Population Storyboard Human impact can be modeled as resulting from 3 factors Production and consumption are variables Expanding variables affecting the IPAT terms creates design opportunities System interventions have different degrees of leverage Interventions can influence bioproductivity Interventions can influence human impact and well-being affluence population Awareness of facts: Earth’s carrying capacity is directly linked to population and its activities Main point Because earth is effectively a closed system, its carrying capacity to support human population is limited and directly influenced by human activity Awareness of strategies: There are many opportunities of intervention to reduce human impact Awareness of personal role: Engineering can strongly influence carrying capacity and well-being technology Bioproductivity as supply health Example: Urban metabolism Ecological footprint as annual demand This work was made possible by the National Science Foundation’s DUE# | Jane Qiong Zhang and Linda Vanasupa

Population 2

Global Growth Trends Source: Mihelcic et al., 2010 Classroom Activity (5 minutes) What factors influence the total population of the planet?

Population Source: United Nations, Global Urbanization Trends Classroom Activity (5 minutes) Turn to your neighbor. Which type of living is inherently less impactful, urban or rural? Why? How are engineers involved in the impact of human activity?

Population Uneven burden of health risks Much of the burden of this risk is born by people living in the developing world. Classroom Activity (5 minutes) What are the causes of poor environmental quality? Poor environmental quality contributes to 25% of all preventable illnesses in the world. –World Health Organization

Population Carrying Capacity 6

Population System Boundary Conceptually “separates” the system and surroundings How many people can the earth support? Carrying Capacity 3 E Can exchange energy but not enough mass to affect its thermodynamic state Classroom Activity (2 minutes) Turn to your neighbor. Together determine what would you need to know in order to compute how many people the earth can support each year?

Population System Boundary Conceptually “separates” the system and surroundings How many people can the earth support? Carrying Capacity 3 E Can exchange energy but not enough mass to affect its thermodynamic state Classroom Activity (2 minutes) Turn to your neighbor. Together determine what would you need to know in order to compute how many people the earth can support each year?

Population Carrying Capacity Carrying capacity (# of people that the earth can support) Resource production Resource consumption/person Definition: Time basis=1 year Classroom Activity (5 minutes) What assumptions are embedded in a computation of carrying capacity? Hint: To get at this, try to figure out what terms would go on the right side of the equation.

Population An upper limit to population or community size (biomass) imposed by environmental conditions. Source: Mihelcic et al, (2010) Limits of Growth

Population Bioproductivity (resources produced per area of land) Mass of resources produced area of land Definition: Time basis=1 year Classroom Activity (2 minutes) Toxins can reduce the bioproductivity of an area of land. How? What other ways can bioproductivity be reduced? How can it be increased?

Population Ecological Footprint Ecological footprint Area of bioproductive land required to support one’s annual lifestyle Definition: Time basis=1 year Global hectares (gh)

Population Earth’s bioproductivity: ecological footprint

Population Basis of analysis = 1 year (annual) Ecological footprint Consumption (kg) person Resource & waste intensity of consumption (hectares needed/kg) Footprint (hectares) person Classroom Activity (10 minutes) According a study published in 2002 by Wackernaagel et al., the footprint of global human activity has exceeded earth’s annual biocapacity by 40% every year since What happens to the earth system when the consumption exceeds the supply?

Population Accumulation of CO 2 from Human Activity Source: National Geographic, by Nigel Holmes; used with permission

Population Footprint and biocapacity factors that determine overshoot Carrying Capacity

Population Per Capita Biocapacity v. Ecological Footprint Source: Data from Mihelcic et al, (2010)

Population Carrying Capacity Carrying capacity (# people) Total annual earth biocapacity (hectares) Consumption (kg) person Resource & waste intensity (hectares needed/kg) Basis of analysis = 1 year (annual) © Jane Qiong Zhang and Linda Vanasupa Classroom Activity (15 minutes) The average ecological footprint for a Chinese citizen in 2006 was 1.7 global hectares (gha). For the U.S. citizen, it was 9.4 gha. The earth’s biocapacity was 11.9 billion gha in What is the earth’s carrying capacity if we all lived like the average Chinese citizen in 2006? The average U.S. citizen? The resources consumed by a U.S. baby is equivalent to the resources consumed by how many Chinese babies?

Population Intervention Strategies Using systems thinking 19

Population Events Mental models beliefs, assumptions Systemic structures policies, technology Patterns trends symptoms Source: Peter Senge

Population Events Mental models beliefs, assumptions Systemic structures policies, technology Patterns trends symptoms Source: Peter Senge

Population Material objects subject-object Efficient Final transpersonal Formal subject-subject Aristotle, Roger Burton natural capital processes design intent

Population natural capital intent design Roger Burton, Donella Meadows Redefining goals Transcending paradigms Empowering self-organization Changing System Rules Altering numbers, stocks and flows processes

Population Consumption Patterns P. Erhlich and J. Holdren, (1971) Impact of population growth, Science, 171, 1971, pp. 1212–1217. The IPAT equation impactpopulationaffluencetechnology Classroom Activity (5 minutes) Which terms in the IPAT equation can engineers manipulate in an ethical way? How would they go about manipulating them? What level of intervention is this?

Population Consumption Patterns Classroom Activity (5 minutes) Data shows that all these factors influence the IPAT terms. Now which of the terms can engineer change? How would they change them? Expanded IPAT

Population Earth’s bioproductivity Recall Classroom Activity (10 minutes) Identify possible high-leverage interventions that can me made to improve the earth’s bioproductivity.

Population Example Urban metabolism 27

Population Urban heat island effect

Population City metabolism Classroom Activity (5 minutes) What would a circular metabolism look like?

Population Urban Metabolism A Sankey Diagram of inputs and outputs