Greenland - What Do We Know, What Is The Long Term Future And Is There Any Evidence Of A Melt Out?

[cheeky_monkey]

On 29/03/2018 at 12:43, knocker said:

 

there are similar articles that appeared in the late 1930s stating that there had been a rapid rise in the amount of ice melt in Greenland since the turn of the century and the whole system was in danger of a catastrophic collapse

[Gray-Wolf]

16 hours ago, cheeky_monkey said:

there are similar articles that appeared in the late 1930s stating that there had been a rapid rise in the amount of ice melt in Greenland since the turn of the century and the whole system was in danger of a catastrophic collapse

But then we saw the impacts of the dirty side of our then polluting combine with naturals that slowed AGW to a crawl. Only when naturals had flipped to augmenting AGW and first impacts of the european/U.S. 'clean air acts did we see temps begin to rapidly increase again?

We have just seen a similar impact, though geographically removed, from the rapid industrialisation of China? Now China is rapidly cleaning up her act again we see global temps on an accelerated rise.

Sadly , unlike last time, we are close to, or upon, feedbacks which will drastically alter our planet over the coming decade.

Greenland is one of those feedbacks with some of the Ocean terminating glaciers now seeing year round discharge as 'ice cliff failure' takes over as the main means of calving bergs as glaciers retreat up valley and glaciers 'float off' the bed below. We have to remember that the Island is a huge inland sea surrounded by a ring of mountains so there comes a point where ocean inundation will reach that inland basin?

As it is Peterman may bring us another major calve this season as a new fissure is spotted in the centre of the ice that looks like it could join up with the existing cracks on the northern flank of the glacier. this looks like it will retreat back beyond two hanging valleys so we would be able to see how fast their glaciers retreat once the ice of Peterman is no longer holding them back?

[tablet]

published online 4th April 2016

Melting at the base of the Greenland ice sheet explained by Iceland hotspot

http://www.geo.uu.nl/~seismain/pdf/ngeo2689.pdf

 

[tablet]

16 November 2017

Predicting the Geothermal Heat Flux in Greenland: A Machine Learning Approach

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2017GL075661

[knocker]

 

Edited July 18, 2018 by knocker

[Gray-Wolf]

Yet 'melt' has seen some big events and is still running as it should......

With N.Hemisphere snow cover anoms now all gone there is only the snow from last winters ,Arctic bound, storms left on the eastern side of Greenland?

Edited July 24, 2018 by Gray-Wolf

[knocker]

 

Edited August 13, 2018 by knocker

[knocker]

 

Edited August 16, 2018 by knocker

[Gray-Wolf]

Had this drawn to my attention;

https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2018JD028714

Looking at Atmospheric Rivers and their impacts both on melt and mass balance via increased snowfall events ( as we witnessed along East Greenland last year as the lows bound for the Arctic Basin trawled up that side of the land mass?

My concern has been the potential for 'maga' avalanches if individual events leave unstable masses on top of the ice sheet? Such rapid movement to lower elevations would mimic the saddle/lobe melt of the great ice sheets at the end of the last ice age?

'Gravity' is not temp dependant so both Ice cliff fraturing to remove Glaciers/ice shelfs in rapid order and avalanch both use gravity to bring ice/snow into melt zones that could have remained stable for decades?

When the papers looking at 'hot house' potentials talk of 'cascade' events making matters worse and these may well fall into the 'cascade' category?

[knocker]

 

Edited August 22, 2018 by knocker

[soft lad]

1 hour ago, knocker said:

 

The end of the 2017/2018 season is in and over 500 billion tonnes of snow/ice has been added to the Greenland Ice Sheet. If including figures from the 2016/2017 season there has been an increase of approximately 1 trillion tonnes to the ice sheet.

