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This guest post was contributed by a scientist, student or a professional in the Earth, planetary or space sciences. The EGU blogs welcome guest contributions, so if you've got a great idea for a post or fancy trying your hand at science communication, please contact the blog editor or the EGU Communications Officer to pitch your idea.

Cryo-Comm – Six reasons why you should communicate your science

Here is Ella speaking at one of the Natural History Museum’s ‘Nature Live’ events in London, July 2019. [Photo Credit: Natural History Museum]

What inspired you to get into polar or cryospheric research? Perhaps it was a passion for the outdoors, a drive to protect the environment for the people and animals that live there, or a fascination with wild places. For me, it was all three – and the more I learned about Antarctic climate science, the more I realised that the polar regions are vital to the functioning of a healthy planet, and so should be important to all of us. In this blog, I give you six reasons why you should communicate your science and give you some tips along the way.


What happens in the cryosphere affects us all: from the impact of declining Arctic sea ice on weather patterns in the northern hemisphere or the effect of melting Himalayan glaciers on the water supplies of a billion people, to the potential contributions to sea level rise of the Greenland and Antarctic ice sheets.

One of my favourite quotes of all time is from Professor Sir Mark Walport, who at the time was Chief Scientific Advisor to the UK government. He said: “Science is not finished until it’s communicated”. For me, communicating science in a way that everybody and anybody can understand is one of the most important parts of the job. After all, if it affects everybody, everybody should be able to understand it, right?

Ella did some ’60 second science’ videos about the British Antarctic Survey’s airborne atmospheric measurements while she was in Antarctica during a field campaign in 2017. [Photo credit: Ella Gilbert]

Now, if you’re not already sold on the importance of science communication, I’m going to convince you why you should be, with six reasons.

One

First of all, there’s a moral obligation. I have been privileged enough to go to both poles and to some incredible mountain regions as part of my work. I am also lucky enough to be able to access the enormous wealth of literature on polar science and climate change, and to have the time and educational background to engage with it. I understand the scale of the problem, which can be a blessing and a curse. Knowing what I know, I could not stand by and keep this to myself. I feel it is my moral duty to shout from the rooftops about the importance of the polar regions, cryosphere and environmental change.

Two

Whether or not you agree with this, how about this for another argument: if you’re publicly funded, you should be communicating the results of your research with the people who paid for it – the taxpayers! And of course, not everyone has the ability to access pay-walled academic journals, nor the ability to understand scientific language and format. So it’s down to you to communicate accessibly, whether that’s in plain-language blogs, videos, podcasts, public talks, events or simply in the pub with your mates.

If you’re not doing it for others – then think of science communication as a way of developing your own work.

Three

A pretty famous scientist – one Albert Einstein – once said that if you can’t explain something simply, then you don’t understand it yourself. Synthesising and distilling the key points of your work into simple messages can be an excellent way to spot themes or even flaws in your work, and to increase your understanding of the subject. Very often, talking to the public can give you another perspective – perhaps asking questions from an angle you hadn’t considered before, or asking questions that you don’t know the answer to. We all have our expertise, and non-scientists often bring a refreshing alternative outlook that can help you develop your work.

Four

Communicating simply is also a great way of promoting yourself – just think, a paper in a journal reaches a relatively small but specialist audience within your field, but a blog post or online video has the potential to reach millions of non-scientists who might be interested in learning more about your research.

Five

Next, think tactically. Funding agencies are increasingly interested in creating impact beyond academia. If you can demonstrate that you have reach beyond the hallowed halls of academe, then you are more likely to win funding to continue your work. Outside academia, more and more employers are seeing science communication as a desirable skill, so you never know – that podcast might just get you a job too.

Six

The final – and possibly most important – reason to communication your science is that it’s fun! It’s incredibly rewarding, and you learn a huge amount by doing it.

So, what are you waiting for? Get out there and start communicating! Your first piece of science communication could be a guest piece for this very blog. Or, maybe your second, third or 100th piece of science communication could be writing for us… just get in touch with our editors.

Edited by Jenny Turton


 

Ella Gilbert is a PhD student at the British Antarctic Survey. Her research focuses on the atmospheric processes that cause melting on ice shelves around the Antarctic Peninsula, and she regularly writes blog posts, makes youtube videos and communicates science at festivals, schools and museums. She tweets from @Dr_Gilbz and you can see more of her science communication at www.ellagilbert.co.uk or https://www.youtube.com/channel/UCjaBxCyjLpIRyKOd8uw_S4w.

 

Did you know… about the fluctuating past of north-east Greenland?

Did you know… about the fluctuating past of north-east Greenland?

Recent geological data shows that during a very cold phase of our Earth’s climate (between 40,000 and 26,000 years ago), there was a huge expansion of polar ice sheets, yet the north-eastern part of the Greenland ice sheet was less extensive than today. How could this have occurred? In this post we shed light on the potential causes of this ice sheet behaviour.


What do we know about present-day north-east Greenland?

The North East Greenland Ice Stream is one of the most interesting icy features of the present-day Greenland Ice Sheet. Extending for more than 600 km from the ice-sheet interior to the ocean, this ice stream drains almost 12% of the whole ice sheet and terminates through a system of fast-flowing outlet glaciers, known as Nioghalvfjerdsfjorden glacier (also called 79N), Zachariae Isstrøm and Storstrømmen (Fig. 1).

These three outlet glaciers belong to the disappearing category of marine-terminating glaciers, i.e. glaciers flowing into the ocean that possess an ice tongue (or small ice shelf) floating on the seawater. These tongues are connected to the main trunk of the glacier that is grounded over the continent, and the zone where the glacier starts to float is called the grounding line. The grounding line can move forward (or backward) if the glacier gains (loses) sufficient mass and can then expand (or retreat).

But how can a glacier gain mass? This is possible if the glacier mass balance is positive, i.e. if the glacier accumulates more ice (through snow precipitation) than is melted away (through surface and basal melting). Therefore, if surface air or oceanic temperatures increase, the glacier will likely lose mass, reducing its floating tongue and potentially making the grounding line retreat.

Recently, the 79N and Zachariae Isstrøm glaciers have lost a huge amount of ice mass via this mechanism due to rising temperatures. This suggests that this part of the ice sheet is very sensitive to climate change. Under a warmer climate, these glaciers could even lose their whole floating tongue, potentially causing irreversible consequences to the stability of the region.

How did north-east Greenland behave in the ancient past?

On millennial timescales, the north-east Greenland has had a very animated past too. Understanding the history of polar ice sheets requires a lot of effort both collecting and analysing paleoclimatic data (i.e. data archives providing information on the past evolution and climate of the ice sheet, e.g. from ice cores, marine sediments, …), which are usually very sparse, and running numerical simulations. Thanks to both disciplines, we know today that during the last glacial period (when Homo Sapiens were still in the Stone Age), the north-eastern part of the ice sheet expanded by hundreds of kilometers away from the coast into the ocean. During its maximum phase (in the Last Glacial Maximum, 21,000 years ago), this north-eastern part very likely reached the continental shelf break, the edge of shallow waters (see Fig. 1). However, very little information is available on the evolution of north-east Greenland before the Last Glacial Maximum.

One of the most interesting contribution to this gap in knowledge came less than two years ago from a group of researchers headed by Dr. Nicolaj Larsen, who ran an expedition at 79°N for new evidence. They focused their research on marine material found on moraines (eroded material deposited by the glacier). There, they collected and dated fragments of marine shells and were able to pinpoint when the moraines were formed, indicating the timing of glacier retreat. Their new data suggested that these moraines were a few thousand years older than the Last Glacial Maximum, meaning that the edge of Zachariae Isstrøm was located at least 20 km upstream of its current position at that date (Fig. 2, right).

Fig. 2: Left: Sample site at Zachariae Isstrøm [Credit: Supplementary Material of Larsen et al., 2018]. Right: Reconstruction of the North East Greenland Ice Stream grounding line distance from its present-day position for the last 45,000 years in the Marine Isotope Stage 3 (MIS-3) and Last Glacial Maximum (LGM) [Credit: I. Tabone, data from Larsen et al., 2018].

How could north-east Greenland be less extensive than today during a cold climate?

How could it be possible that these glaciers were less extensive than today, despite the cold, dry climatic conditions during the last glacial period? Well, it is a complex story! We are actually talking about a glacial time interval called Marine Isotope Stage 3 (~ 60,000-25,000 years ago), a period studded with several rapid abrupt climate events in which polar latitudes received larger incoming summer radiation than during the rest of the glacial period.

