Sophie Berger is a PhD student of the glaciology unit, at the Université Libre de Bruxelles (ULB), Brussels Belgium. She is using various remote sensing data and techniques to investigate the dynamics and stability of the ice shelves in Dronning Maud Land (East Antarctica).
She tweets as @SoBrgr.
Left: Projection of sea-ice extent in the Northern Hemisphere [NH], for the different scenarios of the IPCC ( RCPs). The dashed lines are the mean of all the models used in the CMIP5 experiment while the solid lines come from a subset of models that fit the observations the best.
Right: maps of multi-model results in 2081-2100. The white and grey coloring result from the ensemble and the subset of models, respectively.
(Credit: IPCC (2013), Assessment Report 5, Working Group I, Technical Summary , Figure TS.17, p92)
The Arctic sea-ice extent has declined in the past 20 years and its future is uncertain. In the end, greenhouse gas emissions will determine the impact on the sea-ice from man-made climate change through radiative forcing (i.e. Representative Concentration Pathways or RCPs). The COP21 can determine the path we will follow and which course we will take to reduce emissions.
Reduction in sea-ice cover ranges from 43% (RCP 2.6) to 94% (RCP 8.5) in the period 2081-2100 compared to 1986-2005.
Why is sea important?
Decrease in sea-ice extent would:
– decrease the albedo of the Arctic ocean, therefore more heat would be absorbed by the ocean which would enhance the warming in this region.
– affect the global oceanic circulation as sea-ice formation influences the density of ice masses, which drives oceanic circulation.
– completely alter the ecosystem in the Arctic.
(Upper) Distribution of ice loss determined from Gravity Recovery and Climate Experiment (GRACE) time-variable gravity for (a) Antarctica and (b) Greenland, shown
in centimetres of water per year (cm of water yr –1 ) for the period 2003–2012. (Lower) The assessment of the total loss of ice from glaciers and ice sheets in terms of mass (Gt) and
sea level equivalent (mm). The contribution from glaciers excludes those on the periphery of the ice sheets. (Credit: IPCC (2013), Assessment Report 5, Working Group I, Technical Summary , Figure TS.3, p41)
On the eve of the COP21, it is of paramount importance to recall how strongly the cryosphere is affected by Climate Change. Today, we present the impact of melting ice on sea level rise, as it is presented in the latest assessment report of the Intergovernmental Panel on Climate Change.
-Since 1992, the Glaciers, Greenland and Antarctic Ice Sheets have risen the sea level by 14, 8 and 6 mm, respectively.
-The Greenland and Antarctic ice losses have accelerated for the last 2 decades.
In Greenland ice-loss rates increased from 34 Gt/yr* (between 1992-2001) to 215 Gt/yr (between 2002-2011), which was caused by more widespread surface melt + run-off and enhanced discharge of outlet glaciers.
While in Antarctica, ice-loss rates “only” rose from 30 Gt/yr (between 1992-2001) to 147 Gt/yr (between 2002-2011), this loss mostly occurred in West Antarctica (Amundsen Sea Sector and Antarctic Peninsula) and was driven by the acceleration of outlet glaciers.
*An ice loss of 100 Gt/yr is approximately 0.28 mm/yr of sea level equivalent
Always wondered how it looks like under the sea ice?
Getting an answer is simpler than you might think: Just go out to the front of McMurdo ice shelf in Antarctica and drill a tube into the sea ice. Then let people climb down and take pictures of the ice from below.
– Photo taken by Marcus Arnold, Gateway Antarctica, University of Canterbury during his November 2015, Antarctic Expedition.
– More photos of their expedition on https://instagram.com/the_ross_ice_shelf_programme/
Two polarimetric SAR images Artctic Sea Ice. The colours reflect the different polarimetric channels of the SAR (red = VV, green = HV and blue = HH). Credit: Jakob Grahn.
