California’s flooding reveals we’re still building cities for the climate of the past

Read the full story from NPR.

Heavy storms have flooded roads and intersections across California and forced thousands to evacuate over the last few weeks. Much of the water isn’t coming from overflowing rivers. Instead, rainfall is simply overwhelming the infrastructure designed to drain the water and keep people safe from flooding.

To top it off, the storms come on the heels of a severe drought. Reservoirs started out with such low water levels that many are only now approaching average levels—and some are still below average.

The state is increasingly a land of extremes.

New infrastructure must accommodate a “new normal” of intense rainfall and long droughts, which has many rethinking the decades-old data and rules used to build existing infrastructure.

As heatwaves and floods hit cities worldwide, these places are pioneering solutions

Erik Anderson/AAP

by Thami Croeser, RMIT University

Climate change is going just as badly for cities as we have been warned it would. Extreme weather is increasingly common and severe globally. Australian cities have endured a number of recent disastrous events.

It’ll get worse, too. The Intergovernmental Panel on Climate Change (IPCC) factsheet outlining impacts on human settlements is a very sobering read. It also pithily sums up the situation cities face:

Concentrated risk and concentrated opportunity for action.

Implicit in this wording is a hopeful truth: adapting to climate change is a daunting task, but the “how” is not a mystery. The opportunity is right in front of us, in our streets, buildings and parklands. Around the world we are seeing effective retrofitting of cities to adapt to more extreme weather.

Here are a few inspiring exemplars.

Keeping the city cool

Planting trees to create shade is an obvious response to hot weather. However, in many cities it’s still a struggle just to stop the losses of trees. Future hot, dry climates will add to the challenge of urban greening.

Medellin in Colombia is one city making inspiring progress on this front. With an urban greening budget of US$16.3 million, it has created a network of 30 “green corridors” through the city. These have reduced urban heat island effects by 2℃ three years into the program. As these densely vegetated corridors mature, they are expected to eventually deliver 4-5℃ of cooling.

One of Medellin’s 30 green corridors with dense tree and understorey plantings runs along La Playa Avenue. Shutterstock

Vienna, Austria, has had an urban heat island strategy in place since 2018. It includes planting 4,500 trees each year and subsidies for street-facing green walls.

The city has developed a series of “cool streets” – traffic-calmed spaces with light-coloured road surfaces, “fog showers” that activate on hot days, water features, shade trees and drinking fountains. Eighteen cool streets were delivered as pop-ups, with another four in place permanently to provide refuges on hot days. Vienna also has an extensive network of public swimming pools where residents can cool off.

Park with trees and fountains
Esterhazy park was redesigned in 2020 as Vienna’s first ‘cooling park’, with mist sprays lowering the temperature on hot days. Carla Lo/City of Vienna

Limiting flood damage

Urban green space can also be valuable for intercepting and absorbing stormwater to prevent flooding.

A spectacular example is Bishan-Ang Mo Kio Park in Singapore. It was the site of a concrete drainage canal that was transformed into a 3.2km winding stream in 2012.

Bishan Park has become one of Singapore’s most popular parks since a utilitarian concrete channel was transformed into a naturalised river landscape.

The 62-hectare park along the gently sloping banks of the stream serves a densely developed residential area. In wet conditions, the stream swells up to 100 metres wide. As stormwater gently flows downstream, it drains away into the landscape.

Since the park was created, visitor numbers have doubled to 6 million a year. Biodiversity has increased 30%.

A very urban version of this approach is the “floodable square”. A good example is Rotterdam’s Watersquare Benthemplein, a sunken public plaza and basketball court that becomes a major stormwater basin when it rains.

Stairs surround a sunken city plaza being used by people to play with a basketball
Benthemplein has a series of pools that fill after heavy rain, connected by channels that control stormwater flows through the city. Michiel Brouwer/Flickr, CC BY-NC-SA

While this approach is a win-win on large development sites, it can be tricky to retrofit built-up areas. Fortunately, there are many more compact approaches that can deliver large benefits when delivered at scale.

