Tag Archives: city

Third Chinese city goes back into quarantine to control local COVID-19 flare-ups

Chinese authorities have placed a third city under lockdown as part of efforts to control flare-ups of COVID-19. Around six million people in the country are now living in quarantine.

Image via Pixabay.

This year’s Winter Olympics games are scheduled to take place in China’s capital city of Beijing. Due to this, local authorities are keen to stamp out any COVID-19 cases in their country, both to protect the athletes and, likely, in hopes of getting praised at home and abroad.

As part of this effort, several Chinese cities are observing partial or full lockdowns. On Tuesday, the city of Lanzhou in the Gansu province was placed under complete quarantine. Today, the third city — Heihe — has been placed under the same restrictions.

Locked down again

China has had a hardline stance on the spread of the virus ever since it first emerged in 2019. The country was quick to institute targeted lockdowns, quarantine whole cities, and enact border closures to stop the spread of the virus. In broad lines, all these measures did pay off, and China grappled with the first wave of the pandemic quite effectively.

But they didn’t stop the coronavirus entirely. Several new flare-ups have been recorded in at least eleven of the country’s provinces, sparking a whole new round of lockdowns and quarantines.

Together with the four-million-citizen-strong Lanzhou, the city of Ejin (home to around 35,000 people) in Inner Mongolia has also been placed under lockdown three days ago. This decision follows a period of several days during which locals were ordered not to leave the city until further notice. Throughout China, an estimated six million people are now under quarantine. A few more tens of thousands are under orders to stay at home and limit their outside interactions to those that are strictly essential.

This Thursday, the city of Heihe in Heilongjiang province has also issued orders for its citizens to stay at home and forbidding travel outside of the city except in emergencies. Local authorities have also begun performing a testing campaign for its 1.6 million residents, and contact-tracing efforts for those identified as infected.

According to state media, public transportation and taxi services inside the city have been suspended, and vehicles were not allowed to go outside its bounds.

Residents in Beijing have also been ordered not to leave the capital since Monday, and quarantines have been imposed in certain residential areas.

Spray-on treatment could keep roads strong for longer while also making cities cooler

Is the heat getting you down? Most people can empathize. Enough of them, in fact, that one company is piloting a new asphalt treatment meant to reduce temperatures and eliminate pollutant particles, all while helping to keep roadways in good condition.

Image credits Maxx Girr.

The compound’s exact makeup is, as you’d expect, still a company secret. But we do know that it is based on titanium dioxide and meant to be sprayed over asphalt surfaces in cities struggling with the urban heat island effect. Although it does help reduce overall temperatures by making built surfaces absorb less heat, the treatment — named A.R.A.-1 TI — is marketed as a “road rejuvenator” and a seal for roadways.

Spray the heat away

The company behind this treatment, Pavement Technology Inc., is collaborating with Texas A&M University to measure its efficiency. This process involves sending road cores (samples retrieved from treated roadways) and air quality measurements to the university’s labs in order to determine what effect the treatment has in real-life situations.

But if the theory translates to practice, it should definitely help cool cities down. The source of the urban heat island effect is sunlight, which carries energy in the form of heat to asphalt and concrete surfaces, such as roads and buildings. These are very good at heating up, which makes everything that much more unbearable during the day (because you’re now standing, on a hot day, in a mile-wide hot surface). At night, these surfaces cede heat back into the environment, keeping the night’s air from cooling down. The more buildings there are in the city, the taller they are, and the more densely-packed, the more heat will be captured, and cities can be between 1 to 7 degrees F (0.6 to 3.4 degrees C) warmer than the areas around them.

All in all, a terrible experience for everyone involved.

Titanium dioxide is more commonly known as titanium white. Chances are that most white things you’ve ever encountered in your life, apart from foods, were painted using titanium white as a pigment. The plan is for this substance, which reflects incoming sunlight, to have a cooling effect on the dark surface of asphalt, which absorbs a lot of heat during the day. We’ve seen previously how green spaces can help reduce the intensity of the urban heat island effect by blocking sunlight; this treatment can be seen as a complementary to greenery, in that it helps reflect part of the sunlight that isn’t blocked by plants such as trees.

The titanium dioxide in the spray scatters and absorbs both visible light and ultraviolet rays — which makes it a popular component in sunscreens — but it also starts a chemical reaction in the presence of light which oxidizes and breaks down pollutants. Although it’s still in the pilot phase so the figures aren’t final yet, Pavement Technologies says its treatment so far has reduced levels of nitrogen oxide (NOx) by 30% to 40% in areas where it’s being trialed. One mile of roadway sprayed with this treatment has the same pollution-eating effect as 20 acres of trees, the company further claims.

The compound is being tested in three regions in Charleston County as of April 2021.

Still, its main intended role is to keep roads working for longer. The spray works by replacing compounds known as maltenes in old asphalt. Maltenes are found in bitumen, the black, oily fraction of asphalt, and they’re what gives fresh asphalt its bouncy, flexible nature. Over time, however, they degrade, and the material becomes brittle, cracking under strain.

Small towns are bigger than we think — and the world is more connected than ever

Here’s a mental experiment: take a moment to ponder the entire global population and where they live. Some, your mind will envision, are in the sprawling megacities of the world, while others are in smaller towns or villages. How many live in remote areas?

According to a new study, less than one percent of the global population lives in truly remote hinterlands. The surprising study shows that smaller cities and their surrounding areas are having an increasing influence on people’s livelihoods, contradicting the narrative that big cities are where most development happens.

How long it takes to get to large towns. Image credits: FAO.

Not islands

Since the industrial revolution truly took over in the 20th century, mankind has slowly moved from rural areas to urban areas. We’ve also become more connected, thanks to trains, cars, and more recently, planes. But according to a new study, even areas that are mostly rural (and you might think, isolated) are usually pretty well-connected.

The study analyzed multiple spatial datasets and calculated the time needed for rural populations to reach nearby urban centers. This is the so-called peri-urban area.

Cities often sprawl about, growing unrestrictedly in their desire to provide housing and commercial development towards the edge of the city. Thus, the ‘edge’ of the city gets pushed more and more, until it’s not clear where the city ends, and where neighboring areas begin. There’s no real agreement as to how to classify ‘peri-urban’, but typically, even a sprawling, sparsely-populated area around a city can be considered peri-urban.

According to the new study, 40% of the planet’s population lives in peri-urban areas, which is not necessarily surprising. What was surprising is that this 40% are almost equally distributed around small, intermediate, and large cities. Furthermore, small and intermediate towns seem to draw more inhabitants into their orbit than large cities.

The problem is that peri-urban environments often slip through the cracks of regulation and policy. They were traditionally considered rural, countryside environments, but as cities continue to expand, this is starting to change. Designing and managing areas in a way that’s suitable for both farmers and city dwellers is challenging, the researchers highlight.

“Rural and urban have been thought of as separate for too long. Development planning needs to focus on rural people’s access to employment opportunities and services in nearby urban centers, and acknowledge that urban centers are not islands upon themselves,” said Food and Agriculture Organization Senior Economist Andrea Cattaneo.

Mountain valleys of industrialised countries (e.g. Inn valley) are often periurbanised. Image credits: Lonesome Crow.

But what is perhaps even more striking is the percentage of residents that live in isolated hinterlands — areas defined as needing more than three hours — measured in terms of the available mode of transit from an urban settlement — to get to a town (of over 20,000 people). Just three countries have more than 5% of their population living in hinterlands: Madagascar, Niger, and Zimbabwe. Globally, less than 1% of the world’s population lives in these isolated areas.

The findings build on an overly simplistic view that higher-income countries are more urban. Real development is more complex, and often falls in the grey peri-urban area that’s neither truly urban nor rural.

Another important finding concerns food supply chains. The dominance of these peri-urban landscapes, combined with the fact that the urban and rural components are managed differently, suggests that local food chains could be managed more effectively and sustainably through local collaboration between farmers and urban dwellers.

“Agri-food chains connect rural and urban areas,” said Professor Andy Nelson from the Faculty of Geo-Information Science and Earth Observation, University of Twente in the Netherlands, and a co-author of the study. “Our data set supports both research and policy for transforming food systems to sustainably meet the increasing demands of urban markets.”