During Marine Isotope Stage 3, summer air temperatures were about 6 to 8ºC higher than during the Last Glacial Maximum (Fig 3, middle panel). This is likely due to long-term variations in incoming solar radiation associated with changes in the Earth’s orbit. Marine Isotope Stage 3 was also very dry, with low accumulation (snowfall) rates in northern Greenland (Fig 3, low panel). These warm temperatures and low accumulation could be a possible explanation for the expansion of the north-east Greenland ice sheet during Marine Isotope Stage 3 (Larsen et al., 2018). However, summer air temperatures at high latitudes were still well below 0°C during this time, so it is unlikely that they could have strongly affected ice mass loss in the region. The conclusion is: the atmosphere alone probably could not be the only climatic driver of this strong ice fluctuation at 79°N.

Fig. 3: Grounding line (GL) distance from the present-day (PD) position (a); summer temperature at 79N (b); accumulation rate at North Greenland Eemian Ice Drilling (NEEM) ice-core site [Credit: I. Tabone, data from Rassmussen et al., 2013, figure inspired from Larsen et al., 2018].

So it’s not the atmosphere… What about the ocean?

As the ocean has been recently argued to have an important role in the present-day retreat of the North East Greenland Ice Stream (see this study, this one and this one), it is reasonable to think about the ocean as a possible player in this large past fluctuation. Thanks to a 3D ice-sheet model, we performed simulations of north-east Greenland evolution in the past to assess how sensitive the ice-sheet margins were to variable oceanic conditions during the last glacial cycle. We represented these different oceanic states in the model by imposing melt at the grounding line and at the ice-shelf bases (also called submarine melt). Past submarine melt rates are inferred from past oceanic temperatures changes, because any increase in oceanic temperature results in increased submarine melting. Over long-term timescales, this means submarine melt rates were higher during Marine Isotope Stage 3 compared to during the Last Glacial Maximum.

Results of these model runs are pretty neat: with sufficiently high submarine melting along its margins, the North East Greenland Ice Stream retreats several tens of kilometres upstream from its maximum glacial position. Importantly, this suggests that increasing oceanic temperatures during Marine Isotope Stage 3 could have driven this large instability in the north-eastern ice-sheet margin during the last glacial. This is likely to have caused large reorganisations of the entire region and major ice discharge into the ocean (here is an animation showing the modelled north-east Greenland evolution during the last 45,000 years).

Fig. 4: Evolution of the north-east Greenland grounding-line (GL) distance from its present-day (PD) position simulated by our ice-sheet model. The model was run with no submarine melting (red line) and with progressively higher melting (other coloured lines). The dashed black line shows the reconstruction by Larsen et al. (2018). The three horizontal black dotted lines show the today’s NEGIS grounding-line position (0 km) and the maximum (300 km ± 50 km) reconstructed advance of the north-east Greenland during the Last Glacial Maximum according to Funder et al. (2011) [Credit: I. Tabone].

More investigation is needed!

Today we are aware that the north-east Greenland ice sheet is one of the most vulnerable regions of the ice sheet to current climate change. Figuring out its past evolution will help to understand its behaviour in a warming world, and its importance in the future stability of the entire Greenland ice sheet. However, as our study is the first attempt to look at the causes of this anomalous retreat from a modelling point of view, further work is needed and many questions are still unanswered. Was the ocean the major player in this past fluctuation? To what extent were surface air conditions also a factor? How much abrupt atmospheric warming events have influenced this margin fluctuation at smaller timescales? Further modelling work and observations at the North East Greenland Ice Stream are needed to unravel this icy riddle…

Further reading

Edited by Jenny Arthur and Clara Burgard


Ilaria Tabone is a Postdoc Researcher at the University Complutense of Madrid (Spain) in the Paleoclimatic Analysis and Modelling (PalMA) research group. She investigates the evolution of the Greenland Ice Sheet in the past glacial-interglacial cycles by working with ice-sheet models of continental scale. Her research focuses on ice-ocean and ice-atmosphere interactions. Contact Email: itabone@ucm.es

For Dummies – How do wildfires impact permafrost? [OR.. a story of ice and fire]

Fig 1: A permafrost peatland in the Northwest Territories, Canada, which was burned in 2014. Peatlands are complex, and we are just starting to understand how northern peatlands respond to fire. This picture was taken in 2015, and shows regions which remain charred a year after the fire, with the green areas representing bogs which were too wet to burn. 2014 was a record breaking year, where a total of 3.4 million hectares burned in the region! Similar large fire years have been seen in other areas of Canada, Alaska, Russia, and China in the last few decades. [Credit: Jean Holloway]

Wildfire – like the ones observed in the Northwest Territories, Canada in 2014 (Fig. 1) – is a natural part of permafrost landscapes, but fires are expected to get more frequent and severe as the climate warms. This could accelerate the degradation of permafrost, with negative consequences on the local and global scale! We have a pretty good understanding of how permafrost responds to fire today, but what should we expect as the climate warms and fire regimes change in the future?


What is permafrost anyway?

  • Permafrost is ground that is frozen for two or more consecutive years, and it typically forms in any climate where the mean annual air temperature is less than 0°C.

Fig 2: Permafrost is a mixture of ice, soil and rocks. This is a core of particularly ice-rich permafrost. [Credit: Jean Holloway]

Nerdy terminology break: when you talk about permafrost, it THAWS, it does not MELT. Melting implies phase change from solid to liquid. Permafrost isn’t just made up of ice, it also has soil and rock, which don’t melt when they go above 0°C (Fig 2). When you take a turkey breast out of the freezer it doesn’t turn into a puddle of chicken goo – it thaws! Here is a cool blog post about this issue.

Leftover Turkey Trot

Why the heck should you care about permafrost and fire?

There are three main reasons why we as a society should care about the impacts of fire on permafrost, and permafrost degradation in general. I will go into greater detail in the upcoming sections, but the take home messages are:

  1. Thawing permafrost causes ground settlement which affects local infrastructure.
  2. Post-fire changes to biogeochemistry can alter downstream water quality, which is important for local communities.
  3. Thawing permafrost releases more carbon into the atmosphere, triggering a positive-feedback loop and accelerating global climate change.

Now that I have your attention, let’s learn about some fire and ice!

How does permafrost respond to fire?

Wildfire is a natural and essential component of many permafrost landscapes, including boreal and subarctic forests, but also tundra regions. For some species in the boreal, such as black spruce (Picea mariana) and jack pine (Pinus banksiana), fire is essential because they need it in order to reproduce – they have what are called serotinous cones that open after fire and release their seeds! Fire has been a part of these permafrost landscapes for thousands of years. Changes occur immediately following the disturbance but mostly return to normal (pre-fire) levels after a few decades.

Permafrost is impacted when severe fires destroy the tree canopy and the surface organic layer (a thin layer of dead and decaying plant material, ranging from ~10-50 cm but can be much thicker!) that insulates the ground. Think of it like a blanket that keeps the heat in while you sleep, except the opposite – it keeps the ground cold. Permafrost LOVES the organic layer, because its thermal properties promote permafrost stability. For example, frozen peat has very high thermal conductivity (Fig 3). So, in the winter, it allows the cold air temperatures to penetrate deep into the ground. But… in the summer it is dries out and has low thermal conductivity, which means heat can’t get in. This helps the permafrost stay frozen!

Fig 3: Peat soil (left) and Sphagnum moss (right) favour permafrost presence due to unique thermal properties that help keep the ground cool. [Credit: Jean Holloway]

So, when fires destroy this layer it leaves the permafrost vulnerable to thaw. Further, fires destroy the tree canopy and other vegetation, which shade the ground and intercept the snow, both which protect the permafrost (Fig 4).

Fig 4: Snow trapped up in the tree canopy by coniferous trees at an unburned site near Yellowknife, Canada. This allows cold air to penetrate into the ground and protects the permafrost. [Credit: Jean Holloway]

Some other key factors that impact the permafrost following a fire include:

  • Decreased albedo (albedo is how much a surface reflects sunlight – dark charred surfaces absorb a lot of heat and make the ground warmer)
  • Changes in snow cover
  • Alterations to the surface energy balance (basically, how much energy moves in and out of the ground) and micro-climate
  • Reduction in evapotranspiration and changes in soil moisture (when there is vegetation present it moves water from the soil to the roots and up into the leaves, so when fire destroys the vegetation there is more water left in the ground)

In combination, these changes result in warmer and wetter soils, greater heat moving into the ground, and increased active layer thickness. The active layer is the top of the permafrost which freezes and thaws annually, and usually it is ~1 m deep. But after fire the active layer thickness can increase dramatically, sometimes to 3 m!