New York City, for example, has spent over US$1 billion on smaller, distributed solutions in flood-prone streets. These measures include “raingardens” that drain water from streets, and infiltration basins that divert and store stormwater.

Women walks past a kerbside raingarden
Raingardens like this one in Brooklyn, New York, divert water from hard surfaces, so it sinks into the soil instead of overloading drains. Chris Hamsby/Wikimedia Commons, CC BY-SA

Green roofs that capture rainwater also help reduce flood risk in built-up areas. Again, Rotterdam’s approach is interesting; while reducing stormwater flows is a focus, the city’s rooftop greening program focuses on multifunctionality by integrating solar panels, social spaces and rooftop farming. The retrofitted “Dakakker” (rooftop farm) has advanced stormwater storage, vegetable beds, beehives, a few chickens and a popular café.

rooftop farm with cafe on top of office block
Rotterdam’s ‘Dakakker’ inspired a large rooftop greening program. Shutterstock

Of course, a green roof program usually requires private building owners to get on board. Rotterdam subsidises owners who deliver rooftop greening that intercepts significant amounts of stormwater. In 2021, Rotterdam had 46 hectares of green roofs, equating to around 0.5 square metres per resident.

The Swiss city of Basel leads the world with 5.7m² of green roofs per person (as of 2019). Basel has had incentives as well as laws requiring green roofs since the late 1990s; this highlights the value of putting regulations in place early.

The principle seems to work for bigger cities too: Tokyo has mandated green roofs since 2000, and has around 250ha of them.

rooftop gardens on multistorey city buildings
Tokyo has about 250 hectares of green roofs. Rachid H/Flickr, CC BY-NC

What does this mean for Australia?

Our cities remain woefully unprepared for extreme weather. But many of the above approaches are starting to crop up in Australia. The challenge is to move from a handful of trials to a large-scale, systematic roll out of infrastructure to adapt our cities to climate change.

The experience of the cities profiled above points to a few crucial ingredients.

First, cities must be willing to invest heavily, both in new green spaces and in subsidies to encourage greening by private property owners.

Second, reallocation of existing grey space, like roads and canals, must be pursued fearlessly and systematically. Paris’s elected mayor since 2014, Anne Hidalgo, is a spectacular example of the political courage required for large-scale greening.

The mayor of Paris has announced plans to turn the Champs-Élysées into an ‘extraordinary garden’.

Third, the law can play a real role in guiding development, through measures such as mandating greening on buildings. This can be achieved through fairly simple tools like Toyko’s green roof requirement, or more sophisticated area-based instruments that require a portion of a development to have green walls and/or roofs. Cities like Seattle and Brisbane are using these tools, which are also being mooted in Melbourne.

Recent disasters have made clear the urgent need to step up urban climate adaptation. The costs of not acting decisively to protect ourselves and our cities will be considerable, but the playbook is ready for us.

Thami Croeser, Research Officer, Centre for Urban Research, RMIT University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Burying short sections of power lines would drastically reduce hurricanes’ future impact on coastal residents

Read the full story from Princeton University.

As Earth warms due to climate change, people living near the coasts not only face a higher risk of major hurricanes, but are also more likely to experience a subsequent heat wave while grappling with widespread power outages.

Princeton researchers investigated the risk of this compound hazard occurring in the future under a “business-as-usual” climate scenario, using Harris County, Texas, as an example. They estimated that the risk of undergoing at least one hurricane-blackout-heat wave lasting more than five days in a 20-year span would increase 23 times by the end of the century. But there is some good news: Strategically burying just 5% of power lines — specifically those near main distribution points — would almost halve the number of affected residents.

As climate warms, a China planner advocates “sponge cities”

Read the full story from the Associated Press.

To cushion the impact of extreme weather due to climate change, a Chinese landscape architect has been making the case for China and other countries to create so-called “sponge cities.”