However, the importance of large cities should still not be underestimated: 40% of the world’s urban population (and almost 50% in Latin America and the Caribbean) live in large cities.

The study was published in Proceedings of the National Academy of Sciences.

Foxes living in the city are starting to become domesticated

Red foxes living in the city are evolving traits associated with pets or livestock animals such as shorter snouts or smaller skulls among other physical characteristics, a new study suggests.

Image credits Tony Hisgett / Flickr.

Dr. Kevin Parsons, of the University of Glasgow’s Institute of Biodiversity, Animal Health and Comparative Medicine explains that there are some important physical and behavioral differences between red foxes that live in the UK’s urban and rural environments, with the former becoming more similar to domesticated dogs.

The findings help further our understanding of how domestication processes take place and could help uncover how humanity domesticated other animals in the past

Wild is out of fashion

“We wondered whether this change in lifestyle was related to adaptive differences between urban and rural populations of red foxes,” said Dr. Parsons, of the University of Glasgow’s Institute of Biodiversity, Animal Health and Comparative Medicine, lead author of the paper.

“We assessed skulls from hundreds of foxes found within London and the surrounding countryside and saw that urban foxes had a smaller brain size capacity but also a different snout shape that would help them forage within urban habitats. There was also less of a difference between males and females in urban foxes.”

Coronavirus lockdowns around the world have created space for wild animals to roam (or even take up residence in) our cities more often. However, they present a very different habitat compared to the wilds, and many species just can’t adapt to long-term life in the city.

But some are especially good at it. Red foxes are one such species, and they’ve become quite prevalent in urban areas, especially in the UK. They’re also adapting to be better suited to life here, and to living in proximity to humans.

The team explains that the changes they documented in the study are the same that they would expect to see during a domestication process. The foxes are far from being domesticated, but they are taking on characteristics seen in domesticated animals. The team explains that their findings here can help us piece together how dogs, for example, evolved into pets from predators.

The changes observed by the team are “primarily involved with” the length of their snouts, braincases, and reduced sexual dimorphism (i.e. physical differences between the two sexes). Urban foxes have shorter snouts and smaller braincases, the paper explains. Differences between the two populations are “widespread and related to muscle attachment sites”, they add and likely driven by different requirements for cognitive ability and physical characteristics when feeding in the two habitats.

These changes matched up with what would be expected during a domestication process. In other words, while urban foxes are certainly not domesticated, they are changing in ways that move them closer to what is seen in many domesticated animals.

“This is important because human-animal interactions are continuous and some of the basic environmental aspects that may have occurred during the initial phases of domestication for our current pets, like dogs and cats, were probably similar to the conditions in which our urban foxes and other urban animals are living today,” adds co-author Dr. Andrew Kitchener from National Museums Scotland.

The paper “Skull morphology diverges between urban and rural populations of red foxes mirroring patterns of domestication and macroevolution” has been published in the journal Proceedings of the Royal Society B: Biological Sciences.

While we quarantine, some animals take to the streets, some get lonely, and a panda may get pregnant

As we keep to our homes more and more, wildlife is coming into the city to explore. Luckily for us, there’s always a camera nearby to capture such moments for “d’awws” and “aawws” on social media.

But not all animals are enjoying themselves equally. With zoos shutting their gates to the public, and amid growing concern that staff could unwittingly infect them, some zoo animals are starting to miss getting attention — but they’re also getting busy.

The goats of Llandudno

Wild goats roaming through Llandudno in North Wales by Andrew Stuart, a video producer at Manchester Evening News.
Image via Medium.

“Llandudno has a herd of wild goats, which date back to the 1800s. They do like to come down the hillside, as seen many, many times previously — and documented extensively by my colleagues at North Wales Live and the Daily Post,” Stuart explained for Medium.

“They are still wary of people and human life. Normally, they are put off going much further than the bottom of the Great Orme because of how busy it is (in relative terms — this is still Llandudno after all, and not inner-city Manchester). However, thanks to the Covid-19 lockdown, the goats didn’t have any traffic, people or noise stopping them — so they ventured out.”

The goats do seem to enjoy themselves, as they chew through local shrubbery and gardens, sunbathe in a churchyard, and even “blocked traffic”. However, they are still wary of coming close to humans.

This sleepy fox somewhere in Canada

Image credits SaraReneeRyan / Twitter.

Sara, who is currently pursuing a Ph.D. at Texas Tech, Tweeted that her dad who lives somewhere in Canada “had been sending me and my sister updates [on the fox] all day” and has even named it Nezuko.

It’s not hard to see why.

Foxes are one of the more often-spotted animals in this period, from what I’ve seen so far. There’s a lot of fox photos to enjoy in the replies to Sara’s tweet if that’s your thing (it definitely is mine).

A chill coyote

A coyote spotted in San Francisco.
Image credits beccatravels / Reddit (Becca Cook).

San Francisco is no stranger to coyotes. They live in the woods near the Bay Area and are generally content to stay away from people or ignore them if they meet. This one, however, looks very pleased that the normal hustle and bustle of the city has been curtailed in order do get some peace and quiet with a view.

But while this coyote is enjoying itself, others are hard at work resolving local politics.

“We had coup d’etat if you will,” Presidio Wildlife Ecologist Jonathan Young told ABC News about a fight that broke out in between the animals a few days ago. “A new alpha pair came and took over and kicked out the old alpha pair.”

“Since the COVID shelter-in-place, the winding trails and idle golf course [around the city’s Presidio] have become a go-to refuge for neighbors and more importantly their dogs. For the next few weeks or months, that’s potential trouble.”

The Presidio Trust cautions people that coyotes aren’t typically aggressive, but will regularly be on the hunt or defend themselves from domestic pets. It’s also a pupping season currently, so people would best try to avoid these animals. Sections of the Park Trail and the Bay Area Ridge Trail will be closed to hounds starting April 6 for the next few weeks or months over concerns about safety.

What’s happening in the zoos

We’ve just had our first confirmed case of the coronavirus jumping from a human to a tiger, and zoo staff are understandably worried that they may unwittingly infect their charges. As such, zoos around the world are implementing measures to limit the risk by reducing the animal’s exposure with their handlers and the public.

The US Centers for Disease Control and Prevention (CDC) has since reiterated that there is no evidence yet that pets can spread COVID-19 to people or that they might be a source of infection in the US, but zoos and conservation centers are still being especially careful. For example, the Borneo Orangutan Survival Foundation, a rehabilitation center for orangutans in Borneo, closed its doors to all visitors and asked the caretakers to wear masks and protective gloves when working with the primates, which are burned after the working day is over.

Grosser Panda.JPG
A giant panda at Ocean Park, Hongkong.
Image credits J. Patrick Fischer,

Nathan Hawke from Orana wildlife park in New Zealand told The Guardian that although visitors are no longer permitted, many of the park’s animals continue to come for their daily ‘meet the public’ appointments. Other groups of animals that are accustomed to human presence also seem to miss us, too, although the feeling may be forming through their stomach more than through their hearts.

Privacy, perhaps, was just what some of these species had been missing, however. Staff at the Ocean Park in Hong Kong reported that the 14-year-old resident female and male giant pandas Ying Ying and Le Le have “succeeded in natural mating” two days ago — because there aren’t any rules on panda social distancing.

This is the first success since attempts at natural mating began a decade ago, and the staff is excited for the birth, as the species is currently considered vulnerable in the wild but attempts to breed more giant pandas in captivity have been remarkably frustrating.

Urban farming can feed surprisingly many people — at least in Sheffield

Using 10% of a city’s green spaces such as gardens and urban parks could provide the fruit and vegetables to feed 15% of the local population, according to a new study.

Gateway Greening Urban Farm, St. Louis, Missouri.
Image via Wikimedia.

Researchers at the Institute for Sustainable Food at the University of Sheffield analyzed the potential of urban horticulture in feeding Sheffield citizens by mapping its green and grey spaces.

Domestic gardens, allotments, and suitable public green spaces put together would correspond to 98 square meters per person in Sheffield for growing food. Commercial horticulture across the UK currently uses around 23 square meters per person, the paper adds.

Local produce

Green spaces cover around 45% of the city, which is similar to other cities in the UK. Allotments represent 1.3% of this surface, with domestic gardens, which have immediate potential to start growing food, making up 38%.

