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A practical guide to climate-resilient buildings & communities

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UNEP
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Lead Authors: Rajat Gupta (Oxford Brookes University), Mittul Vahanvati (RMIT University), Julia Häggström (SEfficiency), Jacob S. Halcomb (SEfficiency).

Contributing Authors: Matt Gregg (Oxford Brookes University), G. Bradley Guy, Michelle Bosquet (SEfficiency).

1 Introduction

The 2019 Tropical Cyclone Idai, one of the strongest cyclones to strike Africa, and Tropical Cyclone Kenneth, the strongest storm in modern memory to lash Mozambique, devastated infrastructure and destroyed homes, workplaces and schools through high winds, flooding and heavy rainfall. The severity and extent of the damage from these two events have raised awareness and desire for improved approaches to ensure homes and other buildings are resilient and adapted for the warming climate and the associated increased risk of natural hazards.

These two recent cyclones are only an example of the global challenges projected by a changing climate over the coming century. During the past two decades, almost 90 per cent of deaths from weather-related disasters took place in lower-income countries, though they endured only a quarter of total weather events. There is consensus in the scientific community that climate change is increasing the frequency, intensity, spatial extent, duration and timing of extreme weather and climate events, leading to increased climate-related hazards.

Climate hazards can cause loss of life, injury or other health impacts, as well as damage to, and loss of, property, infrastructure, livelihoods, service provision and environmental resources. Between 2000-2019, there has been a worldwide average of 361 disasters per year. In 2019, approximately 91 million people were affected by natural disasters across the globe. It has been estimated that global economic losses due to weather and climate-related events amounted to 0.4 per cent of global GDP in 2017. While not all events can be directly attributed to climate change, the uncertainty, frequency and intensity of extreme weather events is growing, increasing the impact on our built environment and creating a call for attention.

For the twenty-first century, climate scenarios predict more extreme weather-related events, such as heat waves and excessive precipitation. The most severe effects are predicted to occur in tropical areas, where many developing countries are located. According to the Notre Dame Global Adaptation Index (ND-GAIN), countries at the highest risk of climate change are concentrated in Africa and South/Southeast Asia, where the capacity to prevent or cope with climate impacts is poor. It is further expected that these regions will host nearly all of the anticipated 2.5 million additional urban residents by 2050.

The increase of storm events with the increase in urbanization and population growth is placing additional pressure on decision-makers, cities and local governments to adequately address these risks and ensure the safety and well-being of their residents. Furthermore, climate hazards tend to be particularly detrimental to the most disadvantaged groups of society, such as the elderly and women, who are disproportionately exposed and vulnerable to climate hazards.

The huge impacts, loss of life and societal risks of these natural disasters do not come ashore with the storms or down the rivers with the floods. In fact, these impacts are a result of society’s interaction with the hazard and the natural environment. Disasters are produced when people and their settlements are either exposed and vulnerable or ill-suited to their local environment and conditions. Disasters are not only natural and are not neutral actions. Instead, they are a result of insufficient planning and preparation. With thoughtful attention to the design and construction of our built environment, we can reduce vulnerabilities and thereby lower the disaster risk to human life and well-being.

1.1 Aim of this practical guide

This practical guide has been prepared because the United Nations Environment Programme (UNEP) recognizes the key role buildings can play in enhancing climate change adaptation, improving resilience and addressing and mitigating risk. Furthermore, there is a recognized need for additional resources addressing good practice for buildings in communities and towns that face risk from disasters but may suffer from a deficit of professionally trained architects, engineers, contractors, manufacturers and other practitioners. Therefore, this note is written for a broad audience, including those with little experience in the building and construction industries.

The term “built environment” encompasses all areas of development, including infrastructure (roads, utilities and major transportation hubs) as well as buildings, parks and other urban features. While this note will provide an overview of important infrastructure and community-scale considerations, it is principally focused on building structures and their immediate surroundings.

The practical guide sets out to provide an overview of the fundamental types of interventions at the building scale. It specifically offers concepts and approaches for the building envelope, roof, structure, orientation and materials. The approaches and technologies presented in this document are tailored toward a developing country context and a built environment that is largely self-constructed. However, the majority of the techniques identified in this practical guide can be upscaled and applied to buildings of any type, including apartment complexes, hospitals and schools.

Furthermore, given the broad geographic scope, this note will identify and explore scalable interventions that are applicable to key climatic types, with special focus on technical approaches in those regions that are expected to see the highest rates of population growth and urbanization in the coming years. For example, this includes design approaches to minimize heat gain, which could be applied to single family homes in hot and arid and hot and humid regions but also upscaled for larger commercial or governmental buildings. Many of these countries can also have regions that experience cold or temperate weather; therefore, the report also includes some design ideas for cold and temperate climates.