The carbon footprint of builndings: understanding the different sources of emissions
The construction sector plays a significant role in greenhouse gas emissions, which contribute to climate change. Indeed, buildings account for 40% of energy consumption and 36% of CO2 emissions in Europe. In this context, carbon footprint has become an increasingly used indicator to assess the environmental impact of buildings. This measure allows quantifying the amount of greenhouse gases emitted throughout the life cycle of a building, from its construction to its demolition. In the face of the current climate emergency, the quantification of the carbon footprint of buildings has become a major issue for actors in the construction and real estate sector. In this article, we will explain what a building's carbon footprint is, how it is measured, and why this measure is important. We will also address the different methods of calculating the carbon footprint.
How to define the carbon footprint
The carbon footprint is a concept that emerged from the idea of ecological footprint, which was developed in the early 1990s by Canadian ecologist William Rees and Swiss-born regional planner Mathis Wackernagel at the University of British Columbia. The ecological footprint is a measure of the total area of land required to sustain an activity or population, taking into account various environmental impacts such as water use and land use for food production. On the other hand, a carbon footprint is usually expressed in terms of weight, such as tons of CO2 or CO2 equivalent per year. Greenhouse gas (GHG) emissions occur at every stage in the life cycle of a product, and they can be direct, such as from animals, fertilizer application, and fuel use, or indirect, such as from electricity generation. Moreover, each GHG has a different potential to increase atmospheric temperature. To facilitate common discussions, characterization factors are used to compare the impact of different GHGs against a standard radiative effect, which refers to the act of emitting or causing the emission of radiation. The characterization model for climate change was developed by the Intergovernmental Panel on Climate Change (IPCC) and contains a set of internationally recognized characterization factors. By applying these factors, we can quantify the carbon footprint of a product, service, or activity, which is a crucial step towards mitigating its impact on the environment.
Why measure the carbon footprint of a building?
Measuring the carbon footprint of a building is important for several reasons. Firstly, it allows for understanding the environmental impact of a building on the climate and comparing it to other buildings. This can help building owners and managers to identify areas where improvements can be made to reduce greenhouse gas emissions. Secondly, measuring the carbon footprint is significant for construction companies and real estate professionals because it allows them to comply with existing environmental regulations and policies. In many countries, buildings must meet certain environmental standards, such as LEED (check out our LEED Blog) or BREEAM certification, which require the measurement and reduction of carbon footprint. Finally, measuring the carbon footprint is considerable for consumers and building tenants, who are increasingly aware of the environmental impact of their lifestyle and work choices.
Two ways of measuring carbon footprint: Life cycle analysis and carbon accounting
Life cycle analysis is a tool for assessing the environmental impacts of a product or service. It allows for the identification and quantification of the material and energy flows associated with all stages of a product's life, from raw material extraction to disposal. This method provides a comprehensive and multi-criteria view of the environmental impacts related to a product or activity. In the case of buildings, life cycle analysis allows for the consideration of all environmental impacts, including those related to the construction and demolition phases. Carbon footprint is a process for quantifying the amount of greenhouse gases directly and indirectly produced by the activities of a company or organization. It is a method that allows for the measurement of the carbon footprint of a building or product. The carbon footprint takes into account all greenhouse gases, but carbon dioxide (CO2) is the most commonly emitted by human activities. Other greenhouse gases are converted to carbon dioxide equivalent (CO2e) by multiplying the quantity of each gas by its global warming potential (GWP). This measurement allows for the comparison of different gases and for their expression in a common unit: the tonne of CO2 equivalent. The higher the GWP, the more the gas contributes to global warming. The carbon footprint is therefore an essential tool for quantifying and reducing greenhouse gas emissions from buildings and for encouraging more sustainable and environmentally friendly construction practices.
In conclusion, the carbon footprint of buildings is a critical issue for the construction and real estate sector, as well as for the environment and society as a whole. Measuring the carbon footprint of buildings allows for the identification of areas where improvements can be made to reduce greenhouse gas emissions, comply with environmental regulations and policies, and respond to the growing demand for sustainable and environmentally friendly construction practices. Life cycle analysis and carbon accounting are two complementary methods for measuring the carbon footprint of buildings, which provide valuable insights into the environmental impacts associated with the construction, operation, and demolition of buildings. As the construction sector continues to grow and evolve, it is essential to prioritize the reduction of greenhouse gas emissions and the promotion of sustainable building practices to mitigate the negative impact of buildings on the environment and ensure a sustainable and livable future for all.