Fire changes the hydrology and biogeochemistry of permafrost landscapes

Fires can also have significant effects on the hydrology, biogeochemistry, and soil microbial communities of permafrost landscapes (for a good overview of this, check out: Tank et al., 2018). Fire changes the chemistry of the soil and water in streams and lakes. For example, we know that fire decreases soil acidity AND increases microbial activity (warmer soil temperatures after the fire = happy active microbes). Further, active layer thickening releases solutes, nutrients, and other things that were previously trapped in the frozen ground, allowing them to be transported by water. Sometimes, active layers get very thick and create thawed zones called taliks, which allow water to travel through the previously impermeable frozen ground year round! Studies have shown that aquatic ecosystems recover rapidly following fire but we don’t really know how climate warming and changing fire regimes will affect this in the future.

Lastly, fire changes the ecosystem carbon balance, because the increases in soil temperatures and active layer thickness that happen after fire make previously frozen organic matter available for decomposition by those happy microbes. The microbes eat the organic matter and release carbon into the atmosphere. This results in a positive feedback to climate change – fire thaws permafrost, releasing carbon into the atmosphere, leading to more climate change and warmer temperatures, which leads to more fire and more thawing permafrost, which releases more carbon… and so forth. This is not good! We need better regional sampling of permafrost carbon estimates to be able to predict how bad this is going to be in the future.

How does permafrost recover from fires?

In the past, permafrost in many places have been stable after fire, where changes occur immediately after fire, but return to pre-fire conditions in the next several decades (see, for example, this study: Rocha et al., 2012). This happens because the vegetation undergoes what is called succession, which basically means it regrows. So that organic layer and tree canopy which is so essential for permafrost returns to normal! Factors that determine how permafrost is impacted by fire and how it will recover include landscape position, soil type, organic layer thickness, burn severity, drainage and soil moisture conditions, snow, pre-fire permafrost and vegetation conditions – it’s complicated!! As an example, a poorly drained lowland site with a thick organic layer won’t be as vulnerable to fire as a dry high site with coarse soil.

Fire causes permafrost thaw and thermokarst development

It is important to mention that when ice-rich permafrost thaws following fire we can also get the development of what is called “thermokarst” (If you want to read more about this, see: Gibson et al., 2018). Thermokarst is pitted or irregular landscapes that are formed with ice-rich permafrost thaws and settles (Fig 5). These types of landscapes with thermokarst don’t follow the same post-fire recovery patterns, likely taking much longer to recover to pre-fire conditions (if at all… we don’t really know yet!). In addition, thermokarst changes drainage, can result in forest loss, and can impact infrastructure. We have seen this type of damage after fire (and also following general permafrost thaw) all around the globe: in Alaska, Canada, China, and Russia. In addition, thermokarst can also release large amounts of carbon. However, predictive models don’t take this into account yet – exciting research to expect here in the future!!

Fig 5: Thermokarst that developed after a wildfire at a permafrost site in the Northwest Territories, Canada. You can see the water pooling, which results in even further permafrost degradation. [Credit: Jean Holloway]

Fire, permafrost, and future climate change

So permafrost is impacted by fire, but usually it has been able to recover. HOWEVER, these patterns of permafrost recovery will likely be affected by changing fire regimes. In the Alaskan and Canadian boreal, we are currently seeing more fire than ever before (Here is one of many papers that shows this: Jain et al., 2018), particularly in the western provinces and territories. As global temperatures rise everything gets drier, and there is actually more lightening, which means larger and more severe fires. These fires typically result in more of the organic layer being removed, which leads to greater permafrost thaw. Predictive models indicate that fire in tandem with climate change, will accelerate the disappearance of permafrost. Some sites may still be able to recover, but greater warming results in longer recovery periods, if at all…

And the ability to recover might currently be overestimated: modelling suggests that permafrost in poorly drained landscapes with thick organic layers, such as peatlands, tundra, and other lowland systems, will likely be stable to fire over the long-term. BUT these landscapes are often impacted by thermokarst, and right now our models don’t have the capacity to incorporate the effects of thermokarst on the system. More work needs to be done to understand this!

Further Reading


Jean Holloway is a PhD student at the University of Ottawa, in Ottawa, Canada. Her research interests surround the impacts of fire on discontinuous permafrost in the Northwest Territories, Canada. She uses a variety of techniques to investigate this, including monitoring ground temperatures, conducting annual geophysical surveys, and applying thermal modelling to predict future change. Contact e-mail: jean.holloway77@gmail.com

 

Ice-hot news: The IPCC Special Report on the Oceans and the Cryosphere under Climate Change

Ice-hot news: The IPCC Special Report on the Oceans and the Cryosphere under Climate Change

You have probably heard the name “Intergovernmental Panel on Climate Change (IPCC)” mentioned frequently over the last few years. The IPCC is the United Nations body for assessing science related to climate change and it publishes global assessment reports on this topic every 5 to 10 years. Due to the current urgency of the global climate crisis and the need for more information by decision makers, the IPCC decided to publish several smaller more “special” reports between its fifth (published in 2013/2014) and sixth (planned for 2021/2022) assessment reports. The Special Report on the Oceans and the Cryosphere in a changing Climate (short “SROCC”) was published about a month ago. In this blog post, we will give you an overview of the take-home messages about the fate of the  cryospheric elements of our planet – those parts which are frozen!


Why is there a special report about ocean and cryosphere?

Discussions about global warming are often centered around changes in air temperature and changes in places where people live. The cryosphere and the ocean are, by contrast, remote areas without dense human population. However, climate change has a high impact on the cryosphere and oceans and this, in turn, has an effect on places where people live, one prominent example of this being land loss due to sea-level rise. Less talked about but equally impactful, is thawing permafrost, leading to high carbon release to the atmosphere, and melting Arctic sea-ice cover, enhancing Arctic Amplification, which can influence climate in mid-latitudes and globally.

The Special Report on Oceans and the Cryosphere in a changing Climate (SROCC) has the aim of highlighting the links between oceans, cryosphere and sea-level rise to improve policy makers’ understanding of these key elements and of the interdependencies between them (see Fig. 2). This is particularly critical at present, as the 25th Conference of Parties (COP25), organized by the United Nations Climate Change Convention, will be happening in around one month’s time in Santiago de Chile.

Fig. 2: Summary of the changes discussed in the IPCC Special report on the Oceans (white circles) and the Cryosphere (grey circles) under Climate Change [Credit: Box 1, Figure 1 in SROCC].

The Special Report is based on peer-reviewed literature from natural sciences, social sciences and humanities. It represents the most current scientific view on the oceans and the cryosphere. But what exactly are the conclusions of this report and why is it important? This post will guide you through the key points relevant to the cryosphere: permafrost, snow cover, glaciers and ice sheers, and sea ice!

Info box: What is an RCP scenario?

In IPCC reports, the projections for the future climate evolution are conducted using scenarios for the future greenhouse gas emissions. As we do not know how our economy, agriculture, and greenhouse gas emissions will evolve in the future, scientists have developed so-called Representative Concentration Pathways (RCP). Each RCP represents one of several possible futures in economic and agricultural development, resulting in different evolutions in atmospheric greenhouse gases. The higher the concentration of atmospheric greenhouse gases, the more of the heat radiated to space by the Earth’s surface is trapped, leading to a warming of the atmosphere. RCP2.6 represents a future where we radically cut greenhouse gas emissions after a peak in 2020,  RCP4.5 a scenario, where we cut emissions after a peak in 2040, and RCP8.5 represents a scenario in which greenhouse gas levels continue to rise.

Permafrost

Permafrost – ground, which is soil or rock frozen for more than two years in a row – contains one third of global near-surface carbon stocks, and thawing of parts of the permafrost-affected area can render this carbon more available for microorganisms, thus causing emissions of stored carbon as the greenhouse gases CO2 and CH4. This additional source of greenhouse gases could cause more surface warming, thus more permafrost thaw, thus more warming and so on (Mu et al., 2017; Sun et al., 2018a).

Because ice is solid, but water drains away, permafrost thaw can cause changes in the surface (subsidence) in Northern land areas, thus damaging infrastructure and buildings. Thaw can further cause landslides or increase rockfall rates, thus risking mountain accidents and the safety of local communities (PERMOS, 2016).

The IPCC reports that permafrost temperatures have increased by 0.29°C ± 0.12°C from 2007 to 2016 on average for polar and high mountain areas. Sparse long-term data series in heterogeneous alpine environments is the largest challenge faced when quantifying temperature trends in alpine permafrost, which makes up about 28 % of global permafrost, but estimates show a 0.19°C ± 0.05 °C warming per decade in alpine permafrost on average.

Arctic long time series are sparse, but estimates show that from 2007 to 2016, the coldest permafrost areas have warmed by 0.39 °C ± 0.15 °C, whereas the ‘warmer’ permafrost close to thaw has warmed on average by 0.2 °C ± 0.10 °C – more energy has been used for melting of ice.

