Greenland has a 'heat wave'?

That is quite a conspiracy theory. But when periodic events are predicted, it is unlikely that they stem from other causes. Mojo gave you some sources. When they pulled the ice cores, we received a temperature record. In most years about half the surface of the ice melts, but on the average of 153 years (80-250) weather events melt most of the surface of the sheet. We see the refreeze in winter in the core. The last time many people were around to observe this directly was the medieval warm period, and we don't really fully trust that historical record. This is the first time - unprecedented - that we can observe this event with satellites. It should give us clues to how fast the glaciers will melt, and sea level will rise in the future. Definitely an exciting time to be a scientist studying the ice.

Certainily it is jumping to conclusions that this was affected by anthropomorphic green house gasses. NASA says they are studying this. Is it a combination of warm weather and certain AMO that has a random chance of around 153:1? Just like the northern hemisphere getting warm every summer, this may simply be a natural event. Correlation is not causation, and there is not even correlation here yet. That would take an attribution study.

 

AG#21 I'll take it as established that the annual variation in net accumulation is as wide as this, though I failed to access the Alley and Anandakrishnan 1995. One could always email the authors for a copy. I certianly should, were it closer to my interests.

We might learn from some Greenland thermometer records whether this such surface temperatures are distinctive in the period of record. They are certainly presented as such in these media reports.

I thought the soot question was quite an interesting one and it did send me to the lit. Would quite recommend
"Long-term perspective on wildfires in the western USA" in PNAS early 2012
Their money graph is quite complex, but I'll dare to simplify it. For the past 1400 years, Western US fire burn area is closely related to paleo-reconstructed climates. Warm & dry more burn. It 'should have' increased in the last 100 years, but fire-supression policies have intervened.

Tilman et al 2000 in Ecology " Fire suppression and ecosystem carbon storage" Has the whole-USA graph that I was looking for. Since 1930's (generally warm and dry like now), the burn area has been dramatically released. I believe even the recent biggest year (2009?) was far below. So, there is not a general case for high Greenland sooting, absent some special process transferring the soot to the 'right' place. So, I think we can set that aside as contributing largely to the present Greeland situation.

Bob's paleo agriculture thing refers to WF Ruddiman, several publications, and we have discussed them here before. Ruddiman suggests that both methane and CO2 (ice cores) increased in an unusual way and attributes to the rise of forest clearing and paddy rice. Others don't see that as clearly in the record.

For me this is a big deal because there has been so much loss of forest carbon and soil carbon (gradually) over the 7000 years, and it simply does not show up as CO2. Estimates vary but it is probably more than the total fossil fuel burn since we started doing that. What's up with that? (TM)

[FONT=Times New Roman]Speed, my friends. Change something slowly and the and the biosphere can maintain homeostasis. In this case it was all ocean; too bad for people like me studying land stuff. Exceed the speed limit (one to few PgC/yr) and the biosphere gets beat. Like now.[/FONT]

[FONT=Times New Roman]I consier all this perfectly topical for the Envtl sub forum. Julian Assange, not unless he does something 'environmental'. To me, the point of the thread has been established. The media again has overshot. If NASA also, then they have a lesson to learn.[/FONT]

 

The numbers are from nasa glaciologist Koenig. You can decide if you trust her, she looks like she has credentials. Here she is at summit, greenland
Winter Camp: A Blog from the Greenland Summit : Feature Articles
The statement is from Revkin's .earth column in the NY times opinion section.
'Unprecedented' Greenland Surface Melt - Every 150 Years? - NYTimes.com
It references the paper, and anouther one from 1994, and includes this chart from it, showing melt events with arrows and includes the 1889 event.
Some of those other “unprecedented” melt events at...

I don't think they had thermometers at summit in 1889. We do have the firn, and they do provide some evidence of warm enough to melt. In the comment section of the revkin column they talk about summit being one of the last places to melt, which indicates that there is a widespread melt event if it shows up in that core.

This link to a blog will help people understand melt events in the firn and the ice core in the comments.
New Summit Melt Layer « Dartmouth IGERT – Polar Environmental Change

 

AG@25 you link the same graph I did @13.

Certainly there were not summit T records in 1889, but this reconstruction

http://www.cru.uea.ac.uk/cru/data/greenland/vintheretal2006.pdf

may merit our attention. In that, the hottest years do not seem to equal the current situation. 47 oF 'usta be' big. To consider elevation, the lapse rate is 11 oF per 1000 meters. It differs for dry and wet atmospheres, but this is a fine number to remember, if one wants to remember such things.

Staying with the thread topic, we could wonder how long this heat will persist and how much ice it can melt.

 

Sorry for the repeat graph. Thanks for the temperature reconstruction. The ice has already reformed at summit. It is a great opportunity to study how the ice melts, and how much will go into the sea.

From anouther blog link about 1889 similarities
Two warmest winter months in Midwest, U.S. history may have connection

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Perhaps similar La Ninas and Artic Oscillations in the winter, led to weather patterns in the summer.

 

No thanks (as we say in China ) my only goal is to get closer to the truth.

Perhaps the latest in PNAS can help with that

"Bedrock displacements in Greenland manifest ice mass variations, climate cycles and climate change"
doi: 10.1073/pnas.1204664109
the authors paid for open access to this article so y'all will be able to d/l it directly.

What did they do?
Put a bunch of precise GPS stations around Greenland, and decompose the vertical signals into isostatic rebound, air pressure (! yes even that !) and icemelt.

What have they found?
Fig 4 has local curves through time and Fig 5 has spatial ice-loss rates. As this is open access, there is no need for me to interpret.

Could they be wrong?
If their ongoing data agrees with GRACE and other local measures, one would have doubts. If their future findings disagree with the global tidal gauge network, that would indicate a problem needing resolution.

Global significance?
There is much more meltable ice in Antarctica than Greenland, so one might hope for a similar GPS network in 'the big A'. Antarctica is a horrible, deadly place to work though, so it may not come quickly. Funding is also an issue because govenments (subsiding fossil fuels and fighting unwise wars ) feel poor. Gonna have to see how all that plays out.

So?
Look to unbiased analyses of the global tidal gauge network to see what has happened to sea level. Look to studies like this for information about future accelerations

Are we all gonna drown?
Surely not in the next decade. If you live within 1 meter of sea level, pay attention. If you live within 3 meters of sea level and you have strong local storm surges, pay attention.

DAS

 

More on Greenland

Aerial photos reveal dynamic Greenland ice sheet: Ice sheet has recently retreated then restabilized

refers to a ms that will be in Science, but no DOI yet apparently.

Since 1980, authors report several speedups and slowdowns in Greenland ice loss. This seems not inconsistent with the 150 +/- (large) years thing, though the time scales differ.

Seems long records are golden to assess such processes. Seems there may be little to learn from the 'crisis du jour', or from the snow storm that disproves global warming.

Apologies to all those who already found that to be obvious.