The full article can be found here , a danish version was published at videnskab.dk can be found here. The news story also featured in the large danish newspaper Jyllandsposten.
Paul Valleonga and Ray Bradley discussing Greenland temperature trends from lake sediments and ice cores.
The 3-day Ice2Ice Holocene workshop took place from the 23rd to the 25th of January in Dronningmølle, DK. 26 participants mainly from the Ice2Ice network were involved in a dynamic exchange of knowledge and ideas on the climate of the Holocene epoch as seen from different records. The format of the workshop was open and informal something that allowed for more discussions than talks and allowed the participants to present data and ideas.
Audrey Morley giving a potential explanation of the Holocene climate changes by changes in the position of the atmospheric jet, which could be driven by changes in the latitudinal temperature gradient.
The 2 invited talks from Audrey Morley (National University of Ireland, Galway) and Camilla Andersen (Geological Survey of Denmark and Greenland) initiated a fruitful exchange of ideas while talks by Martin Miles, Kerstin Perner, Vasileios Gkinis and Trond Dokken gave an overview of the data based picture of the Holocene climate as it is seen in ice and marine cores. Some of the discussions particularly focused on seemingly common climate signals around the mid Holocene and resulted in the initiation of future collaborations and projects integrating climate records focusing in that particular period. There also seems to be anticipation in the promising Bromine records that Niccolo and Paul are working on, the upcoming NEEM water isotope diffusion reconstruction by Vasileios and the planned transient Holocene run by Kerim with focus on the Scandinavian pattern. Future strategies on tephra studies have also been the subject of a discussion on Tuesday evening.
The tephra team in discussion of future strategies
The second edition of the Ice2Ice PhD bootcamp recently came to an end, this time held in Geilo in the midst of the Norwegian winter, a couple of hundred kilometers to the east of Bergen. Based on the idea that each PhD student should benefit, in term of hers/his own project, from collaborating with other students working on related problems, the fourteen participating PhD students were divided into three groups several months prior to bootcamp. Within each group, a project was defined and sufficient preparations were made on beforehand such that the bootcamp week provided the ideal surroundings and time to work intensively on the project, and to answer the related scientific questions.
Photo: Martin Olesen
One group worked on the momentum balance of the Northeast Greenland Ice Stream (NEGIS) outlet glaciers and had a specific emphasize on the potential back-resistance provided by the glacier tongue. Another group investigated the possibility to establish a self-sustained extensive sea ice cover in the North Atlantic in a coupled general circulation model by assimilating sea ice in an energetically consistent way. The last group focused on comparisons of proxy records obtained from sediment- and ice cores, specifically sea ice reconstructions based on Bromine enrichment as seen from the Greenland ice sheet and concentrations in sediments of organic matter from diatoms that live below the sea ice edge. Each group were guided by a mentor of their own choice, who were either available through a web connection throughout the week or were present at the bootcamp itself.
Photo: Mads Poulsen
Besides the group work, the bootcamp also hosted scientific talks by mentors Rasmus Anker Pedersen (PostDoc, Centre for Ice and Climate) and Lars Henrik Smedsrud (Professor, University of Bergen) as well as student-organized seminars on plotting possibilities with python and GMT, and proxy interpretations and uncertainties. The week culminated with a presentation by each group on the results obtained during the bootcamp and on the possible prospects.
Photo: Martin Olesen
Despite the military discipline which is associated with a bootcamp, the week did allow for a few cultural and social inputs. The owner of the bootcamp venue gave a brief introduction to the Hardanger fiddle, a delicate Norwegian instrument, and during Thursday a couple of hours of break were taken away from science as the groups went for a 5km dog sledge ride in the outskirt of Geilo.
The results from the three groups, as well as the perspectives and the possibilities to integrate the projects further into the Ice2Ice synergy, will be presented on the all-staff meeting in Myrkdalen in March.
ERC writes in its newsletter “With an ERC Synergy Grant, Prof. Jansen and three Nordic world class researchers are currently investigating the dramatic loss of Arctic sea ice.”
In their last newsletter of 2016 the European Research Council (ERC) puts the spotlight on the ice2ice project and writes: “With an ERC Synergy Grant, Prof. Jansen and three Nordic world class researchers are currently investigating the dramatic loss of Arctic sea ice.” The article includes a picture of the flagpole on top of the Renland ice cap in East Greenland that mark the multinational effort.
In October the ERC arranged a conference focusing on how frontier research can contribute to science diplomacy. The conference included a presentation of the ice2ice project presented by the Ice2Ice Coresponding Principal Investigator Eystein Jansen.
