The Folgefonn Centre in Rosendal, a two hour boat ride South East of Bergen, was the base  of nine ice2ice PhD students from Bergen and Copenhagen for four days in late January. They set out to engage in a dialogue with different audiences to improve their science communication skills. The PhD students formed groups of two to three and aimed to find out what 12 to 13 year-old children from Omvikdalen barneskule and 16-year old teenagers from Kvinnherad vidaregåande skule want to learn about the local and global climate. A third group met tour guides and representatives of the local turistforening.

On Monday the groups visited their individual audiences. Kartia and Sunniva, the elementary school group, asked the children what they would like to know about climate change and asked them to draw pictures regarding climate. Many of the children drew the local Folgefonna glacier and sea ice and were very interested in sea level rise. The children  got a sneak peek into the daily life of a climate scientist by working with a microscope and running a simple climate model.

Anaïs, Eva, and Ida, the high school group, chose a different approach. The teenagers were asked to write down words that came to their mind when they think about local climate, global climate and climate change.

Silje and Jonathan presented the idea behind the “Turspor”-project to tour guides and the local turistforening. “Turspor” is an outreach project of the University of Bergen that provides descriptions of local landscapes and their development for hiking trails. But getting to know their audience was only the first step.

The PhD students were going to meet their audiences again the following Thursday. So they had two days to work out how they would answer the questions of their audiences. Thursday was a busy day at the Folgefonn Centre.

First the high school children came. Anaïs, Eva, and Ida started with the whole group and presented word clouds of what the teenagers wrote down on Monday. Then the three PhD students discussed different aspects of their common theme “ice melting” in individual groups. Anaïs explained stratification of the ocean and illustrated it with an experiment. Eva talked about how she is reconstructing past climate changes with the help of marine sediment cores. And Ida focused on the change of Arctic sea ice from a modeling perspective and how it might influence the local climate.

The elementary school children came to the Centre shortly after. Karita and Sunniva answered the children’s questions in a card game where the children had to match their questions and Karita’s and Sunniva’s answers. The children got excited about investigating a sediment core from the Arctic Ocean and seeing an experiment illustrating the difference between melting sea and land ice.

In the afternoon, Silje and Jonathan presented their interpretation of the development of local landforms and how they plan to write up a “Turspor” as an addition for a local hike trail project in Rosendal.

In the end everybody was happy, audiences and PhD students alike. It was a great week where all of us learned a lot. We thank everybody involved for their efforts, and especially Mathew Stiller-Reeve for his enthusiasm and support in the planning phase and during the bootcamp week. He also gave a great lecture with tips on writing skills. Furthermore, we want to thank Ellen Viste for her very nice lecture on presentation techniques. But the whole week would not have been possible without the dedicated teachers at the local schools and especially the employees of the Folgefonn Centre, Karen Løvfall Våge and Ivar Baste. Science communication works best when you initiate a dialogue with your audience to make sure that you really address relevant topics. Go out and talk to your audience :-)!

 

Lisa Griem, Andreas Plach

Henning Åkesson successfully defended his thesis ”Deglaciation of the Norwegian fjords” 9th of January 2018 at the University of Bergen. Henning is closely affiliated to the ice2ice project and has combined ice flow models with geological and paleoclimatic data to study the dynamics and response to climate of marine outlet glaciers and ice caps in western Norway and Greenland. Henning’s supervisors have been Kerim H. Nisancioglu, John Inge Svendsen (UiB) and Mathieu Morlighem (Univ. California, Irvine), and his thesis consists of five papers; one already published, three in review and one to be submitted.

The new doctor has already got a new job. He will continue his academic career as a postdoc at Stockholm University, modelling Greenland outlet glaciers of the past.

The main scope of the thesis was to study the behaviour of the western Scandinavian Ice Sheet during the last deglaciation. Henning also co-authored a paper on changes to Jakobshavn Isbræ since the Little Ice Age, West Greenland, as well as lead a paper on Holocene evolution of an ice cap in southern Norway.