Yu Kongjian, who spoke to The Associated Press in Beijing, uses sweeping language to express his vision for cities that can withstand variable temperatures, drought and heavy rainfall. The challenges for implementing this vision at a time of ambitious economic development in China are multifold.

Yu criticizes much of Asia’s modern infrastructure for being built on ideas imported from Europe, which he says are ill-fitted to the monsoon climate over much of the Asian continent. He points to recent floods that have wreaked havoc in many Asian cities, which he says are caused by this architectural mismatch.

Bridging the gap: Equitable investment in city greenspace

Read the full story from U.S. EPA.

Green infrastructure encompasses a variety of practices that use soil and vegetation including vegetated rooftops, roadside plantings, tree-lined streets with natural canopy cover, and absorbent gardens to capture, filter, and reduce stormwater. Manufactured materials such as porous pavement is another example of GI often used in sidewalks, parking lots and driveways to increase surface permeability. Porous pavement allows rainfall to seep through to underlying layers of soil that filter the surface water before becoming groundwater.

Creating more greenspace in urban areas not only adds natural beauty to the surrounding area but can also improve the health and well-being of its residents. The presence of parks, community gardens and other vegetation can create recreational spaces, revitalize ecosystems and boost the local economy – all of which are highly beneficial to people living within those urban areas. However, these services are not always distributed equitably and can result in or perpetuate environmental injustices in received benefits.

EPA actively supports the use of both constructed and natural GI as cost-effective alternatives to traditional stormwater infrastructure to help manage wet weather flows and conducts research to identify and quantify the effects of green infrastructure and urban greenspace.

As part of this effort, a team of EPA scientists led by Matt Hopton and Page Jordan focused on identifying benefits received from urban greenspace and supporting integration of these benefits into stormwater management planning. In 2019, Hopton and team began designing a framework to demonstrate a practical approach to help communities access benefits of greenspace while managing stormwater. This effort led to the team conducting a case study to test the framework and learn if those benefits could be used in underserved urban areas. 

How pavement can help cool overheated cities, even in chilly Mass.

Read the full story at WBUR.

Reducing pavement or making it more reflective are strategies more communities must adopt to help cool cities, experts say, and slow global warming. One of the dire challenges with pavement is how much heat it radiates at night.

What a ‘sponge city’ designed to withstand extreme flooding looks like

Read the full story in Time.

Most cities today are not built to handle the kind of extreme weather that climate change inflicts. The asphalt and concrete that are the building blocks of the modern metropolis absorb heat, making heatwaves hotter. Those same materials, used to construct buildings and pave over the wetlands and streams that predated urban development, also repel water, leaving it nowhere to go. And that, as residents of Vienna, Berlin, and other European cities learned the hard way last year, can lead to devastating storm surges and flash floods.

Sponge cities provide one solution. Urban designer Yu Konjian first articulated the idea in 2012 after flooding wreaked havoc on dozens of cities in his native China. Instead of paving over the land with impermeable concrete and asphalt, he proposed adding green spaces that could act like sponges and absorb excess rain water. Instead of a “gray” infrastructure of pipes and dams that whisk water away from the city and dump it into rivers or the sea—systems that are prone to overflowing during storms and wearing out with time—sponge cities would use simple gravity to channel water steadily into soil where it could support plant life, or into reservoirs where it could be stored and repurposed. In other words, the sponge city would replicate the natural water cycle.

These climate tech entrepreneurs are teaming up to scale equity-based solutions

Read the full story at GreenBiz.

The Upside Tech Alliance is minimizing the individual sales calls its founding climate tech startups need to make to busy mayors and city planners.

What cities can do better to protect themselves from hurricanes and other floods

Read the full story from NPR.

NPR’s Ailsa Chang speaks with civil engineering professor Brett Sanders about what’s needed in terms of infrastructure planning to make communities more resilient to serious floods and storms.

