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The EUGEN e.V. meeting – a unique (geological) experience

The EUGEN e.V. meeting – a unique (geological) experience

Extracurricular activities for current and former geosciences students provide great value to early career scientists in terms of networking and broadening their scientific horizon. PhD student Maximilian Döhmann, who studies rock deformation with numerical models based on high temperature and pressure torsion experiments in the Geodynamic Modelling group of GFZ Potsdam, shares his experiences with the yearly EUGEN meeting.

PhD Student Max Döhmann.

Today I would like to introduce to you the EUGEN e.V., the EUropean GEosciences students Network. The network’s main goal is to bring together geosciences students (and former students) from all over the world through organizing annual meetings throughout Europe (see map of meeting locations). The network can already look back at a continuous history of meetings since 1996 and this year’s 22nd meeting took place in the beautiful Croatia.

Map of EUGEN Meeting locations. Red flag pinpoints the 2017 meeting location Croatia. Credit: eugen-ev.de.

In the second week of August, roughly 100 geoscientists met to enjoy a week of geological and cultural field trips, talks and presentations, making new contacts and simply meeting old friends. The camp ground was located at the karst-river Mrežnica – a perfect location during the hot Croatian summer. There, we experienced a typical EUGEN week starting with the ice-breaker party on Monday, followed by three days of field trips, one day of the traditional and challenging Geolympix and one day of cultural sight seeing.

Three varied field trip destinations were offered this year, organized by the local hosts (students from the University of Zagreb): the Velebit mountain range (part of a fold and thrust belt), the Istria peninsula and the Skrad valley in north-west Croatia. As a part of the Dinarides, the latter is known for the Devil’s Passage canyon and the Green Whirlpool. Composed of Permian clastic rocks, Triassic clastic rocks and dolomites as well as Lower Jurassic limestones, the area has a lot to offer for sedimentary geologists. But also structural geologists get their money’s worth due to the complex tectonic history resulting in nappe tectonics, extensional features and impressive folding structures.

Waterfall close to the Green Whirlpool (Skrad valley) due to an impermeable Permian or Triassic layer. Folds are younger carbonates. Credit: Max Döhmann.

The Geolympix rope-bound team-running. Credit: Mario Hendriks.

Besides having fun on the spectacular field trips, we also competed in a big social event – the Geolympix. The competition traditionally consists of highly entertaining (see photo) games played between teams composed of people from as many different countries as possible. Among others, we played rope-bound team-running (very effective for getting to know each other), platform diving (from ~5 m height) and wheelbarrow-jousting. The team with the most points in the whole competition won a delicious price (no spoiler here, find out what the price entails for yourself next time!).

To decide where the next meeting would be located, every country interested in hosting the event gave a presentation about themselves and their country during the week. On the last evening a decision was made by all participants, it will be … drum rolls … Austria! The next day everyone started their journey home feeling a little sad because the week went by so fast. But, after this so called post-EUGEN-depression, you will soon start to feel better when looking forward to the upcoming meeting. On that note, I hope that I have given you a compelling impression of what the EUGEN is all about and that I will see some of you August next year in Austria!

Why there should (not) be more women in geodynamics

Why there should (not) be more women in geodynamics

Nowadays, equality is cool. Everyone is always going on about how women and men should get the same opportunities. In science, and hence, geodynamics, women are still a bit behind men for both historical (women only recently started graduating more in exact sciences) and unconscious-bias reasons. Therefore, there are lots of programs in order to stimulate women to go into science and, more importantly, stay there.

However, no one really considers the negatives of having more women in geodynamics. And that’s why I’m here. Let me present to you a very comprehensive and entirely unbiased list of reasons why there should not be more women in geodynamics:

  • There would be a queue for the ladies toilet during coffee breaks at conferences.
  • None of our male colleagues would be able to focus on work any more, because we are distractingly sexy.
  • Ultimately, peer review would be less strict, because men would be afraid they might make us cry with their criticism.
  • More posters would be pink or purple (so mine won’t stand out any more).
  • The science would be better and there would be more discoveries, and who wants that, really?
    • And now the floor is yours: I hope I initiated a healthy discussion (without a weak seed! Or potato!) – surely you agree there shouldn’t be any more women in geodynamics, right? Leave a comment below!



