Here's how you can use social media to spot early signs of gentrification

London's rapidly gentrifying East End. Image: Getty.

When you walk through a neighbourhood undergoing gentrification, you can sense it. The area is dominated by strange contradictions. Public spaces are populated by vagabonds and cool kids; abandoned buildings sit in disrepair next to trendy coffee shops; blocks of council housing abut glassy new developments.

Urbanists describe gentrification as a form of urban migration, where a more affluent population displaces the original, lower-income population. In statistics, gentrification appears as the lowering of crime rates, rising housing prices and changes to the mix of people who live there.

If we could only predict where gentrification is likely to strike next, we might be able to alleviate its negative impacts – such as displacement – and take advantage of its more positive effects, which include economic growth.

That’s why our latest study – conducted with colleagues at the University of Birmingham, Queen Mary University of London, and University College London – aimed to quantify the process of gentrification, and discover the warning signs.

Detecting urban diversity

We constructed four measures of urban social diversity using data from social media. By combining these measures with government statistics about deprivation, we were able to pinpoint a number of neighbourhoods undergoing gentrification in London.

Of course, social media is notoriously unsuitable for population studies, because of the “digital divide” – the split between people who can access the internet and those who can’t exists even within urban areas. And so, information from social media only captures part of the overall picture. Twitter users in particular are known to be predominantly young, affluent and living in urban areas.

But these are precisely the demographics responsible for gentrification. So, we used information from social media from 2010 and 2011 to define the “social diversity” of urban venues such as restaurants, bars, schools and parks.

Urban social diversity – in terms of population, economy and architecture – is known to be a factor in successful communities. In her famous book The Death and Life of Great American Cities, urban activist Jane Jacobs wrote that “cities differ from towns and suburbs in basic ways, and one of these is that cities are, by definition, full of strangers”.

Dropping in. Image: David Abrahamovitch/Flickr/creative commons.

In our work, we first measured the amount of strangers that a place brings together as the fraction of the social network of visitors who are connected on social media. This gave us an idea of whether a place tends to be frequented by strangers or friends. We further explored the diversity of these visitors in terms of their mobility preferences and spontaneity in choice of venues. Although we did not consider demographics or income levels, there is a known relationship between the wealth of people and the diversity of their geographical interactions.

We studied the social network of 37,000 London users of Twitter, and combined it with what we knew about their mobility patterns from geo-located Foursquare check-ins posted to their public profiles.

By studying the amount of strangers versus friends meeting at a bar, or the number of diverse versus similar individuals visiting an art gallery, we were able to quantify the overall diversity of London neighbourhoods, in terms of their visitors.

Networks are powerful representations of the relationships between people and places. Not only can we draw links between people where a relationship – such as friendship – exists between them; we can also draw connections between two places if a visitor has been to both. We can even connect the two networks, by drawing links between people in the social network who have visited specific spots in the place network.

In this way, we are able to extract the social network of a place, and the place network of a person. By the time we’d finished crunching the data, we could take stock of the range of people who had visited a specific place, and the different places visited by any individual.

When we compared the diversity of urban neighbourhoods with official government statistics on deprivation, we found that some highly deprived areas were also extremely socially diverse. In other words, there were lots of diverse social media users visiting some of London’s poorest neighbourhoods.


Diminishing deprivation

To find out what was going on, we took the newly published deprivation indices for 2015 and looked for changes in the levels of deprivation from our study period in 2011. The relationship was striking. The areas where we saw high levels of social diversity and extreme deprivation in 2011 were exactly the same areas that had experienced the greatest decreases in deprivation by 2016.

A prime example can be found in the London borough of Hackney. Anyone visiting Hackney might describe it in terms of the contradictions we mentioned before – but few of us could afford to live there today. In our study, Hackney was the highest ranking in deprivation and the highest ranking in social diversity in 2011. Between then and now, it has gone from the being the second most deprived neighbourhood in the country, to the 11th.

So, although social media may not be representative of the entire population, it can offer the key to measuring and understanding the processes of gentrification. Neither entirely good nor thoroughly bad, gentrification is a phenomenon that we should all watch out for. It will undoubtedly help to define how our cities transform in years to come.The Conversation

Desislava Hristova is a PhD candidate at the University of Cambridge.

This article was originally published on The Conversation. Read the original article.

 
 
 
 

Mexico City’s new airport is an environmental disaster. But it could become a huge national park

Mexico City’s new Norman Foster-designed airport, seen here in a computer rendering, is visually striking but environmentally problematic. Image: Presidencia de la República Mexicana/creative commons.

Mexico City long ago outgrew the two-terminal Benito Juárez International Airport, which is notorious for delays, overcrowding and canceled flights. Construction is now underway on a striking new international airport east of this metropolis of 20m. When it opens in late 2020, the LEED-certified new airport – whose terminal building was designed by renowned British architect Norman Foster in collaboration with the well-known Mexican architect Fernando Romero – is expected to eventually serve 125m passengers. That’s more than Chicago O'Hare and Los Angeles’ LAX.

But after three years of construction and $1.3bn, costs are ballooning and corruption allegations have dogged both the funding and contracting process.

