Tuesday, January 25, 2011


. What are “Low Carbon Buildings”?

b. What is ecological footprint?

c. Calculate your carbon and H2O foot prints based on your energy and water consumptions per year.

A “Low Carbon Buildings” (“LCB”) is a building which has been engineered to release significantly less GHG than a regular building over its lifetime. Typically, a LCB will consume much less energy than a traditional building and integrate distinctive technologies, such as renewable energy system which will reduce its GHG emissions. LCB sets to balance the production and emissions of GHH, of which CO2 the principles of gas, from mix of internal and external reductions.

Today, the built environment accounts for around half of all the UK’s carbon emissions. Anything we can do to lessen that impact will help reduce climate change, meet our environmental goals, improve air quality and make this country a better place to live in. Creating buildings that generate fewer carbon emissions is not only socially desirable but they can be cheaper to build and more pleasant to occupy. Because low-carbon buildings use less conventional energy sources for heating and cooling – and have less associated hardware – they cost less to run and are cheaper to maintain and refurbish. Thus, low carbon buildings make both economic and environmental sense.

There are some general points why must we go for low carbon building:

- Reducing and adapting to the threat of climate change is a major issue
- The buildings sector is responsible for about 40% of the CO2 emissions
- The public sector is by far the largest owner/user of buildings
- Untapped potential for cost-effective energy and CO2 savings through operational innovation, passive building design, energy efficiency and renewable and low carbon energy systems.
- Innovation, in its widest sense (not just technical) will be the key to:
Ø Cost effective carbon reductions from public and commercial buildings in a way that does not compromise their functionality and desirability.
Ø Opportunity: to create the next generation of low carbon healthcare facilities and create a powerful lead market for low carbon technologies.

There are some well-established, over-arching principles of LCB design:
1. Understand energy use in the building type
It’s vital that architects understand the breakdown of energy use for the building type, at least by fuel type and ideally by end-use, i.e. heating, cooling, lighting etc. This enables the designer to focus on the most important issues and identify how to minimize CO² emissions. The pattern of energy use is important, not just annual totals, particularly when renewable energy technologies are being considered.

2. Use the form and fabric of the building to do the work
Architects should use the form and fabric of the building to do as much of the work of environmental modification as possible, thus minimizing the demand on services such as heating and lighting. LCB should exploit useful solar and internal heat gains (from people, equipment, etc.) to satisfy as much of the heat demand as possible, but exclude unwanted solar gains when they may lead to overheating1.

3. Focus on insulation and air tightness
Low carbon designs seek to reduce unwanted heat losses and gains by adopting appropriate standards of insulation and air tightness. To identify appropriate standards it is necessary to understand the heating and/or cooling balance of the building. Generally the design of a dwelling will focus on keeping heat in and making use of heat gains, while the design of an office will focus on keeping the building cool.

4. Use high efficiency building services with low carbon fuels
The architect should satisfy the remaining energy demand with building services that are as efficient as possible, and that use fuels with low CO2emissions factors. Architects should also ensure that heating controls are as responsive as possible, making use of solar and internal heat gains without over-heating the building.

5. Use renewable energy systems
Low carbon buildings use renewable energy systems to reduce the CO2 emissions associated with the provision of heat and power within the building.

6. Manage energy within the building
Low carbon design is not enough; low carbon operation is also needed. Architects can enable efficient operation of the building by ensuring that appropriate metering and energy management systems are in place, and that the occupants are well-informed about how the building and its services are intended to be used.

Construction details – points for architects to watch
Achieving low carbon homes requires a fundamental rethink of many traditional construction details. They need to be reexamined in terms of their levels of insulation, thermal bridging and air-tightness. Many common details are poorly insulated, contain repeating, non-repeating and random thermal bridges and are poor at reducing infiltration

Answer 3(b)

The ecological footprint is defined as "the area of productive land and water ecosystems required to produce the resources that the population consumes and assimilate the wastes that the population produces, wherever on earth the land and water is located”. It compares actual throughput of renewable resources relative to what is annually renewed. Non-renewable resources are not assessed, as by definition their use is not sustainable.

The total “footprint” for a designated population’s activities is measured in terms of ‘global hectares.’ A global hectare (acre) is one hectare (2.47 acres) of biologically productive space with an annual productivity equal to the world average. Currently, the biosphere has approximately 11.2 billion hectares of biologically productive space corresponding to roughly one quarter of the planet’s surface. These biologically productive hectares include 2.3 billion hectares of ocean and inland water and 8.8 billion hectares of land. The land space is composed of 1.5 billion hectares of cropland, 3.5 billion hectares of grazing land, 3.6 billion hectares of forest land, and 0.2 billion hectares of built-up land. These surfaces represent the sum total of biologically productive hectares we rely on for our survival. They represent the earth’s natural capital, and their annual yield represents our annual natural capital income.

- A carbon footprint is a "measure of the impact human activities have on the environment in terms of the amount of GHG produced, measured in units of CO2.
- It is meant to be useful for individuals and organizations to conceptualize their personal (or organizational) impact in contributing to global warming.
- A conceptual tool in response to carbon footprints are carbon offsets, or the mitigation of carbon emissions through the development of alternative projects such as solar or wind energy or reforestation

Ecological Overshoot Demonstrated
Dividing the 11.2 billion hectares available by the global population indicates that there are on average 1.8 bioproductive hectares per person on the planet. The 2004 Living Planet Report indicates that the actual usage was 13.5 billion global hectares or 2.2 hectares per person – more than a 20% overshoot. The overshoot result indicates that our annual draw down of natural capital is liquidating natural capital income, as well as reducing natural capital itself. Such an overshoot is ecologically unsustainable. Time series of the global ecological footprint indicate that human activities have been in an overshoot position for approximately three decades, and the overshoot is increasing over time.

