Showing posts with label Urban. Show all posts
Showing posts with label Urban. Show all posts

Friday, September 9, 2022

Thinking about cities: Were ancient cities greener than modern ones?

  

*This is part of a series called ‘Thinking About Cities’ which are parts of a book I am working on about urban green space that I’ve decided to cut out of the book manuscript.

 

Picture a large modern city. Undoubtedly, your mental image includes a lot of grey. Grey buildings. Grey roads. Maybe grey skies saturated with ozone and particulate matter. Yet we don’t see green as a dominant feature of a city despite the undeniable importance of vegetation and green space to the well-being of a city. 

 

Now picture an ancient city. This image probably has a lot less grey and more browns and greens. We likely see dirt (unpaved) roads, wooden structures, trees here and there, a river with a natural bank, and chickens and other livestock intermingled with human activity. 

 

Were ancient cities inherently greener than modern cities? If so, was this done by design, or by accident, or because humans lacked the technology to completely transform the landscape? Before we delve into this question, we need to think about what a city is and where it comes from.

 

History of the city

Cities have evolved from small permanent settlements to massive human-created landscapes that house large and densely packed populations. As Gordon Childe argued (Childe 1950), the city is a revolution. They represent revolutions of technology, governance, economics, and our relationship with nature and place. Nothing like cities existed in all of human history until about 9-10 thousand years ago when the first known large settlements appeared near the shores of the Mediterranean Sea ( These were Jericho in what is today the West Bank and Catal Huyuk in Turkey. These cities housed somewhere between 2 and 6 thousand people).  To understand the origins of the city, we need to look to the birth of the major civilizations, and to find these, we need to go to the banks of the major rivers of the Middle East and Asia. The Nile, Ganges, Tigris, Euphrates, Indus, Yangtze, and Yellow rivers were the cradles fostering the birth of cities. Just like a germinating seed, cities required water to grow. The rivers were the lifeblood of these new forms of civilization and was essential for the irrigated agriculture that fed populations, a supply of drinking water and for construction, a means for moving waste away from human populations, and were the express highways of the day –moving people and goods.

 

These first major cities were home to several thousand people (certainly less than ten thousand) living in loosely organized communal areas, and though these do not seem like cities by today’s criteria, they were massive by the standards of the day. Pre-agrarian societies supported population densities of about 0.04 people per square kilometre and early agrarian societies, which gave rise to the first permanent settlements, had between 1 and 5 people per square kilometre. Cities today have densities of hundreds or thousands of people per square kilometre.

 

The shift from nomadic cultures to agricultural ones was the necessary development for cities to emerge. Having a permanent source of food drastically changed how people spend their time and allowed them to produce more food than they could personally eat. Sounds trivial, but this new reality allowed for specialized occupations that were not focused on finding and gathering food. The farmer produces the food, while others pursue their own vocational callings like carpenter, artisan, priest, and so on. With new occupations involving training and expertise, innovation and technological development ensued. Metal workers tested new methods and alloys, farmers found ways to increase yield, and the priests and elites organized people and resources.

 

By this point, cities were all but inevitable. As different cultures shared information and technology, small cities began to emerge along the great rivers of the world. These rivers all supported the eventual growth of large cities of ten thousand or more people by about 5 thousand years ago. But the rivers also needed to be controlled. While they were an invaluable resource, they could also be unpredictable and devastating. The ancient city of Petra in modern Jordan, was a thriving capital city between 300 BC and 300 AD, but it was subject to floods after heavy storms and the Petroneans built damns and culverts to reduce flooding. This was not unique to Petra. Many ancient city archaeological sites include evidence of engineered structures designed to control flooding.

 

Cities also required governance. Ten thousand people living together would be chaotic if there wasn’t some sort of government in place to create and enforce rules. For these early cities, this governance was intertwined with religion. Temples were the centre of these early cities and provided guidance, worship, laws, education and were the focal points for political power. People no longer relied solely on family or clan allegiance but were increasingly tied to loyalties to king, high priest, and nation-state. These power structures were important for organizing people and pooling efforts and creativity into larger and larger projects, while promising protection from other nation-states, which were also increasing in power.

 

The emergence of cities was a slow evolution from small permanent settlements to large centrally governed and densely populated ones. It is hard for scholars to say with certainty when the first city appeared because both the evidence has been washed away by time and it is not entirely clear what a city is.

 

For ancient settlements, we can say that the designation as a ‘city’ corresponds to certain features that are necessary to successfully house thousands of people in a small area. These would include: sturdy streets capable of sustaining constant use, dense and organized housing, central governance and control of law enforcement, taxation to pay for services and common good building projects (e.g., aqueducts, city walls, etc.), specialized occupations and trades that provide expertise in various elements of culture, governance and construction of cities (e.g., engineers, teachers, etc.), markets allowing specialized occupations to trade goods and services, because blacksmiths do not grow much food and farmers make few metal objects, and finally cities have large and permanent impacts on local environments.

 

Let us paint a picture of an early city by looking at the largest city in the world during the 11th century –Kaifeng, China (historically called Daliang or Bianjing). Kaifeng was the capital of the Song dynasty (960 - 1279) and at the height of its glory, it was home to somewhere between six hundred thousand and one million people. We actually know a lot about Kaifeng. China is the oldest continuous civilization on Earth and has tremendous collections of historical documents. Further, Kaifeng is still a major city today with a population of about five million people –a medium-sized city by Chinese standards, but a very large one by standards elsewhere. Most importantly, one of China’s most cherished historical artifacts is a giant scroll measuring 5.25 meters (or over 17 feet) long called “Alongthe River During the Qingming Festival”, and it beautifully depicts Kaifeng life during a national holiday. 