      PS: For those less trained in sarcasm or irony: I mean the complete opposite, of course – these are all silly reasons! I also wanted to highlight some recent comments on women in science that reached the media, to show that there still is a significant bias against women in science. There should be more women in geodynamics! Although I would be devastated about the toilet queue.

How good were the old forecasts of sea level rise?

How good were the old forecasts of sea level rise?

Professor Clint Conrad

The Geodynamics 101 series serves to showcase the diversity of research topics and methods in the geodynamics community in an understandable manner. We welcome all researchers – PhD students to Professors – to introduce their area of expertise in a lighthearted, entertaining manner and touch upon some of the outstanding questions and problems related to their fields. Our latest entry for the series is by Clinton P. Conrad, Professor of Geodynamics at the Centre for Earth Evolution and Dynamics (CEED), University of Oslo. Clint’s post reflects on the predictions of sea level rise since the first Intergovernmental Panel on Climate Change (IPCC) report in 1990 and the near three decades of observations and IPCC projections that have been made since then. Do you want to talk about your research area? Contact us!

This past week I flew over the North Atlantic with a direct flight to California from Europe. From the plane we had a beautiful view of glaciers on the western edge of the Greenland ice sheet, where the ice seems to be disintegrating into the ocean. We’ve been hearing lately that the ice sheets are slowly disintegrating – is this what that looks like? Using my mobile phone’s camera, I took a photo of the glacier that happened to be visible from my seat and compared it to images of the same glacier saved in Google Earth (Figure 1). This is an interesting exercise if you like looking at glaciers, but I can’t tell about the overall dynamics of the ice sheet this way.

Figure 1. A glacier on the west coast of Greenland on September 2, 2017 (left) taken with my iPhone. From my plane’s in-flight entertainment system, it seems that this glacier is between the villages of Upernavik and Niaqornat. For comparison, the image on the right is a screenshot of the same glacier from Google Maps.

Actually, we’ve been worried about ice sheet melting – and the sea level rise with it – for decades. I re-realized this during this past summer, as I finally started unpacking the boxes that we shipped to Oslo one year ago from Hawaii. Some of these boxes probably didn’t need to be unpacked, like the one labeled “High School Junk”, but it turns out there is interesting stuff in there! Here was my diploma, a baseball glove, some varsity letters, and a pile of old schoolwork – most of which I have no recollection of creating. But I did remember one of the items – a report on global warming that I wrote for Social Science class in 1989. In particular, I remember being fascinated by the prediction that human activity would eventually cause enough sea level rise to flood land areas around the world. For years, I have been personally crediting that particular high school report as being my first real introduction to the geosciences – but until this past summer I had never revisited that report to see what I actually wrote at the time. Now here it is – twelve yellowed pages of dot-matrix type, with side perforations still remaining from the printer feed strips that I tore off 28 years ago.

My report is entitled “Global Warming – What Must Government Do?” and now I can see that it is mostly a rehashing of reporting from a bunch of newspaper articles written in 1989. It was a bit disappointing that my younger self wasn’t more creative or inspirational, but the content of the report – really the content of the newspaper articles from 1989 – is fascinating because much of the material could have been written today. There is discussion of how the warmest years in recorded history have happened only recently, that climate skeptics were unwilling to attribute recent changes to human activity, and that a few obstinate countries (then, it was Japan, the USSR, and the USA) were standing in the way of international agreements to curb CO2 emissions. Another statement is also familiar: that “oceans could rise from 1.5 to 6.5 feet”. For those of you not familiar with that measurement system, that is about 0.5 to 2.0 meters! I know that recent predictions are not quite as dire as 2 m of rise (at least in the 2100 timeframe), although sea level acceleration has been getting more attention lately. Did people in 1989 consider 2 m of sea level rise a possibility? I checked the cited New York Times article from 1989, and indeed it seems that I dutifully reported the estimate correctly. The article says that 1.5 to 6.5 feet of sea level rise is expected “to occur gradually over the next century affecting coastal areas where a billion people, a quarter of the world’s population, now live”.

Figure 2. Projections of sea level in 2100 (relative to 1990 sea level) for the five IPCC reports between 1990 and 2013, plotted as a function of IPCC report date. Shown are the minimum and maximum projections (range of red bars), and the mean of estimates (black circles).

