After the last ice age, glacial melt caused sea levels to rise rapidly by 120 meters. Large expanses of land that were once migratory paths and habitations for prehistoric civilizations gradually submerged through a series of catastrophic floods and mega-tsunami. (Meltwater Pulse 1A and 2B are discussed in the video at the bottom of this story.) If this event in Greenland is the start of another Meltwater Pulse we are effed.
From Robert Scribbler.
The remnants of hurricane Alex were pulled into a storm system just south of Greenland on Friday January 15, 2016. An event that then flooded both Baffin Bay and Western Greenland with warm, tropical air. At the same time, Greenland observers both noted what appears to be ice mass losses over Western Greenland as well as a possible large melt water outflow issuing from the Disko Bay area.
Perhaps more ominously, this widespread clearing of ice from these Arctic bays occurs in concert with what appears to be a large ice-calving event along the ocean-facing front of the Jacobshavn Glacier.We see a large retreat of the glacier together with what looks like a major sediment outflow. Sediment hitting water in this way would be a sign that a very large volume of water had been expelled along the basal zones of the Jacobshavn. In addition, the ice itself appears to have been forcibly ejected. This apparent sediment flush, the concave bowing of sea ice away from Disko and Uummannaq and the inland recession of the calving face are all indicators that something terrible is afoot in Western Greenland.
A large flush of melt water coming from Greenland during Winter would, indeed, be that terrible thing. Something that now may become a more and more common feature of our age as Winter continues its ongoing retreat against a relentless assault by human greenhouse gas emissions.
Glaciologists Tenney Naumer, Alun Hubbard and Jason Box believe that a large melt water pulse occurred at Jackobshavn Glacier — one of the swiftest-melting glaciers on Greenland. Over recent years, it has been one of the primary hot-spots for summer Greenland ice mass loss. But during recent days, mass loss also appears to have occurred in this area."
It is evident from the PROMICE weather records on the ice sheet just south of the Disko Bay region that temperatures have been exceptionally high since January 5th and atmospheric pressures have been high since January 9th. The Polar Portal mass balance model indicates some actual declines/ablation in the last week. This is more likely sublimation from föehn conditions than actual melt. The real changes are in the sea ice fronts and ice in the coastal inlets illustrated by MODIS. Below are images from January 9, 11, 13 and 16 for Disko Bay and January 9, 13 and 16 from Uummannaq Bay.
The arrow at location 1# is an area of sea ice across the fjord in front of Jakobshavn Glacier on January 9, that disappears by January 13. Location #2 is at the fjord mouth and location #3 is at the sea front south of Disko Island on January 9. There is no real cloud cover evident in any of images. Maybe low level fog in places. By January 11th a plume is sweeping from Point 2 towards Point 3. Notice the sea ice in the fjord disappears by January 13th and the ice front is pushed back in a concave fashion at Point #3. This indicates a clear push of water driving sea ice offshore. The Ilulissat Fjord mouth lack of ice is also evident in Webcam images from 1-16-16 and 1-17-16 at the Hotel Arctic, last images below with two boats plying the open water. on the 16th and icebergs clogging the fjord mouth on the 17th. The Sentinel-1 image from January 16th shows a significant flushing of icebergs from Ilulissat Fjord, pointed out by black arrows. This image has better clarity and with the icebergs scattered through the plume, indicate more clearly the plume is a water source change event, even if wind driven. The iceberg plume in the fjord has a brighter aspect due to the varied surface aspect-reflectance and has expanded down fjord. The event must be due to or enhanced by strong offshore winds and Ruth Mottram (@ruth_mottram) indicates there was at least one föehn event this week. The plume indicates the ice melange in front of Jakobshavn has been largely removed.
In Uummannaq Bay a very similar sequence plays out, note on January 9 the sea ice connecting islands near #4. By January 13th the ice at location #4 is gone. The ice front is now at location #3, which on January 9th was well into the ice pack. Again we have a clear push of water leading to a concave sea ice front that is pushed well offshore. Icebergs can be seen amidst plume on January 16th, the plume opacity and size has diminished since January 13th.
In both of the January 13th images there is a plume leading to the concave sea ice front, the question being is this sediment laden water, with the resultant higher reflectivity or is it a combination of a surface water change from wind or a combination. Jason Box suggests it is aeration of the surface water from the strong offshore winds. The ice must in part be driven back by a surface water push. You can see icebergs in sections of the plumes closer to shore suggesting this is a surface near surface phenomenon. This is a short term event. However, it could have broader implications, Moon et al (2015) indicate the importance of a rigid ice melange at the front of tidewater outlet glaciers in Greenland. In this case the ice melange in front of Jakobshavn has been removed, and probably from in front of other glaciers. I look forward to further insights from the community.
All of the below images can be seen as a larger image by clicking on them at Robert Scribbler story.
We are in so much trouble and it is only January. 2016 is going to be a disastrous year for the Greenland ice sheet.