 

A small segment of the painting “Along the River During the Qingming Festival, painted by Zhang Zeduan (1085-1145). It depicts city life in Kaifeng, China at the height of its prestige when it was the capital city and the largest city in the world.


From this beautiful illustration, you can see the elements of what it means to be a city. First, there are lots of people milling around and participating in different activities. There is trade, we see people moving goods in carts and on camels. There are specialized occupations, notice the tea houses and restaurants. There is organised building construction lining a major road. We see the overwhelming evidence of codified economics as people are buying goods and exchanging money (and gambling!). And with economics we see class inequalities as the lady pulls aside the silk curtains and looks out of the litter, or shoulder carriage, being carried by porters. There is a city gate protecting the population and regulating and taxing the flow of goods. If we move along the scroll, we would see the Yellow River and the docks and ships necessary to move people and goods over great distances. Looking at the amazingly detailed depictions in the scroll, we can almost smell the odours and aromas and hear the sounds that permeate through a dense city. Horses neighing, dogs barking, people shouting, and dishes clanging. This was a city by any definition.

 

So was Kaifeng greener than modern Beijing?

Obviously, Kaifeng, if it existed today, would be a greener city than Beijing. Modern Beijing, or any other megalopolis, is defined by a massive concentration of material and energy that results in a concrete landscape capable of housing millions of people. Keifeng simply had less impervious surface and more space for nature. So, the short answer is yes, ancient cities were physically greener.

 

But if we think of ‘green’ as being a philosophy or approach that directs how we interact with nature, then I don’t think we can say that ancient cities were greener. Humans have created cities precisely to alter local environments to better suit our needs. A city is the embodiment of our innate desire to increase our own fitness by removing threats (from predators and other people), creating security through strength in numbers, and reducing environment unpredictability. We might want to romanticize early human relationships with nature, but the reality is that once technologies were created that advance urbanization, they were implemented and spread rapidly. Being susceptible to flooding, early cities channelized rivers once they were able to. In response to threats from other groups of people, cities around the world accepted being encased in walls as the technologies emerged.

 

The history of cities can be seen as a continuum from small and low-impact settlements to large, urbanized landscapes like Tokyo. What drives a smaller and greener city towards being a megalopolis? So long as the population demand is there and the technologies to build a city exist, the megalopolis is all but inevitable.

 

Unlike previous generations, we are in a unique position to ask the question, what do we want a city to look like? Most of the technological hurdles that would limit urbanization have been overcome. We now have the conceivable ability to create a completely urbanized planet, like Coruscant from Star Wars. But most people would think that this is a bad idea. But is barely constrained sprawl around urban centres like Los Angeles, Mexico City, Delhi, and Toronto not a microcosm for these urbanizing forces that we think are ultimately undesirable?

 

The point is that neither in ancient times nor now do people have an agreed upon vision of urbanization’s endpoint. Urbanization has been and is driven by the mix of demand and technology, but we now need, more than ever, an agreed upon vision and set of principles directing urbanization. We need cities that minimize environmental impact, reduce the effects of inequality, and ensure people realize the potential benefits of green space.

 

So, were ancient cities greener than cites today. Yes and no. While they had less impact on their local environments, the megalopolises of today were written into their DNA. The devaluation of nature has always been a defining feature of cities. Now, more than ever, we need to rethink the relationship between the city and nature, and rewrite what is coded in a city’s DNA.

 



Childe,V. G. (1950). The urban revolution. Town Planning Review, vol. 21, pg. 3-17.


Thursday, March 18, 2021

COVID-19 and nature: Is wildlife conservation also in “lockdown”?

Guest post by Nina Adamo, Masters of Environmental Science Candidate at the University of Toronto-Scarborough

Within the surge of news coverage for the COVID-19 pandemic, you may have heard about the increase in the reporting of wildlife sightings in some urban areas across the globe, such as in this CBC article. With less people venturing outside of their homes in efforts to prevent the spread of the coronavirus, the media in multiple countries around the globe have been reporting more sightings of wildlife that are usually rarely or uncommonly seen in suburban and urban areas.6,7 This was the case when a herd of Kashmir goats were seen strolling through the deserted streets of a town in Wales during the lockdown.7


A herd of Kashmir goats roaming the empty streets of a town in Wales.3


This also happened in Toronto, Canada this past summer, where foxes were seen denning in typically busy areas of the city during lockdown.2 To read more about the Tale of Toronto’s boardwalk foxes, check out this article in Maclean’s magazine. What does this unusual and greater number of wildlife sightings in urbanized areas mean for wildlife behaviour and wildlife conservation as a whole?



Fox kits on the boardwalk of Woodbine beach in the city of Toronto, Canada.4

The “rolling lockdowns” implemented as strategies to contain the novel coronavirus have severely restricted human activities, and have had cascading effects through public health systems and economies.6 What is less clear however, is what impacts this sudden change in human behaviour may have on wildlife and what the long-term implications are for the fate of wildlife conservation across the globe and into the future. The interaction between our societal response to COVID-19 and wildlife is a novel and emerging topic that scientists have only just begun to investigate. Unsurprisingly, initial findings tell a complex story, where lockdowns have had both positive and negative impacts on wildlife and the conservation of biodiversity.1,5,6

