GeoLog

GeoLog

Cities of the future

Cities of the future

Over half the world’s population lives in cities. Many a metropolis rises high above carpets of concrete and tarmac, vibrant, bustling, and prosperous. But this urban environment comes with many a problem. From poor air quality to hazardous temperatures, there are several dangers present in urban environments. Scientists speaking at the European Geosciences Union General Assembly in Vienna earlier this year have been testing designs that could change cityscapes and tackle the challenges of urban living. The solution, it seems, is making these areas greener.

As well as making cities more aesthetically pleasing, more vegetated urban environments come with a wealth of benefits, including improving wellbeing, absorbing noise and creating new habitats. With horizontal space at a premium, scientists and engineers are looking to city walls to make environments greener, exploring how growing vertical gardens can help address the challenges associated with urban environments.

“We should have much more vegetation than we currently have. That’s the source of a number of problems,” says Fulvio Boano an environmental engineer at Politecnico di Torino, Torino, Italy.

The problems include a phenomenon known as the urban heat island effect. Cities are typically warmer than the surrounding countryside. Dense networks of dark roads and pavements absorb more solar radiation than natural vegetation, and high-rise buildings can also interfere with natural cooling effects, like wind. Combined, these urban features make cities warmer than their surroundings. The effect is more pronounced at night, leaving urban areas several degrees warmer than their suburban counterparts, resulting in an urban heat island.

The difference may only be a few degrees, but the impact that this change can have is no small matter, especially when combined with a heatwave. For vulnerable members of the population, including those over the age of 65, deaths due to heat stress are much higher when night-time temperatures exceed 25 °C indoors. Of course, air conditioning can help bring room temperature down, but there may be more sustainable solutions out there. Thomas Nehls, a researcher at Technical University Berlin, Germany, suggests vertical gardens are among them. He presented his recent research at the Assembly in April.

Roof and wall structures are ideal for urban greening, but with much more wall space going, vertical gardens could well be the future. Credit: Ryan Somma

Planting building walls with greenery provides shade, reducing the solar radiation reaching the building and the way plants uptake and lose water also helps remove heat. Between a bare wall and a green one, the difference in temperature can be as much as 16 °C on a hot summer’s day and – over a large area – these vertical gardens could help cities stay cooler. “For indoor night-time heat stress, every single wall especially south, south-west and west oriented walls will reduce the heat stress inside the buildings,” explains Nehls, whose interest in urban greening started with ideas around how to handle rainwater in cities.

“Water needs to get evaporated into urban atmospheres instead of being drained to the sewers and, finally, rivers or surface waters,” asserts Nehls. Vertical gardens slow down water movement, allowing it to be used by plants, and evaporated back into the atmosphere, rather than racing down a gutter. It means the gardens can be watered sustainably too.

Ongoing research at the Department of Land, Environment and Infrastructure Engineering (DIATI) in Torino, Italy, goes one step further – exploring whether vertical gardens can clean up domestic wastewater too.

A tiny vertical garden in testing at the Department of Land, Environment and Infrastructure Engineering at Politecnico di Torino. Credit: Alice Caruso

The average person uses 200-250 litres of water per day, and most of this ends up as wastewater, which usually requires energy to treat and make reusable. But, with vertical gardens, we can do the same with much less energy and fewer resources.

The idea is simple, by covering building walls with layers of plants, you get the many benefits of urban greening, and your very own wastewater treatment facility.

How domestic wastewater purification works. Credit: Alice Caruso

The design is currently being tested on university buildings at Politecnico di Torino, and is capable of cleaning all domestic wastewater except sewage. With roughly 100 litres of this produced daily per person, the technology could be a big step towards meeting water treatment demands. Scaling up the technology is the next challenge, including working out how the vertical wall should be built to meet the needs of a family.

Domestic wastewater provides plants with the water they need and, as it percolates through the system, the water is slowly cleaned and stripped of many ‘undesirables.’ The process removes many common pathogens, present in concentrations orders of magnitude lower than the original wastewater. Microbes in the soil and roots are thought to do most of the work, but exactly how they purify the water is not yet known. Together, the plants and microorganisms remove nutrients and contaminants.

“We need energy to treat water, we need energy to make water drinkable and we need energy to pump it into houses. This kind of application is going to reduce all that,” Boano explains.

