Greenland: is this as bad as it sounds?

Hi Paul,

Your link doesn’t appear to be valid, I believe this is the article you were referring to http://www.guardian.co.uk/environment/2010/aug/10/...

Glacial dynamics are complicated as there are many factors and influences involved. In a nutshell, global warming has…

• Increased the rate of ablation

• Increased the amount of snowfall in the zones of accumulation

• Accelerated glacial advance

• Produced large scale basal sliding

• Increased stressing and fracturing of the ice-mass

• Melted 400 billion tons of Greenlandic ice each year

As we are seeing in other parts of the world, in particular the Arctic and mountain environments, warming is leading to a decrease in the extent of snow and ice cover which is affecting the local albedo which in turn exacerbates warming (see note 1).

I think the statement about losing the entire ice mass as a consequence of a 2°C rise is wholly inaccurate, 7°C would certainly be enough but not 2°C.

Assuming that a 2°C rise in the average global temperature did occur, then factoring in the regional feedbacks specific to Greenland could produce temp rises in the order of 3.4°C (2 + 30% + 30%). This would have a huge impact and would result in the loss of massive amounts of ice, perhaps up to 100km retreat away from the shoreline (not compensating for altitude).

Globally temps are expected to rise by between 2°C and 4°C by the year 2100 but for Greenland the projection is between 3°C and 7°C (anomalous values compared to the Hadley Centre 1961 to 1990 base period).

A typical climate for a coastal area of Greenland sees winter temps of between –10°C and 0°C, in summer the highs are generally between 0°C and 10°C. Once you move away from the periphery and into the interior the ice mass soon gains altitude with the result that much of Greenland is above 1000m and in places it’s above 3000m. At these elevations the temperatures are significantly colder and locations on the higher altitude ice mass have summer time highs that rarely exceed –10°C.

To melt the ice in such regions would require a significantly greater increase in ave global temps than 2°C. It would need to be closer to 6°C before any of the high altitude ice began to melt, and even then it would only be during the height of summer. To fully and permanently melt the ice would require a a rise in ave global temps of somewhere in excess of 10°C.

However, let’s not play down the importance of rising temps on the Greenlandic ice. Already 400 billion tons of ice are being lost each year and this is accelerating as temps continue to rise. This current rate of loss is the consequence of a 1°C rise in temps, the next 1°C rise could see the annual ice loss approaching the 1.5 trillion tons mark, enough to raise sea-levels by 4mm a year.

- - - - - - - - -

Note 1:

Albedo can be thought of as reflectivity or reflectance. Typically in Greenland the amount of sunlight being reflected is between 35% for old ice and up to 80% for newly formed ice and fresh snow cover. When the ice melts and reveals the land beneath the reflectivity falls to between 6% and 28% (depending on the surface that is exposed).

In recent years there has been a significant decline in the extent of the Greenlandic ice cover, this means that more energy from the Sun is being absorbed into the newly exposed land which is warming it up. In turn this melts more ice which then reduces the albedo further, leading to more warming of the surrounding land and water, and so it goes on.

Another significant factor is the amount of water vapour in the atmosphere. Insolation not only melts the ice but it also causes some of it to evaporate, this coupled with a rising average global temperature means there is more water vapour in the atmosphere. Water vapour is a greenhouse gas and therefore more heat will be retained in the atmosphere above Greenland.

Other contributory factors include the natural variability of temperatures, small changes in the thermohaline circulation, the North Atlantic Oscillation, solar winds and earth’s magnetic field and the magnetosphere.

I think it is as bad as it sounds.

It's as simple as that. No long discourses including all the scientific information, although I really appreciate the info and links provided by our resident scientists like Trevor and Dana.

Another article you might be interested in is from National Geographic that you can find in one of their recent issues this year, or from their channel's online website - a very good report on what is happening in Greenland. Besides 100 square mile chunks of glacier becoming part of the ocean, another incredible thing that is happening is that ice and snow on top of the glacier is melting, creating large pools and lakes that melt deeper and deeper into the Greenland ice cap until they reach the ground below and drain out the bottom of the glacier, creating spectacular ice caverns and probably helping to destabilize more and more of the ice cap and allow more and more extremely large chunks of glacier and ice to fall into the Arctic Ocean...

Of course, I don't want to alarm you are anybody else, this is just, factually, what is happening. It hasn't happened for thousands and thousands of years so that makes this event unprecedented in our recorded and more recent history of the past 6000 years. When unprecedented things happen, such as this, it becomes difficult to determine what might happen next, other than to know, as you have mentioned, that when the Greenland ice sheet is completely melted, the level of the world's oceans is predicted to rise by 7 metres (over 21 feet). I've lived along the coast, so it's amazing to me to know that the town I lived in years ago might be under water in my lifetime...