Initial positive effects of lockdowns on the environment, in general, include reductions in industrial activities and manufacturing, and restrictions on the transport of natural resources, leading to a decrease in global emissions and an increase in air and water quality.1,5 Other studies report decreases in noise pollution leading to an increase in sightings of animals in cities and harbours, along with reduced numbers of animals being killed by ships in waterways and by vehicles on roads.1,6 Similarly, a study conducted in Italy, the first country to implement a lockdown, found a greater proportion of sightings of species such as the crested porcupine in suburban and urban areas in 2020 compared to previous years.6 The same study also found evidence for an increase in the abundance and breeding success of certain species of birds during lockdown in urban areas, likely due to general decrease in the presence of humans.6

A crucial point to consider about all of these positive observed effects is that many of these effects, such as the presence of uncommon animals in urban areas, are likely to only be temporary and prone to reversal once restrictions are lifted and humans begin to revert back to pre-lockdown behaviours.5,6 It is also worth noting that many observed increases in animal numbers under lockdown conditions could have resulted from an increase in observation effort with more people participating in hobbies such as birding due to restrictions on other activities during lockdowns.6 Similarly, the greater detection of bird species could have been attributed to an increase in detection rates because of a reduction of background traffic noise with less traffic volume in lockdown conditions.6

There is great concern that the COVID-19 pandemic will severely hinder efforts to conserve biodiversity in the present as well as in the long term.6 During lockdown, there have been substantial delays in both species at risk management efforts and invasive species control programs,6 reduced funding available for conservation because of overstressed economies, reductions in wildlife-based tourism due to travel restrictions, and governmental capacity generally being prioritized for COVID-19 relief measures.1,5 The pandemic has undoubtedly put a strain on our capacity for conservation, and many initiatives will be playing catch-up to make up for precious lost time, where many of these conservation efforts are focused on species that are already teetering on the brink.

Increased human threats to nature are also expected to occur as a result of the lockdowns.5,6 As more people, especially in rural areas, are forced to navigate pandemic-driven economic downturns, they may have no choice but to turn to protected areas for resources.5 In addition to this, the reduced funding available for hiring patrol staff such as park rangers in protected areas can result in a lower likelihood of detecting poachers and can lead to an increase in illegal killing of wildlife, which has been the pattern already observed in multiple places across the globe including Europe, Africa, and Asia.1,5,6


Schematic of the potential impacts of the COVID-19 pandemic on different areas related to the conservation of wildlife in Africa, with the arrows indicating the directionality of these impacts.5


The surge of research examining the interaction between societal response to COVID-19 and wildlife tells a complex story.6 Although there were some positive effects of the lockdown observed on wildlife, these will likely only be temporary until restrictions are lifted, but the potential negative impacts could have long-lasting effects on the conservation of biodiversity.5,6 Furthermore, activities focused on the conservation of species and habitats can also help to reduce the risk of future pandemics as the restrictions put in place to protect certain species and their habitats can help to reduce our exposure to species that are a high risk for virus transfer to humans, leading to a lower risk of future outbreaks and subsequent pandemics.5

Overall, although the COVID-19 lockdowns have shown some initial positive impacts on the environment and wildlife, there are significant risks associated with these lockdowns that may negatively impact the effectiveness of wildlife conservation. In order to effectively prevent the accelerated loss of biodiversity that could result from lockdowns, countries must ensure funding for conservation actions is not neglected.

  

References

  1. Bates, A. E., Primack, R. B., Moraga, P., & Duarte, C. M. (2020). COVID-19 pandemic and associated lockdown as a “Global Human Confinement Experiment” to investigate biodiversity conservation. Biological Conservation, 248, 108665. https://doi.org/10.1016/j.biocon.2020.108665
  2. Dhopade, P. (2020, July 7). The tale of Toronto’s boardwalk foxes. Retrieved from https://www.macleans.ca/society/environment/toronto-boardwalk-foxes-coronavirus-lockdown/  
  3. Furlong, C. (2020, April 5). A herd of Kashmir goats invaded a Welsh seaside resort after the coronavirus lockdown left the streets deserted. Wildlife take to the streets as people stay indoors. [Getty Images]. Retrieved October 26, 2020 from https://www.cbc.ca/news/world/photos-wildlife-animals-take-to-streets-as-people-take-shelter-indoors-1.5519538
  4. Lautens, R. (2020, July 7). A few of the young kits at Woodbine Beach in Toronto; when passersby began taking selfies with the animals, a local wildlife centre intervened. The tale of Toronto’s boardwalk foxes. [Image]. Retrieved October 23, 2020 from https://www.macleans.ca/society/environment/toronto-boardwalk-foxes-coronavirus-lockdown/
  5. Lindsey, P., Allan, J., Brehony, P., Dickman, A., Robson, A., Begg, C., Bhammar, H., Blanken, L., Breuer, T., Fitzgerald, K., Flyman, M., Gandiwa, P., Giva, N., Kaelo, D., Nampindo, S., Nyambe, N., Steiner, K., Parker, A., Roe, D., … Tyrrell, P. (2020). Conserving Africa’s wildlife and wildlands through the COVID-19 crisis and beyond. Nature Ecology & Evolution, 4(10), 1300–1310. https://doi.org/10.1038/s41559-020-1275-6
  6. Manenti, R., Mori, E., Di Canio, V., Mercurio, S., Picone, M., Caffi, M., Brambilla, M., Ficetola, G. F., & Rubolini, D. (2020). The good, the bad and the ugly of COVID-19 lockdown effects on wildlife conservation: Insights from the first European locked down country. Biological Conservation, 249, 108728. https://doi.org/10.1016/j.biocon.2020.108728
  7. Wildlife take to the streets as people stay indoors. (2020, April 5). Retrieved from https://www.cbc.ca/news/world/photos-wildlife-animals-take-to-streets-as-people-take-shelter-indoors-1.5519538



Tuesday, January 12, 2021

A crack in the green: when ecosystem services become drivers of inequality in cities

Guest post by Marylouisse Feliciano, recent MEnvSc Graduate from the University of Toronto-Scarborough

Can health-related ecosystem services actually increase health inequality? What does the uneven distribution and varying quality of urban green spaces say about social justice in urban environments? Not all park spaces and green spaces are created equal. As urbanization marches forward, steps have to be taken to address inequalities and prevent this pattern from continuing.

