Resilient and Sustainable Cities in the Face of Climate Change

Cities are central to global sustainable development. The built environment has a major impact on urban sustainability. In 2014, the buildings sector represented 31% of global final energy use, 54% of final electricity demand, and 8% of energy-related CO2 emissions (excluding indirect emissions from electricity). When including upstream electricity generation, buildings were responsible for 23% of global energy-related CO2 emissions, with one-third coming from direct fossil fuel consumption (IEA, 2017a). It also drives deforestation through construction materials and generates substantial waste and consumption of natural resources.

These trends will persist and by 2050, energy consumption is expected to rise 20–50% compared to 2010 levels. ( IPCC Special Report on the impacts of global warming of 1.5°C – 2019).

The resilience of the built environment

Before we delve into the details, let’s understand the concept of resilience. According to the Intergovernmental Panel on Climate Change (IPCC), resilience refers to the ability of a system or society to withstand and recover from the impacts of climate change. This involves building adaptive capacity, enhancing coping mechanisms, and reducing vulnerabilities to ensure long-term sustainability in the face of ever-changing climate conditions.

Thermal comfort: adapting to local needs

One of the important aspects to consider when designing buildings is the thermal comfort of the occupants. Thermal comfort bands, as proposed by Fanger in 1970 and by ASHRAE, assume that thermal neutrality provides the greatest comfort for most people. However, it is important to remember that these bands were developed based on European principles and may not be directly applicable in regions with warmer climates, like Brazil.

In the Brazilian context, where temperatures can be higher, it is necessary to adjust these comfort bands. Humans have the ability to adapt to different temperatures over time, which we call thermal adaptation (Taylor 2015 – human adaptation to heat). Therefore, it is important to consider the thermal adaptability of people when setting temperature thresholds. While the range of 21 to 24 degrees Celsius is commonly used, it is essential to adjust these parameters in warmer regions to ensure the comfort of the occupants. In this case, it is interesting to use local and national thermal comfort legislations, such as NBR 15575 and 15220, and also the Adaptive Thermal Comfort metric. I have a post already explaining everything about thermal comfort metrics and tools, click here to read.

Increasing resilience at the urban scale

In addition to ensuring resilience within buildings, it is also essential to increase resilience at the urban level. Urban heat islands have been intensifying due to climate change, becoming a significant challenge for cities. According to the IPCC 2023, approximately 3.3 to 3.6 million of the global population live in areas highly vulnerable to climate change and extreme weather events are becoming more frequent.

In Brazil, specifically, we are facing extreme weather events, such as the increase in droughts and heatwaves. According to the Brazilian Panel on Climate Change (PBMC), the temperature increase in the country can be from 1°C to 6°C by 2100. This impacts not only temperature but also creates an imbalance in rainfall regimes. In the Central, North and Northeast regions, a decrease in rainfall is predicted, and in the South and Southeast regions, an increase. We can already clearly perceive these impacts with 2023 being the year that broke records in heat levels and extreme weather events. These adverse climate conditions have significant impacts, such as the intensification of river droughts, directly affecting riverside and indigenous populations. The lack of rainfall also compromises food security due to the scarcity of fish and the impact on agriculture. This creates a vicious cycle of harmful events and consequences, therefore increasing thermal resilience in cities is crucial.

Vulnerability and Susceptibility to Climate Change

In addition to the direct impacts of climate change, such as increasing temperature and extreme weather events, it is important to consider the relationship between vulnerability and susceptibility of urban communities to these changes.

Vulnerability refers to the sensitivity and the ability to adapt to the impacts of climate change. Communities with a lower response capacity and limited resources are more vulnerable to the adverse effects of climate change. This includes low-income groups, marginalized populations, the elderly, children, and people with chronic diseases.

Susceptibility, on the other hand, is related to exposure and the likelihood of being affected by climate change. Communities located in risk areas, such as coastal zones subject to flooding, regions prone to landslides, or densely built urban areas, may be more susceptible to the impacts of climate change.

Therefore, it is essential to consider the vulnerability and susceptibility of communities when developing urban adaptation and resilience policies and strategies. This involves identifying and implementing measures to reduce inequalities, strengthen community response capacity, and ensure the inclusion of all social groups in adaptation policies and programs.

The integrated approach, which takes into account social, economic, and environmental aspects, is key to reducing vulnerability and increasing city resilience in the face of climate change. This includes investing in green infrastructure, promoting climate justice, improving access to basic services such as potable water and sanitation, and strengthening local governance for more inclusive and participatory decision-making.

Taking steps to reduce the vulnerability and susceptibility of urban communities, we can move towards sustainable, inclusive, and resilient cities, capable of facing the challenges of climate change and providing a better quality of life for all.

The path to resilient and sustainable cities

To make our cities more sustainable and resilient, it is essential to adopt a holistic approach. This includes implementing strategies that promote efficient energy use, the adoption of renewable sources, smart urban planning, the creation of green areas, and the encouragement of public transportation. In addition, it is necessary to invest in research and innovations that can boost urban resilience, as well as engage the community and stakeholders to create meaningful change.

In this context, I truly believe that an effective public policies play a crucial role. Governments and local authorities need to adopt measures to encourage the construction of sustainable buildings, promote stricter regulations, and develop awareness and education programs for citizens.

We try to do what we can on an individual scale, hoping that it contributes in some positive way. However, I believe that there also needs to be intervention on a larger scale. This is where government action comes in, with public policies and regulations for more sustainable development. It bothers me very much that green parties or candidates who prioritize the climate and the environment in their campaigns still do not capture the public’s attention, even in face of the current climate crisis, when our own future is at risk. My hope is that is not too late when we wake up.

In conclusion, the pursuit of inclusive, resilient, and sustainable cities is a global challenge. Through the development and implementation of effective strategies, we can ensure a better future for future generations. It is time to act and work together to build a built environment that promotes quality of life, social equity, and the preservation of our planet.

I hope this article has provided a comprehensive overview of the importance of making cities sustainable and resilient. If you have any questions or comments, do not hesitate to share them below!