GeoLog

GeoLog

Imaggeo on Mondays: Polar backbone (Arctic Ocean)

Imaggeo on Mondays: Polar backbone (Arctic Ocean)

This image was taken during the Arctic Ocean 2016(AO16) expedition that ventured to the central regions of the Arctic Ocean, including the North Pole. It shows a pressure ridge, or ice ridge, as viewed from onboard the deck of the icebreaker Oden. It was quite striking that the ice ridge resembled an image of a spine – sea ice being a defining characteristic of the broader Arctic environment and backbone to global climate interactions.

An ice ridge is a wall of broken ice that forms when floating ice is deformed by a build up of pressure between adjacent ice floes. Sea ice can drift quite quickly, and is driven by wind and ocean currents. Ridges are typically thicker than the surrounding level sea ice, being built up by ice blocks of different sizes. The submerged portion of the ridge is referred to as the “keel”, and the part above the water surface is called the “sail”. Ridges can be categorized as “first year” or “multi-year” features, with weathering affecting the morphology.

In the Arctic, such ridges have been measured to in excess of 20 m in thickness including keel and sail. As someone who studies plate tectonics, these collisional boundaries between plates of ice reminded me of a downscaled mountain-building setting.

The AO16 expedition ran from August to September 2016 and involved the Swedish icebreaker Oden and the Canadian icebreaker the Louis S. St-Laurent. A wealth of geological, oceanographic, meteorological data was collected. This period appeared to have coincided with the second lowest extent of sea ice coverage on record (tied with 2007), with around 4.14 million square kilometers.

The geological evolution of the Arctic Ocean in the regions closest to the margins of northern Greenland and the Canadian Arctic Islands are some of the most poorly understood. This is largely a function of the oceanic gyre system, which causes the thickest sea ice to build up in these areas making physical access difficult. From a maritime engineering perspective, the ice ridges pose a challenge and risk to icebreaking operations and navigation. Ice ridges may determine the design load for marine and coastal structures such as platforms, ships, pipelines and bridges, and are important for both ice volume estimations and for the strength of pack ice.

By Grace Shephard, geophysicist from the Centre for Earth Evolution and Dynamics (CEED) at the University of Oslo, Norway.

Heat waves in cities getting worse under climate change

Heat waves in cities getting worse under climate change

The effects of climate change are being felt all over the world but towns and cities are feeling most hot-under-the collar, a new study finds.

Cities are usually warmer than their surroundings due to the urban heat island effect where artificial surfaces absorb more heat than their natural counterparts. Coupled with the loss of the shady effects of trees, urban areas regularly record the hottest temperatures around.

However a study by Dr Hendrik Wouters and colleagues from KU Leuven in Belgium has found that cities are getting even hotter from the effects of climate change with an increase in heat-waves.

Heat-waves are periods of time where temperatures exceed the ‘normal’ high levels. These events are already problematic in urban areas causing power surges, excessive hospitalisations and even deaths.

Wouters and colleagues have investigated how much worse this problem is likely to get as extreme weather events become more common.

Speaking at a press conference at the EGU 2017 General Assembly on 25th April, Wouters said ‘we look at how much temperature levels are exceeding during heat waves‘. Using the expected average temperatures, the climatologists can calculate a threshold of ‘normal’ temperatures and then quantify how often these values are exceeded.

This information was gathered for the whole of Belgium over the 34 years prior to 2015. In rural areas this ‘alarm’ threshold was exceeded at least twice. In urban areas the heat-stress was considerably higher- up to 16 exceedances. Overall, heat-stress was twice as large in cities for the mid 21st century.

Cities (red) show much higher annual degree exceedances than rural areas (green). These exceedances are set increase into the future. (Wouters et al., EGU 2017).

In order to anticipate how much worse this problem might get, the group have modelled heat-stress events for the next 58 years. Wouters was keen to highlight that the severity and frequency of the events is dependent on many factors: ‘There is not only one scenario for the future, it depends on how many greenhouse gases we emit and how much land change will evolve in the future.’

In an extreme scenario, where greenhouse gas emissions and urban growth increase, as many as 25 days in a year could exceed alarm levels by up to 10 degrees celsius. However, if we start to reduce our emissions, the heat-stress problem is likely to stay at current levels.

By Keri McNamara, EGU 2017 General Assembly Press Assistant

Imaggeo on Mondays: Sneaking up from above

Imaggeo on Mondays: Sneaking up from above

Take some ice, mix in some rock, snow and maybe a little mud and the result is a rock glacier. Unlike ice glaciers (the ones we are most familiar with), rock glaciers have very little ice at the surface. Looking at today’s featured image, you’d be forgiven for thinking the Morenas Coloradas rock glacier wasn’t a glacier at all. But appearances can be misleading; as Jan Blöthe (a researcher at the University of Bonn) explains in today’s post.

The picture shows the Morenas Coloradas rock glacier, a pivotal example of actively creeping permafrost (ground that remains frozen for periods longer than two consecutive years) in the dry central Andes of Argentina. The rock glacier is located in the “Cordon del Plata” range, some 50 km east of the city of Mendoza.

The rock glacier fills the entire valley and slowly creeps downslope creating impressive lobes and tongues with steep fronts. With more than 4 km length, the Morenas Coloradas is one of the largest rock glaciers of the central Andes.

Taken from a drone, the picture looks straight up the rock glacier into the main amphitheatre-like valley formed by glacial erosion located at ~4500 m.a.s.l. From there, large amounts of loose debris are moved down the valley at speeds on the order of a few meters per year. The creeping process forms tongues of material that override each other, producing the characteristic surface with steps, ridges and furrows.