 Health, urbanization, and parks: what we know

            Nature is good for your physical and psychological health and wellbeing. The benefits of spending time in nature is a subject that continues to gain traction, both in research and among the public sphere. However, as more and more of the population moves towards urban living, spending time in nature has increasingly become something of a luxury. Although access to healthcare and health resources has increased, urban living itself can lead to more sedentary behaviours and increased exposure to pollution. In addition, there are mental and emotional aspects of city life that impact public health. Of particular note are the trends in psychological well-being associated with cities.

            Consider the CAMH Monitor survey in Toronto, which finds that reports of fair or poor mental health increased from 7.1% to 10.1% between 2016 and 2017. Furthermore, reports of suicidal thoughts have almost doubled in the same timeframe, and visits to the CAMH Emergency Department have increased by 70% between 2012 and 2017. Are there within city trends that we should be paying attention to? One of the most studied risk factors affecting urban mental health is socio-economic status (SES). Its association with mental health has been consistent—a 2017 literature review observed that mood disorders were more frequent among residents of large cities in Germany (Gruebner et al., 2017). There are several reasons for this, from the heightened difficulty in building and sustaining supportive social relationships in disadvantaged areas to the possibility that people with poor health or life difficulties move to more “deprived” areas due to lower rent costs.

A greenspace planning workshop in Victoria, BC. Retrieved from: https://www.oala.ca/ground_articles/the-powers-in-the-process/

What role do urban parks and associated greenspace play? The list is long. At its most basic, urban parks provide space for citizens to participate in physical activities, such as running and exercising. These spaces provide more opportunities for people to engage in an active, healthy lifestyle. While physical activity in urban green spaces is no doubt essential, its increasing noted that the psychological benefits of urban park space should are of equal importance. In addition to being a place where physical activities can occur, parks can act as a space for relaxation and reprieve from noise. As urban lifestyles becomes more stressful, having a place to distance oneself from that aspect of modern life can help in preventing emotional distress and crisis. These spaces can also foster community and relationship building. The positive mental health values of park space can be broadly described as “psychological ecosystem services”.

What we know but don’t admit: park space quality is not equal

            Socio-economic status doesn’t just directly affect health. It plays a role in the quality of park-space, especially in the context of a city. For park space to provide the psychological ecosystem services they are touted to have, they must be maintained and cared for (Branas et al., 2011; Hunter et al., 2019). Park spaces that are available to low-income communities are often poorly maintained, vandalized, or even unsafe. Some parks even become hotspots for drug use, sometimes acting as a gateway to substance abuse and associated health risks. In light of this, access to the positive psychological ecosystem services that urban green spaces provide are inequitably distributed through many cities around the world.    

A used needle found in a park in Lawrence, Massachusetts. Retrieved from: https://www.citylab.com/equity/2019/02/opioid-epidemic-data-drug-addiction-deaths-urban-rural/582502/

            The issue is more complex than mere park space availability. Whether or not disadvantaged groups have more or less access to park space is less clear—these neighbourhoods tend to be in less developed spaces, meaning that they might have more access to forested park space than people living in typically higher income city centres. However, the quality of park space has a more predictable trend—it’s typically of poor quality in disadvantaged communities, and access tends to be negatively associated with average income. For example, a study in Portugal found that, although the majority of neighbourhoods had accessible greenspace, distance to them increased with neighbourhood deprivation (Hoffimann et al., 2017).

          Yet, the group of people who could most benefit from the health aspects of park space are the disadvantaged, and good access to park space and associated green space can reduce observed socio-economic and mental health inequalities between advantaged and disadvantaged groups. Having good park space puts people living in cities on a more even playing field health-wise (Mitchell et al., 2015). However, although this pattern is known, issues with the quality of park space make it hard to believe that planners are taking the potential health benefits of park space seriously. 

            Although findings are mixed regarding geographic access to greenspace and socio-economic status, the aspect of park quality is less ambiguous. City planners need to consider both proximity and quality if they wish to address inequality in access to park space, and the associated health-related ecosystem services they should to provide to everyone.

A conceptual rendering of Rail Deck Park in Downtown Toronto. Retrieved from: https://www.toronto.ca/city-government/planning-development/planning-studies-initiatives/rail-deck-park/

When ecosystem services are not for everyone: the cracks we fall through

            Urban park spaces provide health-related ecosystem services, and their quality tends to not be distributed equally across cities. Put the two together and it becomes clear that socio-economic factors are leading to park spaces not benefitting all urban citizens equally. Of course, there is the issue of “which came first”: are disadvantaged neighbourhoods provided with poor quality park space, or does the installation of quality green space lead to housing prices increasing, making them only affordable to the advantaged population? Fundamentally, what led to what is less important than taking action to prevent and remove this trend.

Urban planning and design can and must do better if it wishes to utilize park space in a way that doesn’t amplify health inequalities that already exist. Ecosystem services that are not spread equitably across a populace do a disservice to the communities that need them the most.

