Politics, history, science and the continuation by other means

War is not merely a political act, but also a real political instrument, a continuation of political commerce, a carrying out of the same by other means. All beyond this which is strictly peculiar to War relates merely to the peculiar nature of the means which it uses. 

Carl von Clausewitz, On War

I have lots of thoughts about this really great Timothy Snyder piece on the US 2016 elections, (not least, I wonder what it means for how we understand Brexit too?)

But most of all I’m reminded of Gary Kasparov’s declaration that the point of modern propaganda is not to make you believe something but it’s to make you believe nothing. (I paraphrase slightly). Much of the piece is about how the Russian propaganda operation as been so successful at engendering doubt about Ukraine and the state of relations between Russia and Ukraine.

I sometimes feel the invasion of Ukraine has really been a wake-up call for many of us because it’s just so undeniable. An actual event happening to real people that we know with a pretty clear narrative. The genius of Russian influence operations has always been to muddy the waters sufficiently that it was a little hard to trust anything that anyone said or wrote.

In this sense I’ve also found Timothy Snyder’s series on the making of modern Ukraine (which I’ve been listening to over the last few weeks) brilliant and helpful and interesting. The subject is fascinating, but it also because it becomes clear listening to a historian that, yes there can be different ways to interpret events, but the events themselves are real and we have a duty to try to learn the facts before judging them.

This is of course exactly how scientists should think, that we have to establish good observational data before trying to interpret it. We also need, inevitably to consider what are the uncertainties and likely range within that data. What is missing? What can’t we know? What is the most likely interpretation based on the things we can observe? How reliable are our measurements?

One of my favourite teachers at school who really helped to develop the way I think was very clear on how to do this. And he was not a scientist, he was a historian.

Ultimately, I was more interested in understanding the physical world and went on to study glaciers, ice sheets and the climate system at the poles. However, as I’ve been focusing more on sea level rise and how on earth we adapt to a changing climate it’s quite clear that going back to the social sciences will be important to understand human behaviour. And the murky way other actors seek to influence us as we adapt to climate change is also going to be important to understand. There has been undue influence from a “Merchants of Doubt” perspective for sure for many years when it comes to the causes of climate change and the effects. This is very clear in the mess of climate denial that the new Lord of Twitter has unleashed, it’s a little bit like returning to 2009.

But here we are in 2023 and there are apparently serious politicians having hissy fits over the idea that a significant source of indoor air pollution should maybe be replaced with a far more efficient alternative (yes I’m talking about replacing gas stoves with electric induction), imagine how climate adaptation can be weaponised just as for example COVID vaccination was as part of the culture wars?

Anyway, this is a bit incoherent maybe. But it’s a great piece for clarifying what we know now and maybe for working out what comes next in terms of Russian interference in democratic institutions. And from a climate scientist perspective it’s also another reason to try to avoid (if we can), becoming just another cultural battleground. This is also key: it’s not always about money, sometimes people really are being manipulated for other reasons:

“When people act in the interest of a foreign power, it is sometimes for money, it is sometimes because the foreign power knows something about them, it is sometimes for ideals, and it is sometimes for no conscious motive at all — what one thinks of as one’s own motives have been curated, manipulated, and directed.  It seems quite possible — I raise it as a hypothesis that reasonable people would consider — that some mixture of these factors was at work at FBI New York in 2016.”

Well worth reading the whole thing.

The vanishing of the ice…

I was recently asked to comment on this interesting new paper by David Rounce and co-authors for AP by Seth Borenstein called “Global glacier change in the 21st century: Every increase in temperature matters”. You can read his resulting summary here . I’m posting here the slightly expanded and lightly edited response I sent to Seth in response to his (very good) questions.

The authors only look at the small glaciers and ice caps in this study, not the big polar ice sheets, though they do also cover small peripheral glaciers in Greenland and Antarctica that are not part of the main ice sheets. Of course, this means that sea level rise from all the other important processes like thermal expansion and ice sheet met also have to be taken into account on top of the numbers given here.