There may be other benefits too, “green surfaces in your direct surroundings will keep you calm, reduce blood pressure and other symptoms of stress,” suggests Nehls, emphasising that while the benefits to wellbeing aren’t fully known, there’s a lot of potential.

For the scientists working on the future of our cities, the reasons for making them greener couldn’t be clearer: “[we want] to make the environment more comfortable for people and our children,” says Politecnico di Torino’s Alice Caruso, who presented the work at the Assembly.

By Sara Mynott, EGU Press Assistant

Call for new EGU network blogs!

Call for new EGU network blogs!

Here is your chance to join the EGU blog network! Since 2013, the Union’s network blogs have enjoyed thought-provoking and engaging contributions on a range of topics: from the workings of the inner Earth and palaeontology, through to geomorphology and air quality. The network aims to foster a diverse community of geoscience bloggers, sharing accurate information about geoscientific research in a language understandable not only to fellow scientists but also to the broader public. The network blogs complement the EGU official blog and division blogs.

If you are an Earth, planetary or space researcher (whether you’re an early career scientist, or a more established one) with a passion for communicating your work, or a geoscience communicator, we’d like to hear from you!

We currently feature blogs that cover international development (Geology for Global Development), volcanology (VolcanicDegassing), and groundwater (Water Underground). We’d love to receive blog proposals from fields within the Earth, planetary and space sciences we don’t yet feature, including interdisciplinary and trans-disciplinary topics (e.g. ‘Sustainability’ or ‘Geoscience and Art’).

The benefits: apart from your site gaining exposure by having its posts listed on the front pages of the EGU website and the EGU blogs, we will also share highlights of your work on our social media channels (Twitter, Facebook, LinkedIn, Instagram) and advertise the blog network at our annual General Assembly, which has over 16,000 attendees. And, of course, you’ll get to join a great community of bloggers (21 blogs run by more than 60 volunteers)!

Having an existing blog is not a requirement for application. However, if you don’t have a blog already, we’d like you to have at least some experience of writing for a broader audience, be it as a guest blogger, or contributing to outlets such as The Conversation. In this case, let us know what you’d like your blog to be called, what topics you would cover, and link to articles you’ve published in the past. Interested in blogging, but don’t want to go solo? We also are accepting applications submitted by a blog team!

If you’d like your blog (or blog idea) to be considered for our network, fill out this form by 16 September.

Network bloggers should be prepared to publish at least 1-3 blog posts a month. Please note that only blogs in English will be considered, as this is the EGU working language, and the language of the EGU blogs. We particularly encourage applications from all European countries, not just English-speaking countries, but bloggers from outside Europe can also apply.

Feel free to contact the EGU Communications Officer Olivia Trani if you have any questions. In the meantime – happy blogging!

By Olivia Trani, EGU Communications Officer

Imaggeo on Mondays: how short-term storms can impact our landscapes

Imaggeo on Mondays: how short-term storms can impact our landscapes

In the Sierra de Aconquija, a mountain range in the southern Central Andes of Argentina, strong storms often come and go at a moment’s notice, but they can have a long-lasting impact on the Earth’s surface.

The thunderstorm cell featured in this photo formed in less than half an hour, giving all those nearby only a few minutes to take cover. Mitch D’Arcy, a geomorphologist and postdoctoral researcher at the University of Potsdam and the GFZ German Research Centre for Geosciences, had the opportunity to witness this storm (and snap this picture!) while carrying out field work in the area.

“It was a spectacular experience, pouring heavy rain onto a very localised part of the mountain range, but it was also a hazard because the storm was quickly moving towards us with a lot of lightning. Without any trees around, we were likely targets for lightning strikes!” said D’Arcy. Luckily, he and his colleagues were able to find shelter in their truck while the huge downpour passed over them.

These kinds of thunderstorms are short-lived, but have intense precipitation rates. In this case, the temperature dropped by 14 degrees Celsius, and the storm was accompanied by heavy hail and lightning. And while these natural hazards are transient, they can have a long-term impact on the region’s landscape. Severe storms are capable of triggering landslides and floods and can relocate large amounts of sediment and debris in a short period of time.

D’Arcy is part of an international research programme called StRATEGy (Surface processes, Tectonics and Georesources: The Andean foreland basin of Argentina), which looks into how past and present climate change makes a mark on the terrain of the Argentine Andes, among other topics.