Environmentalists are also concerned. The new airport is located on a semi-dry lake bed that provides water for Mexico City and prevents flooding. It also hosts migrating flocks and is home to rare native species like the Mexican duck and Kentish plover.

According to the federal government’s environmental impact assessment, 12 threatened species and 1 endangered species live in the area.

The airport project is now so divisive that Andrés Manuel López Obrador, the populist winner of the country’s 2018 presidential campaign, has suggested scrapping it entirely.

An environmental disaster

Mexico’s new airport sits in a federal reserve. Image: Yavidaxiu/The Conversation.

I’m an expert in landscape architecture who studies the ecological adaption of urban environments. I think there’s a way to save Mexico’s new airport and make it better in the process: create a nature reserve around it.

Five hundred years ago, lakes covered roughly 20 percent of the Valle de Mexico, a 3,500-square-mile valley in the country’s south-central region. Slowly, over centuries, local residents – first the Aztecs, then the Spanish colonisers and then the Mexican government – built cities, irrigation systems and plumbing systems that sucked the region dry.

By the mid-20th century, the lakes had been almost entirely drained. In 1971, President Luís Echeverría decreed the area a federal reserve, citing the region’s critical ecological role for Mexico City. The smattering of small lakes and reforested land there now catch and store runoff rainwater and prevent dust storms.

The new airport will occupy 17 square miles of the 46-square-mile former Lake Texcoco. To ensure effective water management for Mexico City, the airport master plan proposes creating new permanent water bodies to offset the lakes lost to the airport and cleaning up and restoring nine rivers east of the airport. It also proposes planting some 250,000 trees.

The government’s environmental assessment determined that the impacts of the new airport, while significant, are acceptable because Lake Texcoco is already “an altered ecosystem that lost the majority of its original environmental importance due to desiccation and urban expansion.” Today, the report continues, “it is now only a desolate and abandoned area.”

Environmentalists loudly disagree.

Make Mexico’s airport great again

I see this environmental controversy as an opportunity to give Mexico City something way more transformative than a shiny new airport.

Nobody can entirely turn back the clock on Lake Texcoco. But the 27 square miles of lake bed not occupied by the airport could be regenerated, its original habitat partially revitalised and environmental functions recovered in a process known as restoration ecology.

I envision a huge natural park consisting of sports fields, forests, green glades and a diverse array of water bodies – both permanent and seasonal – punctuated by bike paths, walking trails and access roads.

The airport will come equipped with new ground transportation to Mexico City, making the park easily accessible to residents. Extensions from the surrounding neighborhood streets and highways could connect people in poor neighbourhoods abutting the airport – dense concrete jungles like Ecatepec, Ciudad Nezahualcoyotl and Chimalhuacan – to green space for the first time.

The nine rivers that empty into Lake Texcoco from the east could be turned into greenways to connect people from further out in Mexico State to what would become the area’s largest public park.

Space could also be reserved for cultural attractions such as museums, open and accessible to passengers in transit.


New master plan

This idea is not as crazy as it sounds.

As early as 1998, Mexican architects Alberto Kalach and the late Teodoro González de León proposed rehabilitating the lakes of the Valley of Mexico. Their book, “The City and its Lakes,” even envisaged a revenue-generating island airport as part of this environmentally revitalized Lake Texcoco.

Under President Felipe Calderon, Mexico’s National Water Commission also proposed building an ecological park in Lake Texcoco, which was to include an island museum and restore long-degraded nearby agricultural land. But the project never gained traction.

Granted, turning a large, half-constructed airport into a national park would require an ambitious new master plan and a budget reallocation.

But in my opinion, evolution and change should be part of ambitious public designs. And this one is already expected to cost an additional $7.7bn to complete anyway.

Toronto’s Downsview Park – a 291-acre former air force base turned green space – has transformed so much since its conception in 1995 that its declared mission is now to “constantly develop, change and mature to reflect the surrounding community with each generation.”

Local communities neighboring Mexico City’s new airport were not adequately consulted about their needs, environmental concerns and their current stakes in the Lake Texcoco area. A revamped park plan could be truly inclusive, designed to provide recreation and urban infrastructure – and maybe even permanent jobs – for these underserved populations.

Presidential race

Three of the four candidates in Mexico’s July 1 presidential election wanted to finish Mexico City’s new international airport. But eventual winner López Obrador was not so sure.

Early in his campaign, he said he would cancel it if elected. Instead, López Obrador suggested, a former air force base could become the new international terminal. It would be connected to Benito Juárez airport, 22 miles south, by train.

López Obrador has since said he would support completing construction of the new international airport if the remaining financing came from the private sector, not the Mexican government. Currently, some two-thirds of the project is funded by future airport taxes.

The ConversationLópez Obrador’s promise to review and likely upend the airport plan could open the door to its wholesale transformation, putting people and nature are at the core of a plan ostensibly designed for the public good.

Gabriel Diaz Montemayor, Assistant Professor of Landscape Architecture, University of Texas at Austin

This article was originally published on The Conversation. Read the original article.