Their main findings were that at 1.5 °C above preindustrial, we can expect total glacial mass loss between 2015 and 2100 would be 26% with 90 mm of sea level rise and 49% of the small glaciers and ice caps lost globally. The paper only deals with these small glaciers and does not count the big ice sheets!

At 4°C, we’re looking at 41% mass loss with ~154 mm of sea level rise and 83% of glaciers lost. At 2.7 °C, where the world is now heading, 32% mass loss, 115 mm of sea level rise and 68% of glaciers lost.

I’m sad to say that the results aren’t exactly a surprise – the community has known for some time that the loss of glaciers is basically linear with temperature, so the title of the paper is really spot on, every tenth of a degree really does matter. This earlier paper by my Horizon 2020 PROTECT project collaborator Ben Marzeion shows something very similar But it’s a nice new result with the latest generation of glacier model and updated with the latest CMIP (IPCC) scenarios and they included some new processes that weren’t very well accounted for in previous work.

My first thought was that these latest estimates were actually a little lower than I expected, but the baseline in the paper is 2015 – we should remember that many of these glaciers have already lost quite a lot of ice (see my two photos of Nigårdsbreen in Norway, taken only 13 years apart) – so the new estimates are basically in line with what I would have expected given earlier work. I’d also expect that they will continue to lose ice beyond 2100 so it’s definitely not an end state that they are giving here. As they state in the article there will be widespread deglaciation of some pretty iconic parts of the world, even under the present planned emissions reductions..

In many ways part of the problem has been the previous studies have not always accounted for all the processes: frontal ablation (melt and calving of vertical ice cliffs, mostly in contact with water), the effect of debris cover and so forth (the latter will likely reduce the rate of loss, the former probably increases it). Given what we know about these processes and how to represent them in models, I still consider this work to be a more realistic estimate. Then we also need to account for the climate models and the scenarios used to force them – there are some important differences between CMIP5 and CMIP6 which might also account for some of this shift.  We have actually seen something somewhat similar for the projected changes in the big ice sheets.

It’s probably important to remember though that this study still needs to make simplifications, especially when looking at so many glaciers in so many different regions, so there will always be new updates to come with improved computing power and computational techniques and better representation of processes. Having said that, I do not think the picture will substantially change in future, though I can always be proved wrong, and the glaciers community are now at the stage of refining estimates for rates of mass loss.

Globally the loss of glaciers means sea level rise. Regionally and locally the biggest consequences will be for for water resources and we’re likely to see a local increase in natural hazards like outburst floods and avalanches that will need to be carefully managed. There have been a couple of instances already in the last year or two that probably demonstrate this well (e.g. the Marmolada glacier in Italy last year).

Sea level budget divided into components, from Legeais et al. 2018 ESSD The steric component is the expansion of sea water as it warms.

The small glaciers are currently a larger contributor to sea level rise than the big ice sheets, but that will of course change as they disappear and even small amounts of sea level rise, as represented here, are important in coastal communities where storm surges can occur. So we definitely need to account for their loss in planning for sea level rise and extreme storm surges. Locally and culturally there will also need to be changes. I think this will be a little traumatic for some cultures which have always considered themselves “glaciated” nations. The response I see to pictures  of the current state of the European Alps where people are skiing on artificial snow in green fields is a case in point here. It’s a shocking thing to witness.

I include myself in the group who has to get used to the cultural shift.  I have worked on glaciers in the Alps and Norway which are really rapidly disappearing. It’s kind of devastating to see, but it’s not actually surprising. We have known it was coming and in many cases (including the authors of this paper), measured the massive losses (last year, 2022 was a disaster for the Alps and both Fabien Maussion and Matthias Huss who are co-authors on the paper are running very comprehensive programmes that show in real time how much of a disaster) and predicted it with some accuracy. But we’re now at the point where it’s really undeniable that these glaciers are going fast.

