Expert witnesses

Climate Change and the Built Environment was the title of the sixth meeting of CIB W180, the climate change commission of the International Council for Research and Innovation in Building and Construction.

Representatives from research establishments and professional institutions from Europe, Asia and Australasia, as well as the USA, attended the meeting at the Technical University of Catalonia, in Terrassa (near Barcelona), last October.

The aim was to discuss and disseminate the latest findings and research. Of particular interest were the forthcoming assessment report from the IPCC (Intergovernmental Panel on Climate Change) and recent research results on the analysis and use of weather data in building design. Topics covered included climate models, scenarios and data, climate change impacts studies and impact assessment methods and adaptation strategies.

Mitigation and adaptation

The first session focused on the current drivers for considering climate change mitigation and adaptation in building design and construction. A presentation by Professor Geoff Levermore of Manchester University informed participants of the greenhouse gas (GHG) emission trends from buildings and in relation to other sectors as presented in the IPCC report. The presentation highlighted the importance of energy-efficient systems and energy management, renewable technologies and passive measures, and overall good design and operation of buildings in the reduction of GHG emissions.

Extra attention was given to the retrofitting of buildings to improve energy performance, by improving insulation, window performance and building services. The presentation also pointed out the significance of existing policies such as building performance codes, energy star labelling, financial incentives, as well as overcoming barriers such as fragmentation of building design.

A presentation from Jean-Luc Salagnac of the Centre Scientifique et Technique du Bâtiment in France, attempted to link mitigation and adaptation of buildings to climate change and presented this as an opportunity for the building industry to technically progress.

Weather data analysis

Weather data generation and analysis for use in building design was the main topic of the second session of the meeting. Dr Kwan-Ho Lee of Ulsan College, South Korea, and Dr Lisa Guan of Queensland University of Technology, Brisbane, Australia, presented an analysis of test reference years (TRY) by comparing them with observed data and global model outputs from the Met Office Hadley Centre (HadCM3 global model).

The analysis served as a validation of the baseline (period 1961-1990) currently used in building design in order to produce TRY for future time slices. Both projects used the global model outputs from the HadCM3 global model to generate weather series for 2020s, 2050s and 2080s. A method of generating TRY for South Korea was presented by Dr Lee.

Next generation of climate change projections

My own presentation, representing the UK Climate Impacts Programme (UKIP), was about the forthcoming UKCIP08 probabilistic climate change projections (the fifth generation of national climate scenarios to be published for the UK, produced by the Met Office Hadley Centre) to replace the UKCIP02. (For information on both UKCIP02 and UKCIP08, go to www.ukcip.org.uk/scenarios/).

I highlighted the importance of having a range of probabilities, as opposed to a single number, in order to make a robust design decision based on attitude towards risk. Because of the probabilistic nature of the UKCIP08 climate/weather information, some “customisation” will be needed in order for the information to be used in the building industry in a consistent way. The Engineering and Physical Sciences Research Council (EPSRC) has called for research proposals which explore the use of probabilistic weather information in building design. It is expected the outcome of the research projects will add some knowledge to the use of probabilistic information (UKCIP08) in building design.

Building performance predicted for the future

The third session of the meeting highlighted the importance of using future weather scenarios in building design, in order to assess the impacts of climate change in buildings, and inform adaptation options to increase their resilience to such impacts.

Presentations from Dr Rob Marsh of the Danish Building Research Institute, Dr Lisa Guan of Queensland University of Technology, Brisbane, and Dr David H C Chow of Sheffield Hallam University, UK, examined how future climate change scenarios could be used with computer based tools (such as thermal models) to assess impacts of climate change on energy demand for heating and cooling and building performance in general.

The presentation explained that the period 2001 to 2006 contained five of Denmark’s eight hottest years since 1874 and that global warming and climate change will result in summer and winter temperature increases which will increase the demand in Denmark for cooling and reduce the need for heating. It is predicted that energy for cooling a typical house will increase by 50% in the 75 years from 2005 to 2080, while energy for space heating will decrease by 30% over the same period.

Conclusions

Overall, the meeting highlighted the opportunities and challenges that the building industry is increasingly facing due to a changing climate. Both mitigation of the causes and adaptation to the impacts of climate change should be addressed by the building professionals in order to provide occupants with buildings that offer a comfortable environment.

Weather information based on past observations (such as the TRY) is not sufficient any more to guarantee a desirable future performance. The UK is leading the way in the state-of-the-art science of providing climate change scenarios over the next century, to be used in impacts and adaptation assessments. Research proves that such knowledge could provide the building industry with a powerful tool towards low energy but high performance buildings.