Fig. 3: Left: Trend in annual average temperatures in high-mountain regions divided into geographical regions and ground material [Credit: Figure 2.5 in the SROCC. Right: Projections for global permafrost area following emission scenarios RCP 2.6, RCP4.5 and RCP8.5 [Credit: Figure 3.10 in the SROCC].

The Special Report concludes that the frequency and intensity of wildfires has increased, removing the organic topsoil and degrading permafrost faster than historically. Read more about fire in the Arctic in this post.

The amount of projected permafrost thaw by 2100 is directly related to the RCP scenario followed by humanity (see explanatory box on RCPs). Overall, permafrost occurrence is projected to be reduced by 8 to 40% for the low-emission scenario RCP 2.6 and 49 to 89 % for the high-emission scenario RCP8.5. While the Arctic permafrost within the first three meters of the surface is projected to have decreased by 2 to 66 % in RCP2.6 and by 30 to 99 % in RCP8.5, the permafrost area of the Tibetan plateau is projected to decrease by 22 % in 2100 under RCP2.6 by 64 % in RCP8.5. In conclusion, if we follow the high-emission scenario RCP8.5, tens to hundreds of gigatons of carbon will be released to the atmosphere by 2100.

The reason for the large intervals of projections are mainly that “translating” air temperature to a ground temperature, hence permafrost presence or absence, is a difficult task due to the impact of surface properties, such as snow depth and vegetation, and ground properties, such as ground ice and carbon content, on energy propagation into and out of the soil surface. IPCC projections are based on a comparison of many models for a more robust estimate – and they simulate precipitation and vegetation patterns differently, thus impacting the simulated permafrost area.

For communities in permafrost regions, for whom 70 % of local infrastructure will be at risk of damage due to permafrost thaw by 2050, short- and long term adaptation and mitigation measures need to complement each other. Measures need to be developed with the use of scientific and local knowledge from Northern communities, and local ecosystem monitoring can be a key data source for this.

You can find full details about permafrost changes in the SROCC Section 2.2.4 and 3.4.

Snow cover

Snow cover is a critical element of the cryosphere, firstly because it absorbs surface runoff from glacier and ice sheet surfaces, and secondly because it has a high albedo, meaning that it reflects more incoming solar radiation than the darker surfaces they cover, such as ground, trees, and ice. Snow covers the terrestrial Arctic (north of 60 ºN) for up to nine months each year, and influences the surface energy budget (through its reflectivity), freshwater budget (through water storage and release), ground thermal regime (through insulation) and ecosystem interactions.

Since the beginning of the satellite era in 1981, spring snow cover extent has declined by over 13% per decade. Snow cover duration has also declined, both in spring (by up to 3.9 days per decade in certain regions) and autumn (by up to 1.4 days per decade in certain regions). Maximum snow depth has been declining, though trends are uncertain because of sparse observations and large spatial variability. These reductions are very likely driven by surface temperature rise in the Arctic. Warming-induced snow cover reduction creates a self-reinforcing cycle where the surface is darker than when it is snow covered and therefore reflects less incoming solar radiation, leading to a warmer surface and even more melting.

Fig. 4: Observed changes in June snow cover extent anomalies, and projected change in June snow cover under low (RCP2.6, blue), medium (RCP4.5) and high (RCP8.5) greenhouse gas emissions scenarios [Credit: Figure 3.10 in the SROCC]

Arctic snow cover duration is projected to decrease (later autumn onset in and earlier spring melting), as a result of continued Arctic-wide warming. However, trends differ between model scenarios. For example, Arctic snow cover duration stabilizes by the end of the century under RCP4.5, whereas under RCP8.5 it declines to -25% (compared to the period 1986 – 2005). In Greenland, snow cover is projected to retreat to higher, flatter areas of the ice sheet. The rate at which this could occur is currently not well reproduced in climate models, mostly due to uncertainty in the way snow processes are included in these models.

Snow cover reductions are already being felt negatively in the Arctic, especially by communities reliant on snow cover for food sources, drinking water, and livelihoods, such as reindeer herding.

You can find full details of the estimates and predictions for ice sheets in SROCC, section 3.4 and in FAQ 3.1.

Sea ice

Sea ice is frozen sea water and displaces as much water as is produced when it melts. Melting sea ice therefore does not play a role for sea-level rise. It is, however, an important element for climate as it reflects large amounts of incoming sunlight back to space (similar to snow); it provides habitat for bacteria, plants and animals below, in, and above the ice; and it influences weather in mid-latitudes, the region between roughly 30 and 60 degrees of latitude, home to over 50% of the human population.

In the context of climate change, sea ice is also an especially good element of the cryosphere  to illustrate the effects of global warming. The Arctic September sea-ice area is directly linked to cumulative CO2 emissions (see this previous post) and therefore changes in sea ice directly reflect, in a very visible way, the path of climate change.

Fig. 5: Observed and modelled historical changes in the Arctic September sea ice extent since 1950 and projected future changes under low (RCP2.6, blue) and high (RCP8.5, red) greenhouse gas emissions scenarios [Credit: Figure SPM1 in the SROCC].

The sea-ice review in SROCC is similar to the Special Report on 1.5°C published end of 2018 (see this previous post). Arctic sea-ice loss was observed in both area and thickness in the past decades and is projected to continue through mid-century. The rate of the loss depends on the amount of warming. In the Antarctic, there is low confidence in the projected sea-ice evolution.

More details about the sea-ice evolution under climate change can be found in Section 3.2 of SROCC.

Polar ice sheets and glaciers

The two polar ice sheets and the world’s glaciers are a fundamental element of the world’s cryosphere. Glaciers and ice sheets cover about 10% of the Earth’s surface and contain around 70% of the world’s fresh water. They regulate the global climate system by interacting with the ocean and atmosphere and provide valuable fresh water resources to much of our planet.

The overwhelming consensus is that the polar regions are losing ice, and that the rate of ice loss has increased. In Greenland, ice loss is occurring through a combination of enhanced surface melting and runoff, and increasing dynamic thinning (ice loss as a result of accelerated ice flow). Greenland has lost around 247 Gt of ice every year between 2012 and 2016. In Antarctica, incursion of warm ocean waters is driving rapid, accelerating ice loss from the West Antarctic Ice Sheet. The mass loss signal from the West Antarctic Ice Sheet (-122 ± 10 Gt yr -1 from 2003 – 2013) is dominated by the increasing ice loss from outlet glaciers in the Amundsen Sea Embayment. On the Antarctic Peninsula, the majority of marine-terminating outlet glaciers are retreating. The pattern of change on the East Antarctic Ice Sheet is more ambiguous and complex, with regional gains and losses and no clear overall mass trend. Increased surface melt intensity and duration on both ice sheets has led to a self-reinforcing cycle, where, like for snow, the melt of the ice sheets uncovers dark surfaces, which absorb more incoming solar radiation than ice, and therefore heat up and lead to further melt. This reduces the capacity of snow and firn to store runoff.

Fig. 6: Ice sheet from above [Credit: Matt Palmer on Unsplash].

Continued ice loss from Greenland and Antarctica is projected to alter the polar regions. While glaciers have been the dominant contributor to global sea-level rise, this will be replaced by ice sheets as they continue to lose mass into and beyond the 21st century.

However, a number of processes that could potentially lead to rapid ice loss in Antarctica are poorly understood, particularly their timescale and future rate. Therefore, large uncertainty remains in projecting future changes to these polar regions, especially beyond this century. Portions of Antarctica resting on bedrock below sea level could be vulnerable to self-sustaining feedbacks such as the Marine Ice Sheet Instability (MISI, see this previous post). It is uncertain from current observational data whether irreversible retreat is underway.

Ice shelves and their interactions with surface meltwater will play a key role in the response of Antarctica to future warming. Freshwater input to the oceans, from icebergs and ice shelves melting, is freshening global water mass currents and circulation, and this may be accelerating. This could inhibit the formation of important oceanic water masses such as the Atlantic Meridional Overturning Circulation and Antarctic Bottom Water. Surface runoff and basal melting from both ice sheets are enhancing the input of dissolved nutrients into fjords and the ocean such as iron, which has been linked to enhanced primary productivity.

The report stresses that low emissions scenarios will potentially limit the rate and magnitude of future changes to the cryosphere. For example, polar glaciers are projected to lose much less mass between 2015 and 2100 under RCP 2.6 compared with RCP 8.5. Ice loss from polar ice sheets and glaciers presents a growing challenge to polar governance, and requires more coordinated efforts to build long-term resilience. In the Arctic, mitigating the effects of climate change can benefit strongly from community-led adaptation.

