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Geodynamics

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.

NetherMod Day 4 & 5 – Secret Summary

NetherMod Day 4 & 5 – Secret Summary

I hear you exclaiming: “Why merge day 4 and 5 together? What happened to the secret summary of day 4?” Well, I have to admit, apart from being your daily NetherMod reporter, I also needed to present my poster, so apologies for the delay and merge.

Day 4 started with a keynote talk from Dave Stegman with a surprise topic (He had never handed in his abstract. Apparently this is a possibility. Probably only tolerated for keynote speakers though). Dave presented a symphony in four movements about the inconvenient truth of the possibility of a molten lower mantle in the early Earth. We were also very lucky to see the one and only picture of the moon forming impact: truly impressive. Steering the discussion towards politics, Dave introduced two great slogans:

The geodynamics liberation front

and

Viva la subducción

Talking about subduction, Fanny Garel had a great keynote talk about modelling subduction zones, followed swiftly by a talk by Yury Podladchikov on resolving ductile strain localisation and porous fluid channeling due to thermo- and hydro-mechanical coupling (a “scary talk” according to chair Dan Bower) and Manuele Faccenda’s talk on coupled geodynamic and seismological modelling of subduction zone dynamics. During the final discussion with everyone, Carolina Lithgow-Bertelloni imposed on us the scary truth that

Models are only useful if they fail

I think that’s particularly encouraging for every ECS, although we might be talking about different flavours of model failing…

Day 5 (the final day! how time flies when you’re having fun!) was an excellent day for your NetherMod reporter, because of the incredible amount of bad jokes, puns, and food related analogies in the talks. Thanks! I can work with that!

Paul Tackley kicked of Thursday morning with an interesting talk on the influence of melting on the Earth’s evolution. One of his animations caused the most seasoned scientists to giggle. Unfortunately, I can’t comment more on that; in fact, I have been specifically asked by Dave Stegman to refrain from quoting him on this subject. Indeed, I am a classy girl and this is a classy blog, so I won’t go into details, but props to those who know what I am talking about!

Next, Carolina Lithgow-Bertelloni talked about the carbon compensation depth and she once again had a great comment on modelling etiquette (I see a pattern here):

The goal of a study should be defined before the tools are chosen

Clint Conrad discussed how we could infer dynamic topography from bathymetry and plate motions. He noticed that the degree 1 net motion characteristics of plate velocities all seem to point towards North Korea. Interesting point, isn’t it? I won’t make any (political) remark about that, because, you know, I like my home nuke-free. A lovely quote from Dan Bower during the subsequent question round was that

One person’s observation is another person’s model

Think about it. Keep it in mind.

Things really started to get spicy when Louise Kellogg discussed comparisons of different models and chemical geodynamics for mantle convection. She gave a very nice introduction about the concept of modelling (which was open for debate, of course) and particularly hastened to broaden René de Borst’s previous statement about the fact that the devil is in the boundary conditions: the devil is also very much present in the initial conditions and perturbations. There is no escaping him, really. Louise also added several (chemical) spices in our mantle dynamics curry by looking at the Earth as a chemical factory with several reservoirs connected by fluxes.

Now that we have had potatoes, sausages, and a dynamical curry at NetherMod, the desert was served by Louise when she compared the Earth to a marble cake. I will leave you this time with that delicious idea for a dinner party. NetherMod 2017 finished after a splendid party until the wee hours. Next time it will be in Italy (with a masked ball? Can we please make sure that happens? Like Romeo & Juliet? Pretty please?), and maybe I will report that as well.

For now though, I leave you with the suggestion that we should get together soon for a dinner party. Anyone who would like to volunteer to cook the potatoes?

NetherMod Day 5 – Putten an end to Nethermod: interviews with attendees

NetherMod Day 5 – Putten an end to Nethermod: interviews with attendees

Today is the fifth and final day of the XVth International Workshop on Modelling of Mantle and Lithosphere Dynamics, or “Nethermod”, here in Putten, The Netherlands. Despite the overcast conditions outside, the lively scientific program included keynotes by Paul Tackley and Carolina Lithgow-Bertelloni in the morning and Clint Conrad and Louise Kellogg in the afternoon. With over 120 attendees, and a program built around selected keynote presentations with plenty of time for posters and discussions, Nethermod offers a unique meeting format. Today’s post includes interviews with three attendees at different stages of their career – student, mid career and more established – and asks about their experiences of the workshop and their perspective on the future of geodynamics.


Kiran Chotalia here at Putten

— Early Career Researcher —
Kiran Chotalia (University College London).
Kiran is entering the third year of her PhD, and is a first-time attendee to the workshop.

– What is your PhD project about and what did you present here?
My project looks into the effects of water on mantle circulation, firstly using parameterized models and then 2-D models. I had a poster on day 2 which presented some parameterized models that included a time-lag to simulated delayed mixing.

– The conference is aimed at leaving extra time to develop student-keynote interactions. What have your impressions been? Do you have any suggestions for changes for future workshops?
Considering the format and length of the lectures (45 mins + 15 questions), I think that 30 mins with the keynotes presenters was sufficient. However, there are around 40-50 other student attendees so perhaps the option to write some anonymous questions to help find consensus within the broader group’s needs could be incorporated. This would also help achieve a more overview style session, which cannot be covered in the lectures.

