GeoLog

environment

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

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/.

GeoTalk: “Grown-ups are not focusing on the plastic problem, not as much as I want them to”

GeoTalk: “Grown-ups are not focusing on the plastic problem, not as much as I want them to”

Lucie Parsons, a ten-year old girl from the small village of Walkington, in England, is on a personal mission to save the environment from plastic pollution. After seeing on the BBC Blue Planet II documentary how litter in the ocean is damaging ecosystems, she decided to take action. Now she gives talks and is co-researcher in her mother’s PhD on climate change and the youth voice. Lucie has come to the European Geosciences Union General Assembly in Vienna with her mother, Katie Parsons, to tell scientists that children want to be involved in addressing environmental issues.

Unless the flow of plastics and industrial pollution into the world’s oceans is reduced, marine life will be poisoned by them for many centuries to come.

David Attenborough, The Blue Planet II: Episode 4, BBC One

 

How did you learn about the impact of plastic pollution in the oceans and marine life?

L: Through Blue Planet. I saw an episode about a whale and her calf, and how the contamination poisoned the whale’s milk. When I saw that I got really, really upset so I wrote a poster about it. Then I asked my mummy and daddy to photocopy it so that I might be able to put it around the village. I read and watched documentaries to learn more, and I found out that it is a big problem. I wanted to do something about it.

So you started giving talks… 

L: Katy Duke, the head of the [aquarium] Deep in Hull, got in touch with daddy because she saw my poster.

K: I tweeted Lucie’s poster to show what she had done after she was so moved by the documentary. The CEO of the Deep saw that and contacted us to ask if Lucie would like to give the opening talk at the European Union of Aquarium Curators Conference, which the Deep were due to host.

What do you tell people in your talks?

L: I have done two conferences and talks, also at schools. I have also been interviewed for the radio and profiled by the Earth Day Network. In my talks I basically tell people how bad the problem is, what it is doing to the animals and what they can do to help.

Here at the EGU General Assembly people were really touched by your presentation. Do you think your talks make people take action? 

K: Gilles Doignon, from the European Commission for Environment, was really moved about what Lucie had said at the Deep. He promised her that he would get the aquariums to sign up to a plastic pledge.

L: And he managed to do it.

K: He said that, thanks to Lucie, thousands of turtles will be saved. This is where she got her inspiration from to carry on. If she can talk and say the things she has done, even if just one or two people do something about it, that creates a knock-on effect.

Why do you think children should be involved in the fight against climate change?

L: Children are the next generation; when they get older they will take over the work grown-ups have done. So they should start now. Children can do the same things as grown-ups, there is not really a difference with helping, you need to get as many people to help as you can get.

K: Getting schools and individual children involved in science will make it real and manageable, part of life. Otherwise much science ends up in dusty journals. We need people to live it and understand it.

Are grown-ups doing enough?

L: I think they should be doing a tiny bit more. They are not really focusing on the problem, not as much as I want them to.

You have talked to politicians before, why do you think it is important to talk to scientists also?

K: When Lucie was affected by Blue Planet she luckily had me and her dad to help her. But other children will have their passion stopped unless they have an adult who supports them. Some schools don’t do environmental education, it is not within many curriculums, and some parents might not carry on informing their children.

There is amazing science going on and some scientists who communicate get through to the children. There is a youth rising at the moment. Children are interested, they want to know and they want to be involved. But, how? Scientists have to continue feeding the information to the children and involve them in citizen science so they will carry on with that passion.

What can people do to help?

L: Inform other people, go on litter picks and map the areas where they found the litter to help prevent more litter. With my friends and my family, we have cleaned three areas so far in my village and we are mapping them to feed in the data about where we found the litter. Also, stop using single-use plastics.

Is there any other documentary, book or podcast you would recommend to people who want to learn about plastic pollution in the oceans?

L: Drowning in Plastic. We have watched about three quarters of that.

K: You are enjoying that, aren’t you?

L: Yes… Well, I wouldn’t say we are enjoying it.

Interview by Maria Rubal Thomsen, EGU Press Assistant