You can find full details of the estimates and predictions for ice sheets in SROCC, section 3.3 and in FAQ 3.1.

In summary

As a summary of our summary, and if you are interested in the ocean topics as well, have a look at this useful infographic by John Lang!

Here, you can see the most important points for the cryosphere (click on the link below or the picture to have a larger view):

Fig. 7: Parts of a summarizing infographic about SROCC [Credit: John Lang].

Further reading

Edited by Emma Smith


Laura Helene Rasmussen is a Danish permafrost scientist working at the Center for Permafrost, University of Copenhagen. She has spent many seasons in Greenland, working with the Greenland Ecosystem Monitoring Programme and is interested in Arctic soils as an ecosystem component, their climate sensitivity, functioning and simply understanding what goes on below.

 

 

Clara Burgard is a postdoctoral researcher at the Max Planck Institute for Meteorology in Hamburg. She investigates new methods to compare sea-ice as simulated by climate models, sea-ice as observed by satellites, and real sea ice. She tweets as @climate_clara.

 

 

 

Jenny Arthur is a PhD student at Durham University, UK. She investigates supraglacial lakes in Antarctica using remote sensing, and is especially interested in their seasonal evolution and interaction with ice dynamics. She tweets as @AntarcticJenny.

Cryo-adventures – Behind the scenes of cryo-fieldwork

Cryo-adventures – Behind the scenes of cryo-fieldwork

As the Arctic is warming faster than the global average, Arctic glaciers are rapidly melting. My research is about the fate of glacial organic carbon when the ice containing it melts. To investigate these processes, I travelled to several glaciers, an activity full of challenges… and rewards!


My research

Glacier ice covers about 11% of Earth’s land surface, and contains within it a globally significant reservoir of easily degradable carbon, known as glacial organic carbon (GOC). GOC is found within glacier ice, subglacial sediments, as well as the sediments and soils located close to the ice front of a glacier.

Much of the GOC is situated within the Arctic, a region that is already experiencing the most rapid and largest amount of warming on Earth. As the organic material melts out of the ice and degrades, it releases greenhouse gases into the atmosphere. This process creates a self-reinforcing cycle, leading to a further warming of the Arctic region, and therefore more organic material melting out.

There has been little research on the release of GOC so far and as with any new area of research, more studies are needed! Especially, we need measurements from several locations to try and reduce the uncertainties in our knowledge of the amount of GOC. This is where I come in! The aim of my research is to clarify the role of GOC as a carbon source in the fast-changing Arctic region by comparing three contrasting catchments all currently losing their glaciers: Vatnajökull ice cap in Iceland, Tarfala in Sweden, and Zackenberg in Greenland. This topic gives me the opportunity to travel to several amazing locations, but also means the challenges of Arctic fieldwork are multiplied!

Challenge 1: Permits and Visas

Every country I have visited during my PhD has its own policy when it comes to obtaining permits to access sites, collect and export samples. While the process can be quite bureaucratic and slow, the key is to start the application process well ahead of the deadline. So far, this has worked for me. However, as a Kazakhstan citizen, I also require a visa to travel to most of these countries. Even though the same approach of giving myself a head start on the application process has worked, when there are back-to-back field campaigns in two different countries, it can get stressful and a little complicated. Luckily, for me, it has always worked out!

Challenge 2: Logistics

Booking a flight and accommodation, and hiring a car online is a common practice these days whether you are travelling with work or going on a holiday. However, when I hear the word logistics the first thing that comes to mind is “how am I going to ship my equipment and, more importantly, how am I bringing back my precious samples?” I’ve tried a variety of ways: shipping the equipment beforehand and shipping it back, arranging postal delivery of my samples, as well as taking extra luggage on the plane with me – double wrapping glassware and making sure I stick on several “fragile” labels to good measure. Taking the equipment, and especially my samples, on the plane seems a better option as it gives you peace of mind – I “knew” where my bags are and was “sure” they would arrive at the final destination with me. On top of it, it is actually kinder on your budget to pay for couple extra bags rather than shipping. The one downside was that this way I had always had a couple of broken glass bottles and spilled samples. But hey, that is why you collect samples in triplicates 😉

Figure 2: Tarfala valley, Sweden 2018 [Credit: Saule Akhmetkaliyeva].

Challenge 3: Actually being in the field!

After months of planning, obtaining permits, visas, ordering equipment and consumables, packing and shipping, we would finally arrive in the field. I will not surprise anyone if I said that working in the Arctic even in the summer gets cold, windy and wet. On top of that, we would have to carry around heavy backpacks while trying to keep our footing on slippery lichen-covered rocks. Some sites, like the Vatnajökull ice cap in Iceland, are easy to access, Tarfala valley in Sweden requires a bit more effort to reach, while it takes a couple days of camping to get to a glacier in Zackenberg, Greenland. That said, if you love what you do, you don’t notice the effort. The Arctic has the most amazing, beautiful and unique scenery.

Challenge 4: Evenings

The “fun” part of research when working with water samples was usually the evenings. In order to reduce the amount of filtrate that needed bringing back, I would spend my evenings filtering water samples collected earlier in the day. Thankfully, I did not have to do it by hand, but instead using extremely loud electric pumps – they got the job done but scared away the rest of the field team in process!

Figure 3: Filtering station set up at the kitchen of a field accommodation, Iceland 2018 [Credit: Saule Akhmetkaliyeva].

In summary: a hugely rewarding experience!

Fieldwork can have many challenges associated with it. Planning ahead, and being well-equipped and well-prepared therefore makes your life so much easier! Most importantly, as long as you enjoy being in the field, all the challenges are worth it — especially if you have likeminded people for company. Just make sure you have enough energy, are well rested, and take breaks if you are tired. After all, it is a great opportunity to experience a unique and amazing environment, see the changes happening to our home planet with your own eyes, whilst making a positive difference…

Figure 4: Disturbingly warm August at in beautiful Zackenberg, Greenland 2019 [Credit: Saule Akhmetkaliyeva].

Edited by Andy Smedley and Clara Burgard


Saule Akhmetkaliyeva is a PhD student at MMU (Manchester Metropolitan University), UK. She studies organic carbon transport from receding glaciers in northern latitudes. Saule is also part of the UK Polar Network committee. Contact email: saule.akhmetkaliyeva@stu.mmu.ac.uk.

Did you know? – Proglacial lakes accelerate glacier retreat!

Hooker glacier and its proglacial lake, Aoraki/Mt Cook National Park. [Credit: Jenna L. Sutherland]

In a global context, New Zealand’s small mountain glaciers often get overlooked and yet they are a beautiful part of New Zealand’s landscape. They are the water towers for the South Island and an essential part of its tourism, thanks to a few undeniable heroes (Frans Josef and Fox Glaciers), but sadly, they may not be as prominent in the future. In this post we review the state of modern glaciation in New Zealand, explain why glacier-lake interactions are important and why we need to turn to the past for answers.


Glaciers in New Zealand are losing mass…

New Zealand is home to over 3000 glaciers. However, their mass is quickly declining. New Zealand has one of the oldest and most continuous records of annual ice volume, provided by the End of Summer Snowline Survey, and pioneered by the late Trevor Chinn. Now undertaken by NIWA, aerial surveys on 51 index glaciers have been carried out every year for more than 4 decades (records began in 1977). The surveys document the snowline on the glaciers at the end of every summer, which give us a timeline of glacier-climate interaction. Glacier snowlines, also known as Equilibrium Line Altitudes (ELAs), provide a direct measurement of a glaciers health. They record how much of the previous winter’s snow remains at the end of summer, contributing to long-term glacier ice accumulation. The higher the ELA, the less winter snow remaining, indicating the glacier has shrunk. If the ELA is lower, a larger amount of winter snow remains and the glacier has increased in size. An almost continuous trend from this 40 year archive reveals that glaciers in New Zealand are retreating rapidly – they are getting shorter and losing mass. The significant retreat of Southern Alps glaciers has accelerated over the last decade and recent studies have found that a third of total ice volume has been lost since records began.

…leading to the development of proglacial lakes

The formation of proglacial lakes in mountainous regions, specifically those in contact with the ice margin, is one of the consequences of glacier recession. As a glacier margin retreats, meltwater is impounded in the topographic low between the ice front and the abandoned moraine ridges. The increasing number and size of proglacial lakes is one of the most visually obvious effects of present deglaciation in New Zealand. Most of the existing ice-contact lakes in New Zealand formed when glaciers began to recede from large moraine ridges constructed during the Little Ice Age (LIA), about 150 years ago.