– What are your plans for after the PhD – is the Brexit process seriously weighing into your decision making?
I am definitely now more open to considering the idea of moving outside the UK. In any case, with time I have felt more integrated with the geodynamics community, and have a broader picture of who else is also out there and what the cutting-edge ideas are.

– What are your takeaway potatoes of wisdom from the meeting?
Dave Stegman’s comment – “Don’t always believe what you read” has stuck with me. It is important to be reminded of this fact! Science is only the best description at that time, and also considering the current state of pressure to publish, it is easy loose this perspective. It is also nice to be at a smaller, manageable conference with other researchers doing similar things. It is a chance to meet and talk to those beyond the home institute and I feel more up-to-date with what others are up to.

 


Fanny Garel at the poster of her PhD student Manar Alsaif

— Mid Career Researcher —
Fanny Garel (Géosciences Montpellier)
Fanny is a lecturer at Montpellier, and was an invited keynote presenter from the “Subduction and mantle flow modelling” session. Nethermod is her third workshop of this series.

– Your presentation built upon work from your earlier paper (Garel et al., 2014) that has had quite a reception in the community. Can you please summarize the talk for us?
My presentation was on numerical models that (re)produce the seismically imaged slab morphologies by varying different parameters and understanding the physical controls (e.g., slab sinking and bending).

– From your perspective as a keynote speaker, how did the daily student question session go?
Half an hour was perhaps slightly too short. The session is a key opportunity to open the discussion to more of the limitations and assumptions of the model. Students can ask more about the basics which you cannot fit into a presentation. Teaching is not just presenting, and vice versa. It is also helpful for speakers in terms of feedback for their own presentations!

– What are some of the biggest and outstanding questions in the modelling community?
Understanding when present-day subduction zones initiated, is one. Exploring a self-consistent interaction between single subduction zone specific-scales and global scales, both spatially and temporally, is still outstanding.

– Any tips or suggestions for ECS researchers at the end of the thesis and thinking of whether to continue for a postdoc?
You are already experts of your PhD subject, so keep your options open and try to change topic or your approach for a postdoc. There are plenty of different scales in geodynamics to explore, and perhaps it is best to change tools rather than objects. Consider your longer term view too and what the hot topics are that will lead to new opportunities in the next ca. 5 years.

– What are your takeaway potatoes of wisdom from the meeting?
There is always the requirement for simple models to help understand the Earth. Models can have lots of complexity but we can lack a fundamental and first-order understanding of problems – including the physics and relevance of feedbacks e.g. the Marianas trench, and surface and deep dynamics.
The generation and modelling of melt was also discussed, including the different ways of approaching it, and the links chemical evolution and dynamic evolution in a self-consistent manner.

 


Dave and the sunset

— Established Career Researcher —
Dave Stegman (Scripps Institute of Oceanography)
Dave is an Associate Professor of Geophysics and was a keynote speaker within the “Global modelling of Early and recent Earth” theme.

– This is the 15th time it has been run – how many conferences within the series have you attended?
My first in the series was in 2001 as a grad student and I have missed two of them since then. Some of the fellow students I met there the first time are here this week, so there is a real community building aspect to this meeting series and it is really important for the fabric of the community.

– How has it evolved since your first conference?
The format similar is pretty similar and has become increasingly student focused. The attendance of a high proportion of students makes the meeting fresh and dynamic.

– Can you summarize your presentation from earlier this week?
The take home message of my presentation was to shift our mindset in order to allow for scenarios that permit a molten lower mantle and a magnetic field in places outside the core. It was provocative, sure, but ensured a healthy scientific discussion.

– Origins of the geodynamo and core formation is a shift from your earlier work. Can you comment on the interdisciplinary aspects of modelling on vastly different temporal and spatial scales? 
This work really integrates geo- and paleo-magnetism, geodynamics and mineral physics, which really inform each other. Collaboration is required to progress.

– The “Geodynamics Liberation Front” was a big success and you are rolling out a new geodynamics themed t-shirt. Can you tell us more?
It will come in different sizes. The first was wildly popular – some more community themed fabric. Email me if you are interested in knowing more, else I’ll be bringing a suitcase full to AGU.

– What are some of the biggest or outstanding questions in the modelling community generally?
Those regarding Earth’s evolution and it’s entire history. The roadmap that makes most sense to me is to firstly calibrate our models of plate tectonics to present-day or recent timescales before going back in time, or to exoplanets.

– As a non-EU based researcher, do you have many active collaborations with researchers back on this side of the Atlantic?
Science is an international and you need to follow problems wherever they take you. Our community is really open to collaborations and in-person opportunities are important; they add much more value to Skype level meetings.

– Any tips for the next generation of ECS members of the geodynamics community, or those PhD students not sure whether to transition to postdoc?
Don’t underestimate yourself. The skills required to accomplish a PhD are valued in many settings… persistence, attention to detail, the ability to think at different levels, time management. Students often don’t realize they have these abilities and they are a starting point for many paths.

– Finally, what are your takeaway potatoes of wisdom from the meeting?
The informality of the venue and meeting format enables everyone to expand from their comfort zone. This is critical for learning as you cannot be inhibited to ask questions and start discussions. The financial support to bring so many students to the meeting really tips the scales… when students and ECSs are the dominant force they do not feel intimidated to make the most of it.


Thanks Dave, Fanny, and Kiran for your time!