GeoLog

urban

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

Climate-proofing the Netherlands

Emerging Leaders in Environmental and Energy Policy (ELEEP) fosters transatlantic relations, forges dialogue, and promotes leadership across energy and environmental policy landscapes. Former EGU Science Communications Fellow and ELEEP member Edvard Glücksman reports back from the Netherlands, where citizens manage the continuous threat of climate-related devastation through a combination of creatively adapted urban spaces and innovative new technologies.

In late January 1953, a storm over the North Sea wreaked havoc, causing one of the most devastating natural disasters that Northern Europe has ever seen. The surge of seawater overwhelmed coastal defences, causing extensive flooding along the Belgian, British, and Dutch coastlines.

The infamous North Sea Flood claimed roughly 2,500 lives, and damaged or destroyed tens of thousands of houses. In the Netherlands, where roughly 70% of the nation’s territory lies at or below sea level, the flood submerged over 1,300 km² of the country’s territory, destroying around 10% of agricultural land and crippling its economy.

Rotterdam is Europe’s largest and busiest port. (Credit: Edvard Glücksman)
Rotterdam is Europe’s largest and busiest port. (Credit: Edvard Glücksman)

Climate-proofing with blue solutions

The nation’s history of flooding has shaped urban design and construction initiatives across the Netherlands. This trend is particularly striking in the Dutch city of Rotterdam, which lies in a delta roughly 7 m below sea level and is vulnerable to flooding from both seawater and heavy rain. Its complex system of dikes and seawalls have a one-in-10,000 years chance of breaking, high enough for the city to take pioneering steps towards developing sustainable water management practices in preparation for the most extreme future climate scenarios.

In the offices of the Rotterdam Climate Initiative (RCI), Lissy Nijhuis, Project Manager at Rotterdam Council, depicts the city’s climate adaptation strategy as one that has recently grown to embrace ‘blue solutions’ – mitigation strategies that allow humans to protect themselves against potential catastrophic flooding events, while continuing to live with and enjoy water. 

The Watersquare Benthemplein plaza discretely weaves flood management systems into the city’s urban landscape. (Credit: Edvard Glücksman)
The Watersquare Benthemplein plaza discretely weaves flood management systems into the city’s urban landscape. (Credit: Edvard Glücksman)

According to Nijhuis, these new solutions contrast starkly with conventional approaches, which rely on separating humans from water using the most robust and resilient physical barriers available.

The blue solutions approach means that, in recent years, the RCI has adopted a long-term strategy of ‘climate-proofing’ the city by subtly adding water management infrastructure to standard urban maintenance and redevelopment activities. Nijhuis explains that this is most effectively achieved by developing first with a practical, beautiful outcome in mind, and working backwards to adjust it to particular flooding mitigation requirements.

To that end, we visited the city’s notorious Watersquare Benthemplein pilot project, a water plaza that doubles as a flood buffer during heavy rainfall, pooling water from surrounding streets and thus relieving the most immediate pressure on public drainage systems. The construction, seven years in the making and used during our visit as a basketball court by school children, is a prime example of Rotterdam’s understated but highly effective water mitigation strategy. Other similar examples – built to reduce pressure on drainage sites in times of severe flooding – include car parks that double as water storage units and the presence of absorbent green roofing on houses.

ELEEP members gather in Rotterdam’s port area. (Credit: Edvard Glücksman)
ELEEP members gather in Rotterdam’s port area. (Credit: Edvard Glücksman)

Halving emissions by 2020

Earlier this year, ELEEP visited Hamburg and witnessed first-hand the city’s commitment to transforming previously flooded and industrial areas into hubs for the development of green architecture and urban regeneration. Likewise, the Drijvend Paviljoen (Floating Pavilion) lies at the heart of Rotterdam’s mission to climate-proof itself in a sustainable manner.

Comprising three connected, floating hemispheres, anchored within the city’s old harbour, the Floating Pavilion serves as a pilot project within Rotterdam’s ambitious plan to construct a future community of floating homes. The pavilion floats on a 2.5 m-thick layer of polystyrene, which allows for construction directly on the water and is made of materials that are hundreds of times lighter than those used in conventional buildings. The roof, for example, is made of a triple-layer of foil, filled with pressurised air that insulates and keeps the building warm.

The solar-powered Floating Pavilion is a showpiece within Rotterdam Municipality’s goal of halving energy consumption and CO2 emissions in housing by 2020. It also allows stakeholders to better understand the potential challenges involved in drastically altering the city’s urban landscape, including for example how to interpret the city plan when the harbour areas becomes living quarters virtually overnight.

Rotterdam’s Drijvend Paviljoen (Floating Pavilion), a pilot in climate-proofing infrastructure. (Credit: Edvard Glücksman)
Rotterdam’s Drijvend Paviljoen (Floating Pavilion), a pilot in climate-proofing infrastructure. (Credit: Edvard Glücksman)

Rotterdam’s port is by far the city’s most prominent industrial feature. Europe’s largest and busiest port, it covers an area of 5,299 hectares and shifts nearly 12 million cargo containers per year. It also hugely impacts Europe’s energy landscape, serving as the northwestern European hub for the arrival, production, and distribution of conventional and renewable energy. The port, which has a capacity of nearly 7,000 megawatts, powers nearly a quarter of the industry and homes in the Netherlands. At the same time, twice as much electricity will be generated by other power plants in northwestern Europe as a result of coal, biomass, and natural gas imported via Rotterdam.