Using data from Ordnance Survey and Google Earth, the team showed that a further 15% of the city’s green space (such as parks and roadside verges) could also be converted into community gardens relatively easily.

If all the green areas in Sheffield were to be turned over for food production, the team estimates it could provide fruits and vegetables for approximately 709,000 people per year (that number is, currently, 122% of the city’s population). But even if only 10% of available green space is used to grow food, it could provide for 87,375 people, or 15% of the city’s population. The team explains that this would greatly improve the UK’s food security, by increasing the share of locally-grown food in the economy.

The team also analyzed soil-free farming on flat roofs through means such as hydroponics (plants grown in a nutrient solution), and aquaponics (a system combining fish and plants). Such farms would allow year-round growing of food with minimal lighting requirements, and virtually no ecological impact — the greenhouses would be powered by renewable energy and heat captured from buildings, with rainwater harvesting for irrigation. The 32 hectares of flat roof cover in Sheffield would translate to only half a square meter per local, but the team says it could have a significant impact on local food security.

“At the moment, the UK is utterly dependent on complex international supply chains for the vast majority of our fruit and half of our veg — but our research suggests there is more than enough space to grow what we need on our doorsteps,” says Dr. Jill Edmondson, Environmental Scientist at the University of Sheffield and lead author of the study.

“Even farming a small percentage of available land could transform the health of urban populations, enhance a city’s environment and help build a more resilient food system.”

The paper “The hidden potential of urban horticulture” has been published in the journal Nature Food.

Experiencing wilderness keeps us happy, so we should protect it even in cities

Experiencing wilderness is particularly important for physical and mental health finds new research led by the University of Washington (UW).

Lighthouse at the Discovery Park, Seattle.
Image credits Michael Camilleri / Flickr.

We’ve gradually lost touch with nature as our cities grew wide and tall around us. The luckier among us city dwellers might live close to a park, or on a green-roofed building, giving us some access to natural areas; but wild ones are virtually non-existent. A new study reports that exposure to wilderness is an important factor for human physical and mental health, especially so in urban landscapes, even compared to other types of natural areas.

Wild at heart

“It was clear from our results that different kinds of nature can have different effects on people,” said lead author Elizabeth Lev, a graduate student in the UW School of Environmental and Forest Sciences.

“The wilder areas in an urban park seem to be affording more benefits to people — and their most meaningful interactions depended on those relatively wild features.”

The study focused on the Discovery Park in Seattle, the largest in the city (roughly 500 acres in size). The park is situated about 20 minutes by car from Seattle’s downtown areas, and has faced the same development pressures as others in cities with growing populations, the team explains. The research was prompted by the park’s advisory board, which asked the team to find out which elements are most important for park-goers in order to better inform decision-makers.

Despite focusing on this single park, the team is confident that their findings hold over well for most other major cities and beyond.

“We looked at Discovery Park, but this is about the entire planet,” said senior author Peter Kahn, a UW professor of environmental and forest sciences and psychology. “Everywhere, development is chipping away at wild areas. Humanity has caused so much destruction and there’s no stopping it — unless we stop.”

“We’re trying to show that if you’re going to develop an area, you at least need to understand the human costs.”

The team asked several hundred visitors to the park to submit a written online summary of a meaningful interaction they had at Discovery Park, obtaining 320 submissions. Then they set about coding these experiences into several categories (which the researchers call “interaction patterns”) to allow for better handling of the data. For example, an account stating “we sat and listened to the waves at the beach for a while” was assigned to the categories “sitting at beach” and “listening to waves.”

They found that six categories were consistently rated as important to visitors. These included encountering wildlife, walking alongside a body of water, enjoying the view, or following an established trail. They further looked at how the wilderness component factored into these experiences, finding that it had a role to play in nearly every interaction the visitors reported on. For example, “spotting bald eagle” references a relatively wild bird, and “watching birds perched on an old-growth tree,” denotes a wild habitat.

Additionally, the researchers looked at whether the park’s relative wildness was important in each visitor’s most meaningful experiences in the park. They defined “relatively wild” as including Discovery Park’s varied and relatively unmanaged land, its high levels of biodiversity, its “big nature” like old growth trees, large open spaces, expansive vistas, and people’s experience of the park’s solitude and removal from civilization.

The team explains that it’s important to know what these interactions are and what makes them valuable to us, so that we may better recognize and engage in them. Walking along the water’s edge on a weekend may be very fulfilling, but it’s not really an option most of us have on a busy weekday — but more ‘tame’ versions of it, such as walking along a fountain or other water feature to unwind, are.

“We’re losing the language of interaction with nature and, as we do, we also lose the cultural practice of these deep forms of interaction with nature, the wellsprings of human existence,” Kahn said.

“We’re trying to generate a nature language that helps bring these human-nature interactions back into our daily lives. And for that to happen, we also need to protect nature so that we can interact with it.”

It’s definitely an interesting study, and I do personally like the idea of mixing in more natural spaces in our lives. But as out cities become ever more crowded and space ever more expensive, there’s bound to be intense pressure to turn parks and recreational areas into more ‘productive’ landscapes. Studies such as this one go a long way towards reminding us that efficiency and profit aren’t the only ingredients of a good life; sometimes, happiness is as simple as sitting down and looking at an old tree.

The paper “Relatively Wild Urban Parks Can Promote Human Resilience and Flourishing: A Case Study of Discovery Park, Seattle, Washington” has been published in the journal Frontiers in Sustainable Cities.

More green spaces can help some cities keep cool

Researchers looking into how to help keep our cities cool say that more green spaces can help, although not everywhere.

Image credits Khusen Rustamov.

The urban heat island effect is a phenomenon through which the temperature in a city is noticeably higher than in the surrounding rural area. Which is, obviously, very irritating.

In a bid to find out how to control the effect, an international team of researchers looked at the role of precipitation and population size have on city temperatures compared with the surrounding countryside. All in all, they report that more green spaces can help bring city temperatures down, but not everywhere.

Plant some plants

“We already know that plants create a more pleasant environment in a city, but we wanted to quantify how many green spaces are actually needed to produce a significant cooling effect,” says Gabriele Manoli, former postdoc with the Chair of Hydrology and Water Resources Management at ETH Zurich and lead author of the study.

When urban heat island effects compound with the sort of heatwaves that hit most of Europe this summer, it can pose a very real and deadly threat to the elderly, sick, and other vulnerable groups.

The team looked at urban heat islands across the globe and at the different heat-reduction strategies they employ. The effectiveness of these strategies depends heavily on regional climate, they explain.

Manoli and his team — with members from ETH Zurich, Princeton University and Duke University — studied data from around 30,000 cities worldwide and their surrounding environments. The factors they analyzed include average summer temperatures, population size, and average annual rainfall.

The larger the city, the more dramatic its urban heat island, the authors explain — but also more rainfall in the region. As a rule of thumb, more rain means more plant growth, meaning that areas surrounding large cities are much cooler than them. This effect is the strongest when annual rainfall averages around 1500 millimeters (as in Tokyo), but does not increase further with more rain.

Cities in very dry regions (like Phoenix, Arizona) can, through carefully-targeted planting efforts, bring their average temperatures below that of the surrounding countryside. Those surrounded by tropical forests on the other hand (such as Singapore) would need far more green spaces to reduce temperatures — but the authors warn that this would also increase humidity.

Therefore, cities located in tropical zones should look to other cooling methods, such as increased wind circulation, more use of shade, and new heat-dispersing materials.

One of the main takeaways from the study, Manoli explains, is a preliminary classification of cities to help guide planners on possible approaches to mitigate the urban heat island effect.

“There is no single solution,” Manoli says. “It all depends on the surrounding environment and regional climate characteristics.”

“Even so, searching for solutions to reduce temperatures in specific cities will require additional analysis and in-depth understanding of the microclimate. Such information, however, is based on data and models available to city planners and decision-makers only in a handful of cities, such as Zurich, Singapore or London.”

The team is now working to determine which types of plant are most useful for reducing the heat island effect.

The paper “Magnitude of urban heat islands largely explained by climate and population” has been published in the journal Nature.