Links

CAMH Monitor Survey

National Recreation and Park Association – Parks & Recreation Magazine

References

Branas, C. C., Cheney, R. A., MacDonald, J. M., Tam, V. W., Jackson, T. D., & Ten Have, T. R. (2011). A Difference-in-Differences Analysis of Health, Safety, and Greening Vacant Urban Space. American Journal of Epidemiology, 174(11), 1296–1306. https://doi.org/10.1093/aje/kwr273

Gruebner, O., A. Rapp, M., Adli, M., Kluge, U., Galea, S., & Heinz, A. (2017). Cities and Mental Health. Deutsches Ärzteblatt International, 114(8), 121–127. https://doi.org/10.3238/arztebl.2017.0121

Hoffimann, E., Barros, H., & Ribeiro, A. I. (2017). Socioeconomic Inequalities in Green Space Quality and Accessibility—Evidence from a Southern European City. International Journal of Environmental Research and Public Health, 14(8). https://doi.org/10.3390/ijerph14080916

Hunter, R. F., Cleary, A., & Braubach, M. (2019). Environmental, Health and Equity Effects of Urban Green Space Interventions. In M. R. Marselle, J. Stadler, H. Korn, K. N. Irvine, & A. Bonn (Eds.), Biodiversity and Health in the Face of Climate Change (pp. 381–409). Springer International Publishing. https://doi.org/10.1007/978-3-030-02318-8_17

Mitchell, R. J., Richardson, E. A., Shortt, N. K., & Pearce, J. R. (2015). Neighborhood Environments and Socioeconomic Inequalities in Mental Well-Being. American Journal of Preventive Medicine, 49(1), 80–84. https://doi.org/10.1016/j.amepre.2015.01.017

Monday, December 21, 2020

Bright Goes North

Guest post by Kate Davies, a recent MEnvSc Graduate from the University of Toronto-Scarborough


She could feel the pull in her body. It was time.

She had done this journey before, but even the first time it felt familiar. Like a memory that she was born with.

She was called Bright because she was known by the others for her deeply golden tail feathers and her clear eyes. Bright was late leaving her winter home this year, and many of the others had left already, departing at the first signs of change. The air had started to feel heavy signaling that the rains would come soon. She had to start north before daybreak. Bright hopped around the tree canopy from branch to branch. She dropped her wings by her sides and fanned her tail to spook the insects and quickly grab them in her beak. She had spent her winter in brushy scrubland that was not the best feeding grounds, but she was older now and had less energy to defend her place in the boggy wetlands filled with ripe insects. She ate her fill before she spread her wings and started to carry her small light body out over the immense open waters. Crossing the gulf was frightening the first time, but she knew even on her first trip that the sky would end, and she would see green again. She traveled in a loose flock with some other Redstart females, some yearlings and others Bright knew from previous flights. She hoped some of her daughters were here, now grown she would not have known their calls. The males always left first; they would meet them in the northern home.

Illustration by Kate Davies

The journey across the gulf lasted into the night, the winds were not favourable this year. Bright and the others she travelled with were weak and needed to eat. There was a wetland they had visited as a stop every year, but Bright was worried they had taken a wrong turn. This was the right place but there was not water, few plants, and it had been filled with stone, humans and a glowing hum. It seemed as she flew north every year there were more angular stone forests filled with humans. Some could tolerate these stone forests but Bright and her companions preferred trees and grass. The birds who lived there like pigeons and house sparrows spoke a different language than the other birds she knew, and some said they came across the water bigger than the gulf. So, despite their exhaustion the females kept flying until they could find somewhere to eat and sleep. They had to settle for an area where the plants all grew in rows, a farm, but there was a river and some insects so it would do for today. These human places had different dangers and predators than in the forests and fields. Bright knew to be cautious of owls, hawks and snakes but where there were humans, other dangers were lurking. They were too tired to find anywhere else to sleep. Bright noticed that her party had shrunk by a few - some were so tired they may have rested in the stone forest. Bright hoped the others would be alright and would catch up to the group.

They travelled for a few more days, finding quiet places to rest. They avoided the stone forests as much as they could with their bright lights, constant noises and hums. They rested at another farm on the fifth night. Bright and her companions were huddled in a dense thicket of bushes near a field and river. They had fallen sound asleep for the night. In the nearby tall grasses, a pair of green eyes shone in the moonlight. A barn cat had been stalking the birds, she moved quietly, softer than the wind. The cat slinked under the low branches of the bush without a sound and spotted a bird on a low branch she could easily reach.  Bright opened her eyes to see one of the yearlings was in the cat’s fangs - she was lost. Bright and her companions moved to another row of bushes closer to the stream, they were all shaken and tired. Fear and anxiety overtook the small flock, they didn’t sleep anymore that night. Bright was relieved when the sun crept over the horizon and they could continue northward.

Illustration by Kate Davies

The air was warm, and they had been lucky that there were no storms along the way. They started to see some males that day, and a few of her companions ended their journey to find a mate. Bright continued her northward flight as did most of the females until they made it over the big lake. It was not as big as the gulf, but it could be dangerous, as there were many humans and stone forests around the water. There were predators near every shore, some had been here all winter and were eager for the small songbirds to return so they could fill their bellies.

