Sustainable Development

• “[D]evelopment that meets the needs and aspirations of the present without compromising the ability of future generations to meet their own needs.” (Bruntland, 1987)

Sustainable Development

• “[D]evelopment that meets the needs and aspirations of the present without compromising the ability of future generations to meet their own needs.” (Bruntland, 1987)

• Is sustainable development attainable or oxymoronic?

Sustainability• I = P A T (after Holdren & Ehrlich 1974)

– Impacts = (Population size) x (Affluence) x (Technology)

• Population size = number of people, often expressed per unit area (population density)

• Affluence = per capita consumption

• Technology = environmental damage resulting from each unit of consumption

Sustainability• I = P A T (after Holdren & Ehrlich 1974)

– Impacts = (Population size) x (Affluence) x (Technology)

– Interpreting this simple equation is remarkably difficult

Sustainability• I = P A T (after Holdren & Ehrlich 1974)

– Impacts = (Population size) x (Affluence) x (Technology)

– Interpreting this simple equation is remarkably difficult

– A sustainable world has low and constant impacts from generation to generation

Structure of this course

• Define impacts

• Understanding population growth

• Affluence, economics, and per-capita consumption

• Scientific background needed to assess effects of consumption

Impacts: an example

• How far did your breakfast travel to reach you this morning?

Breakfast travels

• What do you need to know?– What did you eat for breakfast?– What ‘raw materials’ make up your breakfast?– The basic questions:

• Where were they produced?

• How were they produced?

• How may people were involved in their production?

• How much energy was used in their production?

• What waste materials were generated in the production?

Breakfast travels

• What do you need to know (continued)?– How were they processed (repeat the basic

questions)– By what means were they assembled into

breakfast products (repeat the basic questions)– How did the breakfast products get from their

source of production to you (repeat the basic questions)

Breakfast travels

• Scaling up– How many students ate breakfast this morning

at MHC?• In South Hadley?

• In Hampshire County?

• In the Pioneer Valley?

• In Massachusetts?

– What’s involved in feeding breakfast to so many people?

Our Ecological “Footprint”

• In 1986, Vitousek et al. estimated that human activities ‘appropriated’ 40% of terrestrial photosynthesis. In other words, 40% of all energy reaching the Earth’s land surface is used by human beings. (Source: Vitousek, P. M., P. R. Ehrlich, A. H. Ehrlich, & P. A. Matson. 1986. Human appropriations of the products of photosynthesis. BioScience 36: 368-373.).

Out Ecological “Footprint”

• Human activities ‘appropriate’ 40% of terrestrial photosynthesis.

• What about the other 10 million or so species that share Earth with Homo sapiens?

Ecological Footprints Defined

• An ecological footprint accounts for flows of energy and matter to and from any defined economy and converts them into the corresponding land and water area required from nature to support these flows. (Source: Wakernagle, M. & W.Rees. 1990. Our ecological footprint: reducing human impact on the Earth. New Society Publishers, Gabriola Island, British Columbia, Canada).

Obtaining your Footprint

• Ask yourself: “If you put your home town (or Mount Holyoke College) under a glass dome, how big would the dome have to be so that the town (or MHC) would be able to sustain itself completely and exclusively on the ecosystems within the dome?”

What’s your Footprint?

What’s your Footprint?

• The average ecological footprint of a resident of North America is 5 hectares (50,000 square meters, or 12.4 acres, or 538,200 square feet)

What’s your Footprint?

• The average ecological footprint of a resident of North America is 5 hectares (50,000 square meters, or 12.4 acres, or 538,200 square feet)

• The approximate amount of ‘ecologically productive’ land on the Earth is approximately 1.5 ha per person (1995 data).

What’s the Conclusion?

• The average ecological footprint of a resident of North America is 5 hectares (50,000 square meters, or 12.4 acres, or 538,200 square feet)

• The approximate amount of ‘ecologically productive’ land on the Earth is approximately 1.5 ha per person (1995 data).

• If all 5.9 billion people on the planet lived like a 1990’s North American, we’d need at least 2 additional Earth’s to support them.

What’s the Solution?

• I = P A T– Slow and stop population growth or reduce

population size– Reduce and limit per capita consumption– Increase efficiency of resource use