The Rhonegletscher in the timelapse above is a really iconic glacier in the Alps, I have my own favourites, mostly places I’ve worked, like Norway, Iceland and Greenland, which are all to a greater or lesser extent retreating fast now. The glaciers that people consider iconic or at least well-known tend to be accessible and depend very much where you are and they will be the glaciers we mourn over in the next decades. In the French Alps, it’s probably the Mer de Glace, in Switzerland perhaps Rhone glacier or Plaine Morte (both have monitoring programmes), in Canada perhaps the Malaspina or Athabasca glaciers. There are still (just) glaciers on Kilimanjaro and Mount Kenya, the Ruwenzoris are basically gone, as are the Papuan glaciers.

One of the longest records anywhere in the world for glacier length change is Nigårdsbreen in Norway. This plot was put together by NWE: The Norwegian Water directorate who monitor a number of glaciers

Though they show in the study that ice loss is basically linear with temperature, at some point the glaciers become so small that the remianing melt is highly non-linear. And these won’t grow back under any sensible “overshoot” scenario (never mind that we don’t really have technology to remove carbon from the atmosphere at scale). Once they’re gone, they’re basically gone forever on human timescales Finally, I’d like to add a bit of anlaysis by Ben Marzeion and co-authors , it’s possible to basically put a number on the amount of melted glacier ice each kg of CO₂ leads to.

We find that under present-day climate conditions, every emitted kg of CO2 will eventually be responsible for a glacier mass loss of 15.8 (5.9–20.5) kg. Again, since the global glacier mass is decreasing with increasing temperatures, this number is greater for lower temperatures and smaller for higher temperatures.

Marzeion et al., 2018

It’s past time to stop burning fossil fuels.


I have been meaning to write about my return to field science (after 10 years mostly working on climate models) for the last 2 years, but prompted by this beautifully written piece in the Danish Newspaper information, I decided Christmas Day was the day (it for sure beats the washing up)…

“For at forstå, hvad der er ved at ske ved kloden, rejste vi mod isens ende”
“To understand what is happening to the earth, we travelled to the end of the ice”

Martin Bahn og Anders Rye Skjoldjensen (foto) in Information 23rd December 2022

To make one thing very clear straight away, and as the newspaper article also makes very clear, my colleague Steffen Malskær Olsen has established and maintained a very long-running programme of observations in the fjord near Qaanaaq. This town in northern Greenland on the edge of a large fjord, and close to the North Water polynya has a uniquely interesting location to study and understand Arctic processes. The DMI facility there is long established and part of the INTERACT network of Arctic field stations. The 15-year record collected by Steffen is more or less unbroken and uniquely valuable. None of the science I’m planning to do or to work on would be possible without his dedication, hard work, insight and bridge building within the community in Qaanaaq. He and my other DMI colleagues involved in this programme are brilliant scientists and great field companions and I feel privileged to be able to work with them in this incredible place.

In the field: Steffen and team retrieving an oceanographic mooring with instruments on it after a winter out in the fjord in 2021.

Secondly, as the article also makes clear, scientists are not individualistic heroes who beat the odds, it’s a team sport. And it’s especially true in Greenland where the true heroes of this story are probably not scientists but the local hunters and fishers who guide and transport us and whose knowledge and experience is unmatched. I include also on this category our DMI colleague Aksel Ascanius who lives and works in Qaanaaq has been an essential part of the programme since the earliest days, as well as keeping other long-term observations in the network running in this part of the world.

Collaboration with the people who live in the Arctic has been essential for success in Arctic science since since the days of Franklin and Rae (for British readers) or Suersaq, aka Hans Hendrik, (after whom Hans Island is named) for Danes..

Anyway, back to the science of the present-day. DMI has progressively added more and more elements to the field laboratory in Qaanaaq in addition to the longer running observations. A non-exhaustive list would include an infrasound monitoring station that is part of the CTBTO, weather observations (of course), surface emissivity measurements by drone, fjord salinity, temperature and photosynthetically available radiation measurements plus snow and sea ice measurements as well as work with satellites and biology. One glaring omission, up to this year at least, was the glaciology of the region. How does the ice sheet affect the regional climate, how does the ocean affect the glaciers that calve into the fjord? Can we learn about some important but poorly understood processes like calving and melange dynamics using this area as a test bed? What about surface mass budget and snowfall and snow melt?