By 2050, many cities will have hot weather like they’ve never seen

Thanks to global warming, London will be as hot as Barcelona, while 17 US cities including New York, San Francisco, and Washington will face hotter weather than they’ve ever seen before.


A new analysis carried by researchers at ETH Zurich compared the predicted climates of cities in 2050 with the climates of cities today. The idea behind the study was to help people better visualize the effects of climate change — by describing them not as something which might seem abstract (like an average warming of 1 degree Celsius), but as a comparison. For instance, the study predicts that in 2050, the climate of Madrid in Spain will be like Marrakech, Morocco, is now. Seattle will be like San Francisco is today, while Sweden’s Stockholm will feel like Budapest. Strikingly, London’s climate will become a lot like Barcelona’s.

The approach makes a lot of sense. Cities are hotspots of climate change. They are hotter than their surroundings (due to the urban heat island effect) and also greatly at risk due to the high concentrations of people and infrastructure.

But there’s another reason.

Communicating climate change is notoriously difficult — and city planners are some of the most important people to get the message across to. Even if you do get the general message across, the specifics of how an area is expected to warm can be gimmicky to present.

For instance, since 1901, the planet’s surface has warmed by 0.7–0.9° Celsius. However, that doesn’t say much about particular cities, as the world isn’t heating up uniformly. Some areas are heating more than others, and even if you do get the specifics of a particular city, what does a 0.7 C warming even mean? For most people, that doesn’t exactly come through clearly.

Pairing up cities is a clever idea, as you get a very concrete idea for how things will change. However, it’s also quite a simplistic idea. A city’s climate is complex and depends on the layout, buildings, heat sources, population density, and many other parameters for which there is often no direct analog. So while this is a useful tool, it’s also an approximate one.

Furthermore, there are no good pairings or analogues for around a quarter of the world’s major cities (that is, cities with a population of over 1 million inhabitants). That makes for 115 cities (including Washington and 16 other cities in the US) which will suffer unprecedented climate conditions by 2050. Most of the cities in this category are in the tropics. Metropolises like Kuala Lumpur, Jakarta, Rangoon, and Singapore, will have a climate for which there is just no analogue on Earth at this moment.

In Europe, summers and winters will warm dramatically, with average increases of 3.5°C and 4.7°C, respectively, compared with 2000. Generally speaking, cities in the Northern Hemisphere will have climates similar to that of cities which lie 620 miles (1,000 km) to their south have today,

The study ‘Understanding climate change from a global analysis of city analogues’ was published in PLoS.

Çatalhöyük after the first excavations.

Cities from 9,000 years ago had pretty much the same problems as those of today, study finds

Big city problems are not recent news — in fact, they’re about 9,000 years old, according to a new study.

 Çatalhöyük after the first excavations.

The Çatalhöyük site during excavation work in 2013.
Image credits Omar Hoftun / Wikimedia.

A new study finds that one of the world’s first large farming settlements experienced many of the hazards of modern urban life — overcrowding, infectious diseases, exposure to violence and environmental problems — almost ten millennia ago.

New dog, old tricks

“Çatalhöyük was one of the first proto-urban communities in the world and the residents experienced what happens when you put many people together in a small area for an extended time,” says aid Clark Spencer Larsen, lead author of the study, and Professor of Anthropology at The Ohio State University. “It set the stage for where we are today and the challenges we face in urban living.”

Çatalhöyük in modern-day Turkey is one of the earliest-known large farming settlements in the world. It was a sprawling, populous place inhabited from about 7100 to 5950 B.C. At its peak, Çatalhöyük housed anywhere between 3,500 to 8,000 people. Because it lacks some of the key traits of cities today, however, we call it a ‘proto-city— but don’t let the moniker fool you. An international team of bioarchaeologists reports in a new paper: life in Çatalhöyük was rife with the same perils we’re exposed to in New York or London today.

The findings, which were drawn from 5 years of study of human remains unearthed at the site, show what people from a nomadic hunter-gatherer lifestyle were up against as they transitioned to a sedentary, agricultural life. As part of the larger Çatalhöyük Research Project, directed by Ian Hodder of Stanford University, Larsen first began studying human remains from the site in 2004. Fieldwork at Çatalhöyük ended in 2017 and the paper represents the culmination of the bioarchaeology work at the site, Larsen said.

The ruins of Çatalhöyük were first excavated in 1958, and today the site measures around 13 hectares (about 32 acres) with nearly 21 meters of deposits spanning 1,150 years of continuous occupation, according to the study. The city definitely had its ups and downs during the ages. It was a modest enough settlement in the Early period, a handful of mud-brick houses, but grew to a substantial size by its peak in the Middle period (6700-6500 B.C.). By the Late period, the population had declined sharply. Çatalhöyük was abandoned around 5950 B.C.


Çatalhöyük room restoration.

On-site restoration of a typical interior at Çatalhöyük.
Image via Wikimedia.

Farming was a pretty central part of life in Çatalhöyük. Based on stable carbon isotope analysis of the bones found at the site, the team determined that the residents relied heavily on wheat, barley, and rye for food, a diet they fleshed-out with wild plants. This grain-centric diet caused some locals to develop tooth decay, one of the so-called “diseases of civilization,” according to Larsen. Between 10% and 13% of all adult teeth retrieved at the site showed signs of dental cavities.

Stable nitrogen isotope ratios (nitrogen gets concentrated the further up a food chain you go, so it can be used to see which animals eat which) they also report that Çatalhöyükers primarily ate mutton, goat, and game as far as meats go. Cattle were also introduced to the area during the Later period, but sheep remained the primary source of meat for locals here.

“They were farming and keeping animals as soon as they set up the community, but they were intensifying their efforts as the population expanded,” Larsen said.

Residents also saw high infection rates. Up to one-third of remains from the Early period show evidence of infections on their bones. Pathogens thrived here due to crowding and poor hygiene. The team explains that during the settlement’s peak, houses were built like apartments, with no space between them so that residents came and left through ladders to the roofs of the houses. Excavations showed that interior walls and floors were re-plastered many times with clay. And while the residents kept their floors mostly debris-free, analysis of house walls and floors showed traces of animal and human fecal matter.

“They are living in very crowded conditions, with trash pits and animal pens right next to some of their homes. So there is a whole host of sanitation issues that could contribute to the spread of infectious diseases,” Larsen said.

Crowdedness may have also helped spark violence between locals, the team adds. Out of a sample of 93 skulls the team examined, 25 showed signs of healed fractures. Out of the same sample, 12 showed signs of repeated injuries (between 2 and 5).

Based on the shape of the lesions, they were produced by blows to the head made with hard, round objects. Clay balls with matching size and shape were found at the site. Most injuries were found on the top or back of the heads, suggesting the attacks came from the back (such as would happen during a mugging). Over half the victims were women (13 women to 10 men). The team also found evidence that such injuries were most common during the Middle period, “when the population was largest and most dense,” according to Larsen. “An argument could be made that overcrowding led to elevated stress and conflict within the community,” he adds.

The study also offers some clues as to why Çatalhöyük was abandoned. The authors report finding changes in the shape of leg bone cross-sections of locals over the generations which are indicative of walking long distances. Locals in the proto-city’s Late period had to walk around significantly more than their earlier counterparts, likely for farming and grazing. This finding suggests that drier climate conditions had a key role to play in Çatalhöyük’s demise, Larsen explains.

“We believe that environmental degradation and climate change forced community members to move further away from the settlement to farm and to find supplies like firewood,” he added. “That contributed to the ultimate demise of Çatalhöyük.”

Another surprising finding came from the way the locals were inhumed in Çatalhöyük. Most people were buried in pits dug into the floor of houses, likely under the home where they lived. This showed that most members of a household weren’t biologically related at all.

“The morphology of teeth are highly genetically controlled,” Larsen said. “People who are related show similar variations in the crowns of their teeth and we didn’t find that in people buried in the same houses. It is still kind of a mystery.”

“We can learn about the immediate origins of our lives today, how we are organized into communities. Many of the challenges we have today are the same ones they had in Çatalhöyük—only magnified.”

The paper “Bioarchaeology of Neolithic Çatalhöyük reveals fundamental transitions in health, mobility, and lifestyle in early farmers,” has been published in the journal PNAS.

Central Park.