Empirically demonstrating that ecological overshoot is now occurring by a significant margin is a major contribution to our understanding that we are exceeding sustainable ecological scale on a global level, and by roughly how much. The implications of these results are even more urgent when we realize that the ecological footprint is likely an underestimate of the actual demands we place on the earth’s ecosystems.

The Footprint of Different Activities
This measure can also be presented in terms of the types of products or services provided by the global hectares, for example, in terms of goods from crop lands, animal products, fish, forest products, built up areas, and energy and water use. Such analyses identify which areas are placing the greatest strains on ecosystems, and can help set policy priorities. Growth in animal products and energy use, especially of fossil fuels, are two areas that are rapidly increasing these strains.

Sound Methodology
The methodology for the ecological footprint is detailed but not overly complex. Data inputs are from publicly available national, international and private organizations. A variety of accounting assumptions are made, but they are explicit and always entail a conservative bias. Weaknesses in this pioneering endeavor have been acknowledged, many have been corrected, and others are being addressed with further research.

A Policy Tool: The Footprint as an Indicator
One of the many strengths of the ecological footprint is its immediate intuitive appeal. Along with its reasonable and continuously improving methodology, this appeal has led to its widespread use in a variety of settings, addressing national, regional, municipal and even individual footprints. The measure itself simply describes the size of the footprint for a particular population or activity. But its implication for policy and planning purposes has been recognized, leading to its use by several countries and municipalities to implement and monitor their sustainable development agendas. It has proven a useful research tool to explore the footprint of specific activities such as different modes of transportation or methods of farming. There is also an annual global footprint report that provides a useful overview across many specific areas.

The ecological footprint is not a precise measure of ecological sustainability. While it is perhaps the best estimate to date, it is important to recognize its limitations. In general, the footprint underestimates the impact of human activities on the biosphere. Any applications of the footprint methodology must keep this perspective in mind. Because it focuses on renewable resources, the footprint provides limited information about most non-renewable resources and their impact on ecosystems (with the exception of fossil fuel impacts which it partially addresses).

The concept of “global hectares” of world average bioproductivity is useful for looking at issues related to global footprint. But individual applications refer to specific locations where there is an impact. These local areas may have bioproductivity rates different from the global average; where available, local data can be used. Another limitation is that the approach allows only general types of bioproductive areas to be identified (e.g. cropland, forests, etc). Specific ecosystems within these areas are not addressed. These limitations do not invalidate the footprint, but do underline the importance of interpreting any specific application with these limitations in mind.

Relation to Scale
The ecological footprint is the closest empirical measure now available to estimate maximum sustainable scale. It captures the bioproductive capacity that is required to support a given level of material throughput, with current practices and systems of organization. Maximum sustainable scale relates the physical amount of material throughput in economic activities relative to the biophysical limits of the ecosystems which are involved as sources or sinks. Ecological footprint differs only in that it involves the throughput involved in all human activities. Most, but not all, of these activities are economic ones.

The ecological footprint is connected to many of the other approaches to thinking about and measuring scale:

- Footprint and biocapacity is a way to measure historical human carrying capacity. Most carrying capacity studies try to answer a hypothetical question: how many people could live on the planet. The footprint indicates how much of the planet was occupied by people. This is an historical question that can be empirically determined rather than conjecturing on future possibilities.
- Footprint analysis provides a means of assessing the impact of population, affluence (consumption) and technology identified in the IPAT equation.
- Footprint was used extensively in last update of the limits to growth to give a summary report of human demand on nature.
- Footprint translates material flows in areas necessary to support these flows.
- Footprint translates some of the principles of the natural step into a resource account.
- Footprint is an ecological economics tool.

Future Directions
Efforts are underway to standardize and refine the methodology underlying the footprint, and to incorporate areas or issues not currently captured. This continuous attention to methodological and conceptual rigor is a positive move and promises to increase the usefulness of this sustainability indicator. The intuitive appeal of the footprint is another asset, leading to its adoption for many projects. For applications of the footprint to sustainable scale issues, it would be wise to keep in mind that this measure likely provides an underestimate of ecological impact.

Answer 3(c)

A carbon footprint is defined as:
The total amount of greenhouse gases produced to directly and indirectly support human activities, usually expressed in equivalent tons of carbon dioxide (CO2).

Carbon dioxide is a so called greenhouse gas causing global warming. Other greenhouse gases which might be emitted as a result of our activities are e.g. methane and ozone. These greenhouse gases are normally also taken into account for the carbon footprint. They are converted into the amount of CO2 that would cause the same effects on global warming (this is called equivalent CO2 amount).

In other words: When we drive a car, the engine burns fuel which creates a certain amount of CO2, depending on its fuel consumption and the driving distance. When we heat our house with oil, gas (from cooking) or coal, then we also generate CO2. Even if we heat our house with electricity, the generation of the electrical power may also have emitted a certain amount of CO2. When we buy food and goods, the production of the food and goods also emitted some quantities of CO2. Even, when we are not doing anything such as sleeping and relaxing, if we use the air condition, we also emit CO2. Imagine how much CO2 we emit per day!. Most people are shocked and surprise when they see the amount of CO2 they produced in their daily activities.

The carbon footprint is the sum of all emissions of CO2, which was induced by our activities in a given time frame. Usually a carbon footprint is calculated for the time period of a year. The carbon footprint is a very powerful tool to understand the impact of personal behaviour on global warming. If we personally want to contribute to stop global warming, the calculation and constant monitoring of our personal carbon footprint is essential.

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