What is Sustainability?

Transcription

1 ENGS-44 SUSTAINABLE DESIGN The context - Materials Benoit Cushman-Roisin What is Sustainability? For natural ecosystems, Sustainability can be defined as the carrying capacity, that is, the amount of use that can be sustained over time without degradation of the system. A typical example is pasture land: Without fertilizer, a 100-acre pasture can sustain no more than about 80 dairy cows. More cows would consume grass at a rate faster than soil can regenerate it by natural growth. Exceeding the carrying capacity leads to a collapsed system, bare land and dead cows. Put in a positive way: Achieving sustainability requires staying within the carrying capacity. 1

2 The big question is: What is the carrying capacity of Planet Earth? There is unfortunately no direct answer. Planetary carrying capacity is an elusive concept because of human creativity: Past excesses have generally not been solved by reduction but most often by the invention of new technologies or use of new resources. An example is the large concentration of people in cities; such concentrated occupation of land became possible with the invention of drinking water distribution and sewage treatment by activated sludge. This leads to the concept of Sustainable Development, instead of Sustainability. SUSTAINABLE DEVELOPMENT A definition In 1987, the Brundtland Commission named for its chairwoman, Gro Harlem Brundtland, then Prime Minister of Norway was one of several international entities that prepared the way for the U.N. Conference on Environment and Development held in Rio de Janeiro in In its report, it made the claim: "Humanity has the ability to make development sustainable -- to ensure that it meets the needs of the present without compromising the ability of future generations to meet their own needs." 2

3 There exist many other definitions of Sustainability. Just one more here, because it is from an architect. Sustainability is the ultimate relation between action and consequence Kirsten Childs, Director of Interior Design, ASID, New York (in Sustainable Architecture White Papers, 3 rd ed., 2004, p. 40) SUSTAINABILITY: The triple bottom line It is essential not to endanger Planet Earth, but it would be pointless if it were achieved with no human population or with people living in very difficult conditions. Furthermore, the quality of living standards is intimately tied to the economy. A good economy provides jobs to people who can in turn enjoy goods and services. In the pursuit of sustainability, one ought therefore to consider three distinct elements: environmental quality, human welfare and economic viability. This three-fold vision is commonly referred to as the Triple Bottom Line. A catchy way of describing the Triple Bottom Line is to use the 3P s: Planet People Profit 3

4 Architecture is a case in point: Why do we build houses and other buildings? To shelter people and their activities. And, how can we afford to erect these buildings? Because we have a working economy. ( When construction goes, the economy goes. French saying) Perhaps not traditionally but certainly in modern times, however, architects and builders have largely ignored the environmental impacts of their structures. What are those impacts? When we consider the service economy, we tend to think that, because it does not make products, it does not impact the environment. WRONG! Think of the environmental impacts you create by having a house and living in it, and by studying at a college. 1. These structures are made of materials, which needed to be extracted from the ground and processed. Think: steel, wood, glass and plastics. 2. During occupancy these buildings need to be heated (or cooled) and lit. Think: Energy and the air pollution in generating it. 3. While you go about your activities in these buildings, you consume water, food, paper etc. All these require processing and lead to waste. 4. And, when the building comes to the end of its life, it is demolished. How much of its materials is recycled? Next to nothing. 4

5 Energy issues currently confronting us: 1. We may be running out of oil (no sustainability here!). And, increasing demand from China and India exacerbates the problem. 2. Combustion pollutes (nitrogen oxides, sulfur dioxide, particle matter, mercury, etc.). 3. Combustion of coal, oil and gas the carbon fuels also generates carbon dioxide, which may induce undesirable climate changes. What are our alternatives? Or, are those imperatives? 1. Use renewable sources of energy: sun, wind, water elevation. 2. Develop new technologies that extract energy from these primary sources and convert them in more convenient forms of energy, such as electricity or a liquid fuel to carry onboard of a vehicle. What in particular can be done at the level of a building? Well, we are not going to answer this one now. The entire course will be the answer to the question! Just a couple of thoughts to ruminate on: The right thing must be to make buildings and systems that pollute, contaminate, and deplete less than their predecessors do, right? But in doing that we simply become more efficient at doing the wrong thing. (William McDonough & Michael Braungart, Sustainable Architecture White Papers,2004) Often, when sustainable strategies are embraced, there is a heavy emphasis on energy and resource conservation factors easily quantifiable in terms of economic benefit. However, there is a growing consensus that the human-centered aspects of sustainable design issues of health, well-being, comfort, and safety offer even greater economic returns. (Kirsten Childs, Sustainable Architecture White Papers, 2004) 5