This illustration shows two Synthetic Aperture Radar (SAR) images taken over sea ice in the Arctic Ocean. Both images are polarimetric and the different colours reflect the different polarimetric channels of the SAR (red = VV, green = HV and blue = HH).
The two images are from the two satellites “ALOS-2” and “RADARSAT-2”. These are equipped with radars that operate at wavelengths around 24 cm and 6 cm, respectively. As can be seen, certain types of sea ice appear very different due to this difference in radar wavelength. In particular, leads in the ice, that is, open or refrozen cracks, appear very red for the longer wavelength, but dark for the shorter wavelength. A full understanding of what causes these differences is still not complete, but could help monitor ice properties, such as thickness and salinity, with satellites. These properties are in turn crucial for climate scientists.
Click on the image to see difference between the two images. (Credit: J. Grahn)
Three repeat photos of the Muir Glacier, Alaska taken on 13 August 1941, 4 August 1950 and 31 August 2004 . Credit: U.S. Geological Survey
The Muir is a valley glacier (Alaska) that has significantly retreated over the last 2 centuries. The 3 pictures have the same field of view and record the changes that occurred during the 63 years separating 1941 and 2004.
In the 1941, the terminus of the glacier is on the lower right corner of the photo. The Muir is then a tidewater glacier up to 700m thick and is well connected to its tributary, the Riggs Glacier (upper right part of the photo).
9 years later, in 1950, the Muir Glacier has retreated by more than 3 km, is more than 100m thinner but is still connected to Riggs Glacier.
By 2004, the Muir glacier has retreated further inland and its terminus is no longer visible on the picture. The Riggs glacier is now disconnected to the Muir and has retreated by 0.25km. Vegetation has invaded the place.
The photo comes from and the text is inspired from the section “Repeat photography of the Alaskan Glaciers” on U.S. Geological Survey website. Photo 1: W. O. Field, # 41-64, courtesy of the National Snow and Ice Data Center and Glacier Bay National Park and Preserve Archive. Photo 2 : W. O. Field, # F50-R29, courtesy of the Glacier Bay National Park and Preserve Archive. Photo 3: B. F. Molnia, USGS Photograph
Thickness of the Antarctic ice shelves. Credit: M. Depoorter
Thickness of floating ice shelves in Antarctica. Ice thickness is greatest close to the grounding line where it can reach 1000 meters or more (red). Away from the grounding line, the ice rapidly thins to reach a few hundreds of meters at the calving front. Ice thickness varies greatly from one ice shelf to another. Within ice shelves, “streams of ice” can be spotted originating from individual tributary glaciers and ice streams.
This dataset was used to compute calving fluxes and basal melt rates of Antarctic ice shelves (see Depoorter et al, 2013). This ice thickness map was derived from altimetry data (ERS and ICESat) acquired between 1994 and 2009 and corrected for elevation changes during this period.
The SAFIRE team sets up the drilling device on the Store Glacier, Western Greenland. Credit : T.J. Young
How do you get a hot water drill onto an ice sheet? The Subglacial Access and Fast Ice Research Experiment (SAFIRE) uses a hot water drill to directly access and observe the physical and geothermal properties where the ice meets rock or sediment at the glacier-bed interface. Here, SAFIRE principal investigator Bryn Hubbard and post-doc Sam Doyle help fly in the drill spool at the start of the Summer 2014 field campaign on Store Glacier, Western Greenland. Three boreholes were successfully drilled and instrumented with thermistors, tilt sensors through the ice column, and subglacial water pressure, electrical conductivity, and turbidity sensors at the ice-bed interface. Further work will be carried out in Summer 2016, when more instruments will be installed at the study site, and more helicopter slinging will be needed.
Deglaciation and formation of an ice rise with the ice-sheet model BISICLES. The simulation starts with an ice sheet in steady state that overrides a topographic high in the bed, close to the calving front. The sea level is then forced to rise steadily with 1 cm per year during 15 thousand years, and the simulation goes on until the ice sheet reaches steady state.
The animation below shows that the formation of an ice rise delays the grounding line retreat.