Go to the park, it’s good for you — and makes you happier

New research shows that a 20-minute long visit to the park can make you happier, whether you exercise or not.

Central Park.

Image via Pixabay.

A team of researchers from the University of Alabama at Birmingham Department of Occupational Therapy says that urban parks are great for our emotional and mental wellbeing. Visiting an urban park for as little as 20 minutes will make you feel happier, they say, no matter what you do during that time.

Parking space for your stress

“Overall, we found park visitors reported an improvement in emotional well-being after the park visit,” says main author Hon K. Yuen. “However, we did not find levels of physical activity are related to improved emotional well-being. Instead, we found time spent in the park is related to improved emotional well-being.”

The study points to urban parks as key neighborhood elements, providing residents with the opportunity to enjoy nature and engage in physical activity. Contact with nature and health-promoting and/or social and recreational activities in parks let people reap benefits such as stress reduction and recovery from mental fatigue.

Data for the study was recorded in three urban parks — Overton, Jemison, and Cahaba River Walk Parks — in Mountain Brook, Alabama. These three parks were selected as they were the main three public parks in the town and saw a large volume of visitors each day. The team collected feedback from 98 park visitors, although four reported twice during the study and their second responses were excluded — thus, the team worked with data from 94 participant testimonies.

The findings suggest that everybody can benefit from some park-time. You don’t need to be physically active during your time there, so individuals can gain the health benefits of spending time in an urban park regardless of any disability or limitation they may be struggling with.

Yuen says that the study definitely has its limitations — these include the lack of objective data (as it was self-reported) pertaining to the visit’s effect on health and emotional well-being, and the study’s limited scope, both in number of participants and geographic spread. Still, the findings are exciting, he says, and point to the need for more urban parks and better conservation work on those already in place.

“There is increasing pressure on green space within urban settings,” said Jenkins. “Planners and developers look to replace green space with residential and commercial property. The challenge facing cities is that there is an increasing evidence about the value of city parks but we continue to see the demise of theses spaces.”

The paper “Factors associated with changes in subjective well-being immediately after urban park visit” has been published in the International Journal of Environmental Health Research.


Car-centric suburbs seem to promote right-wing politics and resistance to change

Could suburbs foster right-wing populism? One paper says ‘maybe’.


Image via Pixabay.

Decades’ worth of city-planning decisions may be promoting populism and unsustainable lifestyles, especially in the US, a new paper reports.

Not in my driveway

“As planners kept building suburbs they created scores of new electoral ridings and suburban voters who predictably voted for politicians and policies catering to their lifestyles,” said Pierre Filion, the study’s sole author.

“This translated into increasing automobile dependence, less land devoted to public space, and the continued cycle of building more suburbs”.

Filion analyzed urban planning trends from the end of World War Two up to 2010 outside Toronto, Canada. He also looked at voting patterns in the area over the same timeframe. All in all, he says, it seems that the rise of the car-centric suburb is — at least in part — to blame for the particular political environment we find ourselves mired in right now. In particular, the rise of right-wing populism.

The data suggested to Filion that suburbians’ increasing reliance on automobiles heavily influenced land-use and lifestyle choices among the group. The combination of this dependency on cars and a continued urban sprawl normalized economic and cultural behaviors that promote unsustainable living.

People whose livelihoods and recreation opportunities rely directly on cars will (understandably) be less willing to accept changes to the status quo — i.e. changes that would disproportionately impact them relative to the rest of society. It’s not only about comfort and convenience, Filion explains: these people rely on their cars to go to work. This also makes them less likely to vote for tighter regulations on cars or be willing to phase them out.

“This contributes to a sense of having their values attacked, and could explain some of the waves of right-wing populism in North America,” he adds. “A careful look at the results of the recent mid-term elections in the United States shows the clear ideological division between urban and suburban areas.”

In effect, this nudges suburbanites to resist calls for change which — even if they’d be beneficial for the planet/economy/society at large — would impact them personally.

“It’s something we saw in 2016 as well as the most recent election in Ontario, Canada,” Filion notes.

Illustration of a self-sustaining satellite city outside the Chinese city of Chengdu. Credit: Adrian Smith + Gordon Gill Architecture.

Illustration of a self-sustaining satellite city outside the Chinese city of Chengdu. Credit: Adrian Smith + Gordon Gill Architecture.

Suburbs are far from a necessity. A few years ago, Chicago-based architects Adrian Smith and Gordon Gill showed that even huge cities can get away without building suburbs as we know them — city planning is key. The duo designed a self-sustainable satellite city, the Chengdu Tianfu District Great City, to focus on pedestrians and do away with cars. The distance between any two points in the city is no longer than a 15-minute walk, so there’s no real reason to use cars, and all that free space is dedicated to green areas, instead. The project itself looks quite pretty, and I’d definitely go visit if I ever get the chance.

So what do you think? Are suburbs the bee’s knees, or just overall pretty bad? Let us know in the comments below.

The paper “Enduring Features of the North American Suburb: Built Form, Automobile Orientation, Suburban Culture and Political Mobilization” has been published in the journal Urban Planning.


Woodland hawks flock to cities, research reveals. Other wildlife is doing the same

So, should we call them cityhawks now?


Howdy, neighbah!
Image via Pixabay.

Researchers from the University of Wisconsin-Madison report that woodland hawks, a species that suffered greatly, are making a comeback — and they’re doing it in the big city.

Wildly urban

“Top predators are beginning to use urban areas more frequently and establish breeding populations, and hawks are a nice example of this,” explains Benjamin Zuckerberg, a University of Wisconsin-Madison professor of wildlife ecology and a senior author of the new study.

“For hawks, the secret is out: There is a hyperabundance of prey [in the city].”

Woodland hawks (subfamily Accipitrinae) have made themselves at home in our cities, the team reports. The hawks have adapted so well that an increasing number of those in the neighboring rural areas are city-bred predators.

The secret underpinning their colonization is the 35 million Americans who stock feeders every day to attract songbirds. The hawks themselves aren’t concerned with the seeds — but they’re very interested in the songbirds. This high availability of food is the single most important factor drawing birds such as Cooper’s and sharp-shinned hawks to the city, says Jennifer McCabe, a UW-Madison postdoctoral fellow who led the new study.

Hawks have had a rough time since the industrial revolution. Land clearing combined with increasing use of pesticides and hunting have caused the various species of woodland hawks to plummet in numbers. Things took a turn for the better, first around the 1960s and 1970s, with the US imposing bans on the use of DDT over health and environmental concerns (1972), and later with the Migratory Bird Treaty Reform Acts of 1998 and 2004, offering extra protection for the species against capture or killing by humans.

Still, the problem of habitat destruction remained unresolved and, as populations rebounded, hawks began to move into urban areas, the study concludes. In Chicago’s case, easy pickings at bird feeders significantly aided the hawk in establishing a foothold in the city, says McCabe.

The bird-feeding birds we’re feeding

Cooper's Hawk.

Image via Pixabay.

The study drew on more than 20 years of citizen science data gathered by participants of Project FeederWatch (an initiative of the Cornell Lab of Ornithology). As part of FeederWatch, people who feed birds helped document avian activity in their backyards. Zuckerberg says the program is “perfect […] for this kind of research” as it allows scientists to document both hawks and their prey.

The key insight from the study is that food availability is the key parameter bringing hawks to the city. It’s an unexpected finding, to say the least, because species such as Cooper’s and sharp-shinned hawks are woodland predators par excellence: they’re so-called “perch and scan” hunters, waiting on tree branches for a meal to come within striking distance and swooping down on it. Cities, as you may know, are particularly un-branchy. Finding that canopy cover was not a prerequisite necessity for the hawks to move in was therefore quite surprising.

Here’s where bird feeders come into the picture. These static, abundant, and usually low-lying sources of food attract a lot of birds and create an artificial ecosystem of sorts that the hawks are more than happy to tailor their hunting patterns for. Using Project FeederWatch data from 1996 to 2016, McCabe and her colleagues mapped the steady advance of these birds from rural areas to the urban center of Chicago. The pattern also occurs in many other North American and European cities (with European sparrowhawks, Accipiter nisus), they add.

“Bird feeders,” says Zuckerberg, “are like buffets. It is an easy meal.”