Proglacial lakes currently represent 38 % of the total number of all lakes in New Zealand, and over a third of the country’s perennial ice is contained within lake-calving glaciers. Back in the early 1970s, the Tasman Lake did not exist and the glacier terminated against its outwash sediments. Today, just 40 years later, it now terminates in a large proglacial lake that is more than 8 km long, and over 200 m deep (Figure 1). Since the lake formed, the Tasman Glacier has retreated at an average of 180 m per year and is now in a state of rapid recession.

Figure 1. The Tasman Glacier and its associated proglacial lake. Don’t be fooled by how thin the glacier terminus looks from this perspective, the ice cliff is 50 m tall. The lower part of the glacier is heavily debris-covered but you can see the exposed glacier surface at the head of the valley [credit: Jenna L. Sutherland]

Lake formation is strongly linked to glacier dynamics (Figure 2). The depth of water at the ice margin determines:

  • the distance underneath the glacier that water can travel
  • the rate at which ice calves (or breaks off) from the terminus

Together, these factors increase the speed of ice flow and increase mass loss from the glacier system. The relatively warmer water of the lake compared to the glacier ice also causes thermally-induced melting. An ice-marginal lake can therefore cause glacier margins to fluctuate back and forth, which in turn can cause the speed of the glacier and its mass balance to become partially separated from the climatic signal.

Figure 2. Interactions between the glacier and its proglacial lake. Forces acting upon the glacier are shown in italicised text and with black arrows. The processes between the lake and the glacier are in black text and grey dashed lines [Credit: Jonathan Carrivick, modified from Carrivick and Tweed, 2013]

New Zealand is witnessing unprecedented glacier recession together with lake expansion. It is easy to link one to the other, but the relationship between ice, the development of the lakes, and climate are much more complicated than this. The shift from a land-terminating to a lake-terminating glacier is a defining point in deglaciating environments. This transition represents a threshold and/or tipping point that is critical for the future evolution of the glacier and therefore crucial for us to understand.  Could such glaciers become unstable and catastrophically collapse? Has this happened before? Where and what is this threshold? The current state of knowledge in New Zealand lies in monitoring temporal and spatial evolution of both glaciers and their proglacial lakes. Despite the remarkable record, the short duration of observations in New Zealand (just over 40 years) means that it is difficult to differentiate between natural cycles and occurrences, and dynamic behaviour that is beyond the norm. The answer to such questions lies in turning to the palaeo-record to find out how the Southern Alps ice field has behaved over the last few thousand years or more. It is vital to determine what thresholds control glacier-lake behaviour, and whether these have been crossed in the past. By gaining a deeper understanding of past processes, rates of change, thinning and retreat, as well as previous temperatures and environmental conditions, we will be better placed to understand how the Southern Alps could behave in the future.

Using the past to better understand the future….

The Quaternary record in New Zealand bears witness to the existence of proglacial lakes associated with retreat since the Last Glacial Maximum (LGM; the period between 21,000 and 18,000 years ago). During the LGM, the ice extent and volume was much larger; outlet glaciers advanced beyond the present coastline along the west coast of the South Island (Figure 3). Just like we see in the modern day, the glaciers receded when temperatures began to warm and meltwater ponded, forming large and deep proglacial lakes in contact with the ice margin. Past glacier behaviour in New Zealand has been derived from mapping and dating former ice extents. The maximum extent of ice during previous glaciations is now well constrained, allowing us to determine the speed of glacier recession and thinning. A study has shown that rapid ice recession in the first few millennia saw glacier trunks thin by at least several hundred metres, with implied terminal recession by as much of 40% of the overall glacier length.

Figure 3. The South Island of New Zealand with modern-day glaciers mapped in white and LGM ice extent in light grey. Present day lakes (blue) would have once been in contact with retreating ice margins [Credit: Sutherland et al., 2019]

It has been suggested that the retreat of glaciers in the Southern Alps, immediately after the LGM, was relatively rapid not only because of a warming climate, but also because of the widespread formation of large proglacial lakes accelerating recession. However, despite knowing that large proglacial lakes existed, we have no understanding as to what effect they had on glacier retreat and how much influence these proglacial lakes had on glacier dynamics in combination with climatic warming. The interactions between proglacial lakes and glacier dynamics have not yet been quantified. This is largely a consequence of poor accessibility to modern glacier-lake margins but also because proglacial lakes are currently ignored in ice sheet models (Figure 4). They are treated as an entirely separate component, or, as is more often the case, not at all.

Figure 4. Main components of most ice sheet models (blue), often coupled to other models (green), e.g. ocean and atmosphere models. Note the absence of proglacial lakes as a component of the ice sheet model despite their importance in influencing glacier dynamics [Credit: Jenna. L Sutherland]

…But not without some computer modelling too!

Owing to numerous studies that have dated the recession of ice since 18,000 yrs ago we have a pretty good idea that glacier recession was fast. However, as a concern for the future, what we are more interested in is constraining previous ice volumes and, more specifically, the mechanisms of loss. As well as rates of change, we also need to understand processes of change and how the ice evolved through time. In order to examine and better understand the external (or internal, as the case may be) forcing that drove this rapid recession, we need to resort to relating glacier and climatic changes in numerical ice sheet or glacier simulations.

The physics that govern a glaciers mass balance (the difference between snow gain and snow melt) as well as ice flow are complex. The equations depend on ice thickness, speed, ice and air temperature, elevation, as well as many other factors. Fortunately, these relationships are reasonably well understood and provide the basis of many numerical ice sheet models. We then feed the model with input data, such as topography and past climate, to drive a numerical ice sheet simulation. This enables us to investigate detailed mechanisms driving ice sheet change, such as those between a glacier and its lake and we can become confident in such models when they provide a good fit to the geological record (what we see on the earth’s surface).

The future

Understanding the formation and evolution of proglacial lakes and their outlet glaciers through time can provide insights into the behaviour of glaciers and ice sheets to help us anticipate some of the impacts of present and future deglaciation. Although my research is concerned with just one small valley glacier in a specific region, it is a small step towards a wider understanding of the glacier-lake interaction phenomenon. Of course, every proglacial lake is different, just as every mountain glacier is, but if we can get a handle on what effects a lake had on its glacier in the past, the importance of proglacial lakes might be realised for other regions and more seriously considered when it comes to interpreting glacier response to climatic change.

Further Reading

Edited by Andy Emery


Jenna Sutherland is a final year PhD student in the Department of Geography at the University of Leeds, UK. Her research is focused on the interaction of proglacial lakes and their outlet glaciers during the Last Glacial Maximum in New Zealand, specifically by simulating the presence of proglacial lakes in a numerical ice sheet model and relating these experiments to the sediment-landform record. Her broader interests lie in palaeo-glacial environments. She tweets from @Jennalo13

 

 

 

Cryo-Comm – Degrading Terrains

Cryo-Comm – Degrading Terrains

 
Beneath dusted peaks of mountain dew
A dense and rigid backcloth skulks,
Worn down and compacted with
Fractured decades of aged powder;
Trodden into rocky outcrops
To lie barrenly against
This frozen, ancient soil.
Subtle shifts of these forgotten rocks
Ripple across subterranean sediments,
Dislodging once-stable foundations
That now cascade like an ocean;
Echoing across the fragile firmament
To loudly denounce their buried past.
Beneath the jutting shadows
Of glaring, metallic stations
We bore artificial holes,
Treading carefully
As we silently caress exposed skin;
Mapping the resistance to our touch
Like goose bumps
Rising to the surface
On a withered, sun-kissed limb.
Charting out these imperfections
Reveals the unevenness
Of our approach,
As broken consequences
Reverberate beneath our feet;
An unheard shot across the bow.

This poem is inspired by recent research, which has found that there has been a clear degradation in mountain permafrost across the central Alps over the past two decades.

Permafrost is permanently frozen ground, consisting of rock or soil that has remained at or below 0ºC for at least two years. In Europe, Arctic permafrost is found only in the northernmost parts of Scandinavia, meaning that mountain permafrost is the dominating permafrost across the continent. This permafrost influences the evolution of mountain landscapes and can severely affect both human infrastructure and safety, with permafrost warming (or thawing) affecting the potential for natural hazards, such as rock falls. Mountain permafrost is also sensitive to climate change and has been affected by a significant warming trend across the European Alps over the last two decades. However, as this permafrost occurs across a large variety of very different locations, any warming trends are far from uniform, and in order to better understand these changes more accurate monitoring is required.

The researchers in this study made use of Electrical Resistivity Tomography (or ERT), a technique which involves inducing a current in the ground, and then measuring the extent to which the flow of this current is resisted (see this previous post). Any resistivity will depend on what the subsurface structure looks like, and it can be used to map geologic variations such as fracture zones, variations in soil structure, and the presence of permafrost. By using long-term ERT monitoring across a network of permanent sites in the central Alps, this research has demonstrated that there has been a noticeable degradation in mountain permafrost over the past 19 years across this region. The researchers have also demonstrated that a degradation is detectable across shorter timescales, a finding which is significant for better understanding the impacts of climate change across the region.