This research is essential for understanding and predicting how human-caused climate change will alter weather patterns and impact surface processes (such as how quickly sediments are eroded and transported across landscapes), according to D’Arcy. Having a better understanding of these surface processes and their sensitivity to the climate could help scientists better inform the public about how to prepare for natural hazards, such as flooding, erosion and landslides.

D’Arcy notes that it’s also important to assess how climate and weather trends will impact the sedimentary record, since it is one of the only physical records that scientists can use to examine how the Earth’s surface has change through time.

“North-western Argentina is a fascinating place to study how climate change affects surface processes, because it has experienced pronounced and abrupt changes in hydroclimate through time,” said D’Arcy. Their research has found that even subtle changes in the region’s climate have produced large changes to the surface environment, impacting how rivers take shape and how sediments move.

For example, while the Sierra de Aconquija is a semi-arid environment today, more than 12,000 years ago it used to be much wetter as a result of global climate changes. In fact, back then the mountain range was covered in glaciers and many of the basins were filled with lakes.

“It’s really important that we understand how different landscapes function and how they react to changes in climate. When we look at places like the southern Central Andes in Argentina, we find that the landscape records interesting signatures of ancient climate changes in Earth’s past. However, one of the big questions we still don’t have a good answer to, is how important are these very intense but rare storms for shaping landscapes and creating the sedimentary record from the geological past,” said D’Arcy.

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/.

Conversations on a century of geoscience in Europe: Part 1

Conversations on a century of geoscience in Europe: Part 1

When you think about the last century of geoscience, what comes to mind? Perhaps Alfred Wegener’s theory of continental drift? Or Inge Lehmann’s discovery of Earth’s solid inner core?

Over the last 100 years, geoscientists have made incredible contributions to our understanding of the Earth, the solar system, and beyond. The science community has explored uncharted territory, challenged previously held conceptions, provided vital information to policymakers, worked to address societal challenges, and put forth paths for sustainability. Through the years, researchers have also worked to promote diversity, inclusion, transparency, and accessibility in the geosciences. Many Europe-based scientists have been at the forefront of these advances.

Inspired by the centennials of the American Geophysical Union (AGU) and the International Union of Geodesy and Geophysics (IUGG), which were both founded in 1919, we would like to highlight Europe’s role in shaping the geosciences and the great achievements of European geoscientists within the last century.

In this series of interviews, scientists across different disciplines and scientific fields reflect on the last 100 years of Earth, space and planetary sciences in Europe and share their perspectives on the future:


Anne-Marie Treguier: Research Director at the French National Centre for Scientific Research and the European Institute for Marine Studies in the Ocean Physics Laboratory

The responsibility of geoscientists is huge. We must frame our scientific questions in the context of a wide range of future scenarios..

Read interview →

 

John Burrows: Professor of the Physics of the Ocean and Atmosphere and a Director of the Institutes of Environmental Physics and Remote Sensing at the University of Bremen

The history of discoveries in the geosciences is a fascinating story, involving unexpected and perplexing observations..

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Günter Blöschl: Head of the Institute of Hydraulic Engineering and Water Resources Management and Director of the Centre for Water Resource Systems of the Vienna University of Technology

As Heraclitus said, there is nothing permanent except change. Innovation needs to be permanent. We are in for an exciting future..

 

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Antje Boetius: Director of the Alfred Wegener Institute (AWI) Helmholtz Center for Polar and Marine Research and Professor of Geomicrobiology at the University of Bremen

When one reads the original reports and letters, we can learn how relevant expeditions and fieldwork were – and still are – for the international, collaborative spirit of the geosciences worldwide. The amazing thing is, in many ways we have remained explorers of our own planet Earth even today..

 

 

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Bernhard Diekmann, Head of the Research Unit Potsdam of the Alfred Wegener Institute (AWI) Helmholtz Center for Polar and Marine Research and Professor of Quaternary Geology at Potsdam University

During the last 100 years, the focus in geological research was understanding of processes in Earth’s interior and skin…The geosciences should no longer be seen as an individual field of research, but must be integrated into a holistic view of natural and social sciences..

 

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Interviews by Olivia Trani, EGU Communications Officer