6 Materials from the perspective of the environment: Questions concern not so much - What are the material properties (qualities) - What function do they serve (functions) but rather address - Where do they come from (sources) - Where do they end up (fate) - How much do we use (quantities). MATERIALS NEEDS Needs = Food, Clothing, Shelter Transportation, Communication, Packaging, etc. Needs Products Service Materials But, could we perhaps provide the same level of service with less material or even provide immaterial services? 6

7 From Environment back to Environment Natural Processed Manufactured Consumer Back to Resources Materials Products Use Environment There are three primary ways of reducing extraction from and release to the environment: 1. Reuse of materials Recycling, Remanufacture, Reuse 2. Reduction of materials Dematerialization 3. For organic matter Incineration (to recover energy value) Use of Natural Resources (in USA) (1 Tg = 1 teragram = grams) 7

8 Trends over the 20 th Century But, there is a phenomenon that acts against dematerialization On one hand, we make better, smarter materials This allows us to use less or use the same longer But, on the other hand, there are more of us And, each one of us consumes more. The total amount used of a material = Amount per product x Number of products (Rubber tires) 8

9 Also, some things are getting BIGGER In the USA, private homes are getting bigger and house fewer people. (average size = 2,300 sq.ft., average occupancy = 2.58 people) And, there is a recent preference for SUVs over traditional cars. While we are getting MORE of some other things We are using more electronic equipment (computers, printers, fax machines, cell phones, notepads, ipods, etc.). We also travel more (= more cars and planes + attending infrastructure). Materials consumption versus wealth Materials consumption reflects economic output. In other words, developed countries form a materials-based economy. What if the entire world wanted to be like North America and Europe? China? India? 9

10 Energy consumption versus wealth Most of us have become more energy efficient, but there is nonetheless room to improve Let us now look at the other end of the process... garbage 10

11 Some U.S. garbage statistics Americans generate metric tons of garbage annually, which corresponds to 2.1 kg (4.6 lb) per person per day, not counting industrial waste. 94% of the materials in products are discarded within one year. Americans trash aluminum at a rate equivalent to that of rebuilding their entire civilian air fleet every three months. Not all goes to the landfill 11

12 Barriers to dematerialization 1. Ergonomic: Size of human body (car), fingers (keyboard), 2. Technical: Structural resistance; size of computer chip 3. Economic: Lower profits, Perception of lower quality 4. Informational / Organizational: Lack of knowledge about alternative materials 5. Regulatory / Legal: Safety concerns (too small = dangerous) 6. Societal: Ownership (people take pride in owning big things) Additional remark on dematerialization Dematerialization of products Fancier design (alloys, coatings, etc.) Less recyclability Greater extraction of materials 12

13 Barriers to recycling (according to Frosch, 1997, + other thoughts) Material is diffused in the environment (ex. rubber on roads, solvants in the air) Material is embedded in obsolete product and hardly separable (ex. copper wires in cars) Material is mixed with impurities (ex. zinc in steel, adhesives on used plastic bottles) Material is more concentrated in nature than in waste streams (ex. sulfur) Not economically profitable (low and fluctuating prices, disposal may be cheaper) Lack of information about possible uses Regulations against some hazardous wastes (recycling followed by dumping after new law) Cultural habits Bottom line Wealth appears to be a materializer (Wernick et al., 1997) Some dematerialization has taken place, but there are forces opposing it. Energy efficiency appears easier than material efficiency. 13