The movie shows the ice sheet retreat and the ice rise formation and evolution in between the two steady states. The movie starts after 5 thousands years of sea level rise. The ice upper surface is colored as a function of the velocity magnitude. The ice lower surface is colored either in light gray for floating ice or dark gray for grounded ice. Credit: L. Favier.
What do polar bears and emperor penguins have to do with the Eiffel Tower and Notre Dame? Pole to Paris has the answer.
Erlend, the Northern runner, in the Norwegian mountains. (credit : Varegg Fleridrett.)
Erlend Moster Knudsen earned his PhD in climate dynamics after four years of research from the University of Bergen, Colorado State University and University of Alaska Fairbanks on Arctic sea ice and its interaction with atmospheric circulation. He took some time to answer a few questions about the project he started with Daniel Price, a fellow polar climate researcher and PhD in Antarctic sea ice . The project is called Pole to Paris.
What is Pole to Paris?
Pole to Paris is a climate awareness campaign and outreach project ahead of the 21st Conference of the Parties (COP21) in Paris this year. This December in Paris, the United Nations will meet to negotiate a “climate deal” to pave the way toward a global carbon free future by reducing anthropogenic greenhouse gas emissions. If we plan to curb our emissions, it is of paramount importance that a consensus is reached under COP21.
The aim of Pole to Paris is to raise the understanding on climate changes in general and the importance of COP21 in particular. The campaign follows two journeys from the poles to Paris – by bike and running shoes.
Map roughly showing the route of the 17,000 km-long Southern Cycle and 3000 km-long Northern Run (credit: Pole To Paris)
Could you tell us a bit more about these biking and running journeys?
The 17,000 km Southern Cycle has gotten off to a good start. Carrying with him a flag from the Antarctic continent, Daniel has already biked across Australia and Indonesia, and is now biking through Malaysia. His next stops will be Thailand, Bangladesh and China, where he will spend weeks documenting stories on sea level rise, glacial melt and pollution.
Later this year, I will start the 3000 km-long Northern Run from Tromsø, running with a flag from the North Pole. After 2000 km through Norway, I will team up with other environmental scientists from Edinburgh to bring the flag to Paris. There we will meet up with the cyclists from the south.
What drives you, a PhD in sea ice, to put on your running shoes and run across Europe?
As we were going toward the end of our PhDs, Daniel (Pole to Paris director) and I (Pole to Paris deputy director) realized more and more that people generally are unaware of the clear results of climate science. There is a large gap in the understanding between academia and the general public. We want to bridge this gap by doing something as crazy as biking and running across half of the globe to raise awareness of climate change, document climate change and bring personal stories of climate change from the corners of the world to COP21.
Running and biking, we interact with people who we meet and who join us along the way, we give school presentations and take part in open climate events. As biking and running climate scientists, we are closer to the group of people science should serve: the general public.
Why are you starting from the Poles?
Pole to Paris friend Seamus Donaghue at the North Pole. On an expedition there, Seamus and his team mate Eric Philips brought the Pole to Paris flag to the northernmost point for his scientific colleagues of Pole to Paris. Erlend will bring this flag on from Tromsø. (credit: Eric Philips)
The starting points of the two routes are chosen deliberately. Being arguably the regions with the fastest signs of climate change, the Antarctic and the Arctic are changing in front of our eyes. Not that many of us go to the two poles. But the ones who do repeatedly are overwhelmed with unprecedented facts.
My friend Will Steger is one of them. Having been the first to reach the North Pole by dogsled unsupported and the first to cross the whole Antarctic continent by dogsled with an international team of five in the late 80’s and early 90’s, his team of explorers were the first also to cross the Arctic Ocean by dogsled in 1995. More than that, they are most likely the last ones to have done so, due to rapid sea-ice melt.