In his first paper, Henning and co-authors studies dynamics and sensitivity to climate change of the Hardangerjøkulen ice cap in southern Norway. They use the numerical ice flow model ISSM constrained by glacier and climate reconstructions to simulate ice cap evolution since the mid-Holocene. Here, they find that Hardangerjøkulen grows non-linearly since ice cap inception and that present-day Hardangerjøkulen is exceptionally sensitive to climate change. The latter is related to a flat surface topography and an associated effective surface mass balance-elevation feedback. Read the full paper here.

The second paper shows that fjord width strongly controls the stability of marine-terminating glaciers. Henning and co-authors use an ice flow model purpose-built for fast-flowing outlet glaciers on a suite of idealised fjord geometries, representative of real-world glaciers. They show that identical warming ocean conditions may cause grounding line retreat varying by several tens of kilometers depending on the fjord geometry. The paper is in review.

The third paper gives a decadal to centennial scale perspective of the abrupt retreat of Hardangerfjorden glacier in western Norway at the Younger Dryas–Holocene transition. This well-dated paleoglacier is an excellent past analogue of Jakobshavn Isbræ in Greenland (Paper 4), and other similar outlet glaciers in Greenland, Alaska, and Patagonia. Using the ice flow model from Paper 2 they find that high surface melt and warmer fjord waters are likely triggers and drivers of the reconstructed fast retreat. The study suggests a highly variable retreat history paced by fjord bathymetry and ice tongue buttressing. Periods of high retreat rates contribute significantly to the overall length of retreat, yet these rates are not sustainable for more than a few decades. The paper is to be submitted.

The fourth paper studies the fastest flowing glacier in the world; Jakobshavn Isbræ in western Greenland. This glacier’s floating tongue suddenly collapsed in the early 2000s, with a fast retreat and tripling in speed occurring since. Nonetheless, it is unclear to what extent Jakobshavn’s past history influences its modern retreat. Henning is a co-author on this study, which simulates the history of Jakobshavn since its Little Ice Age (LIA) maximum position in year 1850. The authors find that the glacier responds non-linearly to a linear strengthening in external forcing. The changing forcing following the LIA triggers retreat, while fjord geometry controls the variability of the modelled non-linear retreat history. Because of intermittent grounding line stillstands at geometric pinning points, retreat may be delayed by several decades, only to be followed by an abrupt grounding line migration without additional forcing.

In the fifth paper, Henning and co-authors use the ice flow model ISSM to study deglaciation of the fjords at the Norwegian west coast. Using a first-order climatology based on paleo-records, they suggest that a warming ocean is a highly potent trigger for swift decadal scale grounding line retreat. However, the study finds that multi-millennial deglaciation in this region was driven by surface melt. In addition, the authors find that topography heavily controls the sensitivity marine ice sheet margins; glaciers in fjords with bottleneck inlets and/or shallow sills were significantly more resilient to ocean warming, while wide and deep troughs allow for extensive retreat.

Combined, Henning’s thesis shows that the topography of the landscape itself is fundamental to the sensitivity of glaciers terminating in fjords. His results also suggest that ocean warming and grounding line dynamics are important controls of marine-based retreat over time scales up to a century or two. Beyond these time scales, the atmosphere is found to be the most important driver of ice sheet mass loss.

Henning’s findings on the retreating Norwegian glaciers and likely disappearance within this century, if carbon emissions are left unabated, caught the attention of several broadcasters.

• The local newspaper Bergens Tidende had a one pager where they present and discuss his work and the consequences for people and society. You can read the article here.
• NRK produced this article about the possible dissapreance of the Hardangerjøkelen glacier within a few decades.
• Henning also talked about the demise of Norwegian glaciers as a guest in studio at the news channel TV2 Nyhetskanalen. This was broadcasted live on Saturday 13th of January 2018.

Our two most recent ice2ice Phds; Sunniva and Karita Kajanto, are already busy spreading their knowledge. They have engaged with Norwegian school children to help them understand how the Arctic is currently changing due to sea ice disappearing and the consequences on climate.