Further reading

The poem and blog post was written by Dr Sam Illingworth, and also features on his website here.

Edited by Jenny Turton


Dr Sam Illingworth is a senior lecturer in science communication at Manchester Metropolitan University, UK. His research focuses on how science can be used to empower society through creative tools and products. To read more of Sam’s poetry and blogs, and to listen to more podcasts, visit https://www.samillingworth.com/. He tweets from @samillingworth.

Cryo-Adventures – The Glacial Isostatic Adjustment (GIA) Training School: Personal and Virtual Attendance

Group photo in front of Lantmäteriet. [Photo courtesy of Daniel Vallin (Lantmäteriet)]

The 2019 Glacial Isostatic Adjustment (GIA) Training School was hosted by Lantmäteriet (the Swedish Mapping, Cadastral, and Land Registration Authority) in Gävle, Sweden from 26 – 30 August. GIA is the response of the solid Earth to past and present-day changes of glaciers and ice sheets. Research interests in GIA span the geosciences: from regional planning applications (reclamation/flooding of land due to uplift/subsidence) to constraining past ice sheet history. For this blog, two attendees interviewed lecturers and participants to summarise the five-day training school.


From over 160 applicants, 41 students and early-career researchers from 28 countries (on 6 continents!) were selected to attend the school. Instruction included a mixture of lectures and practical modeling exercises – with ample time for discussions over coffee (or, Fika). An interesting aspect of the training school was that all lectures were live-streamed. Up to 60 people were tuned-in at any given time, and there have been more than 500 individual views of the online content.

“The participants at the 2019 GIA training school were amazing – they came from a wide range of scientific, geographic, and cultural backgrounds, and they threw themselves into the task of extracting as much information as possible from the lecturers and other participants!” said Dr. Pippa Whitehouse, Associate Professor of Geography at Durham University and one of the organizers of the Training School. “In fact, [the students’] input was vital to shaping the content of the entire training school: at the start of the week we challenged them to come up with a series of questions they wanted us to answer, and I think we just about covered everything by the end of the week.”

The lectures and exercises covered a wide range of topics including: History of Land Uplift Research (Martin Ekman), Introduction to GIA (Glenn Milne and Erik Ivins), GIA Modeling (Giorgio Spada), Geodetic GIA Observations (Tonie Van Dam), Sea-level Change (Riccardo Riva), GIA-triggered Earthquakes (Rebekka Steffen), Ice Sheet Modeling (Frank Pattyn), Continental Record of Ice Sheet and Relative Sea Level History (Mike Bentley), Seafloor Record of Ice Sheet History (Julia Wellner), Coupled GIA Modeling and Data-Model Comparison (Pippa Whitehouse), Antarctic Earth Structure and Geologic Record (Terry Wilson), Antarctica Earth Structure and Rheology from Seismology (Doug Wiens), and 3D GIA Modelling (Wouter van der Wal).

Modeling exercises utilized the forth-coming SELEN4 (SealEveL EquatioN solver – preprint available here) by Giorgio Spada and Daniele Melini, and f.ETISh (Fast Elementary Thermomechanical Ice Sheet Model) by Frank Pattyn. A break from the classroom came in the form of a day-long field trip to ancient, uplifted shorelines from the end of the last ice age that now sit 500m above sea level, modern beaches (where the effects of isostatic rebound can be viewed), an enormous esker (a long, winding ridge of sediment transported by meltwater), and an equally impressive 6m-tall glacial erratic (a large, glacially-transported boulder).

Holger Steffen showing students (and lecturers) how GIA has forced the city of Gävle to relocate their harbor, one of the largest in Sweden. [Photo by Peter Matheny (OSU)].

 “This GIA training school really opened my eyes to the diversity of methods that are being employed to approach problems related to GIA,” said Jennifer Taylor, Ph.D. student in the Structure, Tectonics, and Metamorphic Petrology group at Department of Earth and Environmental Sciences, University of Minnesota. Jennifer attended the Training School in person. She was impressed by the breadth of earth science disciplines represented at the course, and the variety of datasets and modeling methods employed in the practical component. “As a researcher who typically works on million-year timescales,” she added, “it was fascinating to visit a region where people have been living with the dramatic results of rapid uplift throughout recorded human history.” Sweden, as well as other regions of Scandinavia, continue to experience significant effects of glacial isostatic rebound, with uplift rates on the order of several mm per year.

Dr. Deirdre Ryan, a postdoc at the University of Bremen’s Center for Marine Environmental Sciences (MARUM), attended the Training School virtually. While Dr. Ryan enjoyed the lectures and was glad for the opportunity to attend virtually, the inability for virtual attendees to participate in the practical component of the course with instructor supervision meant that they missed out on some of the most useful sessions of the week. “However, I think this is something that can be addressed,” she said. “I’m really excited to see that the virtual conference experience can be as fulfilling as in-person attendance without the requirement of travel and can really serve to reduce science’s carbon footprint.”

Financial support for the Training School was contributed by the National Science Foundation (NSF) through the Antarctic (ANET) component of the Polar Earth Observing Network (POLENET) project, the Scientific Committee on Antarctic Research (SCAR) through the Solid Earth Response and influence on Cryosphere Evolution (SERCE) program, the International Association of Cryospheric Sciences (IACS), the European Geosciences Union (EGU), and DTU Space.

The conference organizers were Stephanie Konfal (Ohio State University), Terry Wilson (Ohio State University), Rebekka Steffen (Lantmäteriet), Martin Lidberg (Lantmäteriet), Pippa Whitehouse (Durham University), and Holger Steffen (Lantmäteriet).

This was the fourth such training school, which has been alternatively hosted by Lantmäteriet and the Ohio State University in 2009, 2011, and 2015. All lectures from the School were recorded and are freely available on the POLENET’s website.

Further reading

Edited by Jenny Turton


 

Libby Ives is a PhD candidate in the Department of Geosciences at the University of Wisconsin-Milwaukee. She studies the sedimentary records left behind by glaciers both in the Pleistocene and in the rock record, with a special focus on the Late Paleozoic Ice Age. You can find her on twitter @glaciogeoLives

 

 

 

Peter Matheny is a PhD student in Geodetic Sciences at the Ohio State University, and is currently working with the POLENET project. When not taking classes, he works on improving the speed at which we can process large networks of GPS stations to realise global reference frames.

 

 

Cryo-Comm – Capturing Ice

Cryo-Comm – Capturing Ice

In this week’s blogpost, author, editor, artist, and outreach expert Marlo Garnsworthy gives some insights into her recent trip to Iceberg Alley, gives you some tips on how to communicate icy science, and shows us her inspirational artwork.


If you’re reading this, ice may be on your mind. Ice is surely on mine.

During my day job as a creative and editor, I dip frequently into Twitter for the latest cryosphere news. Memories of the Antarctic rumble like the thrusters of the research vessels I’ve called home: constant, comforting, and rising to a roar when I need stabilizing. Thoughts of polar science keep me steady and on course.

You may think scientists and creatives are very different. In fact, in the creative world, as in science, success comes with years spent developing wide-ranging technical and communication skills, less-than-stellar pay, so many rejections, and hard-won moments of joy. Both worlds require resiliency, a good attitude, and stamina. Incidentally, these experiences forge the soft skills we need for remote expeditions—we’re tough, don’t sweat the small stuff, and play nicely.

 

Going South

I first went south in 2017. I was invited by paleoceanographer Rebecca Robinson to sail on SNOWBIRDS Transect, studying diatoms and diatomaceous ooze, from McMurdo Station through the Southern Ocean. Seeing polar ice—from great grinding glaciers through the window of our Hercules LC-130, to the mosaic of melting summer sea ice in the Ross Sea, to massive icebergs drifting by—was transformative. I was in love with polar ice and with my Outreach role. I had to return.

So, I painted a LOT of polar scenes. I networked via social media and APECS workshops. I learned all I could about ice. I teamed up with my brilliant collaborator Kevin Pluck to form PixelMoversAndMakers.com.

 

And it all paid off.

I was invited to sail as Onboard Outreach Officer on the JOIDES Resolution, a drilling ship for the International Ocean Drilling Program. Expedition 382—Iceberg Alley took us to the iceberg-strewn Scotia Sea, where we cored millions of years of sediment. It will allow our team, led by Mike Weber and Maureen Raymo, to reconstruct past melting of the Antarctic Ice Sheet.