In the editorial to the newsletter, Federica Mogherini, the High Representative of the European Union for Foreign Affairs and Security Policy and Vice President of the European Commission, writes “Scientific cooperation in the Arctic can help stabilise an area where there is much potential for collaboration as there is for competition.”
ERC to reinstate Synergy Grants call
ERC has also announced that they will open another call for Synergy Grants and there is an article covering this in the newsletter. In 2014, the Scientific Council established an ad hoc group tasked with assessing the outcomes of the two synergy calls. In March last year ice2ice was the first project that the evaluation committee would meet with and we believe that this meeting has strongly contributed to the fact that the group recommended reinstating the synergy grant scheme.
Based on the groups findings the ERC President stated: “The Synergy Grants awarded so far have shown that this funding fosters interdisciplinary research and can trigger unconventional collaborations, allowing for the emergence of new fields of study. They will contribute significantly to fill a gap in EU funding for frontier research.” The decision to open another Synergy Grants call is welcomed by the Ice2ice team.
The Warm Arctic workshop was held at DMI on the 5th and 6th December with several invited guest speakers from outside the ice2ice group. Svend Funder and Kurt Kjær from the Centre for Geogenetics at the Natural History Museum of Denmark in Copenhagen gave a good introductory overview of the current state of the art in terms of paleoproxies for Arctic sea ice extent and ice sheet extent in Greenland respectively. This was excellent framing for the remainder of the workshop.
Sea ice processes are not straight forward. credit Vihma
Timo Vihma from the Finnish Meteorological Institute contributed an interesting talk on connections between the Arctic and the mid-latitudes including a very comprehensive diagram showing important processes and linkages, while on the second day, external speakers Wieslaw Maslowski and Dirk Notz (remotely) gave a nice overview of the state of the sea ice modelling from their respective groups, leading to an intense discussion on whether the ocean or the atmosphere was the dominant driver of change in the Arctic. Dirk Notz work shows nicely that sea ice decline follows emissions pretty directly. Internal speakers from DMI, included Rasmus Tonboe who gave a good overview of current sea ice data available from EUMETSAT and Torben Schmidt handled the modelling side with a look at multidecadal variability in the Arctic ocean.
Notz talked about the effect of global CO2 on sea ice
Various ice2ice members also gave talks on different aspects of the project including a presentation by Shuting Yang on the Arctic sea ice loss and Northern hemisphere winters. There was a very comprehensive discussion by Peter Langen on Greenland ice sheet surface mass balance, some early work from Martin Stendel on the Arctic seesaw when there is little or no sea ice and PI Jens Hesselbjerg Christensen on the state of sea ice in a 1.5C world (spoiler: there won’t be very much). Rasmus Anker Pedersen also showed some of his work on the atmospheric response to a sea ice free Arctic.
credit Svend Funder
As the aim of the workshop was to produce a review paper on the subject, there were two wide ranging discussion sessions where a very wide range of related topics were explored, including the aforementioned question of the relative importance of ocean and atmosphere and how the processes and feedbacks between the two might look. There was also much discussion on ways to improve sea ice representations in models and the importance of both including more comprehensive processes and improved model resolution in both ocean and atmosphere models. Finally, the workshop participants structured these issue into a format to create both a publication and potentially a conference session in the future, watch this space!
The workshop was organized by Christian Rodehacke, Peter Langen, Shuting Yang and Jens Hesselbjerg and was held at DMI.
Ice cores from the ice streams of north-eastern Greenland can tell us much about the climate of the past as well future sea level rise. Learn more in the video above.
During the summer of 2016 a team of researchers and students built the base on the ice stream in northeast Greenland, started a comprehensive scientific surface field campaign, and initiated the ice core drilling.
The aim of the project is to better understand the dynamics and properties of the fast flowing ice stream. By the time they reach bedrock in the year 2020, the team will have extracted nearly 2700m of Greenland ice giving a 100,000 year old climate archive.
The ICAT PhD school was held from Monday 31/10 to Saturday 5/11/16. The Ice Core Analysis and Techniques (ICAT) PhD school supported by ice2ice and hosted over 30 students from 13 countries at CIC in Copenhagen. Through a mixture of hands on exercises in the three ice core laboratories, a mixture of lectures all related to ice cores, and several social events to enhance colaborations between students, the students learned all there is to know about ice cores. With student responses like “It was an awesome experience”, “congratulations on a great course-I am very thankful” and “This was a phenomenal PhD course” we hope to secure enough funding to be able to run it again next year.