People of color are as interested in buying electric cars as white consumers – the biggest obstacle is access to charging

More EV charging hookups in public locations like garages and parking lots would prompt more drivers of color to buy EVs. Extreme Media via Getty Images

by Andrea Marpillero-Colomina, The New School

A nationally representative survey of 8,027 Americans shows that across all racial demographics, overall interest in purchasing electric vehicles is high. Among those surveyed, 33% of white respondents, 38% of Black respondents, 43% of Latinos and 52% of Asian Americans say they would “definitely” or “seriously consider” purchasing or leasing an EV as their next vehicle.

The survey was conducted by Consumer Reports, with input from the nonprofit advocacy groups GreenLatinos, the Union of Concerned Scientists and EVNoire and administered between Jan. 27 and Feb. 18, 2022, by NORC at the University of Chicago, an objective, nonpartisan research organization.

Electric vehicles are critical for reducing transportation emissions, but communities of color currently adopt this key technology at lower rates than white drivers. This survey, for which I was an adviser, helps to shed light on some of the reasons for this disparity.

Cleaner air for all

Air pollution in the U.S. disproportionately affects communities of color. To take just one statistic, Latino children are about three times more likely than non-Hispanic white children to live in a county where air pollution levels exceed federal air quality standards.

Transportation is a major source of harmful air pollutants, particularly nitrogen oxides. These compounds contribute to the formation of ground-level ozone and smog, which can cause or worsen many types of respiratory diseases.

Motor vehicles also emit soot and toxic compounds. Because of these pollutants, people who live near roadways are at elevated risk of ailments including heart disease, impaired lung development in children, preterm and low-birthweight infants, childhood leukemia and premature death.

Transportation is also the largest source of global warming emissions in the United States. Light-duty passenger cars and trucks contribute 58% of transportation’s greenhouse gas emissions. Weather-related events such as heat waves, air pollution and flooding can be exacerbated by climate change and disproportionately harm U.S. communities of color.

Climate change is taking a disproportionate toll on low-income and minority communities across the U.S.

Where can we plug in?

Ours was the first consumer-oriented survey to analyze barriers to EV adoption along racial demographic lines. The goal is to help policymakers and advocates better understand why Black and Latino consumers are buying fewer EVs than white consumers and what concerns explain this gap.

We found that charging EVs at home – the most affordable way to charge EVs today – is not an equally viable option for all communities, particularly those with higher proportions of renters or multifamily dwellings. People who own their homes can much more easily have EV charging equipment installed on the premises and use it to charge their cars safely and conveniently overnight.

In our survey, nearly 75% of white respondents owned their homes, compared with fewer than 50% of Black respondents and slightly over 50% of Latino respondents. Multi-unit dwellings, such as apartment buildings, often do not offer EV charging for residents. We found that increasing affordable, accessible and reliable public EV charging infrastructure in safe locations would address all of these groups’ biggest concerns about EV charging.

The survey findings also suggest that improving access to financing and incentives for both new and used EVs would help to accelerate EV adoption.

Getting the message out

Our results show that increasing access to EVs is a key way to educate communities about the benefits of driving them. But it’s not clear yet how to create education and engagement initiatives that focus on Black and Latino consumers and target their specific needs and concerns.

Finding better ways to include Black and Latino communities in the EV transition is important because it can help to address gaps and mitigate systemic barriers to adoption and achieve environmental justice.

Providing help and incentives for apartments and condominiums to install EV chargers will help reduce barriers to widespread EV adoption. Our survey showed that Black and Latino drivers are more likely to use public or on-street parking, so incentives to support the build-out of publicly accessible charging infrastructure are also critical.

Purchase incentives that are more accessible and target buyers at more income levels will bring EVs within reach for more people. For example, tax credits could be made refundable, allowing people without sufficient tax liability to still take advantage of the credit, or incentives could be made available at the point of sale.

We plan further research that can identify ways to overcome the barriers spotlighted in this survey and help create a just and clean transportation future for all.

Andrea Marpillero-Colomina, Adjunct Lecturer in Urban Studies, The New School

This article is republished from The Conversation under a Creative Commons license. Read the original article.