A lead in the sea ice – these fractures in the ice have sea water (the black) welling up between two thick plates of sea ice. The conditions were perfect for frost flowers to grow on the surface. Sea ice turns out to be a lot more interesting – and complex- than I’d ever imagined…

Now, as a glaciologist, I’ve mostly worked with the interface between atmosphere and ice sheet (at least the last 14 years or so, but I am also still (after my PhD topic on ice fracture and crevasses) interested in calving glaciers and the processes that control how fast icebergs form. And the fjord, Inglefield Bredning has *a lot* of calving glaciers in it. It is a natural laboratory for glaciology and for developing numerical models. Calving is actually a surprisingly difficult thing to model with computer models of glaciers.

Or perhaps it’s not that surprising?

Observations are difficult to get (to put it mildly). There are a number of (possibly wild) theories of “calving laws” that remain poorly constrained by observations as a result. Common parameterizations of ice flow makes it hard to deal with fast flowing glaciers where calving is common. Dealing with grounding lines, where glaciers meet the sea and start to come close to flotation can give notorious numerical errors and retreat requires the remaking of ocean grids in fully coupled climate models.

Satellite image from ESA’s Sentinel-2 satellite showing glaciers calving icebergs into the head of the Ingle field Bredning fjord. The black is open water, icebergs show up as blueish dots, the land is carpeted in snow. Low winter sun (in late September 2022) casts deep shadows.

These are not easy or computationally cheap problems to solve. And where there are at least thousands (maybe even tens of thousands?) of scientists working on atmospheric weather and climate modelling, the community working on ice sheet dynamic models is probably only in the low hundreds.

And of course, we really lack long time series of measurements – essential in a system that changes only s l o w l y, but likely irreversibly and which we are, only now as the system is changing rapidly, starting to understand.

This of course is why the fjord observation record of Steffen is so valuable – these are reliable, repeated measurements of ocean properties that are known to affect the outlet glaciers that meet them. It is indeed a natural laboratory.

What we are now also working on is a field lab to study these calving processes in-situ. I have already found the return to the field scientifically valuable. There is really no replacement for going to observe the earth system you want to understand. (My PhD supervisor used to call it “nurturing your inner glacier”). Observations taken in spring/summer 2022 have already changed how I think about some processes and hopefully the follow-up we have planned in 2023 will confirm our new theoretical framework.

Heading home from the deployment of instruments out near calving glaciers at the head of the fjord.

I am fortunate indeed in that at the same research department, we also have colleagues collecting and analyzing satellite data and developing the numerical models we want to use to understand how ice sheets fit into the earth system. All three of these elements – field, satellite and numerical model- are essential.

In this project we are using the satellite observations to extend the time series of field data and we can use both sets of observations together to develop and test a numerical model of this fjord and the glaciers that calve into it. The numerical model we can then extend to other glaciers in Greenland. Hopefully, we can also use this work to understand how Antarctic glaciers might also respond to a warming ocean. Ultimately, the aim of all this work is to understand the contribution of these glaciers to sea level rise both now and in the future.

This is not a frivolous question. In fact, if large (more than a couple of metres).of sea level rise is expected, it is a question that is basically existential for Denmark.

I will add more on the specifics and science in coming months, this is already long enough. However, I’d like to mention a couple of other points:

Firstly, DMI is by no means alone operating up here. Many of the key articles, particularly on glaciology in this region, have been written by the Japanese group at Hokkaido University and their collaborators at the Meteorological Research Institute, the national institute for polar research and others. We at DMI are also working directly with the Greenland institute of natural resources, Asiaq, GEUS, KU, DTU, AU, SDU, ESA, Eumetsat and many others in this research programme.

Secondly, if you want to read more about it, I made these comics for my kids featuring some of their Lego pieces while out in the field this year and last. They’re kind of fun (I hope) and also informative (I hope).

Finally, this work is currently being carried out under the auspices of the Danish National Centre for Climate Research (NCKF), funded by the Danish Government though with contributions also from other research projects mostly funded by the EU’s Horizon 2020 and Horizon Europe frameworks as well as ESA’s climate change initiative for the Greenland ice sheet.