Global warming greenhouse gas emissions and building
The issue
None of us are doing enough to prevent global warming greenhouse gas emissions, and we are all complicit here. How much is enough? There seems to be general agreement that 2000kg C02 per person per year is the sustainable level. Most of us cause the emission of 5 to 10 times this amount in a year.
A long haul flight such as a flight to London and back to Auckland will use 2.5 times a persons annual C02 emission quota, without them doing anything else; living in a house, eating, driving or dressing themselves. There is in the big picture, there is a long way to go.
In NZ the building and manufacturing sectors create about 20% of gross greenhouse gas emissions. This is emission created by building buildings, and does not include emissions that come from buildings in use, and at end of life.
The research
There is a lot of research on this. The world's various heritage and building conservation agencies all have their guidance. In 2015 sustainability was placed firmly on the agenda by organisations that are heritage thought leaders.
A policy was established by Unesco, the organisation that leads on world heritage sites.
Other agencies also have material.
In New Zealand there has largely been silence on this issue from our thought leaders, Heritage New Zealand.
The best paper that I have found on old buildings and GGHG is by Dr Noni Boyd, initially from Wellington, trained in Auckland, and then acheiving success in the building conservation field in Sydney. Some of the quotations Dr Boyd provides are worth repeating here, because they are so apposite, and interesting historically, in their own right.
The present era is characterised by two apparently irreconcilable schools of thought and the great conflict between them is of the greatest possible significance for mankind. On the one hand, we have the dominant doctrine of the modern western society that continuing economic growth is based on industrial expansion and the spread of technology is not only inevitable but is highly desirable.
This view can be referred to as the western idea of progress or simply the Growth Gospel. On the other hand we have the ecological viewpoint which states that, because the resources of the earth are finite, and there are limits to the tolerance of the biosphere to chemical and other forms of damage, unhindered and unceasing growth of industry (and/or population) is not compatible with the long term survival of civilisation. Our society has every reason to take this controversy very seriously, as there is no escape from the logic of the ecological view
Dr Stephen Boyden RAIA, 1980, Energy & Buildings, Submission to the Senate Standing Committee on Natural Resources, Architecture Australia, May 1980.
In our cities and towns a more sustainable approach would be to seek to re-use a building capable of being adaptively re-used whether a heritage item or not. Heritage professionals need to enter into the sustainability debate; the well-established conservation planning process can also become a useful tool for implementing the 3 Ls: long life, loose fit, low energy and a tool for identifying Operational Energy Advantages that were part of the original design intention when passive environmental control and good daylighting were the norm.
Heritage & Sustainability 101, Dr Noni Boyd
Towards a response
Because global warming is a matter of chemistry and physics a numbers based approach is helpful to designers. Each building material, when in use, will have a profile of emissions associated with it.
Building the minimum necessary is the first step. The information on embedded energy of buildings has been available for the last 25 years, with the New Zealand Institute of Architects being early players in the field.
Despite the early entrance in the field of the New Zealand Institute of Architects architecture as a profession is as complicit, or more complicit as anyone else in creating climate change. There has been development of standards based on energy in use, and lots of green wash. Most architects, given the opportunity of a commission (a beach house, six car garage, swimming pool, multi storey office) will not turn it down on the grounds that the project is frivolous and bad for the atmospheric commons. This is understandable given that they have businesses to run, employees to pay, and need income to live, like anyone else.
The carbon footprint of the New Zealand house has grown rather rapidly over the last 25 years. In 1993 a paper was written as a response to global warming, addressing the contribution of the building sector to the problem.
This research was based on a house size of 93 M2. This was chosen because this house design had been used as an index design in the industry for 30 years or so before that 1993 publication date. In the 1990s the average house size was about 135m2. Researchers in the same area are now working with a base house size of 190 m2. Therefore, the local response to developing a post carbon economy, in the building sector has been a 30% increase in gross greenhouse gas emissions at a per house level, at least, in the 25 years since we became aware of the problem. This is without factoring in the large increase in building activity that is driven by growth in economic migration and in mass tourism.
This is also without accounting for increased emissions associated with the greater use of concrete, steel and glass. Arguably, there has been some offsetting of these increases through improved energy efficiency throughout a buildings life.
The counter argument would be that these gains associated with better insulation and heat pumps are not real, as people have increased their use of heat markedly. The traditional pattern for heating in New Zealand was to heat occupied spaces only. Bedrooms were not heated. Living areas were heated in mornings and evenings only. Firewood was the primary heat source. There is evidence for all these assertions in the building fabric that survives from earlier periods.
Some conclusions
Not building a new house, but reusing what exists is a viable strategy. Sensible retrofits of insulation, and energy efficient technologies (eg. led lights, solar hot water) will help achieve lower in use energy and therefore lower co2 emissions, the other side of the equation.
Timber is the most sustainable building material. Its use actually sequesters atmospheric carbon at least for a time. The energy used in production is low. There are land use benefits, stabilisation of marginal land, and potentially, if we switch from the pravalent monocultural pinus radiata based approach biodiversity benefits. Growing trees is supported by the productivity commission report
Small steps; in short.
- Don't demolish, extend the life of your building.
- Retrofit; insulation, led lights, solar hot water.
- Build the minimum, or not at all.
- Build in timber.
- Change behaviours, open windows and doors daily, at the warmest time. Turn off the lights.
- Don't use steady state heating for the whole house, consider using an efficient woodburner, and get your wood from nearby.