you,
you might try finding the nearest cliff.

[Cid_Yama]

It may be that those who have been right all along would just like to have the opportunity to rub their noses in it before we all die.

Unfortunately you will have the media going on and on about how 'no one knew' or 'no could have possibly known' or 'it was just impossible to predict' even though many of us have been warning about this for years.

Frankly, I get my satisfaction in knowing that they will suffer the consequences of their actions, that no one skates on this one. Perfect Dharma.

[Tanada]

I kind of wish the ice sheets would undergo a rapid melt that would actually start seriously flooding a few coastal areas, like Shanghai and New York. It might serve to elevate people's thinking a little.

They are undergoing rapid melting, do you have any concept of just how much energy you have to input to lower hundreds of square kilometers of ice sheet by 1.5 meters a year? Especially when the actual melt season is far less than a year in length, more like 45 to 90 days depending on latitude? To make it melt much faster you would have to make the whole planet difficult to live on, and I personally would like to avoid that scenario if at all possible.

[Lore]

And the lemmings keep on running to the cliff....

Maybe so!
But since we outnumber you,
you might try finding the nearest cliff.

Now why would we want to do that? Just leaves more room for the rest of us. It's called natural selection.

[DryObserver]

Try painting all of the asphalt roofs and roads white, thereby changing the albedo for a substantial part of the Earth's surface (that is presently dark gray to black). That won't stop everything, but if you start in warmer cities and towns you can break the "heat island" effect that afflicts urban areas, thus reducing air-conditioning demand (and its associated emissions). That will help save money that can be used to paint more dark roofs and roads in those regions. Once you're done with those cities, whether Barcelona or Baghdad, Atlanta or Athens, Madrid or Miami, move on to others. Assuming the North Atlantic Current doesn't fail and we don't get a snap ice age (really about the happiest outcome you could get in a true runaway heat up of the planet), then we'll have other balmy candidates soon enough.

And yes, I have been talking about that suggestion one on and offline for a couple of years now and yes, Dr. Steven Chu (Energy Secretary and Nobel Laureate) has also been talking it up of late. But in the meantime, there it is.

[DrGray]

Try painting all of the asphalt roofs and roads white, thereby changing the albedo for a substantial part of the Earth's surface (that is presently dark gray to black).

Yes, great idea! Perhaps if the deckhands had pulled out their paint cans to begin repainting all the deck chairs, the titanic would not have taken a detour to the sea floor.

Sorry for the sarcasm, but come on! If your going to spend that much energy on a project, at least do it for something worthwhile. Instead of painting the roads white, just turn them into bike paths. I know that won't happen, but neither will painting every city in the world white.

You might ask what's the harm in trying this white wash idea? It's pansy ass ideas like this that allow yuppies to feel good about themselves that they voted for something green, meanwhile consuming ever vaster quantities of energy. They did their good deed for the year, they helped protect the planet, now they can go back to their 72inch LCD TV's. Half-ass band-aid ideas hinder real work that could be done, because most people will always choose the easiest way to get something done. If they think they are doing something by buying a green product, they will. And then their done. Finito. Global warming problem solved. On to the next fad.

[lowem]

Painting the roads in any shade is crazy - it would wear off immediately.
Just about as crazy as solar or conductive roads.