More information in the article below (in Norwegian)

 

Christmas holidays and the turn of the year are soon over us. With snow for those who are eager to explore the seasonal cryosphere, and family gatherings and relaxation in line for most of us. 2017 has been an exciting year for our project, where we have taken decisive steps to start integrating results and we start to see how all of our efforts come together. Papers and PhD theses are being produced in increasing numbers and many of you are now active in cross-team integration efforts which we hope will be central in the upcoming all staff in a month or so. 

 We are very much looking forward to working closely with all of you on exiting science in the coming year, and with this wishing you all a merry Christmas and a Happy New Year! 

Mari F jensen successfully defended her PhD thesis 1st of december -2017 on “Abrupt changes in sea ice and dynamics of Dansgaard-Oeschger events”. Mari is the second ice2ice Phd to finish her studies. Luckily Mari has decided to continue in Science, a great benefit to all of us and the ice2ice objectives. Through her Phd Mari has published 1 peer reviewed article and submitted another two, that all form part of her thesis. You can read and download the thesis here.

The subject of Maris thesis has been to study the dynamics of Dansgaard Oeschger events. Changes in sea ice are proposed as an important component in Dansgaard-Oeschger events; the abrupt climate change events that occurred repeatedly during the last ice age. Paleoclimatic reconstructions suggest an expansion of sea ice in the Nordic Seas during the cold stadial periods of the Dansgaard-Oeschger cycles. However, as the present configuration of the Nordic Seas does not allow for an extensive sea-ice cover in this region, the hydrography must have been different during glacial times. In fact, reconstructions show that the Nordic Seas hydrography during cold stadial periods was similar to the stratification of the Arctic Ocean today. However, the dynamic impacts of changing freshwater input and Atlantic water temperature on the Arctic stratification and sea ice are unclear.

Maris study aimed to assess the potential for Arctic-like stratification in the Nordic Seas during the last glacial period and the dynamics behind Dansgaard-Oeschger events, using models and theory. The results are presented in three papers.

In the first paper, she and co-authors developed a simple conceptual two-layer ocean model including sea ice representing the Nordic Seas during stadial times. Here, they find that the sea-ice cover is sensitive to changes in freshwater input, subsurface temperature, and the representation of vertical mixing. Abrupt changes in sea ice can occur with small changes to surface freshwater supply or Atlantic water temperatures. You can read the full paper here.

In the second paper we apply a three-dimensional eddy resolving numerical model to the same problem and find further support for the conclusions from the first paper; the stability of a sea-ice cover in the Nordic Seas is dependent on the background climate and large changes in stratification and sea ice occur with small changes in forcing. In addition, additional results presented in this dissertation show self-sustained oscillations in sea-ice cover without a change in forcing. From the second paper, it was shown that an extensive sea-ice cover and an Arctic-like stratification with a fresh surface layer and a halocline can exist in the Nordic Seas without an external freshwater supply. Under sufficient cold conditions, a halocline capped by sea ice emerges spontaneously due to redistribution of freshwater through sea-ice formation and melt. Further it was shown that an extensive sea-ice cover slows down the local overturning in the Nordic Seas; decreases the heat import to the basin; warms intermediate waters, and cools deep waters. The paper is under review.

In the third paper, the importance of background climate is further stressed. In this study, rather than studying an Arctic-like stratification, the focus is on sea-surface temperature variability in the region of the Nordic Seas and North Atlantic. Mari and co-authors compile all available planktic foraminifera records from the North Atlantic during Dansgaard-Oeschger events with a sea-surface temperature reconstruction. These are then combined with fully coupled climate model simulations using a proxy surrogate reconstruction method. The resulting spatial sea-surface temperature patterns agree over a number of different general circulation models and simulations. However, freshwater forced runs from glacial times are needed to capture the amplitude of the temperature variability as seen in the proxy records. They suggest that sea-ice changes are important in extending the oceanic temperature signals to land. You can read the submitted paper here.

