Not really sustainable
July 04th 2007 We must design and manage buildings that will not only mitigate the effects of climate change but also adapt to the future climate. It is no good have a carbon neutral building today that will need air conditioning tomorrow writes Gerry Metcalf, knowledge transfer manager, UK Climate Impacts Programme
There is now a clear recognition that the UK climate is changing and that these changes will continue throughout this century and beyond. Designers of buildings and their services are therefore challenged in two different, but related,ways:
• to design buildings and their services that will create much lower or zero carbon dioxide emissions. (Mitigation)
• to design buildings and their services that acknowledge and respond to the new climate and weather conditions within which they must operate.(Adaptation)
UKCIP (UK Climate Impacts Programme) provides information,guidance and tools such as climate scenarios to assist designers, engineers and others in addressing these challenges. The next generation of climate information for the UK will be released in October 2008, based upon sound science and climate information generated by the Hadley Centre (Met Office). This will include a ‘Weather Generator’ which will provide projections of weather events with high-resolution temporal and spatial data.
In practice much of the current work on sustainable building design, even much cutting-edge work, fails to acknowledge the changing climatic conditions within which new buildings must perform. Many of the socalled ‘sustainable’buildings, and their services,which are designed today will for example, only be capable of keeping buildings cool at today’s temperatures. Faced with unavoidable climate change, and therefore increased external temperatures, it is almost inevitable that some form of artificial cooling will be needed later during the life of such buildings.The cooling systems will in turn use energy, which will emit carbon dioxide, and thus negate the sustainability objectives. In the South East this phenomenon can be already observed. Modular air-conditioning units are increasingly bolted on the side of buildings designed and built quite recently. If this means that buildings which are intended to be ‘sustainable’ will in practice fail to survive the rigours of the new climate, then they are not really ‘sustainable’ for very long.
The Challenge
The built environment is one of the sectors that should benefit most from considering both mitigation and adaptation together in order to address the twin challenges of climate change in an integrated way. But, designing a project which achieves the following criteria presents a considerable challenge :
• provides internal comfort;
• is resilient to the anticipated climate and weather conditions;
• makes efficient use of energy;
• releases low- or zero-carbon-dioxide equivalent emissions.
So, this article considers the following issues with regard to climate change and energy efficient, low-carbon solutions for the design of buildings:
• why does the mind-set which chooses to ignore the future climate continue to exist amongst low-energy practicioners?
• what arguments might persuade practicioners to include climate impacts and adaptation in their work?
• what tools are now available to assist practicioners in this work?
Why does the mind-set which chooses to ignore the future climate continue to exist amongst lowenergy practicioners?
• adaptation implies failure to mitigate which is difficult for sustainability enthusiasts to acknowledge;
• mitigation is sexy, particularly as it seems to encourage new technologies, such as microgeneration;
• there are no easy or obvious technical solutions for passive cooling in future heatwave conditions, even for new build, and the provision of passive cooling for
existing buildings is recognised as even more challenging;
• even spatial analogues (borrowing contemporary technologies from other locations) are not helpful as most (modern) buildings that work in warmer
climates are large consumers of energy and certainly not low-carbon;
• anticipating a changing climate is still not a formal requirement in the UK
Building Regulations.
What arguments might persuade practicioners to include climate impacts and adaptation in their work?
• climate change is unavoidable at least to the 2050s and probably beyond;
• buildings will need to perform in different climate and weather conditions throughout their operational life;
• insurance and investment may progressively require evidence of the ‘climate proofing’ of buildings;
• professional indemnity insurance may now expose built environment professionals to the risks associated with changing climate and weather;
• we now have a much better understanding of what weather and climate to expect in the 21st century What tools are available to assist practicioners in
this work?
The mission of the UK Climate Impacts Programme (UKCIP), as its name suggests, is ‘to make organisations aware of the changing climate so that they can prepare for its impacts’. To help organisations understand the
future climate several resources are provided by UKCIP.
The most significant of these resources is the set of climate scenarios for the UK in the 21st Century. These are published as the UKIP02 scenarios and have been prepared by the Hadley Centre of the Met Office. The data are typically shown on maps, reporting at a 50km square grid across the UK, (see Figure 1) which are useful in indicating:
• the extent of climate change to be expected through the coming century in different locations across the UK. (Note in particular how the South East of England is projected to experience much greater change, in all weather variables, than the North West);
• the changes for three 30-year periods through the 21st Century,centred around the 2020s,the 2050s and the 2080s;
• the influence of different levels of greenhouse gas emissions. (Note how, particularly towards the end of the century, changes are much greater in the high
emissions scenarios than in the low emissions scenarios.)
These maps,and the underlying information from which they are derived, can set the scene for long-term changes in climate averages. From this we can deduce that, for example, there will be less demand for spaceheating in the projected warmer winters, or that, in a given location, the growing season will be significantly extended.
But these maps don’t address so well the impacts of extreme weather events such as torrential downpours of rain or heatwave conditions. And it is the impacts of weather events such as these that present the greatest threat. So,UKCIP is encouraging the development of an LCLIP (Local Climate Impacts Profile). These will have two main benefits. By starting with the real experience of actual weather events and their impacts in a locality, a tangible understanding will be created of the likely consequences of changes in extreme weather events. This understanding should also reveal critical thresholds (for example in temperature) which will indicate the type of information that will be needed about future weather events in order make well informed design decisions for the future.
In Oxfordshire the County Council has recently undertaken an LCLIP. It started simply by assembling news cuttings of significant weather events and their consequences over the past five years.These have been incorporated into a database which includes information on the weather event, its impacts and its consequences. For example, in July 2006 heatwave conditions (where the external temperature reached 31°C) caused internal conditions to be extremely uncomfortable requiring several schools in the county to be closed.
Such examples provide a broad indication of critical thresholds for external temperatures, which will vary from one building to another. A building professional (architect or engineer) can advise on internal thresholds determined by comfort criteria.
UKCIP will be releasing a new set of resources in 2008 which will, for the first time, allow designers to make use of such threshold data in designing for the future. The resulting climate resource, to be offered as UKCIP08, will provide much more than is available through UKCIP02.It will contain historic climate information, climate projections for the 21st century presented in a probabilistic format, and information at the daily and sub-daily level with more information on extreme events. All this information will be accessible through a user-friendly interactive website. So designers will be in a position to make use of the evidence of current extreme weather events to interrogate the high resolution information on the future weather which will be available in the UKCIP08 package.
So a calculation method might proceed as follows:
• confirm the indicative thresholds as a basis for decision-making about the future. Examples will include maximum temperatures, number of occurrences, duration of occurrence etc. Some of these will be sourced from relevant industry or professional standards, other by evidence from local experience.
• specify the time period over which the design decision will apply eg length of life of a building. This will define the periods in the 21st century for which you need future climate and weather information.
• if the information that you need is predominantly average conditions over a specified period, this will be available direct from the UKCIP02 climate scenarios. If you require more detailed information about extreme events (i.e. future weather), you may need to go beyond the standard UKCIP02 scenarios. For the present,you should approach UKCIP for advice. In due course, the UKCIP08 scenarios will provide daily information online for your direct use.
• We have seen how the challenge for building design is to provide internal comfort in the face of new weather and climate conditions whilst making efficient use of energy that releases low levels of carbon dioxide.There is a need to remove some of the intellectual and emotional barriers to adaptation which still exist amongst the sustainability community. If these can be overcome, the tools and data sets are now becoming available to help engineers take on this design challenge.
Climate is defined as the average weather in a given location over a thirty year period. Weather is what is happening outside the window at this moment. | 