Of course, melting.

As I’ve gained more intimate knowledge of what is happening to our polar ice, making lasting changes to how I live has become my only moral choice. Not doing all I can to inform others has become unconscionable. I continue my work to connect a wide audience to the beauty and plight of our polar ice, always hoping I will return. Yet equally important to me is helping polar researchers better communicate their work.

 

Bringing the Poles to the People

We’re lucky that our science involves places of breathtaking beauty and harshness that most can only dream of seeing in person. It’s not difficult to engage people in the adventure. But conveying polar science comes with unique challenges because the subject of our work is so remote.

As an artist, I think, how can I show the subtle shifts in color, contrast, and texture of icy landscapes? The swiftly changing light, the sudden snow squalls, and the roaring of wind and waves—in a still image? The expanse of space and time in something that will fit on page or screen?

As a storyteller, how do I describe the sounds of a ship’s hull as it breaks sea ice? How it feels to live for months on a heaving surface? The thrill as icebergs pass by our vulnerable ship? The delight of breaching humpbacks and circling penguins? The boredom of eating cabbage at every meal? The bonds that form and the emotional costs of being far from home for months?

As a science communicator, I think, what do I want to say? What do I need to convey? Who is my audience? How do I show our scientific objectives in terms they can understand? How do I make grueling hours of lab- and fieldwork exciting and accessible? How can I most effectively use social media? How can I best speak to a crowd? How can I expand our audience?

Above all, how can I show why it all matters?

The public is becoming more aware of polar melting. But there’s a gaping crevasse between hearing something and really internalizing it. There’s a gulf between knowledge and action. Such leaps in consciousness and behavior can happen suddenly like an iceberg calving; more often, they happen as gradually as a glacier flows.

Ice shelf, ocean and sky [Credit: Marlo Garnsworthy].

Telling a Story

Ultimately, it boils down to this: What can we make people feel? I believe effective science emotion turns facts (data) into “truth” (emotion) and that storytelling is our most powerful tool.

All good stories have a beginning, a middle, a climax, and a resolution. When I tell polar stories, I often aim to take people on this journey:

Beginning: Excitement & Wonder

Come on a faraway adventure: Glaciers! Icebergs! Vast icy vistas! Wild storms and massive seas… PENGUINS!

Middle: Interest & Awe

Whoa. That’s a WHOLE lot of ice. Here’s how we study it. Here’s why we study it.

Climax: Anxiety

Here’s how it feels. Yes, it’s melting. It might be far away, but it’s coming to a coastline near you…

Resolution: Hope & Motivation

But it’s not too late. There’s something we can do. Let’s get going! And…

PENGUINS!!!

(Always remember to include humor.)

What story will you tell?

 

Ice & Fire

On Wednesday 25th of September, the IPCC Special Report on the Ocean & Cryosphere in a Changing Climate (SROCC) was released. It’s unlikely to leave us feeling warm and fuzzy. But please let it fire up your passion to creatively share your science.

What skills can you offer? Do you enjoy photography? Making videos? Can you write a funny limerick or poignant haiku? Are you skilled with numbers or writing code? Are you good at building structures? At telling a story? At playing a musical instrument? At organizing things or people? Are you a social media whiz? (If not, it’s time to become one.) Your unique skills, whatever they may be, are waiting to be harnessed for creative sci-comm.

Speak simply. Speak the truth. Above all, speak your truth. Don’t be afraid to let your emotional connection to your work and polar regions show. And amplify others’ Outreach efforts, too. Together, we’re on the vanguard of this battle for awareness and action.

The interesting life found within the Antarctic inspires some of Marlo’s artwork [Credit: Marlo Garnsworthy].

Further links

  • SNOWBIRDS Transect website
  • Pixel Movers and Makers website
  • Iceberg of Antarctica book (free download)
  • Iceberg Alley and Subantarctic Ice and Ocean Dynamics project website
  • Marlo’s website

Edited by Jenny Turton


Marlo Garnsworthy is the author/illustrator of “Iceberg of Antarctica” (available as a free download) and several other books and is seeking her next polar adventure. Find her at www.WordyBirdStudio.com and PixelMoversAndMakers.com (with Kevin Pluck). Marlo tweets from @MarloWordyBird.

Climate Change & Cryosphere – Summer 2019: The year that the Arctic was sunburned

Wildfires in western Greenland in July 2019 were observed by the Landsat 8 satellite. [Photo credit: NASA/Visible Earth]

June, July and August 2019 saw extensive heat waves across Europe, with air temperatures reaching above 40°C in many countries. In response, record breaking ice melt was observed in Greenland and wildfires in Siberia, Alaska, Arctic Canada and Greenland occurred. A particularly dry and warm summer was responsible for hemisphere-wide changes to the cryosphere. In this week’s post, we will review some of the consequences of this very warm summer of 2019 on our Northern Hemisphere cryosphere.


Wildfires

Whilst wildfires are a natural occurrence in forests all over the globe, they are relatively uncommon in the cool, wet Arctic forests. However, with above average air temperatures over much of the Arctic, the conditions of last summer were perfect for widespread Arctic wildfires. One of the biggest problems associated with wildfires is the high CO2 emissions. Summer 2019 saw the highest CO2 emissions from wildfires inside the Arctic circle since 2003. Other direct effects of wildfires in the Arctic include poor air quality and black carbon particles falling on the ice, decreasing its capacity to reflect the sun’s rays (called albedo, which is normally high for the bright snow surface of the Arctic but can be reduced by dark-coloured dust, ash and algae). This reduced albedo of the ice means it absorbs more sunlight, causing it to warm and melt even more (see this post).

Record-breaking Greenland Melt

The term ‘record breaking’ in relation to melting in Greenland is becoming increasingly common. Summers of 2012, 2016 and 2019 have all seen extremely high melt rates, widespread areas of melt and early melt onset in Greenland. Summer 2019 was record breaking for all three of these metrics. Firstly, the melt extent (area of Greenland ice sheet simultaneously melting) peaked early in summer with approximately 30% of the ice sheet’s surface melting on June 13th. For the next two months, the melt extent was above average. A second peak in the melt extent occurred on August 1st, when almost 60% of the ice sheet was melting and over 11 Gigatons of ice was lost (1 Gigaton of water can fill 400,000 olympic size swimming pools).

The maximum melt extent on August 1st 2019, and a graph showing the melt extent throughout 2019. [Photo credit: Polarportal.dk]

Sea Ice Minimum

At the end of August, sea-ice minimum was below 4.6 million square kilometers, which was the third smallest area since the satellite record began. Earlier in the year, between March and June, the sea ice extent was the lowest ever recorded (see our previous blog post for more information about the reasons of this sea ice retreat). A particularly shocking picture of huskies running through bright blue water over the sea ice in northwest Greenland went viral this summer.

The loss of sea ice has multiple impacts on the climate and cryosphere. When the bright, white sea ice melts, it exposes the darker ocean surface. As the dark ocean surface has a lower albedo (is darker) than sea ice, more sunlight is absorbed, further warming the area. This is called Arctic Amplification (see this post). Sea ice loss can also impact the Greenland ice sheet! A loss of sea ice near the coast of Greenland can cause glaciers to calve (large chunks break away) into the ocean when the pressure of the sea ice is removed. Spalte glacier, a tributary of the larger 79°N glacier in the northeast of Greenland, lost an area the size of Manhattan this summer. The whole northeast region had reduced sea-ice cover throughout summer.

A large part of the Spalte Glacier in northeast Greenland detached after the warm summer of 2019. Figure credit: Prof. Jason Box and Karina Hansen

Melting in the Alps

The two European heat waves experienced in June saw air temperatures above 40°C across Spain, France and Germany. These high, sustained temperatures led to high levels of melting across the European Alps. On the highest mountain in Europe, Mount Blanc, a mountaineer discovered a huge melt lake at 3km above sea level, which developed only a few days after the late June heat wave.

Slushy, wet snow and ice has a blue hue. Large parts of sea ice and land ice have the characteristic blue colour of melting ice this summer. [Photo credit: Robert Bye, Unsplash images]

Was summer 2019 just a blip? Or a sign of things to come? Whilst we don’t know the future, it is becoming increasingly clear that record breaking air temperatures and ice melt are becoming more common, which makes many Arctic communities and cryospheric features vulnerable.

Further reading:

Edited by Violaine Coulon


Jenny Turton is a post-doc at Friedrich-Alexander University (FAU) in Erlangen, Germany. Her research focuses on the atmosphere-cryosphere interactions in Northeast Greenland using observations and atmospheric modelling. Her research forms part of a larger project focusing on the ice-ocean-atmosphere links in the 79° north glacier in Greenland.