In a broad-ranging talk, Ruud Melieste, an economist within the Corporate Strategy Department at the Port of Rotterdam, explains the pressures faced by the port as it strives to improve sustainability credentials. Important, he explains, is the global complexity within which EU energy issues must be understood, and the pressures faced by power, chemical, and refining industries as cheaper alternatives, such as US shale gas, are found elsewhere.

In response, Melieste offers three potential future scenarios for Rotterdam and the rest of northwestern Europe. The first, known as the ‘power’ scenario, focuses on maintaining the domination of fossil fuels through large-scale, centralised energy generation. In this scenario, big countries and companies determine future events. A second option is the ‘fusion’ scenario, which focuses on maintaining a diverse portfolio of stakeholders and solutions, and aims to gradually alter the economy towards sustainable energy use, while using shale gas as a transition fuel. The third, ‘unlimited’, scenario is based on radical innovations and the acknowledgement that climate change is a truly pressing problem. Here, the transition to renewables is seen as an economic opportunity, driven by decentralised energy systems. The Port of Rotterdam is prepared, according to Melieste, for the possibility that any of these three scenarios could play out. The one most likely to emerge, however, remains unknown.

Ruud Melieste, economist for the Port of Rotterdam, explains the dimensions of Europe’s busiest port. (Credit: Edvard Glücksman)
Ruud Melieste, economist for the Port of Rotterdam, explains the dimensions of Europe’s busiest port. (Credit: Edvard Glücksman)

Although the basic idea behind Dutch climate protection strategies has persisted for over half a decade, the sites we visited in Rotterdam demonstrate that the city’s climate adaptation portfolio is slowly changing from a “dry feet at all costs” approach to one of integrative water management, where the duties associated with climate protection and the pleasures of urban space can more freely mix. The city and its port are central features in the supply of energy, water, and food to much of northern Europe. As a result, its pioneering climate-proofing efforts are in future likely to affect millions of European citizens, ensuring that extreme weather events, such as the storm of 1953, can be mitigated in the most sustainable and least invasive way possible.

By Edvard Glücksman, Associate Research Fellow, Environment and Sustainability Institute, University of Exeter

ELEEP is a collaborative venture between two non-partisan think tanks, the Atlantic Council and Ecologic Institute, seeking to develop innovative transatlantic policy partnerships. Funding was initially acquired from the European Union’s I-CITE Project and subsequently from the European Union and the Robert Bosch Stiftung. ELEEP has no policy agenda and no political affiliation. Edvard’s current project is funded by the European Social Fund.

Improving quality of life through urban growth boundaries, 20-minute neighbourhoods, and public transportation in Oregon

The Emerging Leaders in Environmental and Energy Policy (ELEEP) Network brings together young professionals from Europe and North America with the aim of fostering transatlantic relations. Former EGU Science Communications Fellow and ELEEP member Edvard Glücksman reports back from a study tour of the US Pacific Northwest. In this first of two posts, he describes the unique urban planning strategy employed by policymakers in Oregon, giving the state a leading position in the national battle against urban sprawl.

ELEEP members on the Oregon Health & Science University (OHSU) campus looking out over the city of Portland, having just experienced the city’s aerial tramway. (Credit: Edvard Glücksman)

ELEEP members on the Oregon Health & Science University (OHSU) campus looking out over the city of Portland, having just experienced the city’s aerial tramway. (Credit: Edvard Glücksman)

In 2008, for the first time in history, more than half of the human population was living in cities. By 2050, that proportion is expected to grow to 70%. This wave of urban growth is largely seen as beneficial, offering renewed opportunities for jobs, healthcare and education to inhabitants of shrinking rural communities. However, the physical expansion of cities into the countryside, known as urban sprawl, also has major detrimental environmental consequences, damaging and fragmenting natural habitats. That said, CO2 emissions and energy consumption per capita is lower in densely populated cities.

Densely populated cities have higher per capita. (Credit: European Environment Agency)

Less densely populated cities have higher CO2 emissions per capita. (Credit: European Environment Agency)

We recently visited the US state of Oregon, where we were shown first-hand how actions taken in the early 1970s by forward-looking policymakers helped mitigate the challenge of urban sprawl before it was too late. As a result, Portland and urban areas across the state are a unique success story in the context of what are otherwise bloated and sprawling North American cities. As urban sprawl hits global headlines, Oregon’s drastic land management strategies may become increasingly relevant in countries where the fight against urban sprawl is only just beginning.