Since Bright had left late this year, she was eager to build a nest and find a mate. She decided to end her journey on an island at the north shore of one of the long lakes. Most of the others continued north. She was near a stone forest but on an island that was far enough away that the sound of the waves drowned out the hum and noise. It was the time of year where the air was filled with song from many different birds. She fluttered around the island listening for males of her kind, trying to find one who sang strong and clear. She followed a song to a male high up in a red maple tree. In her mind she identified him as Flicker - he was very expressive in the way he flicked his tail. He took her to the sites he had scouted for nesting to see if she approved of any. She was happy that she would be his first and maybe only mate, which would afford her more protection. She picked the third site he showed her. It was a dense area of red dogwood that was covered in fresh young leaves. They were close to a pond in an area rich with insects. She started to gather twigs and build her nest there while Flicker stayed close singing to warn others away from his mate and territory. Together they had four eggs and Bright was happy with her clutch size; it was more than last spring. She left the nest to find some food in early morning and Flicker guarded the eggs. She was chasing a particularly acrobatic fly though the bushes when suddenly a great force stopped her flight and she fell to the ground. She could feel and taste the warmth of blood in her mouth, her beak was fractured, her head pounded, and she could not catch her breath. She had only seen branches before her, it was like a reflective pond in the air made of stone. Bright wanted to live, she wanted to get up go back to Flicker and the young. She could not move; she let out her last breath and died.

The new gardener came around back of the building to trim the forsythia that was long overgrown. At the base of the bush under the window lay a female American Restart, she was dead. The garden gasped and cried out ‘Oh no!’ Another window strike, this was the sixth one this month and perhaps it would encourage management to finally birdproof the windows, thought the gardener. She buried the bird in the garden with a tear for its loss of life and trimmed the forsythia. On her break she reported the window strike on the Fatal Light Awareness Project (Flap) website and continued her duties.

Flicker realized that Bright would not return - what had become of her? He could not care for the babies alone. He would have to leave them. He sung a mournful song for Bright and flew off in search of a new mate hoping that it wasn’t too late.

 

 

Further Reading and References

Further reading: Online resources

The Cornell Lab - All about birds – American Redstart

Overview: https://www.allaboutbirds.org/guide/American_Redstart/overview and

Species account: https://birdsna.org/Species-Account/bna/species/amered/introduction

Toronto and Region Conservation Authority. The American Redstart: A Bird On the Rise In the GTA https://trca.ca/news/the-american-redstart-a-bird-on-the-rise-in-the-gta/

Boreal Songbird initiative. A guide to boreal birds https://www.borealbirds.org/bird/american-redstart

Ontario Nature. Migratory Birds https://ontarionature.org/campaigns/migratory-birds/

North American Birds Declining as Threats Mount By Mel White for National Geographic https://www.nationalgeographic.com/news/2013/6/130621-threats-against-birds-cats-wind-turbines-climate-change-habitat-loss-science-united-states/

Birdwatchers Digest. Your Bird Questions Answered: Flight and Migration https://www.birdwatchersdigest.com/bwdsite/connect/youngbirders/your-bird-questions-answered-flight-migration.php

 

 Further reading: peer reviewed literature

Cohen, E. B., Rushing, C. R., Moore, F. R., & Hallworth, M. T. (2019). The strength of migratory connectivity for birds en route to breeding through the Gulf of Mexico. Ecography, 42(4), 658–669. https://doi.org/10.1111/ecog.03974

Cooper, N. W., Sherry, T. W., & Marra, P. P. (2015). Experimental reduction of winter food decreases body condition and delays migration in a long-distance migratory bird. Ecology, 96(7), 1933.

Hill, G. E. (2004). A Head Start for Some Redstarts. Science, 306(5705), 2201–2202.

Germain, R. R., Marra, P. P., Kyser, T. K., & Ratcliffe, L. M. (2010). Adult-Like Plumage Coloration Predicts Winter Territory Quality and Timing of Arrival on the Breeding Grounds of Yearling Male American Redstarts. The Condor, 112(4), 676–682. https://doi.org/10.1525/cond.2010.090193

Norris, D. R., Marra, P. P., Bowen, G. J., & Ratcliffe, L. M. (2006). Migratory connectivity of a widely distributed songbird, the American Redstart (Setophaga ruticilla). The Auk, 123(4), 14.

Norris, D. R., & Marra, P. P. (2007). Seasonal Interactions, Habitat Quality, and Population Dynamics in Migratory Birds. The Condor, 109(3), 535–547.

Marra, P. P., & Holmes, R. T. (2001). Consequences of Dominance-Mediated habitat segregation in American Redstarts during the nonbreeding season. The Auk, 118(1), 92–104.

McKinnon, E. A., Stanley, C. Q., & Stutchbury, B. J. M. (2015). Carry-Over Effects of Nonbreeding Habitat on Start-to-Finish Spring Migration Performance of a Songbird. PloS One, 10(11), e0141580.

Morris, S. R., & Glasgow, J. L. (2001). Comparison of spring and fall migration of American Redstarts on Appledore Island, Maine. The Wilson Bulletin, 113(2), 202.

Smith, R. J., Mabey, S. E., & Moore, F. R. (2009). Spring Passage and Arrival Patterns of American Redstarts in Michigan’s Eastern Upper Peninsula. The Wilson Journal of Ornithology, 121(2), 290–297. https://doi.org/10.1676/08-051.1

Wuethrich, B. (1998). Songbirds Stressed in Winter Grounds. Science, 282(5395), 1791–1794.