The melting of the Arctic sea ice is indeed alarming. The Arctic Ocean is loosing its lid – fast. In addition to the enhanced heat fluxes into the cooler atmosphere in most of the year, the ice-albedo, lapse-rate and Planck feedbacks each accelerate the warming in positive feedback mechanisms. Additionally, a melting Arctic also causes changes in the oceanic and atmospheric circulations, with alterations in poleward transports of heat and moisture.
The interaction between atmospheric circulation and the melting Greenland ice sheet and Arctic sea ice was the topic of my PhD. Associated with these melts, we found high-latitude storminess to decrease in summer (Knudsen et al. 2015). Instead, cyclones generally tracked more zonally, giving wetter, cooler and stormier summers in north-western Europe and around the Sea of Okhotsk. Coincidentally, unusually warm conditions have prevailed in a wide region from the Mediterranean to East Asia during summer months of anomalous high Arctic sea ice melt. These are areas of already high temperatures climatologically.
A stronger link between Arctic sea ice melt and mid-latitude extreme weather was first put forward by Francis and Vavrus (2012). They linked the Arctic amplification (the enhanced warming in the Arctic compared to the average warming across the globe) to a wavier the jet stream, where more stationary weather systems increase the risk of extreme weather conditions in midlatitudes. Since then, the theory has been and is still heavily discussed within the scientific community. Nevertheless, if their hypothesis should hold, a large fraction of the global population would need to reconsider the Arctic climate changes as too distant to reflect upon.
Of course, an even more alarming scenario is if the entire Antarctic ice sheet and the Greenland ice sheet were to melt completely. This would result in a sea level rise of over 60m. This will probably not happen within our lifetime, but enough ice has already melted to cause severe troubles for many Pacific Islands.
(credit: Pole to Paris)
How do you plan to do climate outreach along the two journeys?
Along the routes, we document climate changes and personal stories of environmental changes seen throughout their lifetime, but also the positive means by which action toward a more sustainable future is made. We give school and community presentations, arrange open climate events and unite people across a wide range of backgrounds. We speak up about climate change, knowing that we must work hard to stay objective in a politicized world.
How is your experience with Pole to Paris so far?
From left to right: Oria Jamar de Bolsée (EU and Indonesia coordinator in Pole to Paris), Beate Trankmann (head of UNDP Indonesia), Daniel Price (director of Pole to Paris), Toto Sugito (leader of Bike to Work Indonesia) and Erlend Moster Knudsen (deputy director of Pole to Paris) from car-free Sunday in Jakarta, Indonesia (credit: UNDP Indonesia)
Pole to Paris has gotten off to a really good start. We got a lot of attention on Indonesia, a key country for bridging the demands of developing and developed countries under COP21 negotiations. There, Daniel (the cyclist), Oria Jamar de Bolsée (EU and Indonesia coordinator) and I (the main runner) worked to raise the awareness of climate changes. This brought us from rural places to megacities, from preschools to high schools and talking with people from farmers to ministers. It has been very engaging.
While climate change is something distant for many of my fellow Norwegians, many Indonesians depend on the land and its resources. While human activities, such as deforestation, overfishing or lack of waste management, are the main source for this environmental degradation, climate change is also appearing in front of their eyes.
So perhaps it is not that far from the Arctic and the Antarctic to Indonesia after all? The Polar Regions are indeed shaping the coast of the archipelago, through sea level rise and erosion.
What do you expect from Paris and COP21?
The French capital is the arena for the most important climate summit this far – COP21. Pole to Paris is using bike, running shoes and our background in environmental sciences to raise awareness about the importance of this meeting.
While there, we will work with partners to arrange open events and share stories from all the corners of the world we have biked or run through. The stories of the farmers and the fishermen, the stories of the Antarctic and Arctic – all are important to remember when our global leaders will make their decision this December.
To conclude is there something you would like to say to your fellow environmental scientists?
In my mind, funded by society, scientists have a responsibility to speak up about our research. Research on climate change is too vital and pressing to keep within academia.
As environmental scientists, we have the knowledge and the tools. One of the latter is our voice. We want to hear yours too.