“Prey biomass wasn’t an important driver of colonization or persistence,” McCabe notes. “Much of the literature states, at least for Cooper’s hawks, that they prefer larger-bodied prey like doves and pigeons. Perhaps these hawks are cueing in on the sheer number of birds and not particular species.”

“However, they aren’t nesting in the winter, meaning they are more concerned about their own survival and not raising young. So it makes sense that food availability would be so important.”

One important lesson to take home from this research is that cities are an increasingly important habitat for wildlife. “Don’t discount urban areas as habitat,” McCabe says, adding that a better understanding of how such species move into urban areas can help us better “manage wildlife in an ever-developing world.”

“Across the world stories are popping up about predators expanding into cities,” she says. “Bear and cougars in the U.S., leopards in India, and red foxes in Europe, to name a few.”

Personally, I think it’s awesome that hawks are coming to crash on our figurative couch. They’re like zero-maintenance pets in my book!

Barn swallows wire.

Barn swallows have evolved to live alongside us, new research reveals

Barn swallows don’t just live next to us — they’re probably alive today because of us.

Barn swallows wire.

Image credits Geograph Britain and Ireland.

New research from the University of Colorado Boulder reveals that barn swallows (Hirundo rustica) — a species of bird that likes to live in bridges and sheds around the world — might be more intertwined with to us than previously thought. The paper explains that the barn swallow and its subspecies likely evolved alongside humans, as we were building our first settlements.

Neighbours with benefits

“Humans could be a really big part of the story,” said Rebecca Safran, associate professor of ecology and evolutionary biology at CU Boulder and paper co-author.

“There’s very few studies that can point to the exact influence of humans, and so here, this coincidence of human expansion and permanent settlement and the expansion of a group that relies really, really heavily on humans is compelling.”

Barn swallows are found throughout the northern hemisphere. They build mud-cup nests almost exclusively on human structures. Other than the fact that they originate in northern Africa, and that there are six barn swallow subspecies — which are have marked physical and behavioral differences — we don’t really know much about their evolution. Previous research suggested that the different subspecies split early, well before human settlement.

The new study gave the issue a fresh look by analyzing the full genomes of 168 barn swallows. Individuals were selected from the two subspecies farthest apart on an evolutionary scale: H. r. savignii in Egypt (a non-migratory species that lives along the Nile) and H. r. erythrogaster in North America (a species found throughout North America that migrates seasonally to South America). The team employed more sophisticated computational resources and methods than were available for previous studies. This gave them a more complete picture of barn swallow speciation over time (i.e., when the subspecies separated). Their results suggest the process happened much closer to the point in time when humans began to build structures and settlements.

Barn Swallow.

Image credits National Park Service.

“The previous studies were playing with the idea of potential impact on population sizes due to humans,” said Chris Smith, a graduate student in EBIO and the Interdisciplinary Quantitative Biology program, and the study’s lead author. “Our results suggest a much more substantial link with humans.”

The findings — still preliminary —  also suggest that the evolutionary link between humans and barn swallows was struck through a “founder event” — a situation which occurs when a small number of individuals is able to take over a new environment quickly due to abundant resources and an absence of competitors. For the swallows, the founder event may have occurred as they moved into a new, relatively empty environment: human settlements.

“Everyone is always wondering how do you study speciation? It’s been viewed as this long-term, million-year (process), but in barn swallows, we are not talking about differentiation within several thousands of years,” said Safran. “Things are really unfolding rather rapidly.”

The paper “Demographic inference in barn swallows using whole-genome data shows signal for bottleneck and subspecies differentiation during the Holocene” has been published in the journal Molecular Ecology.

Think cats are good at keeping rats away? Think again

A new innovative study shows that cats really aren’t really very good predators of rats, and employing this strategy often backfires.

While adorable, these small felines aren’t really good at controlling rat populations — and they might end up killing other animals instead.

While cats may be the undisputed kings and queens of the internet, they weren’t always this popular — and in many parts of the world, they still aren’t. Historically, the reason why cats and humans go so well together was a very practical one: cats keep mice (and other related species away). But in the case of rats, things might not be as clear.

Despite what you may read in some media, it’s not because the rats can fight the cats off — as anyone who’s witnessed a meeting between a cat and a rat can attest, rats are woefully unprepared for the fight, while cats are supreme killing machines. They say that a desperate rat is capable of anything, and that may be true — but even when the two are comparable in size, if the cat wants to kill the rat, it can almost always do so.

The reason doesn’t have anything to do with fighting at all — but rather, with avoidance.

“Like any prey, rats overestimate the risks of predation. In the presence of cats, they adjust their behavior to make themselves less apparent and spend more time in burrows,” says the study’s lead researcher Dr. Michael H. Parsons, a visiting scholar at Fordham University. “This raises questions about whether releasing cats in the city to control rats is worth the risks cats pose to wildlife.”

“New Yorkers often boast their rats ‘aren’t afraid of anything’ and are the ‘size of a cat’,” Parsons adds. “Yet cats are commonly released to control this relatively large, defensive and potentially dangerous prey.”

He and his colleagues took advantage of a favorable situation — when feral cats invaded a New York City waste recycling center, which also hosted a hefty population of rats. They monitored the behavior and movement of microchipped rats in the presence of cats, and they also set up motion-capture video cameras to quantify the effect of the cats on the rats.

It’s the first time this has been studied in such a natural setting.

“We wanted to know whether the number of cats present would influence the number of rats observed, and vice versa,” says Parsons. “We were also interested whether the presence of cats had any effect on eight common rat behaviors or their direction of movement.”

Overall, researchers analyzed 306 videos taken over 79 days, and results were quite surprising: although a few cats were always active around the rat colony, just 20 stalking events, three kill attempts and two successful kills were recorded in this time. The two kills were when cats found rats in hiding and took them by surprise. The unsuccessful attempt was when during a chase, a cat lost interest in the rat.

Even more interesting was that the mere presence of the cats dramatically shifted the behavior of the rats. Rats spent much less time in the open, and much more time hiding.

“The presence of cats resulted in fewer rat sightings on the same or following day, while the presence of humans did not affect rat sightings,” says Parsons. In contrast, the number of rats seen on a given day did not predict the number of cats seen on the following day.

“We already knew the average weight of the rats was 330 g, much more than a typical 15 g bird or 30 g mouse,” says Parsons. “As such, we expected a low predation rate on the rats — and our study confirmed this.”

Ultimately, researchers say, it’s not that cats can’t kill rats, and even that they won’t — they absolutely can, and sometimes, will — but the conditions need to be right, and the right conditions don’t seem to happen that often. Furthermore, as Parsons underlined, using cats to keep rat populations under control seems like a flawed strategy which can easily backfire.

The reason is that while cats may not enjoy killing rats that much, they sure do enjoy killing all sorts of other wildlife, and the risks severely outweigh the advantages.

Journal Reference: Michael H. Parsons, Peter B. Banks, Michael A. Deutsch, Jason Munshi-South. Temporal and Space-Use Changes by Rats in Response to Predation by Feral Cats in an Urban Ecosystem. Frontiers in Ecology and Evolution, 2018; 6 DOI: 10.3389/fevo.2018.00146

Tree park.

The US lost roughly 1 in every 100 urban trees between 2009 and 2014

The USDA Forest Service estimates that the country has lost approximately 36 million urban/community trees per year between 2009 and 2014.

Tree park.

Image credits Albrecht Fietz.

If you’re an American who likes stepping out in the street right under the shade of a tree, the USDAFS has bad news for you — the country’s cities and towns are running slim on trees. Roughly 0.7% of the nation’s urban trees have been felled between 2009 and 2014, which equals approximately 36 million trees, or 175,000 acres of tree cover lost annually over that period.

Fewer trees

Overall national urban tree cover declined from 42.9% to 42.2% over that period, the report states. However, the losses weren’t spread uniformly across the US; 23 states had a statistically significant decrease in urban tree cover, while 45 states showed a net decline.

“Urban forests are a vital part of the nation’s landscape,” said co-author Tony Ferguson, Director of the Forest Service’s Northern Research Station and the Forest Products Laboratory. “Forest Service research puts knowledge and tools into the hands of urban forest managers that supports stewardship and the wise allocation of resources.”