 

 


Monday, March 30, 2020

Early evidence that governmental responses to COVID-19 reduce urban air pollution

There is no doubt that the global spread of COVID-19 represents the defining crisis of the last decade. Governments around the world have scrambled to try to reduce person-to-person spread and deal with pressures on public health infrastructure. Regions with community spread have almost universally faced restrictions on travel, business and social activities. These restrictions are designed to reduce the exponential spread of COVID-19 (that is, to flatten the curve), these restrictions will also have a large number of other economic, social and environmental repercussions. Here, I ask a simple question: Has reductions in economic activity and movement caused by governmental responses to COVID-19 improved air quality in cities? I compare February 2019 and 2020 air quality measures and show that six cities that were impacted early by government restrictions in response to COVID-19 show consistent declines in five of six major air pollutants compared to cities that were impacted later (the text in this post has been modified from Cadotte 2020).


One of the most pernicious and inevitable consequences of urbanization and industrialization is the release of air pollutants. The WorldHealth Organization (WHO) estimates that about 90% of urban residents experience air pollution that exceeds WHO guidelines and that air pollution is responsible for more than four million premature deaths annually (World Health Organization 2018). Air quality is adversely affected by the aerosol release of a number of chemical compounds from agriculture, manufacturing, combustion engines and garbage incineration, and is usually assessed by measuring the atmospheric concentrations of six key pollutants: fine particulate matter (PM2.5), course particulate matter (PM10), ground-level ozone (O3), nitrogen dioxide (NO2), sulfur dioxide (SO2), and carbon monoxide (CO). These pollutants have a number of serious human health impacts (Table 1). Reducing inputs of these pollutants into urban areas requires a combination of technological advancement and behaviour change that can be stimulated by governmental regulations and incentives.


Table 1: The six commonly measured air pollutants in cities and their human health impacts.

Alterations of human, transport and industrial activity are usually the result of long-term economic and behavioural change and difficult to legislate under normal situations. However, the recent emergence of the global COVID-19 pandemic has had clear epidemiological impacts with, as of March 25, 2020, almost half a million confirmed infections and close to 20,000 deaths (World Health Organization 2020). This pandemic has resulted in emergency measures attempting to reduce transmission rates that limit activity, movement and commerce in jurisdictions around the world. While these emergency measures are critically important to limit the spread and impact of the coronavirus, they also provide a glimpse into how governmental calls for behavioural change can alter air pollution levels in cities.

Early evidence reveals that pollution levels have dropped in places that have undergone COVID-19 shutdowns. As Marshall Burke showed in a blog post,  PM2.5 and PM10, levels are lower than expected in parts of China. Here I examine January and February 2020 AQI levels for the six pollutants in Wuhan to what would be expected under normal circumstances. I further compare the change in February air pollution levels over the past two years in six cities that instituted emergency measures by the end of February (early impacted cities) to 11 cities that did not declare states of emergency until March (later impacted cities) using freely available air monitoring data (World Air Quality Index Project 2020) -see Table 2 for a list of cities.

Table 2: The eleven cities used in this analysis, the month that emergency measures were enacted and two- to six-year AQI averages of the pollutants
City-data come from monitoring agencies listed at the end of this post

Wuhan, China was the epicenter for the December 2019 emergence and the first person-to-person spread of the novel coronavirus.  In response, authorities initiated a series drastic measures limiting human movement and activity in Wuhan and large parts of Hubei province by the end of January. Three air pollutants: PM2.5, PM10 and NO2 all showed substantial January and February declines in Air Quality Index (AQI) (U.S.Environmental Protection Agency 2014) values over 2019 levels for those months and what would be expected from long-term trends (Fig. 1). These long-term declining air pollution trends do reveal that China’s recentpollution reduction and mitigation efforts are steadily paying off, but the government-enforced restrictions further reduced pollution levels. The expected air pollution values predicted by temporal trends (red dashed lines in Fig. 1) are all substantially higher than the observed levels, with observed values being between 13.85% lower than expected for January PM2.5 and 33.93% lower for January NO2. Further, the reductions in the pollutants shown in Fig. 1 increased the number of days where pollutant concentrations were categorized as ‘good’ (0 < AQI < 50) or ‘moderate’ (51 < AQI < 100) according to the AQI. The three other pollutants: SO2, O3 and CO, all showed idiosyncratic or non-significant changes, mostly because their levels have already reduced significantly over time or appear quite variable (Fig. 2). 

Fig. 1. Temporal patterns of Air Quality Index (AQI) PM2.5, PM10 and NO2 values in Wuhan, China. Both January and February, 2020 values show significant declines compared to 2019 levels and to that predicted from long-term trends (red dashed line).

Fig. 2. Temporal patterns of Air Quality Index (AQI) SO2, O3 and CO values in Wuhan, China.

Once COVID-19 moved to other jurisdictions, and confirmations of community spread emerged in February 2020, emergency measures, like those in Hubei province, were instituted to limit human movement and interaction. The cities subjected to February restrictions include, in addition to Wuhan, Hong Kong, Kyoto, Milan, Seoul and Shanghai, and the AQI values from these cities were compared to other cities that did not see the impacts of the novel coronavirus or have emergency restrictions in place until well into March. Log-response ratios between the air concentrations of pollutants observed in February 2020 to those from February 2019 reveal that all air pollutants except O3 show a decline in the 2020 values for the early impacted cities (Fig. 3). For later impacted cities, there is no overall trend in changes in the concentrations of pollutants between 2020 and 2019 and the individual cities in this group showed less consistency in the differences between years (Fig. 3). 

