"More and more people now recognise that economic development that is not environmentally sustainable is self-destructive". So said Jonathan Dimbleby to the Royal Institute of British Architects last month. Buildings account for 47% of all CO2 emissions. The technology exists for these emissions to be cut by typically 50%, but as much as 90%. Things have to change.
   If we are to create a more sustainable built environment people must accept that buildings will look different. Communities will be more concentrated with higher densities, although with modern communications and the possibility of being autonomous it will also be easier to live remotely.
   There will be more terraced housing and fewer detached houses, both in towns and the country. There will be much more timber cladding (the most sustainable material). Orientation will play a larger role in dictating the layout of buildings.
   There are of course as many shades of green as there are plants. The important thing is that people do not confuse phoney green architecture with the real thing. Too many architects and developers are jumping on the green bandwagon and introducing superficial, fashionable green dressings to their buildings. Do not be fooled by the odd photovoltaic panel or 'sun space'.
   A true green architecture responds to its local environment in its ground base, locally sourced materials, how much water needs to be shed from the roof, how often it freezes in winter - its microclimate and geography. I hope we will be able to read the geography of the land by its locally changing architecture just as we could before the industrial revolution arrived with its mass housing and cheap transportation.

The BT headquarters at Edinburgh Park finished in 1999 by Bennetts Associates superbly illustrates a more 'high tech' sustainable building. BT is an office for 900 people. All buildings in Edinbugh Park have to conform to strict planning, material and design guidelines, constraints which often preclude the most sustainable solution, such as flat roofs. Benetts met the challenge with an innovatively sustainable office building, one in a series which includes John Menzies headquarters, also in Edinbugh Park, Powergen and Wessex Water. Each one refines an approach based on providing thermal stability with concrete coffered ceilings: in Summer they give free radiant cooling and in Winter they store the heat. Where the prototype becomes interesting is the way in which it varies according to local conditions. It should be mentioned that the primary aim of an office building, used only at daytime, is to cool while for housing it is to heat. There are openable windows, but due to a nearby chicken farm and the severe winds, the Edinburgh Park buildings also needed fan-assisted ventilation. What a shame the Strategic Rail Authority has repeatedly delayed the high-speed rail link to central Edinburgh, which would give Edinburgh Park the sustainable credentials it deserves.

At the low tech end of the spectrum lies Benjamin Tindall Architects' Eight Houses at Cuithir, Isle of Barra, finished in 2001. It is low budget, low-density rural housing. Its simplicity means that its response to the environment is immediately obvious. Houses are one and two storey blocks, 5m wide by approximately 12m long. The similarity to the black house is not contrived. It is the logical result of responding to the local conditions. The East West orientation of all the houses has several benefits including maximising passive solar gain.    Saving energy is of paramount importance on an island where fuel sources are scarce. The weather on Barra is extreme and the houses' narrow ends face the predominant wind direction. This combined with their rounded ends, again reminiscent of several vernacular types, is the best form for diverting the wind away from the house and thereby drastically reducing heat loss. The houses are timber framed and many of the materials are locally sourced including timber, harling and aggregates. The architects' hope that in the future they will be able to combine houses and workplaces to give a more sustainable use to the scheme.

More often that not the most sustainable, and economic, solution to building is to renovate a redundant one. This is the unsexy side of sustainable architecture. 98.5% of CO2 emissions come from older building stock however, so it is important to improve the environmental impact of the building. Norton Park in East Edinburgh, is a Grade II listed former Victorian school. It was redeveloped by Burnett Pollock Associates in 1998 into affordable offices for charities and voluntary organisations. The owners, Albion Trust, set high environmental standards but also wanted the building to be financially viable. The cost per square metre was £750 as opposed to an equivalent new build of £1,250. The annual overall energy consumption is 150 kWh/m2/year, less than half that of a comparable typical office. This is achieved through various measures such as more insulation, better glazing and efficient lighting and heating systems. The energy costs of running a four man (30 sq m ) office at Norton Park (gas and electricity) is £205 per annum as opposed to £425 in a typical office.

These three buildings are all exemplary of their type. There should be more. Unfortunately there are too few enlightened clients and a planning system that does not like change.
    There is a scarcity of information about sustainability and far too few environmental audits on occupied buildings. The only statutary legislation is in the form of Building Standards (Scotland) Regulations issued by the Scottish Executive. These were toughened earlier this year and in some areas, such as insulation values, Scotland is ahead of England and Wales and almost on a par with the rest of Europe. However there is still work to be done in several areas where we lag behind Europe, in particular indoor air quality.
    Developers have an unhealthy dependence on air conditioning. Gaia Research is currently drawing up a consultation document for the Scottish Executive titled "Sustainable Construction and the Regulatory Framework" which puts forward proposals for new and better sustainable regulations in Scotland. They are drawing from Europe and the wider international community.
    Sandy Haliday, director of Gaia Research is "optimistic that Scotland is enthusiastically pursuing best practice in sustainable legislation which will make a difference". Many initiatives are being considered, for example an environmental MOT of your building either annually or when bought or sold. Something similar to this is already happening in more enlightened countries such as Germany.

We need only look over the water to The Netherlands to see systems which encourage such buildings both financially, with tax incentives, and culturally. The Dutch are more aware of sustainable issues at the strategic planning level and more open to changing aesthetics. There is some European legislation on the horizon that would penalise energy-inefficient buildings further.
    Sustainable architecture offers an exciting way forward, away from the homogenisation of mass housing, away from the bland international style of the modern office block and shopping mall that is creeping all over the country. But it is not a return to the vernacular for nostalgic reasons alone. It is not pastiche. Its materials are noble, they look good and feel right because they were chosen for reasons of locality and suitability to the local environment.
    Some architects argue that sustainable architecture is a means and not an end and therefore should not be thrown into the centre of debate. Of course it is only a means, but it is a vocabulary which does and will impact on the current perceptions of architecture. Until it is widely adopted it must be at the centre of debate. As I implied at the beginning of this article there are as many styles of sustainable architecture as there are architects. Sustainability in architecture is a language, not a style. A language that will help save our planet.