Trees help filter air and water, improving their quality, which is especially nice in urban areas, that tend to see the highest levels of pollution. They also help keep down energy bills in the summer by keeping buildings cool. Other benefits urban trees provide include noise reduction, mitigation of runoff and flooding, as well as enhancing our mood and mental well-being, and having a positive effect on health. Overall, the benefits derived from urban forests in the US is estimated at some $18 billion annually, in the form of air pollution removal, carbon sequestration, and lowered building energy use.

The states or districts with the greatest annual net loss in urban tree cover were Rhode Island and the District of Columbia (0.44%), Georgia (0.40%), and Alabama and Nebraska (0.32% each). The states that lost the most tree cover per year were Georgia (18,830 acres/year), Florida (18,060 acres/year) and Alabama (12,890 acres/year).

Mississippi, Montana, and New Mexico saw slight (statistically non-significant) increases in urban tree cover. Maine recorded the highest percentage of urban tree cover across the US — 68%. North Dakota, with just 10%, ranked the lowest.

“Urban forests are an important resource,” said Dave Nowak of the USDA Forest Service’s Northern Research Station, co-author of the study. “Urban foresters, planners and decision-makers need to understand trends in urban forests so they can develop and maintain sufficient levels of tree cover — and the accompanying forest benefits — for current and future generations of citizens.”

Over the same period, urban/community impervious cover (concrete, buildings, so on) saw a statistically-significant increase, from 14.5% to 15.1%. States that saw the greatest annual net percent increase in impervious cover were Delaware (0.28%), Iowa (0.26%), Colorado, Kansas and Ohio (with 0.24% each). States with the greatest net increase in impervious cover were Texas (17,590 acres/year), Florida (13,900 acres/year), and Ohio (8,670 acres/year).

The study comes to flesh out previous research of the USDAFS, looking into the role urban forests will play in future cities.

The paper “Declining urban and community tree cover in the United States” has been published in the journal Urban Forestry & Urban Greening.


Half a degree (C) more global warming would leave 5 million people homeless

The seemingly inconsequential jump from 1.5 degrees to 2.0 degrees Celsius of global warming is anything but — that half of a degree would mean 5 million people across the world will need to move, or find a way to live in flooded areas.


Image credits George Hodan.

The 2015 Paris climate agreement seeks to stabilize global temperatures to less than 2 degrees Celsius above pre-industrial levels, with efforts made to ensure we never go more than 1.5 degrees Celsius above pre-industrial levels. And that sounds like a reasonable, safe goal. An international team from the Princeton, Rutgers, and Tufts Universities, alongside researchers from Climate Central and ICF International, however, wanted to find out what such a scenario would entail for people living in the most at-risk areas — coastal areas.

Still underwater

They drew on a global network of tide gauges and a framework of local sea-level projections to estimate how the frequency of storm surges and other extreme sea-level events would fare under three scenarios: global temperature increases of 1.5°, 2.0°, and 2.5°C.

Their results suggest that by 2150, the minute difference between an increase of 1.5° and 2.0°C would equate to the permanent inundation of areas that currently house 5 million people, including 60,000 who live in small island nations.

“People think the Paris Agreement is going to save us from harm from climate change, but we show that even under the best-case climate policy being considered today, many places will still have to deal with rising seas and more frequent coastal floods,” said first author DJ Rasmussen.

Unsurprisingly, the team reports that higher temperatures will make extreme sea level events much more common than they are today. Based on long-term hourly tide gauge records, they estimated current and future return periods of such events throughout the 22nd century. Under the 1.5°C scenario, this value is still expected to increase. For example, New York City is expected to see one Hurricane Sandy-like flood event every five years by the end of the 21st century under these conditions.

Extreme sea levels can be borne of high tides, storm surges, or a combination of these two — sometimes referred to as a storm tide. When whipped by hurricanes or other large storms, such events can flood into coastal areas, threatening life and property alike. A background of rising average sea levels will only compound the destructiveness and frequency of such events.

How much sea levels rise, on average, depends on how global mean surface temperatures evolve in the future. However, caution to the wise, the team notes that even if temperatures stabilize, sea levels are expected to continue to rise for centuries — because carbon dioxide lingers in the atmosphere for a long time and ice sheets will have inertia in responding to climate change.

Still, the researchers predict that by the end of the century, coastal flooding may be among the costliest impacts of climate change in some regions. Overall, a 1.5°C temperature increase by the end of the century (the best-case scenario under the Paris agreement) would equate to a roughly 1.6 feet (48 cm) mean sea level rise, and a 2.0°C increase to about 1.8 feet (56 cm). A 2.5°C increase would result in an estimated 1.9 feet (58 cm) increase, the team adds.

The paper “Extreme sea level implications of 1.5 °C, 2.0 °C, and 2.5 °C temperature stabilization targets in the 21st and 22nd centuries” has been published in the journal Environmental Research Letters.

Chaotic cities are cooler than orderly ones, researchers report

A new paper reports that street and building layout plays a major role in a city’s urban heat island effect, which makes them hotter than their surroundings.


Cities with an orderly pattern have a much greater urban heat island effect than those with a more disorderly pattern.
Image credits Pellenq et al., 2018, Physical Rev. Letters.

If you’re an American living in a big city, you’re probably used to all the streets and buildings being laid out in an orderly grid. If you happen to be European, not so much — our cities still sport the chaotic, sprawling road networks set down ages ago. While it can make navigation a pain, the latter can also help keep cities cool, according to new research led by MIT and National Center for Scientific Research senior research scientist Roland Pellenq.

The findings suggest that cities laid out in precise grids, like New York or Chicago, experience a far greater buildup of heat relative to their surroundings than those arranged more chaotically, like London or Boston.

The Hot Grid

The heat island effect is a product of the fact that building materials, like concrete, absorb heat during the day and radiate it out at night. Natural areas also trap some heat, but it’s a tiny amount compared to cities — mostly because plants use up incoming sunlight during photosynthesis. Heat island effects can make cities over 5° Celsius (10° Fahrenheit) warmer than surroundings, in areas that get a lot of sunlight. It can cause health issues for city dwellers and causes energy use to spike during hot weather. So, a better understanding of the effect can improve quality of life for residents and presents (several) economic advantages to boot.

To explore the heat island effect, the team adapted mathematical models that were developed to analyze the atomic structures in materials, developing a new and straightforward method to study the relationship between a city’s design and its heat-island effect. Such systems describe how individual atoms in a material are influenced by other atoms, and the team reduced the simulation to much simpler, statistical descriptions of how far away buildings are from each other. Then, they applied them to patterns of buildings in 47 cities, from the U.S. and also from other countries.

Each city was thus ascribed a ‘local order parameter,’ ranging between 0 (total disorder) and 1 (perfectly ordered structure, which is generally a description of how orderly atoms in a material are — typically, this parameter is obtained by bombarding a sample with neutrons. For this paper, however, Pellenq and his team used Google maps to pinpoint the location of each building. The cities included in the paper varied from 0.5 to 0.9 on their local order parameter.

Temperature data was recorded for each city by two stations — one within the city proper, and another outside but still close — which were used to determine the heat island effect in each case.

The team reports that the heat island effect seems to result from the interactions between buildings that radiate and re-radiate heat. This heat can be trapped by other buildings that face them directly, the team reports, meaning the city has a very hard time cooling off. They estimated that in the state of Florida alone, urban heat island effects lead to some $400 million in excess costs for air conditioning per year.

So, understanding how it works and planning around the effect might have significant benefits, especially for countries such as China that are rapidly building new cities, or areas of rapid urban expansion. In hot locations, cities could be designed to minimize the extra heating, while colder places might benefit from amplifying the effect.

“This gives a strategy for urban planners,” says Pellenq.

“If you’re planning a new section of Phoenix, you don’t want to build on a grid, since it’s already a very hot place. But somewhere in Canada, a mayor may say no, we’ll choose to use the grid, to keep the city warmer.”

Other important findings of the study are that research on construction materials can offer a way forward in regards to heat management and heat interactions between buildings.

The paper “Role of city texture in urban heat islands at nighttime” has been published in the journal Physical Review Letters.

Plantscaper concept.