The seriousness depends on how much of the ice sheet can move. If the topography of Greenland is such that most of the ice sheet stays put, melting will take millennia. Glaciers that slide into the sea as icebergs melt in years. Most of the central ice-sheet appears to be trapped - bedrock is 300 meters below sea level and there is high topography all around. Sudden sealevel rise is much more likely to come from Antarctic ice shelves.

The ice-islands calving from the peripheral glaciers are considerably more that minor nuisances, though. They can lock up straits, run over oil rigs and reshape hunks of coastline.

The complacency displayed in other answers is amazing. BGS : "not the most pressing concern related to climate change over the next couple of decades". I think he should repeat the same sentence to Maldivians whose ruling 'Cabinet' held a symbolic sitting under the sea water with all that breathing/diving gear. And see the reaction. Not only Maldives but many Pacific Island nations, huge swathes (St.Lawrence Valley-Great lakes, Holland, a third of Bangladesh, eastern half of Sumatra, Singapore) will vanish. I think it is going to be number one relegating all others to the back-ground. In Ernest Hemingway's paraphrasing John Donne (For whom the Bell tolls) "No man is an Island..." It is going to be really bad and in less than a decade we will be able to see whether Greenland bereft of its mile thick (now it must be less) 'icing' baring the brown bottom, is a solid (contiguous) landmass, an archipelago like the Queen Elizabeth Archipelago (of Nunavut, Canada) or reveals a combination like Scandinavia-Baltic Sea. Dana1981 : "not as bad as the article made it sound, but bad nonetheless". I must say that he (top contributor in Y!A on global warming) has made his own paradise of thinking. Once the ice sheet thaws and the coastal parts of it become frayed, the sheet will rest on a thin film of liquid water on hard rock that is higher than sea-level to give it the necessary gradient and then it slides into sea with full force. We mightn't have witnessed such things in human history. In a few years time all that ice will clutter up the seas - Greenland Sea, Denmark Strait (1500 miles from Denmark), Atlantic Ocean, Davis Strait & Baffin Bay with waters agog with icebergs for a hundred miles. Complete melting depends on the temperature differential (may be 25 - 0 degrees C). The enormous heat of the Ocean this difference entails, unleashed onto the floating ice will do the job in five years. This heat transfer can be computed. For calculating the sea rise, here is a crude way I suggest. We are all nonprofessionals (I hope) and there is no constraint to arrive at accurate figures (within an accuracy of a few centimeters). Add up the total area of Antarctica, Greenland & Queen Elizabeth Archipelago (Baffin, Ellesmere, Melville, Victoria, Banks Is. mainly), Svalbard, (the New Zealand like) Novaya Zemliya, Severnya Zemliya, Franza Iosifa Zemliya, and fringes of mainlands of Canada & Russia. Multiply it by "1 mile (1.6km) / 0.92" (0.92 is the specific gravity of ice) and use this to divide the total Ocean Area (79% of Earth's surface). I am afraid this figure will exceed the 7m touted. The sea rise will hit the main Oceans instantly till it seeps into areas like the Mediterranean and the last to experience it would by Sea of Azov in Black Sea and Gulf of Finland. It will also extend the sway of cold currents - Humboldt (Peru), Benguela (Namib), California & West Australian, farther. It might enlarge the areas of Atacama. Namib, Patagonian, Californian, Sahara & West Australian desert somewhat. Ice covered areas will be exchanged with desert areas.

I think one thing being missed in these answers is not the validity of the findings, but the relevance. The findings may be semantically misleading, but that isn't totally the point. Like one of you said, the papers should be used as a guide, not a source. So maybe it's not a huge deal NOW that a glacier calved (after all it is "natural"). But the fact is that something that is warming our climate is happening FASTER, and much faster than any other climate shift in the past (sorry ice age man, rate beats degree. the ice age may have been a greater temperature shift, but our temperature shift is faster). and people need to accept that. Whether or not it is caused by human interaction or not im not going to get into for the sake of not starting arguments, but what should be taken from this article is that something needs to be done.

Perhaps not as bad as the article made it sound, but bad nonetheless. If the Greenland ice sheet does reach a tipping point where most of its melting becomes essentially inevitable, that's clearly bad news. That being said, it will still take on the order of decades to centuries for the entire ice sheet to melt and raise sea levels 7 meters. Of course there's also the Antarctic ice sheets, glacial melt, and thermal expansion to worry about in terms of sea level rise. And there's also the albedo feedback to worry about with regards to the ice sheet melting.

