Imaggeo on Mondays: Our QUEST for innovative tools to understand changing environments and climates

Imaggeo on Mondays: Our QUEST for innovative tools to understand changing environments and climates

The photo shown here shows typical sampling work underground. You can see Ola Kwiecien and Cinthya Nava Fernandez, researchers at Ruhr University Bochum in Germany, collecting dripwater in New Zealand’s Waipuna Cave as part of a four-year EU-funded monitoring programme. Our research aims at developing innovative geochemical indicators that we can use to quantify changes in the hydrological system or biosphere above the cave that result from variations in weather patterns and climate.

Caves are fantastic natural archives and laboratories. One can imagine caves like libraries of natural history: they host carbonate formations (such as stalagmites, stalactites, flowstones etc., collectively known as speleothems) which, like books, can be read by geochemists to learn about past climatic and environmental conditions. Importantly, these ‘stone books’ must, on the one hand, be protected from destruction by weathering, and on the other, must be written in a language that we can decipher. The secluded cave environment greatly helps protect speleothems from erosion and weathering, while monitoring the cave environment and hydrology allows us to learn the alphabet which nature uses to write natural history into the speleothems. Only then can we reconstruct, and ideally quantify, past environmental conditions.

Of special importance for our work in New Zealand is the El Nino-Southern Oscillation and the southern Westerlies. These two atmospheric subsystems strongly influence weather and climate in New Zealand. Southward or northward shifts of the Westerlies influence New Zealand crop yields and tourism, as well as the fishing economy, among others. El Nino and La Nina have equally strong impacts on weather patterns in New Zealand (and, in fact globally).

Despite many years of research, the mechanisms that cause changes to the ENSO and the Westerlies, and their interaction, still remain poorly understood. This lack of knowledge limits scientists’ efforts to estimate the magnitude and direction of changes that might result from ongoing global warming.

Our team of German, British and New Zealand geochemists, mathematicians, palaeoclimatologists and modellers set out to develop innovative tools and methods that would allow researchers to quantify, for example, changes in rainfall or seasonality, with the ultimate goal that these should be applicable globally. The manual sampling depicted in the photo might soon be replaced by an automatic sampler, which would greatly reduce the costs for regular fieldwork. Especially in remote settings such robots would be of great benefit for our research.

Our team also developed new proxies, such as a lignin-based (biomarker) proxy that allows us to reconstruct changes in vegetation above the cave. We also explored how transition metals behave in the hydrological system of caves, and the factors that control how these metals are transported and incorporated into speleothems. These research activities will hopefully give us powerful and very sensitive tools to quantify changes of environmental parameters, including rainfall, temperature, soil and vegetation and the underlying forcings, like ENSO. Until we have our tool kit properly calibrated, we continue our visits to Waipuna and other caves in New Zealand and Germany.

Our QUEST project has received funding from the European Union’s Horizon 2020 Research and Innovation programme and the Royal Society of New Zealand. Find more at

By Sebastian Breitenbach, Ruhr University Bochum (Germany), and Adam Hartland, University of Waikato (New Zealand)

Imaggeo is the EGU’s online open access geosciences image repository. All geoscientists (and others) can submit their photographs and videos to this repository and, since it is open access, these images can be used for free by scientists for their presentations or publications, by educators and the general public, and some images can even be used freely for commercial purposes. Photographers also retain full rights of use, as Imaggeo images are licensed and distributed by the EGU under a Creative Commons licence. Submit your photos at

Imaggeo on Mondays: Sand and snow on the Tibetan Plateau

Imaggeo on Mondays: Sand and snow on the Tibetan Plateau

Roughly 50 million years ago, the Eurasian and Indian continental plates began to crash into each other, dramatically changing the landscape of modern-day Asia. The force of the collision caused the Earth to scrunch together at the zone of impact, subsequently forming the Himalayan mountain range. However, to the north of the crash, a stretch of the Earth uplifted without bunching up or wrinkling; instead the clash formed an elevated flat surface five times as large as France, now known as the Tibetan Plateau.

The Tibetan Plateau is often called the ‘Roof of the World,’ as the region’s average elevation exceeds 4,500 metres and is home to the Earth’s highest peaks, including Mount Everest and K2. The plateau is also a crossroad for many different kinds of ecosystems and geologic features, including deep canyons, winding rivers, massive glaciers, boundless grasslands and alpine deserts.

This week’s featured image, taken by Monica Cardarilli, a risk and safety engineer at the Sapienza University of Rome in Italy, gives a snapshot into the plateau’s dynamic and diverse environment, where snow, water, soil and organic matter all make their mark on the landscape. “In this picture natural elements are expressed by the colors, like a painting where the whole exceeds the single parts in a mix of perceptions,” says Cardarilli.