Combined, the three papers argue for an important role of the Nordic Seas during DansgaardOeschger events, consistent with paleoclimatic reconstructions. Maris results are also relevant for understanding potential future changes in Arctic sea-ice cover, and we argue that changes in Atlantic water temperature are of large importance.

A recent study co-authored by Joel B. Pedro, a postdoc with ice2ice at the Niels Bohr Institute has received quite some media attention.

The study was published in Quaternary Science Research (QSR), together with lead author Jan M. Strugnell and co-author Nerida G. Wilson and is titled “Dating Antarctic ice sheet collapse: Proposing a molecular genetic approach”

The study proposes a genetic technique to resolve when the West Antarctic Ice Sheet last collapsed. Last time WAIS collapsed, a west Antarctic seaway, facilitating genetic exchange was opened. Thus by looking into the population genomic data on both sides of the basin, one can estimate when the exchange last took place. The approach is novel and serve as an independent test of ice sheet models.

Read the full article in the journal QSR, or the shorter popular version in the Guardian.

 

PhD Nicholas Rathmann is the lead author of a new article on “Highly temporally resolved response to seasonal surface melt of the Zachariae and 79N outlet glaciers in Northeast Greenland” published in Geophysical Research Letters. Below a short description of the main findings. You can find the full paper here.

The northeast Greenland ice-stream (NEGIS) drains 16% of the Greenland ice sheet, holding approximately 1m of sea level rise equivalent, but its response to a warming climate is poorly understood, partly due to its remote location.Now, a team of researchers headed by ice2ice PhD Nicholas Rathmann part of the European ice2ice project have published a study in Geophysical Research Letters where they identify which processes control the present-day mass loss from this less understood region. By using surface images taken every 12 days over NEGIS from one of the newest generation European Space Agency (ESA) satellites, Sentinel 1-A, the researchers derived state-of-the-art surface velocity maps in collaboration with ESA’s climate change initiative project to study the seasonal behavior of the NEGIS terminus region.

Combined with computer models of the ice flow and the present-day atmospheric state, the researchers found that future contribution to sea level rise from this region might be significantly effected by a warming atmosphere, but also raises further questions about the moderating effect sea ice mélanges might have – i.e. the composite “soup” of sea ice and calved ice bergs.

Moreover, the researchers also point to the importance of considering large calving events, such as what recently happened at the Larsen C ice shelf at Antarctica, on an individual basis since the plug-like effect of ice shelfs might depend on the details of the local balance of forces. Specifically, at Nioghalvfjerdsfjorden, one of the marine terminating glaciers of NEGIS, the researchers found up to 80% of the 76km long shelf could be lost without influencing the glacier’s mass loss (contribution to sea level rise).

These conclusions were drawn by the researchers by investigating the influences exerted by four important processes known to control the mass loss from these kind of glaciers:

(1) Melting of snow and ice at the surface, which is subsequently transported to the below bedrock through cracks in the ice where the water may lubricate the bedrock. There, water may lead to enhanced sliding of the above ice and thereby an increased mass loss.

(2) The large amount of sea ice and calved ice bergs (ice mélange) blocking the further escape of ice into the ocean at the Zacharia marine-terminating glacier of NEGIS.

(3) The large ice shelf at Nioghalvfjerdsfjorden, a second marine-terminating glacier of NEGIS, possibly acting as a plug holding back the flow of ice into the ocean.

(4) Sub-glacial “sticky spots” which may moderate the enhanced sliding caused by water lubricating the bedrock.

By combining the surface velocity maps with computer models of the ice flow, the researchers found a large influence is exerted by (1) and (2), but not (3) and (4). This, the researchers say, points to the importance of considering the local processes and dynamics of marine-terminating glaciers when estimating their possible future mass losses, and thus their contribution to sea level rise.

