GeoLog

Natural Hazards

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 http://imaggeo.egu.eu/upload/.

Imaggeo on Mondays: A painted forest fire

Imaggeo on Mondays: A painted forest fire

This week’s featured image may appear to be a painted landscape, but the picture is in fact a photo, taken ten years ago by Victoria Arcenegui, an associate professor at Miguel Hernández University in Spain, during a controlled forest fire in northern Portugal.

The blaze is actually hot enough to distort the image, making some of the flames appear as brush strokes, beautifully blurring together the colours of the fire, trees and smoke.

Intense heat such as this influences how light travels to both the human eye and a camera lens. As air warms it expands, while colder air becomes denser. As a result, light travels quicker through thinner warm air but is refracted more in denser cool air. So when there are shifting pockets of cold and hot air, the speed of light through air is constantly changing, creating a shimmering effect.

The prescribed fire in this photo is not only showcasing an interesting phenomenon, but is also providing an important service to the region’s ecosystem. For decades, forest fires were often considered detrimental to the environment, however, researchers say that small natural fires help strengthen ecosystems. For example, by burning old dead vegetation, these fires cycle nutrients back to the soil and clear space for new plants to grow. In addition, some plant rely on fires to spread or activate seeds. Historically, many wildlife management programmes prevented smaller fires from removing vegetation, subsequently creating overgrown forests, which are more susceptible to larger, more destructive fires.

Now, many researchers are studying the effectiveness of prescribed burning, where forests are periodically set on fire in a controlled setting to replicate the ecological impact of natural fires and reduce wildfire risk.

By Olivia Trani, EGU Communications Officer

References

Santín, C. and Doerr, S. H.: Fire effects on soils: the human dimension, Philosophical Transactions of the Royal Society B: Biological Sciences, 371(1696), 20150171, doi:10.1098/rstb.2015.0171, 2016.

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 http://imaggeo.egu.eu/upload/.

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

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Groundwater springs harbour hidden viruses

Groundwater springs harbour hidden viruses

In many parts of Sub-Saharan Africa, groundwater springs are a vital, precious source of water. They are also a reservoir of disease. Research presented at the European Geosciences Union General Assembly in Vienna reveals that groundwater reservoirs in Ghana, Tanzania and Uganda contain diverse communities of viruses – including those that present a risk to human health.

The work, carried out by IHE Delft in the Netherlands and a number of local universities, is the first to find such extensive virus communities in groundwater. Amongst the 25 virus families found were pox and herpes viruses, responsible for a number of skin infections. Papillomavirus, which causes several types of cancer, was also present in the water. And this is just a fraction of what’s likely to be out there – other methods are likely to reveal many more, scientists involved with the new research say.

According to the new findings, the reason for this plethora of pathogens is poor sanitation in areas where freshwater percolates down from the surface and recharges the groundwater supply. Here, the viruses persist for several years before being discharged at the surface.

The virus communities were identified by extracting DNA from the groundwater. This graphic shows how they enter the groundwater and the local population. Credit: IHE Delft

Better sanitation and safe water supplies are needed to address the issue, but there aren’t always enough resources to tackle both. In areas like Kampala (Uganda) as much as 60% of the population relies on groundwater as a source of water. Simply switching to another source is not an option – there are none available.

In Accra (Ghana) and Kampala – groundwater systems are quite confined, covering an area that closely matches the distribution of the community. This means you can use a local approach to groundwater management, and develop something that works well for the communities living there.

Hydrogeolologist Jan Willem Foppen and his team take time to learn from the community, identifying pathways for the future together – an approach called transition management. Each pathway leads to small interventions, that the team can learn from. “When you work with a community and co-create knowledge, you get beautiful and unexpected results,” says Foppen.

For Foppen, the enthusiasm of the local population towards this approach is one of the most rewarding parts of the job: “we see this being replicated in other communities in Ghana and in Kampala, that is the biggest compliment we can get.”

This is still much to uncover about these virus communities. For example, scientists don’t yet know whether the viruses are dead or alive. 70% of the DNA found in the springs was unidentifiable. What’s more there is a whole separate group of viruses – RNA viruses – that haven’t even been studied yet.

By Sara Mynott, EGU Press Assistant