3/1/14, 7:44 AMEnvironmental Issues & Building Design | Sustainability Workshop

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As ice core records from Antarctica show that changesin carbon dioxide concentrations (blue) track closely withchanges in temperature (red). Carbon dioxide levels arenow higher than at any time during the past 650,000years. (CREDIT: Marian Koshland Science Museum,source)

Environmental Issues & Building Design | SustainabilityWorkshopAccording to the scientific community, climate change is happening and its effects willhave severe consequences for our society and environment. Reducing energy use inbuildings is one of the most important ways to reduce humans’ overall environmentalimpact.

Nearly unanimous scientificconsensus has established thatclimate change is occurring as aresult of human activity.Mathematical models of globalclimate change have linked ahuman-driven increase in GHGs toan increase in global temperatures(especially in the past 250 years,since the industrial revolution).The primary source of this increasein GHCs has been attributed to theemissions generated by the use of fossil fuel-based energy.

Climate change has been linked observable disturbances such as the loss of mountainglaciers and ice cover on the Earth’s polar regions, changes in the timing of the springbud-break, and an increase in the frequency and intensity of extreme weather eventssuch as cold waves, heat waves, large storms, hurricanes and tornadoes, floods, anddroughts.

Climate scientists have theorized that human civilization is in danger of crossing athreshold or “tipping point” that could lead to more radical changes in the globalclimate, and that could accelerate the onset of either a new “hotter and wetter” agesimilar to the Earth’s environment before the appearance of human beings, or a newice age. (Intergovernmental Panel on Climate Change, IPCC Fourth Assessment Report[AR4]).

3/1/14, 7:44 AMEnvironmental Issues & Building Design | Sustainability Workshop

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Quick stats

Buildings account for 40% of energyuse worldwide (WBCSD).

Energy used during its lifetime causesas much as 90% of environmentalimpacts of buildings (Journal of GreenBuilding).

Building operations consume more than2/3 of all electricity(BuildingScience.com)

Residential and commercial buildingsconsume 40% of the primary energy and71% of the total electricity in theUnited States. (ASHRAE)

Scientific estimates place the window of opportunity for reversing this trend in the verynear term—according to some, as briefly as over the next ten years. After that, theglobal climate may change irreversibly, and humans will just have to adapt.

In many arenas of implementing real practical change, architects, engineers, andbuilders are the only ones with the skills and resources that provide real, practical,cost-effective, and inspiring solutions.

Environmental Impacts of BuildingsBuildings account for 40% of worldwide energyuse — which is much more than transportation. Furthermore, over the next 25 years, CO2emissions from buildings are projected to growfaster than any other sector (in the USA), withemissions from commercial buildings projectedto grow the fastest—1.8% a year through 2030(USGBC).

Often, energy use in the form of electricity drivesthe largest environmental impacts. Where thatelectricity comes from determines what those

impacts are. In the United States for example, where buildings account for more than70% of electricity use, most of the electricity is generated by coal-fired electrical powerplants (USGBC).

These exact impacts can quantified by lifecycle assessment (LCA), the most thoroughway to determine the environmental impacts of a design. There is no perfect way tomeasure environmental impact. LCAs can measure greenhouse gas (units = CO2e =

CO2 equivalent) to measure global warming potential, or might measure other things

like human health, water, and land-use impacts. You may hear the word “embodiedenergy” or “embodied carbon” – this refers to the energy or greenhouse gas emissionscaused throughout an object’s lifecycle. Alternatively, sometimes an overall normalized

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Total life cycle impacts by life cycle phase for a prefabricatedcommercial building with average California energy use, thebuilding as built (30% of power supplied by photovoltaics),and net zero energy (100% of power supplied byphotovoltaics), in units of EcoIndicator99 points.

“Lifetime energy use energydominates traditional and evenenergy-efficient building life cycles,by far. In such cases, otherenvi¬ronmental concerns are nearlyalways trumped by energyperformance. Once a buildingmeets all energy needs by cleanpower generation (whether it be on-site PV panels, PV grid power, orother equally clean renewables notanalyzed in this study), then buildingmaterials and manufacturingbecomes the dominant life cycleimpact phase.” (Journal of GreenBuilding)

score is used to combine many kinds of impacts into a single number (i.e. Eco-Indicator 99). A good primer on LCA is here.

A 2012 LCA study found that “Specifically within commercial buildings, the use andoperation phase of the material and building life cycle is so dominant that the impactsof construction, demolition/disposal, and transportation are nearly irrelevant for mosttraditionally constructed buildings.” (Journal of Green Building)

Since 1920, the overall trend in building energy use for comercial buildings is higherenergy intensity per square foot (BuildingScience.com). It is important to reverse thistrend.

In the coming decades rapid development will continue in the developing countries,while many buildings in the developed world will need to be renovated and retrofit. We need to make sure that the engineers and architects working on these buildings areequipped to make design choices that use energy effectively.