The landscape of the plateau and the surrounding mountainous regions is also as fragile as it is diverse, and many scientists fear that climate change and other human activities are rapidly altering this corner of the Earth. For example, research suggests that the Tibetan Plateau is experiencing higher rates of warming compared to the global average, which has already caused concerning levels of glacier melt, flooding, desertification and grassland degradation in the area.

A recent report suggests that, due to climate change, at least one third of the glaciers situated within the plateau and the surrounding Hindu Kush-Himalaya (HKH) region will be lost from ice melt by the end of the century. This level of melting would have major consequences for the surrounding population, as more than 1.5 billion people rely on freshwater that stems from the region and many local communities would be threatened by severe flooding and lake bursts.

The report, undertaken by more than 200 researchers, warns that climate action is necessary to prevent even further melting in this region and avoid worse disasters.

By Olivia Trani, EGU Communications Officer

Imaggeo is the EGU’s online open access geosciences image repository. All geoscientists (and others) can submit their photographs and videos to this repository and, since it is open access, these images can be used for free by scientists for their presentations or publications, by educators and the general public, and some images can even be used freely for commercial purposes. Photographers also retain full rights of use, as Imaggeo images are licensed and distributed by the EGU under a Creative Commons licence. Submit your photos at

Geosciences Column: climate modelling the world of Game of Thrones

Geosciences Column: climate modelling the world of Game of Thrones

Disclaimer: This article contains minor spoilers for Season 8 of “Game of Thrones.” A basic understanding of the world of Game of Thrones is assumed in this post.

The Game of Thrones world of ice and fire is an unpredictable place both politically and environmentally. While the fate of the Iron Throne is yet to be confirmed, a humble steward has been working diligently to make some sense of the planet’s peculiar climate. The results could help scholars assess when future winters will be coming or how wind patterns may influence where eastern attacks on Westeros from invading dragons and ships would occur.  

It is known that the realms of Westeros and Essos are subject to long-living seasons, with many extending over several years, but Samwell Tarly, the former heir of House Tarly and current steward of the Night’s Watch, has developed a new theory to explain this long seasonal cycle.

His research suggests that the seasons’ extended lifespans could be due to periodic changes in the planet’s tilt as it orbits around the Sun. The results were published in the Philosophical Transactions of the Royal Society of King’s Landing in the Common Tongue, with translations available in Dothraki and High Valyrian.

Tarly carried out his analysis while on sabbatical at the Citadel in Oldtown, Westeros. In the published article he notes that his study was “inspired by the terrible weather on the way here to Oldtown”.

Uncovering climate observations and models

Tarly’s first developed his theory after studying observational climate records stored in the Citadel library’s collections. Many of these manuscripts contain useful information on a number of climate conditions present within the Game of Thrones world, including the multiyear length of seasons.

Seasons occur when regions of a planet receive different levels of sunlight exposure throughout a year. The southern and northern hemispheres experience opposite degrees of sunlight exposure due to the natural tilt of the planet’s axis as it orbits around the Sun. For example, when the southern hemisphere is tilted closer to the Sun it experiences a warmer season; at the same time the northern hemisphere is tilted away from the Sun, so it experiences a colder season.

When a planet is consistently tilted on one side as it orbits around the Sun, the world experiences four seasons during one year. Tarly proposed that seasons could last over several years if the tilt of a planet changes during its orbit: “so that the Earth ‘tumbles’ on its spin axis, a bit like a spinning top”, he explains. If a planet were to only change the side of its tilt once a year, it would experience permanent seasons.

Caption: an example of Earth’s orbit in which (a) the angle of tilt of the spinning axis of the Earth stays constant through the year (Credit: Dan Lunt, University of Bristol)

Caption: an example of Earth’s orbit in which (b) the tilt “tumbles” as the planet rotates round the Sun, such that the angle of tilt changes, so that the same Hemisphere always faces the Sun, giving a permanent season (Credit: Dan Lunt, University of Bristol)

Tarly put this theory to the test with the help of a climate model that he discovered on a computing machine stored in the Citadel cellars. “Luckily I learned how to code when I was back in Horn Hill avoiding sword practice,” Tarly explains in the text.

By running climate simulations with the proposed parameters of his theory, Tarly found that his model was consistent with much of the observational data present within the Citadel library. The models also estimated many climatic features of the world of Game of Thrones, including the seasonal change in temperature, precipitation and wind direction across Westeros.

In the published article, Tarly notes that his theory doesn’t explain how the planet transitions between summer and winter. He guesses that the tumbling pattern of the planet’s tilt persists for a few years, but then flips at one point so that the hemispheres experience new seasons. “The reasons for this flip are unclear, but may be a passing comet, or just the magic of the Seven (or magic of the red Lord of Light if your name is Melisandre),” Tarly writes.