As a side note, I really wish David would stop linking to inaccurate (to put it kindly) graphs hosted on photobucket. This is what the Holocene temperature record *actually* looks like.

http://www.globalwarmingart.com/wiki/File:Holocene...

It is very bad in the long term (centuries), but is probably not the most pressing concern related to climate change over the next couple of decades (which is probably political instability related to global food supply and its vulnerability to extreme weather patterns (amongst other threats)).

Greenland/global warming.

http://current.com/shows/vanguard/89521833_i-heart...

To be honest I would say the same thing to you I say to deniers, newspapers should only be used as a guide they have a tendency to play the sensational headline (no matter which side the particular paper is pushing)

There is little doubt that both Greenland & Antarctica are melting but even in a warm world this is a processes that would take at least centuries, and I am reasonable certain that the quoted expert probably said something along those lines (but it was left out) I know from scientists I work with this is a fairly common thing for journalist to do, they can't be accused of misquoting you, they simply left out part of your full quote, that is now a very old journalist trick.

A head line that said Greenland is melting and will cause sea level to rise over the next several thousand years won't sell as many papers as leaving out the timescale and just saying Greenland is going to melt and raise sea level 23 feet.

While it may take Greenland thousands of years to melt as it does melt it will cause a steady increase in sea level. If you look at the end of the last it took ~5000 years for this larger body of ice to melt. But some simple maths (which seems beyond deniers) is that if it took 5000 years for Antarctica to melt then it should take ~100 years for ~2% Antarctica to melt, 2% of Antarctica would add ~1.2m to the worlds oceans if Greenland is added to that the figure would be a little higher. Then look at what the IPCC are predicting is their high end figure 23feet or around 1.5m that should tell you how much of these two ice sheets they are thinking will melt by the end of this century (90 years away).

1.5m (even 1m) is more than enough to cover the Islands that have been talked about and to cause flooding in most of the worlds coastal and river based cities.

The only ones talking about waterworld scenarios (in the near future i.e. ~100 years) are deniers, even in the longer term there simply isn't enough ice if everything melted (and it would take thousands of years) sea level could only ever rise by around 65-70m at that speed of rise the average snail could outrun the flooding but it would still be a long term major issue we would leave for our descendants. Most normal people care about their children and grandchildren and what will happen to them.

Jeff M (the denier one) seems to be playing some of the usual denier points he talks of inland temperature (as they do of Antarctica's inland -60c) while ignoring that the melting is occurring at the coast were temperatures are much warmer (especially in Summer) Antarctica coastal stations have been reporting temps of 10-12c in the last few decades and not the peninsula I'm talking about continental Antarctica. As for his comments on past rapid rise in temperature, based on what!, the ice core record is the long term proxy record, it's the one deniers say can't be trusted (unless they are trying to use it to support one of their own theories)

http://en.wikipedia.org/wiki/File:Vostok_Petit_dat...

Sadly for Jeff it shows a rise in temperature of ~8c which took ~5000 years that is a rise of ~0.8c per thousand years compared to what we have at the moment a rise ~0.8c in just 100 years, time for some new batteries in your calculator Jeff.

He also said this "we do NOT have enough of a comprehensive temperature or climatological record to support the idea that we are experiencing a large temperature shift now" yet strangely he seems to think that the proxy record of 12000 years ago is accurate enough for him to make his claims, spoken like a true denier, Mockingtone would be proud. Silly statements like these are what happens when you try to make up your science on the fly.

The report you have submitted is full of inaccuracies.

Lets start with the simplest. The new Iceburg.

Glaciers calve. That is what they do. As a glacier expands into the ocean you end up with unsupported ice sheet on the ocean. Tidal shifts waves ect fracture the glacier over time and this causes the calving. 100% natural. In addition the faster a glacier is growing the more it will calve and the larger the section of ice the break off will be.

Greenland land mass temps are way too low for a 2 Degree C temp shift to melt ALL of it.

This statement is blatantly false "What is going on in the Arctic now is the biggest and fastest thing that nature has ever done," Fact is that the period shortly after the end of the deepest part of the last ice age saw a MUCH more rapid temperature shift. Also, some records suggest that the period at the beginning of the last ice age saw MUCH more rapid temperature shifts. In addition, we do NOT have enough of a comprehensive temperature or climatological record to support the idea that we are experiencing a large temperature shift now, at least when you attempt to compare the current shifts to the fossil record. The last several milenia have been exceptionally stable. We have not yet seen any movement significant enough to definatively say anything has changed the status quo.