Carbon footprinting in humanitarian construction : what are the CO2 emissions and how to mitigate them?

Abstract

Climate change has become a key driver of humanitarian disasters and forced migration. Its impacts are seen globally but the greatest vulnerability is experienced in the cities of the less developed countries. Although the built environment is globally accountable for around 30% of greenhouse gas emissions, the research of its impact in humanitarian construction is very thin and recommendations for optimising the carbon footprint of transitional shelters or reconstruction are extremely hard to find. Life cycle assessment is often considered to be the most suitable tool for the science-based evaluation of the greenhouse gas emissions of buildings or building products. However, its implementation in the iterative design and decision-making processes is rather difficult. In order to include carbon footprinting in building design, simplifications are needed, especially in the field of humanitarian operations. In this dissertation, the knowledge gaps related to carbon footprint estimation and simplified methods are presented. First the background is presented: climate-related disasters, environmental assessment in humanitarian construction and the existing, standardised methods for estimating the environmental impacts of buildings. Secondly, a series of case studies from different countries reveal the carbon footprint and primary energy demand of transitional shelters and reconstruction projects. Thirdly, novel methods are proposed for setting the benchmark levels of an acceptable carbon footprint in humanitarian construction and for cross-comparing carbon footprint, energy efficiency and construction costs. Finally, the findings are summarised into practical recommendations and a low-carbon humanitarian construction project model. The carbon footprint in humanitarian construction seems to be very material related. Bio-based materials enable low greenhouse gas emissions. In addition, focusing on energy efficiency seems to be relevant in the refugee camps of cold climates, especially if the energy infrastructure is damaged in a humanitarian disaster. Several further research needs are recognised for improving the reliability of life cycle assessment in humanitarian construction. Embedding environmental accountability into the development of core humanitarian standards and guidelines is recommended.