I have contributed a little to sea level research in the intervening years, and am somewhat familiar with the current predictions. I know that the most recent (2013) report of the Intergovernmental Panel on Climate Change (IPCC) predicts up to about a meter of sea level rise by 2100, which was a large increase over the 2007 report that predicted up to about 0.6 meters. Thus, meter-scale sea level rise predictions seemed like a relatively recent development, and yet here was a prediction just as large from nearly 30 years ago. What did the IPCC have to say about sea level at the time?

I plotted the sea level projections of the five reports that the IPCC has released between 1990 and 2013 (Figure 2). Indeed, the 1990 report predicted slightly higher sea level for the year 2100 (31-110 cm higher) than did the most recent report from 2013 (28-98 cm higher). In fact, the IPCC projections for 2100 sea level declined from 1990 through 2007, until they increased again in the most recent report in 2013 (Figure 2). Why is this? Well, we have nearly 3 decades of observations that could help us to answer this question!

 

Figure 3. Sea level projection from the IPCC’s first assessment report (1990), showing that report’s low, best, and high estimates (blue lines) and predicted rates in mm/yr. Also shown is the University of Colorado sea level time series (red line), which is based on satellite altimetry observations from 1992-2016 and records a sea level rise rate of 3.4 ± 0.4 mm/yr.

First, let’s evaluate the initial predictions of the first IPCC report from 1990. Since 27 years have passed since the publication of that report, we can actually compare a sizeable fraction of those 1990 predictions to actual sea level observations. Left, I have plotted (Figure 3) the 1990 report’s sea level projection from 1990-2100 (Fig. 9.6 of that report) along with actual sea level observations made using satellite altimetry between 1992 and 2016, which have been nicely compiled by the University of Colorado’s Sea Level Research Group. The comparison shows (Figure 3) that the actual sea level change for the past 24 years has fallen slightly below the “best” estimate of the 1990 report, and well above the “low” estimate.

In retrospect, the 1990 predictions of future sea level change seem rather bold, because the 1990 IPCC report also concludes that “the average rate of rise over the last 100 years has been 1.0-2.0 mm/yr” and that “there is no firm evidence of accelerations in sea level rise during this century”. Yet, the 1990 report’s projection of 2.0-7.3 mm/yr of average sea level rise from 1990-2030 (Figure 2), represents a prediction that sea level rise would accelerate almost immediately – and this acceleration actually happened! Indeed, three recent studies (Hay et al., 2015; Dangendorf et al., 2017; Chen et al., 2017) have confirmed sea level acceleration after about 1990.

Thus, the IPCC’s 1990 sea level projection did a remarkably good job for the first three decades of its prediction timetable, and the next 8 decades don’t seem so unreasonable as a result. What did the 1990 report do right? Here the 1990 IPCC report helps us again, by breaking down its projection into contributions from four factors: thermal expansion of the seawater due to warming, the melting of mountain glaciers, and changes in the mass of the great ice sheets in Greenland and Antarctica. The 1990 report makes predictions for the changes in sea level caused by these factors for a 45-year timeframe of 1985-2030, and I have plotted these predictions as a rate (in mm/yr) in Figure 4. Thermal expansion and deglaciation in mountainous areas were predicted to be the largest contributors. Greenland was predicted to contribute only slightly, and Antarctica was predicted to gain ice, resulting in a drop in sea level.

Figure 4. Comparison of projections and observations of the various factors contributing to global mean sea level rise (GMSL, in mm/yr). Red bars show predictions that were made in 1990 (table 9.10 of the 1990 IPCC report) for the 45-year period 1985-2030 (range is given by red bars and best estimate is shown with a dark line). Blue bars show the actual contribution from each factor for the 17-year period 1993-2010, as detailed in table 13.1 of the 2013 IPCC report. Note both the sum of observed contributions and the direct observation of sea level change from satellite altimetry (bottom two blue bars) are consistent with recent analyses of tide gauge data (Hay et al., 2015; Dangendorf et al., 2017), within uncertainty.

Now 27 years later, we have actual observations of the world’s oceans, glaciers, and ice sheets that we can use to evaluate the predictions of 1990 report. Many of these observations are based on measurements made using satellites, which can now remotely measure ocean temperatures, changes in the mass of land ice (mountain glaciers and ice sheets) and even changes in groundwater volumes, over time. The IPCC report from 2013 (the most recent report) shows these contributions in the timeframe of 1993-2010, which are 17 years during the 45-year outlook predicted by the IPCC’s 1990 report. I have plotted these observations in Figure 4, and we can see how the 1990 predictions compare so far – remembering that the prediction and observation timescales do not exactly align.

