Author: jorunds

Climate scientists start a dialogue with local audiences

Eva presenting a word cloud of the feelings of high school children about climate change

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.

Sunniva explaining the card game and Mathew assisting with the sediment core.

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!

“From left: Atle Nesje (member of evaluation committee), John Inge Svendsen (co-supervisor), the new doctor Henning Åkesson, Kerim H. Nisancioglu (main supervisor), Chris R. Stokes (opponent), Andreas Vieli (opponent). Not in picture: Mathieu Morlighem (co-supervisor).”

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.

Article in Bergens Tidende 10th January 2018

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.