The ICAT PhD’s in the limestone quarry at Faxe
The ICAT PhD school was run for the first time this last week (31/10-5/11). The course was intended to increase the knowledge on ice core analysis techniques (ICAT) and people from more than 13 countries participated. The students had a diverse background; most were already familiar with ice cores, working on a particular proxy from ice cores, but also a few ice sheet modellers, climate modellers and people working with other paleo-archives attended, among these were 4 ice2ice participants.
Lots of discussion and collaboration between the students in the breaks.
All days started with 5 minute presentations by students. It was great to see the diversity of the students and this way the newest research within ice core science was well represented. A number of Centre for Ice and Climate’s own scientists continued with lectures covering ice core history, water isotopes, Continuous flow analysis techniques, gas extraction and analysis, ice core drilling, dating of ice cores, borehole measurements, multi core variability, statistics and trends, water isotope modelling, ice sheet flow and comparison to other paleo-archives. Furthermore, the invited speakers Professor Joe McConnell, from the Desert Research Institute, Nevada talked about his research in Anthropocene contaminants as observed in ice cores measured by continuous flow analysis and professor Edward Brook, College of Earth, Ocean, and Atmospheric Sciences, Oregon State University gave lectures about the extraction of greenhouse gases and the changes of them as observed in ice cores.
Sune Rasmussen stressing correct (danish) pronunciation of important climate events like Allerød and Bølling.
Lead investigator for ice2ice at DMI Jens Hesselbjerg taught the students about climate modelling and how to compare ice cores to models and Helle Sørensen from the math department at the University of Copenhagen introduced basic statistics of time series.
Exercises and laboratory visits were a great opportunity to get hands on experience with real data
Two of the days the students got hands-on experience by working in the laboratories; ice2ice PhD Niccolo Maffezoli showed the IC laboratory, where discrete ice samples are analyzed for ions. Professor Thomas Blunier ran an exercise in the gas laboratory where the students breath was analysed similar to ice core samples on a methane Picarro analyser, in the water isotope laboratory postdoc Vasileios Gkinis analysed students own water samples to reproduce the meteoric water line and in the CFA laboratory Marius Simonsen and Helle Kjær had the students prepare and run standards for ammonium. Further the student got hands on experience in annual layer counting led by specialist Mai Winstrup and simple Herron-Langway modelling led by Paul Vallelonga.
Students busy in the Faxe quarry looking for 64 million year old fossils of the corals that used to be.
To increase the interaction amongst students an excursion to the UNESCO site of Stevns Klint took place in the middle of the week. Stevns Klint is the best place in the world to see the fish clay layer from the extinction 65 million years ago. Also the excursion brought us to Geomuseum Faxe, and Faxe limestone quarry where students retrieved their own 63 million years old fossils. The excursion ended as the best excursions do with beer at a brewery.
The week ended with an official dinner and a few talks.
The course was organised by ice2ice postdoc Helle Astrid Kjær and Assoc. Professor Paul Vallelonga. This year we unfortunately did not have room for all that applied, so we hope to repeat the course next year.
Ice2Ice members from Centre for Ice and Climate recently published an article in the Nature-affiliated journal Scientific Reports titled “Canadian Arctic sea ice reconstructed from bromine in the Greenland NEEM ice core”. Here you can read the corresponding author Paul Vallelonga’s explanation of the key findings in this new article.
Arctic sea ice: have we reached a climate threshold?
There are two kinds of sea ice in the Arctic – new, thin, sea ice that grows in the winter and melts in the summer (called seasonal or first-year sea ice); and older, thicker, sea ice that survives through the summer and continues to grow each winter (called multi-year sea ice). In the Arctic Ocean there is a central patch of multi-year sea ice, around which the seasonal sea ice grows in the winter and then breaks up and melts in the summer every year. When satellite measurements began in the 1970’s, the amount of old multi-year sea ice was 6 million km2, with more (9 million km2) seasonal sea ice growing around it each year. In the last decade, the amount of old multi-year sea ice has decreased – in 2016 it was 4 million km2 – which means that during the summer, less of the Arctic is covered by sea ice; and during the winter more of the sea ice is thin seasonal sea ice. There is an overall shift toward less Arctic sea ice throughout the year, and a greater proportion of that sea ice being the thin seasonal type.
Figure 1 – Arctic sea ice minima and maxima. These are two images of Arctic sea ice extent showing the maximum (left) and minimum (right) in 2015. The left image shows the combination of seasonal and multi-year sea ice, while the image on the right shows only the multi-year sea ice left at the end of summer. The pink lines show the 1980-2010 median sea ice extent maxima and minima. From nsidc.org.