Caption: The Northern Hemisphere winter (top row (a,b,c)) and summer (bottom row (d,e,f)) modelled climate, in terms of surface temperature (◦C; left column (a,d)) precipitation (mm/day; middle column; (b,e)) and surface pressure and winds (mbar; right column (c,f)). (Credit: Dan Lunt, University of Bristol)

The world of Game of Thrones compared to ‘real’ Earth

Tarly then compared the climate of the world of the Game of Thrones to that of a fictional planet called the ‘real’ Earth; Gilly, his partner and research associate, had found records of this planet’s climate in the Citadel library. The analysis revealed that in winter, The Wall, the northern border of the Seven Kingdoms, was similar in climate to many areas of the ‘real’ Earth, including parts of Alaska in the US, Canada, western Greenland, Russia, and the Lapland region in Sweden and Finland. “I always suspected that Maester St. Nicholas was a member of the Night’s Watch,” Tarly noted.

Caption: High-resolution (0.5◦ longitude ×0.5◦ latitude) mountain height for the whole planet. (b) Model-resolution (3.75◦ longitude ×2.5◦ latitude) mountain height for the region of Westeros and western Essos. (Credit: Dan Lunt, University of Bristol)

On the other hand, the models showed that the climate of Casterly Rock, the southern home of House Lannister, was similar to that of the Sahel region in Africa, eastern China, and a small region nearby Houston, Texas in the US.

Climate sensitivity in a world of ice and fire

Finally, Tarly used the climate models to investigate how climate change might impact the world of Game of Thrones. The simulations were done in response to some “worrying reports from monitoring stations on the island of Lys”; the stations have recently observed increasing concentrations of methane and carbon dioxide in the world’s atmosphere. It is suggested that this spike in greenhouse gas emissions could be due to the rising dragon population in Essos, deforestation from global shipbuilding, and excessive wildfire.

Tarly found that, by doubling the level of atmospheric carbon dioxide in his models, the world would warm on average by 2.1°C over 100 years. The results showed that the greatest warming would occur in the polar regions, since warming-induced sea ice and snow melt can trigger additional warming as a positive feedback.

By comparing this level of warming to the Pliocene period of the ‘real’ Earth 3 million years ago, Tarly predicted that the sea level of the world of Game of Thrones could rise by 10 metres in the long term. This degree of sea level rise is sufficient to flood several coastal cities, including King’s Landing.

In the paper, Tarly stresses that climate action from all the Kingdoms is needed to prevent even more social instability and unrest from climate change. He suggests that all governing bodies should work on reducing their greenhouse gas emissions and invest in renewable energy, such as windmills.

If he survives the war for Westeros, Tarly expects that improving his climate analysis will keep him busy for years to come.

By Olivia Trani, EGU Communications Officer

This unfunded work was carried out by Dan Lunt, from the University of Bristol School of Geographical Sciences and Cabot Institute, Carrie Lear from Cardiff University and Gavin Foster from the University of Southampton during their spare time, using supercomputers from the Advanced Centre for Research Computing at the University of Bristol. You can learn more about the climate models online here.

April GeoRoundUp: the best of the Earth sciences from the 2019 General Assembly

April GeoRoundUp: the best of the Earth sciences from the 2019 General Assembly

The EGU General Assembly 2019 took place in Vienna last month, drawing more than 16,000 participants from 113 countries. This month’s GeoRoundUp will focus on some of the unique and interesting stories that came out of research presented at the Assembly!

Major Stories

Glacial disappearing act in the European Alps

New research from a team of scientists estimated the future of all glaciers within the European Alps, and the results aren’t that hopeful. After running new simulations and analysing observational data, the researchers predict that, if we limit global warming below 2°C above pre-industrial levels, by 2100 glacier volume in the Alps would be roughly two-thirds less than levels seen today.

Furthermore, according to the new research, if we fail to put global warming in check, more than 90 percent of Europe’s glacier volume in the Alps will disappear by the end of the century. “In this pessimistic case, the Alps will be mostly ice free by 2100, with only isolated ice patches remaining at high elevation, representing 5 percent or less of the present-day ice volume,” says Matthias Huss, a researcher at ETH Zurich and co-author of the study.

Evolution of total glacier volume in the European Alps between 2003 and 2100. Credit: Zekollari et al., 2019, The Cryosphere.

The data also suggests that from now until 2050, about 50 percent of the present glacier volume will melt, regardless of how much greenhouse gas emissions we produce in the coming years. This is because glaciers are slow to respond to changes in climate conditions, and still reflect colder climates from the past. In addition to presenting their research at the EGU General Assembly, the team also published the results in The Cryosphere.

