EGU Guest blogger

Hysteresis For Dummies – Why history matters

Julius Garbe December 4, 2020

Simple illustration of the concept of multi-stability and tipping points of an ice sheet: the stability of the large Antarctic Ice Sheet can be seen as a seesaw. It starts off stable on the left side, but as temperatures rise, the ice starts to melt and lose mass, resulting in the left side of the seesaw getting progressively lighter. Up to a certain threshold, the seesaw remains stuck in its initial position, but upon transgressing the critical threshold, the system flips over, the seesaw switches into the right state which is associated with a much smaller ice sheet. Figure credit: J. Garbe.

Perhaps you have stumbled upon the word ‘hysteresis’ before, for example in connection with the stability behavior of our Earth’s large ice sheets and their long-term effect on global sea-level rise, or the long-term stability of the Atlantic Meridional Overturning Circulation, or even in another context outside earth/climate science. Or you might have come across this term during your studies, bu ...[Read More]

Seafloor secrets: traces of the past Patagonian ice sheet

Thale Damm-Johnsen November 27, 2020

Today’s Patagonian ice caps are confined to the high-altitude Andean Mountain range as the Northern and Southern Patagonia ice fields, and they are rapidly melting. The southern part of the Patagonian ice cap drains partially through fast-flowing ice streams into the fjords of Patagonia. Glaciers in this region have been losing ice at accelerating rates by large calving events, due to rising globa ...[Read More]

Did you know… that you can read the edge of Greenland’s ice as an open book?

Joe MacGregor November 20, 2020

Layering of ice along the northern margin of the Greenland Ice Sheet, Daugaard-Jensen Land. Figure credit: John Sonntag.

Scientists struggle to get ice samples from the depths of glaciers where fundamental pieces of information about the climate of Earth are stored. But in many places around the periphery of the Greenland Ice Sheet, you don’t need to drill a deep ice core to obtain ancient ice, you can simply walk across the ice sheet’s margin and look at the layered ice surface. There you can read the ice as though ...[Read More]

How small changes can make a big difference: tipping points in Antarctica

Ronja Reese & Dave Chandler November 13, 2020

As Antarctica’s mass loss increases, the threat of crossing tipping points both in the ice sheet and the surrounding Southern Ocean is increasing. But what actually is a tipping point? Have tipping points already been crossed in the past? And what might the future hold? What do we mean by a “tipping point”? Scientifically speaking, a tipping point is generally understood to be a threshold that, on ...[Read More]

Running a live stream of proglacial processes

Floreana Miesen and Stuart Lane November 4, 2020

Sampling in the glacier-fed stream near the field camp. Photo: Floreana Miesen

In Switzerland, nothing is really remote, but some places are more so than others. Dense infrastructure networks typically provide convenient access to research sites in the Alps where it is difficult to feel far away from home. However, this is not always the case… For us, our home for the summer is a bit different. We work at 2400 m above sea level in Southern Switzerland, in a narrow vall ...[Read More]

The physical and social changes facing the mountainous populations of the Karakoram Range

Shakir Ahmed October 23, 2020

View of Central Hunza valley with lush vegetation. Photo credit: Anas-Najam on unsplash.com.

As a child, Shakir remembers long extreme winters with heavy snowfall and dry blistering winds, where it was hard to play outside. He grew up in a village named Gulmit, located at an elevation of 2500 m, surrounded by the high snow caped mountains in the Karakoram Range in northern Pakistan. That was 30 years ago, when climate change was still not a cause of concern for the local people. Today, in ...[Read More]

Did you know…about regenerated glaciers?

Giovanni Baccolo October 2, 2020

Fig. 1 The Eastern Fellaria glacier, in the Bernina massif (Central Alps). Its lower sector is a beautiful example of a regenerated glacier. Photo credit: Riccardo Scotti.

Ice caps, valley glaciers, cirque glaciers, piedmont glaciers, ice sheets… I’m guessing that if you are a glaciology enthusiast, you have already heard about these types of glaciers. But you probably don’t know anything about regenerated glaciers, am I right? Well, you are in the right place! Let’s find out more about this little-known glacier type. Classifying glaciers Glaciers are classified on ...[Read More]

Climate Change & Cryosphere – A brief history of A68, the world’s largest iceberg

Thomas Rackow & Daniela Jansen September 25, 2020

In July 2017, the world’s largest iceberg known as A68 calved from the Larsen C Ice Shelf, located in the western Weddell Sea, Antarctica. Since then, A68 has lost two chunks of ice, A68-B and A68-C, but still remains a giant after more than 3 years. How did it feel to be the greatest, A68? Being the greatest With a length of 175 km and being about 50 km wide, this giant iceberg also appropriately ...[Read More]

Image of the Week – What darkens snow and ice?

Biagio Di Mauro September 18, 2020

“Be thou as chaste as ice, as pure as snow”. Hamlet, Act 3 Scene 1 (W. Shakespeare) Snow and ice are not always as pristine as one may think. If you have ever walked on a glacier or on a snowfield during summer, you might have already noticed that. In fact, both snow and ice are often darkened by impurities. In this blog post, you will learn about the main processes leading to ice and snow darkeni ...[Read More]

Climatic drivers of permafrost mounds in North American peatlands

Richard Fewster September 11, 2020

Figure 1. Palsas (permafrost mounds) at Stordalen Mire, Abisko, Sweden. Photo credit: Graeme Swindles.

Permafrost, or perennially frozen, peatlands are among the world’s largest terrestrial carbon stores and are particularly threatened by warming climates. Understanding how modern climate controls the distribution of permafrost peatlands is crucial for making confident predictions of their past and future extents. What are permafrost peatlands? Peatlands are wetlands that develop where cold, wet co ...[Read More]