Sustainability Considerations

“Sustainable development is development that meets the needs of the present without compromising the ability of future generations to meet their own needs”.

- Our Common Future (1987)

Global Demand

Population by country: Percentage of World GDP (5 largest)

Historical GDP Per Capita (inflation adj.) • GDP discrepancy between US and 4 largest countries• Acceleration of Chinese growth• Growth fueled by resource demand

The Needs of the World• World population and resource demand are

increasing– Presents largest obstacle to sustainability

• Carrying capacity– The maximum number of people the Earth can support– UN projects 10 billion by 2100

GDP and Health

• Huge increase of life expectancy with first $10,000 of GDP growth– This provides the basics of life (food, water, sanitation etc.)– Similar trend with decrease in infant mortality

• Ideally, entire globe should consume at least at this minimum level

Historical Life Expectancy and infant mortality in US

Life Expectancy and infant mortality as a function of GDP in US

Failed States and Sustainability• Lack of governmental control spawns

unsustainable practices by population– High population growth– Minimal economic growth– Decreased interest in environmental protection

• Threaten stability and sustainability of entire region– Hotspots for terrorism and other radical activity

Resource Demand• World GDP growing at

3% per year and population at 1%– more wealth per person

• Coinciding increase in resource demand

Energy Consumption

• US accounts for 5% of population, but 20% of energy consumption

• China presents largest potential for future demand per capita increase

Water Demand

• Water use tends to increase with income– Tied to GDP growth

• Water shortage seen as a probable cause of future conflict– Essential to food

production and industry

Measures of Sustainability• Include:

– Ecological footprint– Energy footprint– CO2

• Calculations are more of an estimate– Give a sense of how

resource intensive your lifestyle is

• Infrastructure tied to most aspects of ecological footprint

Engineering Sustainability

Sustainable Design• Minimizing environmental

impact is not inherently sustainable design

• Triple bottom line– Include environmental and social

well-being when calculating the value of a project or product

– Mirrors three pillars of sustainability• Economic, environmental, social

Green BuildingsCharacteristics • Use renewable energy• Reduce runoff• Use less land• Closer to city center• Use local materials• Use recycled materials• Conserve water• Natural lighting• Personal climate controls

• Encourage electric vehicle use

• Improved indoor air quality

• Use sustainable materials (e.g. bamboo)

Green Roofs• Long popular in northern

Europe• Gaining popularity in the

US• Varying degrees of

complexity• Benefits:

– Improved heat insulation– Reducing urban heat island– Decrease runoff– Provide natural habitats– Sound insulation

Green Retrofitting• The Empire State

Building to undergo $20-million-dollar retrofit

• 40% reduction in energy use expected

• $4-million-dollar per year estimated savings– short payback period for

project

LEED Certification• Established in 2000 by US

Green Building Council • Four tiers of achievement

– “certified”, silver, gold, platinum

• Five point categories– Sustainable sites– Water efficiency– Energy and atmosphere– Materials and resources– Indoor environmental

quality

Water Reuse• Much of current water use practices deplete

aquifers over time– Wastewater left to overland runoff

• Does not recharge the aquifer

• Definition: the practice of treating wastewater to achieve standards required for drinking water

• Savings significantly reduce strain on aquifers– Especially if rate of consumption is reduced below

the recharge rate of aquifer

Water Reuse Cont.

Conclusion• Clearly, we cannot continue to consume resources at

our current rate– underdeveloped nations are rapidly modernizing

• Environment cannot handle this new strain

• To maintain our current standards of living while increasing our sustainability, we need to turn to engineering

• Definition and goals of sustainable design will be constantly changing, however, sustainability should continue to be an engineer’s goal