The central Andes of Argentina are semi-arid, receiving less than 500 mm of precipitation per year, mainly falling as snow during the winter. The region is famous for its wines, which are grow in the dry Andean foreland that is heavily dependent on meltwater from the mountains. How much of this meltwater is actually stored in ice-rich permafrost landforms is unknown.

As opposed to ice glaciers, rock glaciers show a delayed reaction to a changing climate, as large amounts of debris cover the ground ice, isolating it from rising air temperatures. With large areas located above the lower altitudinal limit of mountain permafrost of ~3600 m.a.s.l., the central Andes of Argentina might store significant amounts of water in the subsurface.

Using mainly near-surface geophysics, our research tries to quantify the water storage capacities in the very abundant and impressive rock glaciers of the region. The Morenas Coloradas rock glacier is of special importance in this regard, as first geophysical measurements date back to the 1980s. Since then, active layer thickness has dramatically increased in the lower parts of the rock glacier, indicating that also the ground ice of the permafrost domain of the central Andes is suffering under the currently warming climate.

A final remark: Thanks goes to the entire team of this research project, namely Christian Halla, Estefania Bottegal, Joachim Götz, Lothar Schrott, Dario Trombotto, Floreana Miesen, Lorenz Banzer, Julius Isigkeit, Henning Clemens, and Thorsten Höser.

By Jan Blöthe, University of Bonn, Germany

The publication issue: the opinions of EGU early career scientists!

The publication issue: the opinions of EGU early career scientists!

The EGU’s General Assemblies have a long tradition of Great Debates – sessions of Union-wide interest which aim to discuss some of the greatest challenges faced by our discipline. Past topics have included exploitation of mineral resources at the sea bed, water security given an ever growing population and climate geoengineering, to name but a few.  This year’s meeting saw the first Great Debate aimed, specifically, at an Early Career Scientist (ECS) audience which boasted an innovative format too: Should early career scientists be judged by their publication record? A set of group debates. Today’s post, written by Mathew Stiller-Reeve, a convener of the session, summarises some of the main outcomes of the discussion.

We, early career scientists, are told that we need to become expert writers, presenters, and teachers if we are going to make it in the world of research. Many of us agree such transferrable skills are extremely important. But if we invest time in developing these skills, it sometimes feels like time wasted. All said and done, we only seem to be judged on our publication record and our h-index. How many papers have we published in high impact journals, and how often have they been cited?

Early career scientists seem very clued up on transferrable skills. They want to invest in these skills. Therefore, we wanted to hear from them about whether ‘early career scientists [should] be judged mainly on their publication record?’ And so we put this question to them (and others) at a Great Debate at the EGU’s 2017 General Assembly. We also wanted to test out a new format where the audience had the opportunity to voice their opinions about important issues concerning modern academia. The publication issue affects us all, so we should have a say.

With only 8 people at each table and over 40 minutes to debate, everyone had an opportunity to speak their mind and contribute to developing solutions. The room was buzzing with over 100 early career and more established scientists discussing, agreeing, disagreeing, and finding compromises.

In the end, each table was tasked to debate and boil their thoughts down to one or two policy-type statements. These statements will be presented to the EGU Council to inform them of where EGU early career scientists stand on this matter.

So without further ado, here are the conclusions of the tables:

– We need more criteria. Quality is most important, measured by prizes, PhD results and the incorporation of the community via new media.

-More activities need to be taken into account in a measurable way, but according to scaled categories #notjustanumber.

-The current system is cheap, easy and fast. A person should be judged on the broader contributions to society, to their colleagues, to their disciplines. We should move beyond metrics.

-Because scientists are more than a list of publications, assess them individually. Talk to them and read their output, including publications, blogs and chapter/book contributions.

-We should not be judged on publication record alone. We need a multi-variant set of criteria for assessment for judgment of impact beyond just academic publications.

-One suggestion is a weighted metric depending on the position you’re applying for which considers other factors such as teaching, outreach, conference participation etc.

-No, the h-index should not be the sole number, even though it is not a totally useless number.

-Quality should be judged on more than quantity and the large number of authors on publications devaluates the contributions of early career scientists.

-Publications are the accepted way of communication in science, but there is not any one number describing the quality of the early career scientist, whom in our humble opinion should not only be judged on the quantity of papers but also on their quality as a part of a complete set of research skills, including other contributions such as project development.

-We acknowledge the publication record as a reliable metric, but we suggest an additional step for assessing applications, based on video or audio presentations to emphasize your other outstanding qualities.

-We doubt that we are mainly judged on our publication record and we think that publications should be part of what we are judged on.

-When hiring, follow the example of the Medical Department at Utrecht University: only ask for the 3 papers, teaching or outreach experiences you think are important for the position you are applying for: we are more than numbers.

Should they be adopted? Do you agree? How can we adopt them?

The message in many of the statements from the Early Career Scientists at the European Geosciences Union is quite clear: We are more than numbers! Several suggestions arose from the debate: new metrics, video presentations, and even new application processes. Now the statements from the debate are recorded. This will hopefully inspire us (and others) to find better solutions. At the very least, the discussion has begun. Solutions are impossible if we don’t talk!

By Mathew Stiller-Reeve, co-founder of ClimateSnack and researcher at Bjerknes Centre for Climate Research, Norway

Editor’s note: This is a guest blog post that expresses the opinion of its author and those who participated at the Great Debate during the General Assembly, whose views may differ from those of the European Geosciences Union. We hope the post can serve to generate discussion and a civilised debate amongst our readers.

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