Abstract
Despite a growing awareness of climate change, there is little evidence that this is being addressed in cities and built environments. Events such as flooding in Houston, USA; landslides in Free Town, Sierra Leone; and water shortages in La Paz, Bolivia and Cape Town in South Africa demonstrate that it is increasingly important that climate change is understood and addressed in built environments to ensure that they become more resilient. This chapter introduces climate change and outlines the implications of this for built environments. It describes measures that can be incorporated into built environments to enable them to adapt to projected climate changes. Understanding climate change and preparing for this by developing built environments that are more resilient will be an increasingly valuable and important skill. Reading this chapter will support the development and refinement of skills and knowledge in this area and it is an essential reference for built environment students and practitioners.
TopIntroduction
Climate change is now considered as one of the most important issues facing the world today (Hamin & Gurran, 2009). Climate change science has also developed to such as extent that climate change projections can be made within an increasing level of accuracy and detail (Hamin & Gurran, 2009; Guan, 2009).
Simulations now provide climate projections with some degree of certainty 20, 50 and 100 years into the future. Projections describe aspects of climate that will change such as temperatures, the occurrence of very hot days, annual rainfall, heavy rainfall, wind speeds and extreme weather conditions. Current weather data already indicates that climate change is occurring and is confirming the accuracy of climate change projections.
As built environments usually have a lifespan of at least 50 years it is important to understand how climates may change over this period and how this can be addressed in new buildings and urban development proposals (Guan, 2009). Existing built environments must also be assessed in terms of projected climate changes and required adaptations carried out.
This chapter has been developed to support a better understanding of climate change and how it can be addressed in the built environment. It aims to answer the following questions:
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What is climate change?
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What are climate change projections?
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What are the implications of these projections for the built environment?
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How can the built environment be adapted for projected changes?
TopWhat Is Climate Change?
Climate change describes a change in the state of the climate that persists for an extended period. This is identified by changes to the mean, for instance, mean temperatures over a long period. Climate change, such as the occurrence of the Ice Ages, can be attributed to natural causes or to human activity. The climate change that is currently being experienced has been directly attributed to human activity (IPCC, 2014).
Current climate change, which is also referred to as global warming, is a result of the greenhouse effect. The greenhouse effect is caused by greenhouse gases, such as carbon dioxide, methane, nitrous oxide and chlorofluorocarbons in the atmosphere trapping heat from the sun and limiting the extent to which this heat is reradiated into space. Increases in these gases in the atmosphere result in a stronger ‘greenhouse effect’ and leads to higher temperatures and climate change.
Of the greenhouses gases, increases in carbon dioxide have had the most significant impact. Rising carbon dioxide levels are attributed to reduced capacity by vegetation to sequestrate this gas through photosynthesis. It is also attributed to human activities such as the burning of fossil fuels for energy and transport.
Human development and increased urbanization have rapidly reduced areas of natural vegetation, such as forests and grasslands that historically sequestrated carbon dioxide and ensured that there was a long-term balance in the atmospheric gas composition. Increasing generation of energy from fossil fuels as well as the growing use of transportation such as cars and flights powered by fossil fuels has also rapidly increased the amount of carbon dioxide emitted into the atmosphere. As a result, levels of carbon dioxide in the atmosphere have increased from 280 parts per million to over 400 parts per million.
The International Panel on Climate Change (IPCC) warns that the continued increase in greenhouse gases will have very severe consequences, as follows:
Continued emission of greenhouse gases will cause further warming and long-lasting changes in all components of the climate system, increasing the likelihood of severe, pervasive and irreversible impacts for people and ecosystems. Limiting climate change would require substantial and sustained reductions in greenhouse gas emissions which, together with adaptation, can limit climate change risks. (IPCC, 2014)
Key Terms in this Chapter
Climate Resilience: Climate resilience is the capacity absorb stresses and maintain function in the face of external stresses imposed upon it by climate change and (2) adapt, reorganize, and evolve into more desirable configurations that improve the sustainability of the system, leaving it better prepared for future climate change impacts.
Carbon Sequestration: Carbon sequestration removes CO2 from the atmosphere. In nature, this occurs during photosynthesis.
Albedo: Albedo is a measure of the “reflectiveness.” It is a way of quantifying how much radiation is reflected back, as opposed to that absorbed. Low albedo has a value nearer 0 and absorbs most of the radiation, while high albedo has a value nearer 1 and reflects most of the radiation.
Carbon Cycle: Describes the process by which living things absorb carbon from the atmosphere, sediments and soil, or food. To complete the cycle, carbon returns to the atmosphere in the form of carbon dioxide or methane by respiration, combustion, or decay.
Greenhouse Gas: The main greenhouse gases are water vapour (H2O), carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), and sulfur hexafluoride (SF6).
Adaptation: Adaptation refers to adjustments to respond to climate change.
Emissions: Substances released into the air and are measured by their concentrations, or parts per million, in the atmosphere.
Drought: A drought is a period of abnormally dry weather marked by little or no rain. It lasts long enough to cause water shortages for people and natural systems.
Biofuels: Renewable fuels derived from biological materials, such as algae and plants that can be regenerated. This distinguishes them from fossil fuels, which are considered nonrenewable. Example of biofuels are ethanol, methanol, and biodiesel.
RPCs: Representative Concentration Pathways are defined according to their contribution to atmospheric radiative forcing in the year 2100 relative to pre-industrial values. An RCP 8.5 therefore represents the addition to the earth’s radiation budget as a result of an increase in GHGs of +8.5 W/m 2 .
Global Warming: Global warming is the warming trend over the past century.
Adaptive Capacity: The ability of systems, institutions, humans, and other organisms to adjust to climate change.
Earth's Atmosphere: This is a layer of gases that surround the Earth.
Climate Change: Describes a change in the state of the climate that persists for an extended period. This is identified by changes to the mean, for instance, mean temperatures over a long period.
Anthropogenic: Anthropogenic refers to man-made impacts, processes, or products.
Climate: Climate describes the average and variations of weather in a region over long periods of time.
Carbon Footprint: A carbon footprint describes the total amount of greenhouse gas emissions caused by an organization, event or product.
Renewable Energy: Energy from sources that will renew themselves within our lifetime. Renewable energy sources include wind, sun, water, biomass (vegetation) and geothermal heat.
Mitigation: Mitigation involves taking actions to reduce greenhouse gas emissions and to enhance sinks, such as carbon sequestration, in order to reduce the extent of global warming.
Carbon Dioxide: The gas that accounts for about 84% of total U.S. greenhouse gas emissions. In the U.S. the largest source of carbon dioxide (98%) emissions is from the combustion of fossil fuels. Combustion can be from mobile (vehicles) or stationary sources (power plants). As energy use increases, so do carbon dioxide emissions.