Danish Meteorological Institute: https://www.dmi.dk/en/groenland/maalinger/greenland-ice-sheet-surface-mass-budget/

[knocker]

How the Greenland ice sheet fared in 2018

https://www.carbonbrief.org/guest-post-how-the-greenland-ice-sheet-fared-in-2018

[knocker]

 

Edited October 31, 2018 by knocker

[tablet]

electroverse  article above

https://www.scientificamerican.com/article/late-snowpack-signals-a-lost-summer-for-greenlands-shorebirds/

quote : Millions of shorebirds descend on the Arctic each year to mate and raise chicks during the tundra’s brief burst of summer. But that burst, which usually begins in mid-June, never arrived this year for eastern Greenland’s shorebirds, a set of ground-nesting species. Instead, a record late snowpack—lingering into July—sealed the birds off from food and nesting sites. Without these key resources avian migrants to the region will not reproduce in 2018, experts say. Breeding failures like this may grow more common because some climate change models predict increased springtime snow in the shorebirds’ nesting habitat.

[knocker]

The Polar Portal season report for 2018 is ready for download.

http://polarportal.dk/en/news/2018-season-report/

[knocker]

Nonlinear rise in Greenland runoff in response to post-industrial Arctic warming

Quote

The Greenland ice sheet (GrIS) is a growing contributor to global sea-level rise¹, with recent ice mass loss dominated by surface meltwater runoff^2,3. Satellite observations reveal positive trends in GrIS surface melt extent⁴, but melt variability, intensity and runoff remain uncertain before the satellite era. Here we present the first continuous, multi-century and observationally constrained record of GrIS surface melt intensity and runoff, revealing that the magnitude of recent GrIS melting is exceptional over at least the last 350 years. We develop this record through stratigraphic analysis of central west Greenland ice cores, and demonstrate that measurements of refrozen melt layers in percolation zone ice cores can be used to quantifiably, and reproducibly, reconstruct past melt rates. We show significant (P < 0.01) and spatially extensive correlations between these ice-core-derived melt records and modelled melt rates^5,6 and satellite-derived melt duration⁴ across Greenland more broadly, enabling the reconstruction of past ice-sheet-scale surface melt intensity and runoff. We find that the initiation of increases in GrIS melting closely follow the onset of industrial-era Arctic warming in the mid-1800s, but that the magnitude of GrIS melting has only recently emerged beyond the range of natural variability. Owing to a nonlinear response of surface melting to increasing summer air temperatures, continued atmospheric warming will lead to rapid increases in GrIS runoff and sea-level contributions.

https://www.nature.com/articles/s41586-018-0752-4

[Gray-Wolf]

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2018JF004775

A 10% acceleration in the flow of Petermann since the 2012 mega calve.

With the latest calve looking likely this year we will likely see this speed increase again..

 

[knocker]

Accelerating changes in ice mass within Greenland, and the ice sheet’s sensitivity to atmospheric forcing

Quote

Significance

The recent deglaciation of Greenland is a response to both oceanic and atmospheric forcings. From 2000 to 2010, ice loss was concentrated in the southeast and northwest margins of the ice sheet, in large part due to the increasing discharge of marine-terminating outlet glaciers, emphasizing the importance of oceanic forcing. However, the largest sustained (∼10 years) acceleration detected by Gravity Recovery and Climate Experiment (GRACE) occurred in southwest Greenland, an area largely devoid of such glaciers. The sustained acceleration and the subsequent, abrupt, and even stronger deceleration were mostly driven by changes in air temperature and solar radiation. Continued atmospheric warming will lead to southwest Greenland becoming a major contributor to sea level rise.

Quote

Abstract

From early 2003 to mid-2013, the total mass of ice in Greenland declined at a progressively increasing rate. In mid-2013, an abrupt reversal occurred, and very little net ice loss occurred in the next 12–18 months. Gravity Recovery and Climate Experiment (GRACE) and global positioning system (GPS) observations reveal that the spatial patterns of the sustained acceleration and the abrupt deceleration in mass loss are similar. The strongest accelerations tracked the phase of the North Atlantic Oscillation (NAO). The negative phase of the NAO enhances summertime warming and insolation while reducing snowfall, especially in west Greenland, driving surface mass balance (SMB) more negative, as illustrated using the regional climate model MAR. The spatial pattern of accelerating mass changes reflects the geography of NAO-driven shifts in atmospheric forcing and the ice sheet’s sensitivity to that forcing. We infer that southwest Greenland will become a major future contributor to sea level rise.

https://www.pnas.org/content/116/6/1934

[knocker]

A misleading graph purporting to show that past changes in Greenland’s temperatures dwarf modern climate change has been circling the internet since at least 2010.