Less densely populated cities have higher energy consumption per capita. (Credit: European Environment Agency)

Less densely populated cities also have higher energy consumption per capita. (Credit: European Environment Agency)

Oregon: a state like any other

Oregon’s progressive land use plan stems from the tireless work of Governor Tom McCall in the early 1970s, a man said to have loved Oregon more than life itself. Watching the state’s cities grow in front of his eyes, he told Oregonians they faced a choice between “sagebrush subdivisions and coastal condominiums” and towns that blended gently into the state’s stunning environment. As a result, in 1973 he signed a law requiring every urban area in Oregon to write land use plans that limited sprawl and protected farms, forests and open spaces. Cities were enclosed in strictly enforced urban growth boundaries, with the threat of heavy legal penalties for development beyond designated limits.

Governor McCall’s dramatic influence on his beloved state can today be seen on any map of Oregon’s major urban areas, characterised by the clear divisions between cities and open spaces.

Oregon’s formula for avoiding urban sprawl is remarkably simple yet highly effective, explains Robert Liberty, Director of the Urban Sustainability Accelerator at Portland State University. Liberty has worked with Oregon’s pioneering land use planning program since its inception. His key message is that half a century ago Oregon was developing like every other US state – with population density within cities in decline as urban areas spread across larger spaces, and that a similar transformation can happen anywhere given the right tools for implementation. Getting over the misunderstanding that Oregon is inherently different from other locations in the US forms the core mission statement of the Urban Sustainability Accelerator, which works with other US communities to focus on implementation of land use planning programs.

High quality of life across 20-minute neighbourhoods

Several of our hosts maintain that Oregon, which is relatively poor compared with other US states, owes its success to maintenance of existing infrastructure rather than the urbanisation of untouched countryside. According to Karmen Fore, Transportation Policy Adviser to Governor Kitzhaber at the State Capitol in Salem, this emphasis on maintenance forms an important part of the state’s development strategy.

Looking forward, Fore outlines the state’s other priorities. She explains that Oregon must focus on harnessing its economic strengths, features that make it unique as a hub for business. Although a major expansion to Portland’s shipping port could be imminent, particularly for exports of coal, oil, and natural gas, the state’s spectacular natural environment and quality of life attributes remain at the forefront of such efforts.

 A streetcar in downtown Portland. The city’s streetcar network opened in 2001 and currently comprises two lines, with a daily ridership of 13,100 (2012-2013). (Credit: Edvard Glücksman)

A streetcar in downtown Portland. The city’s streetcar network opened in 2001 and currently comprises two lines, with a daily ridership of 13,100 (2012-2013). (Credit: Edvard Glücksman)

Quality of life, according to Fore, is tightly linked to the state’s innovative urban transport systems, particularly in Portland. The city boasts a rich portfolio of commuter trains, buses, light rail, streetcar lines, and even an aerial tramway running throughout the metropolitan area. Across the state, Fore is keen to add more passenger trains, especially on short but important routes, in order to alleviate pressure on congested roads and in the densely crowded US airspace.

Comprehensive transit systems and the preservation of natural landscapes are part of Oregon’s multifaceted, targeted approach, aiming to improve general levels of prosperity and quality of life across the entire population. To that end, Eric Engstrom, Principal Planner for the city of Portland (population 603,106), describes the city’s urban planning strategy as anchored around the concept of the ‘complete community’, or ‘20-minute neighbourhoods’, where every citizen has basic services, parks, healthy food and water, and transportation within a 20-minute walking radius.

The mayor of Portland Charlie Hales meets with ELEEP members to hear a European perspective on urban planning and sustainable transportation. (Credit: Edvard Glücksman)

The mayor of Portland Charlie Hales meets with ELEEP members to hear a European perspective on urban planning and sustainable transportation. (Credit: Edvard Glücksman)

Learning from Oregon

In the middle of downtown Portland, where once there was a motorway, sits one of the city’s most popular parks, named after Governor McCall. Today, the city has a tight, dense downtown area, friendly to pedestrians aspiring to reduce car use to a minimum in favor of public transportation. The atmosphere is infectious and nearby Seattle, about double as populous, started its urban downsizing in the mid-90s. At City Hall, the mood seems to be one of optimistic realism, with Mayor Charlie Hales quick to point out that the city is a national leader in reduction of urban sprawl yet it still has a long way to go to ensure a sustainable environment for future generations.

Urban sprawl is classically a US phenomenon but is increasingly prevalent across cities worldwide. In Europe, where cities are traditionally more compact than in North America, developing around densely populated historical cores, more cities are threatened with urban sprawl than ever before. By 2020, 80% of Europeans are predicted to live in urban areas, potentially undermining the EU’s efforts to meet carbon emissions reduction targets and drastically altering the quality of life for citizens across the continent. As policymakers grapple with the range of available mitigation strategies, they would be wise to learn from Oregon’s story, the foresight of Governor McCall, and the central principle of the state’s urban transformation; namely, that only a few decisions ago, Oregon was a state like any other.

By Edvard Glücksman, Postdoctoral Research Fellow, University of Duisburg-Essen

ELEEP is a collaborative venture between two non-partisan think tanks, the Atlantic Council and Ecologic Institute, seeking to develop innovative transatlantic policy partnerships. Funding was initially acquired from the European Union’s I-CITE Project and subsequently from the European Union and the Robert Bosch Stiftung. ELEEP has no policy agenda and no political affiliation.