Swedish company builds food-laden ‘Plantscaper’ to feed the cities of the future

Swedish company Plantagon is tackling the world’s food problems through ‘agritecture’, a combination of architecture, technology, and agriculture. The first of their projects, a massive vertical greenhouse or “plantscaper”, is set to open in 2020.

Plantscaper concept.

Artist’s concept of a plantscaper.
Image via Plantagon.

There are over 7.5 billion people living today, a number that’s expected to skyrocket to 10 billion in the next 30 or so years. Many researchers, politicians, and members of the public are worried that we’ll see dire shortages in the wake of such spectacular population increases. Perhaps most worryingly of which are the looming threats of food and water scarcity, likely to be compounded by climate change and greater migration towards urban centers.

For many of us, these shortages have yet to make an appearance, and it would be just dandy if things stayed this course. To be blunt, however, for that to happen we’ll need to grow much more food than we do today, and we’ll need to grow it more efficiently, especially in regards to water usage. One Sweedish-based company named Plantagon is working today so we’ll have solid footing when dealing with the issues of tomorrow.

Their solution involves dotting urban landscapes with huge vertical farms called “plantscapers”, crop-laden skyscrapers that can feed thousands of city dwellers each year.

The concept of Plantagon’s vertical greenhouses is the brainchild of Swedish innovator Åke Olsson. A passionate organic farmer, Olsson needed to get more surface out of his croplands. So, he designed a rack transport system which slowly cycles planting boxes from the floor of a vertical greenhouse to its ceiling, so he didn’t have to use any artificial light. Shortly after Plantagon International AB and the Plantagon International Association were founded in 2008, they bought the design from Olsson.

Greenhouse inside.

Image via Plantagon.

Plantscapers use the same concept but on a much taller scale, mixed in with a hearty helping of hydroponics to keep everything growing. They resemble high-rise office buildings that churn out delicious veggies instead of water cooler conversations and stressful deadlines. The first plantscaper, The World Food Building, is already under construction in Linköping, Sweden. The 16-story building is estimated to cost around $40 million and should be ready to open sometime in 2020.

The WFB’s layout allows for far more output relative to its surface area than a conventional farm. The building is expected to produce about 550 tons of vegetables annually, which according to the company should be enough to feed roughly 5,000 people. The plants will be grown in watery, nutrient-rich substrates. All factors and growing conditions, from water to nutrition, sunlight, temperature, and air quality will be monitored autonomously, to make sure everything is perfect for the plants and that waste is minimized.

Maintenance and harvesting jobs will similarly be performed by autonomous systems, Plantagon CEO Hans Hassle told Business Insider, likely in a bid to keep costs down. Plantagon hopes their autonomous systems and urban setting will lower transportation, production, and energy costs enough to make the ‘scrapers a sustainable solution to feeding the community. Additionally, the building will help save 1000 metric tons of CO2 emissions and 50 million liters of water that a conventional farm uses for the same amount of food.

Of course, these figures will have to be verified after the WFB is completed, and any eventual teething problems are solved. Still, the plantscaper concept does seem to be a hit so far (I admit I’m quite taken as well, I just love buildings with plants). The company is currently in talks to develop plantscrapers in Singapore, the United States, Hong Kong, and Shanghai.

I’d also be curious to see a cross between Plantagon’s concept and a technology such as that of SolarWindow — one producing food, the other electricity. Such buildings could conceivably feed and power cities at the same time.

Until then, will have to wait and see if the plantscraper concept will succeed. I hope it does.

City sunset.

Urban heat island effect could almost triple the cost of climate change in cities, burn economies to a crisp

Cities might feel the heat of climate change almost twice as worse as the rest of the world due to the urban heat island effect, a new paper reports. Unless cities adapt to ensure more incoming energy is reflected or absorbed, this effect will put a huge dent in the economy, it further reads.


Tokyo, one of the densest urban centers in the world. Not a place you want to be in on a warm day.

It’s a hot day, your apartment is stiffing, and the AC just doesn’t cut it — so you decide to take a stroll in the park by the water to cool down. Or maybe go on that long overdue hike and get a break from the city altogether. Congratulations! You’ve unknowingly felt the effects of and then counteracted the urban heat island effect.

There are millions more who, just like you, are feeling the heat. And that’s actually part of the problem. The ‘urban heat island effect’ is just what it sounds like. These areas of higher ambient temperatures form when natural surfaces like vegetation or water that tend to reflect or use incoming energy are replaced by artificial surfaces such as concrete or asphalt, that trap incoming natural heat (sunlight). The high concentration of cars, air conditioning heat sinks, people, and so on in cities also means there’s a lot of anthropic heat which further drives up ambient temperatures.

Throw climate change in the mix, and it’s only going to get worse. Worse enough, in fact, that it’s going to tank the economy.

Paying the cooling bills

Published by an international team of economists, the study is the first to look at how major cities will fare under global as well as local changes in climate — and it’s not at all encouraging. This analysis included 1,692 cities around the world to quantify the effects of rising temperatures throughout climate zones (and across countries and cultures) on urban GDP, the backbone of modern economies, and found that the costs of climate change for cities this century could be 2.6 higher than we’ve believed once you factor in the heat island effect.

Overall, the team reports that we’re likely looking at a decrease of 5.6% of Gross World Product product by the end of the century, but the effects won’t be distributed uniformly. In the worst-affected cities, for example, climate change-induced losses could shave off as much as 10.9% of GDP by the end of the century.

City sunset.

You could say the profits will melt away.
Image credits Rogerio Rogeriomda.

Particularly bad news since cities, although they cover only around 1% of Earth’s surface, churn out about 80% of Gross World Product, consume about 78% of the world’s energy, and house more than half of the world’s population.

So how do the two tie together?

Well, on the one hand, mean temperatures exceeding 13 degrees Celsius (or 55 Fahrenheit) seem to reduce human productivity, and unstable climate will also eat away at entrepreneurship, meaning that there’s less going into the lump sum we call GDP. On the other hand, higher temperatures mean higher expenses. We’ll use up more energy (which translates to costs) for cooling, there will be higher medical care costs due to falling air quality, lower productivity, even rioting, and healthcare costs associated with social unrest over lack of food and higher levels of aggression — all very nice stuff.

As a side-note, a lot of very important cities might not be viable anymore — no city, no city’s GDP.

The research puts the issue of climate change into perspective. The discussion today revolves around tackling this change — as it well should be. But at the same time, it’s easy to lose sight of the fact that local interventions to mitigate the effects of warming climate are equally important for our economies and quality of life.

“Any hard-won victories over climate change on a global scale could be wiped out by the effects of uncontrolled urban heat islands,” said Professor Richard S.J. Tol MAE, Professor of Economics at the University of Sussex, in a statement.

“We show that city-level adaptation strategies to limit local warming have important economic net benefits for almost all cities around the world.”

The paper further looks at the measures which could limit the costs of this effect, and whose implementation should, therefore, be a top priority for ruling bodies.


To find the most desirable solution, the team performed a cost-benefit analysis for a number of local policies including ‘cool’ pavements and roofs, which are designed to reflect sunlight and thus absorb less heat, increasing vegetation cover including green roofs, and so on.

One Central Park facades.

One Central Park, Sydney — because you can do good for the climate, bring down temperature, and look awesome while doing it.

Medium-scale implementation of cool pavements and roofs came out on top, echoing finds regarding climate change in general that mitigation is the best policy. Turning 20% of a city’s roofs and pavement surface to the cool variety would save up to 12 times their installation and maintenance costs and reduce ambient temperatures by 0.8 degrees Celsius over the following century — not a bad result. The 20% point is just the peak — implementing this policy on a wider scale will provide even more benefits but at a lower cost-efficiency. Another thing to keep in mind is that successful global climate change mitigation efforts, in general, will compound the effects of these local policies, so we should really be working on both fronts here. As Professor Tol concludes:

“It is clear that we have until now underestimated the dramatic impact that local policies could make in reducing urban warming. However, this doesn’t have to be an either/or scenario. In fact, the largest benefits for reducing the impacts of climate change are attained when both global and local measures are implemented together.”

“And even when global efforts fail, we show that local policies can still have a positive impact, making them at least a useful insurance for bad climate outcomes on the international stage.”

The full paper “A global economic assessment of city policies to reduce climate change impacts” has been published in the journal Nature Climate Change.