Based on an early Greenland ice core record produced back in 1997, versions of the graph have, variously, mislabeled the x-axis, excluded the modern observational temperature record and conflated a single location in Greenland with the whole world.

More recently, researchers have drilled numerous additional ice cores throughout Greenland and produced an updated estimate past Greenland temperatures.

This modern temperature reconstruction, combined with observational records over the past century, shows that current temperatures in Greenland are warmer than any period in the past 2,000 years. That said, they are likely still cooler than during the early part of the current geological epoch – the Holocene – which started around 11,000 years ago.

https://www.carbonbrief.org/factcheck-what-greenland-ice-cores-say-about-past-and-present-climate-change?utm_source=Twitter&utm_campaign=IcecoresTwitterVid0319

[Singularity]

Hints from long-range modelling of a more negative summertime NAO in 2019 compared to the past few summers.

Yet also signs of above-normal heights across Europe with the main southerly-displaced trough being across the Azores instead - the weak El Nino making its mark, perhaps.

Is this a means to bring a rare duality of anomalous warmth to both Greenland and Western Europe (with below-normal westerly momentum making it difficult for LPs to break down European heat builds)?
 

If the models are anywhere close to the mark with this, it'll be very interesting to see how it pans out both locally to us and, of course, across Greenland. So much fresh snow mass in the past couple of years to interact with any anomalous warmth that takes place, with the inherent instability that brings.

[cheeky_monkey]

On 27/03/2019 at 11:03, knocker said:

A misleading graph purporting to show that past changes in Greenland’s temperatures dwarf modern climate change has been circling the internet since at least 2010.

Based on an early Greenland ice core record produced back in 1997, versions of the graph have, variously, mislabeled the x-axis, excluded the modern observational temperature record and conflated a single location in Greenland with the whole world.

More recently, researchers have drilled numerous additional ice cores throughout Greenland and produced an updated estimate past Greenland temperatures.

This modern temperature reconstruction, combined with observational records over the past century, shows that current temperatures in Greenland are warmer than any period in the past 2,000 years. That said, they are likely still cooler than during the early part of the current geological epoch – the Holocene – which started around 11,000 years ago.

https://www.carbonbrief.org/factcheck-what-greenland-ice-cores-say-about-past-and-present-climate-change?utm_source=Twitter&utm_campaign=IcecoresTwitterVid0319

This does not square with historical settlement in Greenland..we know the vikings started settling the area around 1000 AD yet these show Greenland was -1c colder than the 1880-1960 average ...they settled and farmed successfully etc for the next 250 years..and records show they slowly died out as the climate grew much colder between 1250 -1400 AD but this shows no such cooling until after 1500??

[Singularity]

https://www.dmi.dk/?id=1042

Greenland melting got underway 2nd earliest since 1980, according to this article by the Danish Met. Institute.

[Gray-Wolf]

There seems to have been a switch back to H.P. both inside the Arctic basin and over Greenland over recent months?

This has me twitched about the export/melt of Sea Ice but also another big loss year across Greenland akin to the 2012 event?

The excessive snow along the East coast of Greenland over recent years will not do well under such forcing and I hope we do not see any slumping from the summit into lower regions?

That layer of year round water below the snow cover may lead to such large scale movements via both lubrication and leakage.

If ever there was a year that a big climate event may prove to our advantage it is this year!!!

[knocker]

Greenland Ice Loss 2002-2016

https://gracefo.jpl.nasa.gov/resources/33/greenland-ice-loss-2002-2016/

[knocker]

Study Predicts More Long-Term Sea Level Rise from Greenland Ice

Greenland’s melting ice sheet could generate more sea level rise than previously thought if greenhouse gas emissions continue to increase and warm the atmosphere at their current rate, according to a new modeling study. The study, which used data from NASA’s Operation IceBridge airborne campaign, was published in Science Advances today.

https://www.nasa.gov/feature/goddard/2019/study-predicts-more-long-term-sea-level-rise-from-greenland-ice