Is the sea ice decrease since the 1970’s normal or extreme? Are these recent changes within the range of natural variability or has the Arctic system crossed some kind of natural threshold? The only way we can know the answer is by measuring how much Arctic sea ice there was in the past. This new study of ice cores published in the Nature-affiliated journal Scientific Reports takes us closer to finding out – giving us a measure of how much Arctic sea ice there was during three key time intervals: 1) 20 thousand years ago during the last ice age – when Greenland temperatures were about 20° colder; 2) 8 thousand years ago when Greenland temperatures were 2° warmer, known as the early-Holocene period; and 3) during the last 3 thousand years of “normal” Arctic climate.
How to reconstruct sea ice from Greenland ice cores?
The key advance here is the use of a chemical marker called bromine, which we have been able to link to seasonal sea ice. Bromine is present in seawater in small amounts – for every kilogram of seawater there are about 11 grams of sodium but just 7 milligrams of bromine – a thousand times less bromine than sodium. The ratio of bromine to sodium in seawater is the same in all oceans, but we have found that seasonal sea ice concentrates bromine much more than sodium. This bromine concentration enrichment is due to two processes:
Firstly the process of making seasonal sea ice concentrates sea salts (including bromine) into surface crystals (frost flowers) and salty brine channels, which are able to react with the atmosphere. This rich salty soup is only present in seasonal sea ice because the multi-year sea ice doesn’t contain brine or host surface salt crystals.
The second ingredient is sunlight. In March and April, Arctic springtime begins with sunlight appearing over the horizon and illuminating freshly-formed seasonal sea ice. The sunlight activates many photochemical reactions; one of the most important is the break-up of bromine gas (Br2) released from the seasonal sea ice surface. When bromine gas splits into two bromine radicals, the radicals start new reactions in the sea ice which lead to the production of more bromine gas. This chain reaction is called a bromine explosion, resulting in an enhanced concentration of bromine in the atmosphere above seasonal sea ice in the Arctic.
In a previous study (Spolaor et al., 2014) we looked at snow and ice in Greenland (at the NEEM ice core drilling site) and Antarctica (from a near-coastal site in East Antarctica called Law Dome) and found a regular spring/summer bromine enrichment peak, matching the seasonal pattern expected from chemical theory and satellite measurements. Bromine was measured in the NEEM ice core using an Inductively Coupled Plasma Mass Spectrometer (ICPMS) instrument located at the University Ca’ Foscari in Venice. The ICPMS is able to separate bromine from other elements such as sodium, and measure their concentrations very precisely. It took about two months to measure the 350 ice core samples from the NEEM ice core.
Figure 2 – Bromine enrichment and transport. Bromine originates from the ocean surface, but is concentrated by sunlight-driven chemical reactions occurring above seasonal sea ice. The enriched bromine is transported over the Greenland ice sheet and deposited onto the snow surface.
What have we found?
We have looked at three different climate periods to interpret the NEEM ice core data:
The coldest part of the ice age, 20 thousand years ago when Greenland was 20°C colder than today.
The warmest part of the Holocene, 8 thousand years ago when Greenland was 2°C warmer than today.
The “recent” period in Greenland covering the last 3 thousand years.
We’ve found that the average bromine enrichment – indicating the amount of seasonal sea ice – over the last 3 thousand years is more than the glacial but less than the warm early-Holocene period 8 thousand years ago. This suggests that the amount of seasonal sea ice during the last 3 thousand years is lower on average than it was 8 thousand years ago, just after the end of the last ice age. The results also indicate that multi-year sea ice will continue to decline into the future as the Arctic warms.
So we cannot yet answer the question “have we reached a climate threshold?” but we do know there was less multi-year sea ice 8 thousand years ago, when Greenland climate was just 2°C warmer, compared to the situation over the last 3 thousand years. This research sets up a whole range of new questions to ask:
How do the sea ice changes over the last 30 years compare to the last 3 thousand years?
What is the bromine record like at other places in Greenland?
What can bromine tell us about sea ice during the Eemian warm climate period before the last ice age, when Greenland temperatures were at least 5°C warmer than today?
Figure 3 – Reconstructing past seasonal sea ice from bromine in ice cores. The graph shows the three climate scenarios studied. During the last ice age there was no seasonal sea ice because the oceans were completely covered by multi-year sea ice. The bromine-to-sodium ratios measured in the NEEM ice core are lower over the last 3 thousand years than in the warmest part of the Holocene 8 thousand years ago, indicating that there was more seasonal sea ice 8 thousand years ago compared to the last 3 thousand years.