First, we see that 1990 report overpredicted the contribution from thermal expansion, and slightly overpredicted the contribution from mountain glaciers. Of course, there is still time before 2030 for these factors to increase some more toward the predictions made in 1990. However, we also see that Greenland melting has already matched the 1990 report’s prediction for 2030, and that the prediction of a sea level drop from Antarctica did not materialize – Antarctica contributed almost as much sea level rise as Greenland did by 2010 (Figure 4). Furthermore, there is another significant contributor to sea level rise – land water, which represents the transfer of liquid water from the continents into the oceans. This occurs because groundwater that is mined for human activities eventually ends up in the ocean. According to the 2013 report, land water caused more sea level rise than ice sheet melting from Antarctica.

Thus, in 2010 the predicted rates of sea level rise from two factors (thermal expansion and mountain glaciers) had not yet reached the 2030 predictions of the 1990 report, but the contributions from Greenland, Antarctica, and land water loss have already nearly met or exceeded the predictions of 1990. Indeed, recent satellite observations between 2002 and 2014 show an acceleration of melting in Antarctica (Harig et al., 2015) and especially in Greenland (Harig et al., 2016). The recognition that Antarctica and Greenland may contribute significantly more to sea level rise in the future compared to earlier estimates is reflected in the 2013 IPCC report (Figure 2).

Figure 5. A dike near the town of Putten in the Netherlands, where the recent EGU-sponsored “Nethermod” meeting was held in late August 2017. This dike is one of many in the Netherlands that protect negative-elevation land (left) from a higher water level (right).

So far, it seems that the IPCC’s 1990 sea level projection has stood the test of 27 years remarkably well (Figure 3). It is rather disheartening to realize that we are on track for the ~60 cm of sea level rise that the 1990 report predicted for the year 2100, or more if the early underestimates of ice sheet contributions prove to be more significant than any overestimates of thermal expansion (Figure 4). Looking at my own high school report from the same time, it is also disappointing that to realize that the warmest years in recorded history have again happened only recently, that climate change skeptics are still unwilling to attribute recent changes to human activity, and that there are still obstinate countries (well, one country) standing in the way of international agreements to curb CO2 emissions. On the other hand, high school students writing reports on this topic today will likely find discussions of dropping beachfront real estate prices, governmental planning for future sea level rise, and engineering techniques for managing future sea level rise (Figure 5). I hope that these students save copies of their reports in a format that they can examine decades later, because it is interesting to consider how predictions of future sea level rise have changed over time, and how society has been responding to the challenges of this geodynamic phenomenon that is operating on the timescale of a human lifetime. One day in the 2040s these students may want to scrutinize another quarter century of data against the projections of the next IPCC report, to be completed by 2022. I wonder what they will find?

 

The Venus enigma: new insights into ‘Earth 2’

The Venus enigma: new insights into ‘Earth 2’

Apart from Earth, there are a lot of Peculiar Planets out there! Every 8 weeks, we look at a planetary body worthy of our geodynamic attention. This week Richard Ghail, lecturer in Engineering Geology at Imperial College London in the United Kingdom, discusses Earth’s sister: Venus.

Geologists have long held the view that they only have the results of one experiment: Earth. The growing list of Earth-like planets around other stars (exo-Earths) means that such a view is no longer valid, even if we have limited knowledge of those worlds. Surprisingly, perhaps, our own Solar System boasts two exo-Earths: and the other one is not Mars, as you might think, but Venus. Our nearest planetary neighbour is also the most similar to Earth: at about 80% of its mass and 95% of its radius, and orbiting arguably within our Sun’s habitable zone, Venus would be recognised as an Earth-like exoplanet if it were in orbit around another star. Yet the results of these two experiments could not be more different: Earth may not quite be Eden, but Venus is certainly the closest place we know to hell. Its dense global shroud of sulphuric acid clouds hides a surface on which a person would be simultaneously roasted (at 450°C), crushed (at 90 atmospheres pressure), poisoned and asphyxiated (its atmosphere is 95% CO₂), and corroded (not by sulphuric acid, which decomposes under the extreme conditions, but by HCl and even HF!). The armoured Soviet Venera landers survived only a couple of hours on the surface, but still managed to return tantalising pictures of a barren rocky landscape bathed in an orange light.

