Self-Built Adaptation: A Resilient Upgrade Model for Informal Settlements in Buenos Aires
Year: 2024
Course: Urban Design & Planning for Climate Transformation, Intense Migration, & Rapid Urban Growth
Instructor: Felipe Vera
Team: Sara Segura, Shariq Shah, Gonzalo Montoya, Michele Chen, Cameron McCutchen, Alice Zhang
23% of
Latin America’s population lives in self-built settlements, a number predicted
to rise in the coming decades. These areas of rapid and unplanned growth are expanding
under increasingly precarious conditions, lacking access to critical
infrastructure, health services, economic opportunities, and education. Current exposure to heat stress, floods, and air pollution is
projected to increase in frequency and severity, as the continent experiences
rapid aridification and worsening water stress.
In
these rapidly urbanizing settlements, climate change will expose cities’ most
vulnerable residents to unprecedented levels of risk. These compounding issues demand a fundamental
shift in contemporary urban discourse.
A Critical History of “Slum Upgrading”
In order to formulate an effective approach to adaptation for the following decades, we must first look critically at the failed approaches to mitigation of the previous decades.
For the last 50 years, the traditional development models for informal settlements have focused almost exclusively on the provision of housing and services. With the given acceleration of urbanization and intensification of climate change hazards, the architectural logic behind slum upgrade models is becoming obsolete. These models have addressed the most immediate needs of self-built settlements at the expense of their medium-term sustainability and resilience, ignoring the urgency and far-reaching implications of the climate crisis.
Slum upgrade models of the last 50 years prioritize housing as the first step.
The timeline shows a series of slum upgrade campaigns beginning in the 1950s and their prioritization of an architecturally inspired model of urbanization.
Paradigm Shift: Landscape First
The development model must first address exposure to climate risk through a landscape-first approach, responding and adapting to the risks at hand.
Forced migrations further drive vulnerable populations to urban centers. In Argentina, 40% of the population living in informality reside in Buenos Aires.
The Continental Scale
As extreme aridification and water stress intensify climate risk across Latin America, self-built settlements in each country will bear the highest impacts.
With large portions of its residents living in these informal conditions, the Southern Cone is a site in need of urgent attention.
The map shows water stress projections to 2040.
The National Scale
With 17% of its resident population living in informal settlements, Argentina is a site of immediate risk. 40% of those informal residents live in Buenos Aires, the largest concentration of informality in the country. The city is centrally connected by transit routes across the comunas. Those settlements are projected to increase in size and density, intensifying their exposure to climate risks and worsening water stress.
The
Local Scale
10% of the population of Buenos Aires resides in self-built settlements, which
amounts to over 300,000 people.
Climate
risks compound with local environmental hazards, including ground
contamination from dump sites and industrial land use, stormwater flooding, and
air pollution. The density of the urban fabric could magnify the impacts of flooding,
landslides, and fire.
In aridifying climates, soils become less able to absorb stormwater runoff;
groundwater supplies are diminished; landslide risks increase; and stagnant
water produces additional public health risks, including dengue fever spread
through mosquito bites.
Despite these intensifying climate risks, conventional intervention models have
privileged primarily the development of housing and services. These investments
alone can no longer keep pace with the intensifying hazards.
To protect
people from increased risk exposure and prevent maladaptation of these regions,
developmental investments in self-built settlements must consider a longer
timescale of resilience and adaptation.
Challenges
1. The limited footprint of open space
and impermeable ground surface reduces water absorption rates in the soil. This
intensifies flood risks, stagnant waters, ground pollution, and urban heat.
2. High-density, mid-rise morphology of
development in self-built settlements intensifies urban heat islands and trap
air pollution. Construction materials are not chosen for their thermal
performance and breathability.
Strategies
1. Ground Cover:
Vegetative
ground cover supports flood resilience, UHI mitigation, air purification, groundwater
replenishment, and evaporative cooling. Ground cover also helps prevent erosion
by retaining moisture, with roots providing additional structural stability. Permeable
ground cover and phytotechnology should be implemented in streets and open
spaces within self-built settlements. Cut-and-fill topographical changes and
urban microtopography can be deployed to channel stormwater into planted zones.
2. Vertical Planting Systems
Vertical
vegetation is practical for narrow urban canyons and dense development, as it
can leverage the limited sunlight that penetrates these urban corridors.
Vegetative wall coverings reduce the albedo and heat absorption of building
materials, mitigating urban heat islands and reducing heat stress. By
increasing the vegetative volume in these dense urban areas, the greenery will
promote evaporative cooling and capture air pollutants, improving air quality
as well.
3. Self-Built Community Empowerment
Upgrade
models should enable community empowerment through inclusive, landscape-first urban
developments. These are not only effective means of adapting to climate change
but also provide additional opportunities for aesthetic pleasure, social
bonding, recreation, environmental education and stewardship, and even employment
and entrepreneurship.
Unlocking Green Funding
A
landscape-driven model can address multiple sustainable development criteria,
including climate change mitigation and adaptation, social empowerment, and
economic development. This makes upgrade campaigns eligible for sustainable
finance, climate bonds, and green finance.