For the duration of 6 days between the 25^th and 30^th of September 2017, 28 young scientists meet up at the Niels Bohr institute in Copenhagen. A collection of master-, phd students and post docs all with varies backgrounds and outlooks came together for the common goal of mastering the analysis of ice-cores. ICAT 2018 had begun.

by Andreas Plach and Jesper Baltzer Liisberg, students at ICAT 2018

The course ICAT (ice core analysis and techniques) first presented us to the history of our climate and the drilling of ice-cores. This was followed with a round of presenting ourselves. Each person had prepared a 3-minute video of who they were, what they did, and why they were interested in ice-cores. This proved an engaging and fun new take on what is often done as forgettable powerpoint presentations, and you got to remember the different people much better.

 

The first two days offered a similar program at the Rockefeller building, with student videos and visits to the different laboratories located there. Here we were presented with the different aspects of ice-core analysis. Isotope, gas and impurity measurements each telling their own side of the combined story that is our climate history.

Following the final lectures Monday we went to see a bit of Copenhagen by going to get an ice-breaker beer (if you will allow us such a pun).

 

Wednesday we started the day at a different building with lectures on determining snow/ice densification and a detailed description about the development of the ice-core drills.
Following the morning lectures we grabbed a sandwich and went on an excursion to see the scars of the last glacial at the Geopark Sjællands Odde.

Thursday morning was focused on gases and dating of ice cores and followed by an afternoon of discussing ice core variability and a lecture on Dansgaard-Oeschger events. On Friday we learned about dust and impurities and how glacier models are used to estimate annual layer thicknesses and reconstruct accumulation rates. This was followed by some ice core statistics including examples on the misuse of statistics. “With a lot of free parameters you can fit everything!” The day was concluded with a nice ICAT dinner.

 

Saturday started out with a lecture on atmospheric and ocean dynamics focusing on the bipolar seesaw. This was followed by a great lecture about the search for the oldest ice on Earth within the Beyond EPICA project. After the wrap up of the summer school around noon, there was an extra treat for people interested in Antarctica. A guest lecturer from Tromsø gave an introduction on Quantarctica, a free GIS package for Antarctica.

This ended a great and informative course on ice core related science. For those of you who did not get the chance to attend this course, be sure to sign up for ICAT 2018!

by ice2ice postdoc Anne-Katrine Faber

During the period 10-22. September 25 students and 10 lecturers travelled to Rondvassbu in Norway to join join this years Advanced Climate Dynamics Courses (ACDC). From the ice2ice project. Kerim Nisancioglu joined as a lecturer and organizer and Mads Poulsen and Anne-Katrine Faber joined as students.

The purpose of the summer school was to explore the role of the seasonal cycle in the climate system. Lectures explained the role of the seasonal cycle in the ocean, atmosphere, land and ice and gave insights into cutting edge research questions exploring how the seasonal cycle can be used as a tool to understand climate change.

In between lectures, students worked on group projects. These projects gave the students hands on experience in the analysis of models, observations and proxy records with a focus on better understanding the seasonal cycle across time scales.

A two-day field excursion gave everyone an excellent opportunity to explore the beautiful nature of Rondane National Park.  Hikes to interesting geological sites included engaging discussions on the processes that shaped the local landscape over the past thousand to several hundred thousand years.

Outreach activities were also a part of the school. The students got a chance to share their newly achieved knowledge with the local community.  Two high school classes came to visit and they learned more about life as a scientist and how tree rings can be used to reconstruct past climate variability.

Overall the ACDC has been a fantastic experience with exiting lectures and   plenty of opportunities for networking, discussion and development of new research ideas. Not only did we learn the power of the seasonal cycle, the largest climate change of our time, we also experienced it first hand as we were surprised by a snow storm in the second week of the “summer” school.

 

by Kerim Nisancioglu & Silje Smith-Johnsen

Sparking off this year governmental election campaign in Norway, Arendalsuka, a political festival in southern Norway, was crowded with top-level politicians and organisations. During the week of the festival, ice2ice scientists organised a joint ice talk and ice concert in the main square of Arendal showcasing ice2ice research on ice and climate. In addition we guided local kindergarten children and high school pupils on a geological and climate tour on Merdø, a tiny island in the new Norwegian marine national park just outside of Arendal, introducing the kids to the geology and history of the deglaciation in the area, as well as putting the past into the context of future changes expected on Greenland.