Where to next?
In the future we plan to expand the published study in two ways – we want to study in more detail the sea ice changes that occurred during the last ice age; and we want to compare the NEEM results to other locations in Greenland. From the published NEEM bromine record, we see that sea ice also changed during the last ice age, particularly during the rapid warming events known as Dansgaard-Oeschger events. Investigating sea ice changes during the glacial is a key goal of the ice2ice project. Also, we are keen to produce sea ice records from bromine measured in East Greenland ice cores, such as Renland and EastGRIP. These ice cores collect sea salts from the Nordic Seas and allow us to study sea ice changes in a different part of the Arctic Ocean. This will tell us more about how sea ice has changed in the Arctic and the role that Atlantic Ocean circulation changes might play in building or destroying sea ice in the Arctic. These newer ice cores will also allow us to collect bromine measurements covering the last 30 years to compare with the satellite observations of sea ice.
Spolaor, A. et al. Canadian Arctic sea ice reconstructed from bromine in the Greenland NEEM ice core. Scientific Reports6, 33925 (2016) doi: 10.1038/srep33925. http://www.nature.com/articles/srep33925
Simpson, W. R. et al. Halogens and their role in polar boundary-layer ozone depletion. Atmos. Chem. Phys.7, 4375-4418 (2007) doi: 10.5194/acp-7-4375-2007. http://www.atmos-chem-phys.net/7/4375/2007/
The end of summer in Bergen has seen a spiked interest from Norwegian media towards the work the Ice2Ice project is conducting.
On 30August the Norwegian national broadcaster NRK included a great news segment dedicated The East Greenland Ice-core Project (EastGRIP) . During the 2 minute segment the audience was given a broad overview of the ice coring activity on EastGRIP including on site video of the station activities, interview with Kerim and NASA graphic of the ice streams.
You can watch the clip here (In Norwegian only. Available when the article was posted on 12.9.16)
The Norwegian Financial daily Dagens Næringliv’s weekend Magazine recently had a long and interesting article about the EastGRIP project.
You can read the article here ((In Norwegian only. Available when the article was posted on 26.8.16)
A scenic view of the one-masted boat “Väderöjulle” and the head of the Gullmar fjord.
Once each year the historic hydrographic station on Bornö sets the stage for the NBI/UH summer school on ocean physics. Bornö, a small rock island with dense vegetation, is beautifully located close to the head of the 25km long Gullmar Fjord on the west coast of Sweden, a couple of hours by car to the north of Göteborg. This year’s topic was ocean small-scale turbulence, and besides the delegation from Centre for Ice and Climate, PhD students, postdocs and faculty from University of Hamburg (UH) and Leibniz Institute of Baltic Sea Research Warnemünde (IOW) participated as well.
Approaching the hydrographic station by boat.
Gullmar fjord has previously been subject to an intense study of its pronounced seiche motion, a standing wave in a closed or semi-closed basin, and the effect of this phenomenon on the turbulent mixing of the dense deep- and bottom water, which is stagnant during the summer months of the year. In perfect alignment with this year’s topic, existing literature on the fjord dynamics was presented during the morning sessions by the PhD students. These presentations was followed by lectures on the fundamentals of ocean small-scale turbulence and fjord physics.
Hans Burchard from IOW giving a lecture on Baltic Sea dynamics.
The lectures and presentations were accompanied with measurement sessions carried out during the afternoons. Various instruments were lowered from the hanging bridge at the hydrographic station to examine the properties of the water column. Of greatest interest was the microstructure profiler, brought by Lars Umlauf from IOW, which measures small-scale variations in the velocity shear that can be used to infer dissipation rates, a measure of the degree of turbulence. No less than 200 microstructure profiles were obtained during the week and provided a glimpse into the evolution of the fjord during the summer school.
Mads (CIC) and Philipp (UH) carry the CTD to the hanging bridge.
One special member of the school cannot go unmentioned, the one-masted boat “Väderöjulle”. In the late hours of the afternoon when reflection had to be made upon the turbulent thoughts that developed during the day, she provided an excellent opportunity to get a better view on the fjord and learn how to sail.
Lars Umlauf (IOW) holds the microstructure profiler while Xaver (IOW) cleans it.
Please see Søren’s website (http://www.gfy.ku.dk/~hpn661/) for further information on past and the present summer school at Bornö, as well as additional photographs and results from our measurement campaign.
A break on the warm cliffs. From left to right: Søren (CIC), Xaver (IOW), Mads (CIC) and Selina (IOW).