Fig. 3. Log response ratios for Air Quality Index (AQI) PM2.5, PM10, NO2, O3, SO2 and CO values between February 2019 and February 2020 values. Negative values indicate a decline in 2020. The green symbols indicate values from an assortment of cities that did not have emergency measures in place until March, 2020 (later impacted cities) and orange symbols are for cities that were impacted by the end of February.
These results indicate consistent air pollution reduction in cities impacted early by the spread of the novel coronavirus. However, the analyses presented here require further investigation as governments increasingly restrict activity world-wide, and some are discussing the possibility of prematurely lifting restrictions in order to spur economic growth. Further, the data analyzed here present point estimates of air quality but air pollution impacts are not homogeneous through urban landscapes and is influenced by spatial variation in industrial activities and transportation (Adams & Kanaroglou 2016). Thus, as higher resolution spatial air pollution data become available, it would be valuable to see how reduced activity affects air quality in different parts of cities.

This analysis of early data indicates that governmental policies that directly reduce human activity, commercial demand and transportation can effectively and quickly reduce urban air pollution. While the COVID-19 pandemic represents a serious risk for health and wellbeing of populations globally, especially those living in high density urban areas, the impacts of air pollution are equally consequential. If governments are willing to expend trillions of dollars in direct funding and indirect economic costs to combat this disease, then why do these same governments permit or even subsidize activities that emit air pollution? Maybe the lessons learned with COVID-19 can serve as the impetus for further action. Perhaps mandating changes to economic or transportation activity or investing in clean technology would better protect human health from the effects of air pollution.

Cited sources
Adams, M.D. & Kanaroglou, P.S. (2016) Mapping real-time air pollution health risk for environmental management: Combining mobile and stationary air pollution monitoring with neural network models. Journal of environmental management, 168, 133-141.
Cadotte, M. W. (2020) Early evidence that COVID-19 government policies reduce urban air pollution. Retrieved from eartharxiv.org/nhgj3
Cesaroni, G., Forastiere, F., Stafoggia, M., Andersen, Z.J., Badaloni, C., Beelen, R., Caracciolo, B., de Faire, U., Erbel, R. & Eriksen, K.T. (2014) Long term exposure to ambient air pollution and incidence of acute coronary events: prospective cohort study and meta-analysis in 11 European cohorts from the ESCAPE Project. Bmj, 348, f7412.
Fann, N., Lamson, A.D., Anenberg, S.C., Wesson, K., Risley, D. &Hubbell, B.J. (2012) Estimating the National Public Health Burden Associated with Exposure to Ambient PM2.5 and Ozone. Risk Analysis, 32, 81-95.
Greenberg, N., Carel, R.S., Derazne, E., Bibi, H., Shpriz, M., Tzur, D. & Portnov, B.A. (2016) Different effects of long-term exposures to SO2 and NO2 air pollutants on asthma severity in young adults. Journal of Toxicology and Environmental Health, Part A, 79, 342-351.
Kampa, M., & E. Castanas. (2008) Human health effects of air pollution. Environmental Pollution, 151, 362-367.
Khaniabadi, Y.O., Goudarzi, G., Daryanoosh, S.M., Borgini, A., Tittarelli, A. & De Marco, A. (2017) Exposure to PM 10, NO 2, and O 3 and impacts on human health. Environmental science and pollution research, 24, 2781-2789.
Raaschou-Nielsen, O., Andersen, Z.J., Beelen, R., Samoli, E., Stafoggia, M., Weinmayr, G., Hoffmann, B., Fischer, P., Nieuwenhuijsen, M.J. & Brunekreef, B. (2013) Air pollution and lung cancer incidence in 17 European cohorts: prospective analyses from the European Study of Cohorts for Air Pollution Effects (ESCAPE). The lancet oncology, 14, 813-822.
U.S. Environmental Protection Agency (2014) AQI: Air Quality Index. Office of Air Quality Planning and Standards, Research Triangle Park, NC.
World Air Quality Index Project (2020) https://waqi.info/.
World Health Organization (2018) Ambient (outdoor) air pollution: https://www.who.int/news-room/fact-sheets/detail/ambient-(outdoor)-air-quality-and-health.
World Health Organization (2020) Coronavirus disease 2019 (COVID-19), Situation Report –65.

City air quality monitoring agencies:
1 Division of Air Quality Data, Air Quality and Noise Management Bureau, Pollution Control Department, Thailand (http://aqmthai.com).
2 Delhi Pollution Control Committee (http://www.dpccairdata.com).
3 Hong Kong Environmental Protection Department (http://www.epd.gov.hk).
4BMKG | Badan Meteorologi, Klimatologi dan Geofisika (http://www.bmkg.go.id).
5South African Air Quality Information System - SAAQIS (http://saaqis.environment.gov.za).
6 Japan Atmospheric Environmental Regional Observation System (http://soramame.taiki.go.jp/).
7 UK-AIR, air quality information resource - Defra, UK (http://uk-air.defra.gov.uk).
8 South Coast Air Quality Management District (AQMD) (http://www.aqmd.gov/).
9 INECC - Instituto Nacional de Ecología y Cambio Climático (http://sinaica.inecc.gob.mx).
10 Agenzia Regionale per la Protezione dell'Ambiente della Lombardia (http://ita.arpalombardia.it).
11 CETESB - Companhia Ambiental do Estado de São Paulo (http://cetesb.sp.gov.br).
12 Department of Public Health of the Sarajevo Canton (http://mpz.ks.gov.ba/).
13 Air Korea Environment Corporation (http://www.airkorea.or.kr).
14 Shanghai Environment Monitoring Center (http://sthj.sh.gov.cn).
15 Israel Ministry of Environmental Protection (http://www.svivaaqm.net).
16 Air Quality Ontario - the Ontario Ministry of the Environment and Climate Change (http://www.airqualityontario.com/).
17 Wuhan Environmental Protection Bureau (http://www.whepb.gov.cn/).