The search for the oldest ice announces their drill site

Ice-core extraction near Concordia station (Credit: Thibaut Vergoz, French Polar Institute, CNRS)

After three years of careful consideration, a collection of European ice and climate researchers have pinpointed the spot where they would most likely uncover the oldest ice core possible, one that dates back to 1.5 million years from today.

The consortium of researchers, also known as the Beyond-EPICA project, hopes to pull out a sample of ice containing a seamless record of Earth’s climate history. Such ice samples contain trapped air bubbles, some sealed off thousands to millions of years ago, thus providing undisturbed snapshots into Earth’s ancient atmospheres. Using this climate data, researchers can make predictions on how Earth’s will warm in the future.

At the General Assembly, the scientists formally announced that the drilling operation will be conducted 40 kilometres southwest from the Dome Concordia Station, which is run jointly by France and Italy. The team plans to collect a three km-long ice core from the site, nicknamed ‘Little Dome C,’ over the course of five years, then will spend at least an additional year examining the ice.

Map of Antarctica showing the areas surveyed by BE-OI and the selected drill site (Credit: British Antarctic Survey (BAS))


What you might have missed

Predicting the largest quakes on Earth

Scientists have long discussed how intense quakes can be on Earth, with some studies suggesting that Earth’s tectonic features cannot generate earthquakes larger than magnitude 10. However, new research conducted by Álvaro González Center from Mathematical Research in Barcelona, Spain estimates that subduction zones, regions where one tectonic plate is pushed under another, subsequently sinking into the mantle, have the potential to release 10.4 magnitude earthquakes. González’ analysis suggests that such events happen on average every 2,000 years.

“Such events would produce especially large tsunamis and long lasting shaking which would effect distant locations,” Gonzalez said to the Agence France-Presse.

His findings also propose that large asteroid impacts, such as the dinosaur-killing Chicxulub event 66 million years ago, may trigger even larger magnitude shaking. According to data analysis, shaking events reaching magnitude 10.5 or more likely happen on average once every 10 million years.

Where deadly heat will hit the hardest

Heatwaves and heat-related hazards are expected to be more prevalent and more severe as the Earth warms, and a team of researchers looked into which regions of the world will be the most vulnerable.

The scientists specifically analysed human exposure to ‘deadly heat,’ where temperatures as so high that humans aren’t able to cool down anymore. By examining data projections for future population growth and annual days of deadly heat, the researchers assessed which areas will be hit the hardest. They found that, if global warming isn’t limited to 2°C above pre-industrial levels, there will be a few ‘hots spots,’ where large populations are predicted to experience frequent days of deadly heat annually.

Dhaka, Bangladesh, is expected to experience significant exposure to deadly heat in the future, according to research presented at the EGU 2019 meeting. Credit: mariusz kluzniak via Flickr

The research results suggest that future deadly heat will most significantly impact the entire South Asia and South-East Asia region, Western Africa and the Caribbean. Sub-Saharan Africa in particular will experience big increases in deadly heat exposure, due to climate change and population growth.

The researchers also found that a minority of large cities in very poor countries will be the most affected by future heat conditions. “There is a big inequality of who takes the toll of deadly heat,” said Steffen Lohrey, a PhD student at the Technical University Berlin who presented the findings at the EGU meeting.

Europe and the Mediterranean at risk of malaria due to climate change

While malaria was eradicated in Europe and the Mediterranean in the 20th century, there have been an increasing number of new cases in this region of the world, primarily due to international travel and immigration. New research presented at the General Assembly by Elke Hertig, a professor at the University of Augsburg, Germany, suggests that Europe’s future climate may further increase the risk of local malaria recurrence and expansion.

Malaria is transmitted to humans by Anopheles mosquitos and these disease-carrying insects are very sensitive to temperature and precipitation conditions. In particular, these mosquitos thrive in areas with warm spring temperatures and high precipitation in the summer and autumn.

Using climate models, Hertig found that the malaria-carrying mosquito population will likely spread northward as Europe’s climate changes, reaching much of northern Europe by the end of the century. Alternatively, her models suggest that mosquito populations will decline in the Mediterranean regions, mainly due to decreases in summer and autumn rainfall.

A statistical analysis also revealed that, by the end of the century, disease transmission from mosquitoes will be the most effective in southern and south-eastern European regions, including parts of Spain, southern France, Italy, Greece, and the Balkan countries.

Other noteworthy stories

To stay abreast of all the EGU’s events and activities, from highlighting papers published in our open access journals to providing news relating to EGU’s scientific divisions and meetings, including the General Assembly, subscribe to receive our monthly newsletter.