A geodynamic surprise: Catastrophe or not?
NASA’s Magellan mission (1989-1994) revealed that geodynamically too, Venus was a surprise. A wealth of volcanoes, rifts and mountains cover its surface but there is little evidence for the spreading ridges and deep trenches that characterise plate tectonics on Earth. More perplexing was the realisation that the 950 or so impact craters – implying a youthful 500 Ma average age – were distributed apparently at random. Had the whole planet been somehow catastrophically resurfaced in one go, half a billion years ago? As strange as it might sound, there appeared to be good reasons to think so: that 450°C surface temperature is enough to stop the crust subducting, effectively shutting down plate tectonics. Without that safety valve, the interior of Venus must be getting ever hotter at the same time that exterior cools and thickens the lithosphere. Such a situation is inherently unstable and calculations showed that Venus should ‘blow its top’ every 500 Ma or so – explaining both the lack of plate tectonic features and the crater distribution. The Venus enigma was solved.

Or was it? The theory divided the community into bitterly opposed sides for the next decade or more. One group could see a global sequence of events in its geological features that seemed to confirm the theory; while the other could see an array of geological complexity at odds with it. ESA’s Venus Express mission (2005-2012) focussed on the planet’s atmosphere but it revealed a remarkably dynamic and changeable system that must somehow reflect geodynamic activity below. It even found tantalising hints of recent volcanic activity. Understanding both the geological evidence and the crater distribution turns out to depend on the very thing that set Venus apart from Earth: its extreme surface conditions. The high temperature not only makes the crust buoyant, but weak, especially so at about 10 km depth, where it is able to shear relative to the mantle below. In this new geodynamic view, plate tectonics does operate on Venus much as it does on Earth, but under 10 km of crust, not 5 km of ocean (Ghail, 2015). As well as explaining the large-scale features of Venus, including its geoid, calculations show that this subcrustal rejuvenation, as it is called, is able to maintain the heat balance on Venus). No catastrophic events are required.

If the crater distribution is not the result of a global catastrophe, what caused it? Mechanically, the basaltic crust of Venus behaves much like Earth’s granitic continental crust, and is similarly broken into many small plates, or terranes, on the order of 500 to 1500 km across, characterised by low strain interiors and highly deformed margins, similar to terrestrial continental blocks. On Earth these terranes are driven by far-field plate tectonic stresses but on Venus they are driven by subcrustal rejuvenation stresses that jostle the terranes against one other but do not move them far across the surface. Impact craters are preserved in terrane interiors but rapidly destroyed at their margins, so that the average crater spacing is similar to the size of terranes. The preserved terrane-interior craters are only destroyed when the terrane is itself destroyed, most likely by interaction with a subcrustal plate boundary (rift or collision), which by inference is something that occurs on average every half billion years. This new geodynamic understanding refines our appreciation of how the geochemistry and geomechanics of the outer few kilometres of the planet profoundly influence stagnant-lid behaviour, promising new insights into early-Earth geodynamics and the nature of newly-discovered exo-Earths.

Welcome to hell Venus. I want you to explore it!
Credit: Pixabay

Exploring Venus
So our views of Venus have changed; our Solar System’s second experiment is, geodynamically, rather more similar to Earth than once imagined. Even so, these ideas have yet to be tested, and our nearest neighbour retains many secrets. Almost nothing is known about its interior, its rates of activity, or even how Venus maintains such a hostile atmosphere. A new phase in Venus exploration is called for, and within Europe the most promising is the proposed EnVision mission, which is currently undergoing evaluation by ESA. EnVision will use an advanced Earth Observation heritage interferometric radar to measure and monitor geological activity over a 5-year period and obtain images at up to 1 m resolution – sufficient to locate and track the Venera landers, providing the precise geodetic control needed to measure terrane deformation. A radar sounder will probe the near subsurface and an IR/UV emission spectrometer will map geochemistry and follow volcanic gases from their source to the upper atmosphere. NASA has proposed landers that could probe interior seismicity, and in the future balloons may directly sense cloud chemistry and dynamics. Unlike the Moon and Mars, these missions will be exploring a world that is – in a geodynamic sense, at least – very much alive.

References
Ghail, R. (2015). Rheological and petrological implications for a stagnant lid regime on Venus. Planetary and Space Science, 113, 2-9.