1. Humans and Sustainability

2. Sustainability
Sustainability: the capacity of the earth’s natural systems and human cultural systems to survive, flourish, and adapt into the very long-term future

3. Nature’s Survival Strategies Follow Three Principles of Sustainability
Reliance on solar energy
The sun provides warmth and fuels photosynthesis
Biodiversity
Astounding variety and adaptability of natural systems and species
Chemical cycling
Circulation of chemicals from the environment to organisms and then back to the environment
Also called nutrient cycling

4. Solar Energy Chemical Cycling Biodiversity
Figure 1.3: Three principles of sustainability.
We derive these three interconnected principles of sustainability from learning how nature has sustained a huge variety of life on the earth for at least 3.5 billion years, despite drastic changes in environmental conditions (Concept 1-1a).
Chemical Cycling
Biodiversity
Fig. 1-3, p. 8

5. Sustainability Has Certain Key Components
Natural capital: supported by solar capital
Natural resources: useful materials and energy in nature
Natural services: important nature processes such as renewal of air, water, and soil
Humans degrade natural capital
Scientific solutions needed for environmental sustainability

6. Natural Capital = Natural Resources + Natural Services
Solar energy
Natural Capital = Natural Resources + Natural Services
Air
Renewable energy (sun, wind, water flows)
Air purification
Climate control
UV protection
(ozone layer)
Life
(biodiversity)
Water
Population control
Water purification
Pest control
Waste treatment
Figure 1.4: These key natural resources (blue) and natural services (orange) support and sustain the earth’s life and human economies (Concept 1-1a).
Nonrenewable minerals
(iron, sand)
Soil
Land
Soil renewal
Food production
Natural gas
Nutrient recycling
Oil
Nonrenewable energy
(fossil fuels)
Coal seam
Natural resources
Natural services
Fig. 1-4, p. 9

7. Natural Capital Degradation
Figure 1.6: Natural capital degradation.
This was once a large area of diverse tropical rain forest in Brazil, but it has now been cleared to grow soybeans. According to ecologist Harold Mooney of Stanford University, conservative estimates suggest that between 1992 and 2008, an area of tropical rain forest larger than the U.S. state of California was destroyed in order to graze cattle and plant crops for food and biofuels.
Fig. 1-6, p. 10

8. Natural Capital Natural consequence of energy flow
Provide ecological services
Purify, recycle and detoxify
ex: bee pollination of crops
rocks, sand purifying stream water
marshes controlling flood waters
soil formation from eroding rock,
decaying organisms

9. Sustainability- Altogether Now

10. Some Sources Are Renewable and Some Are Not
Resource
Anything we obtain from the environment to meet our needs
Some directly available for use: sunlight
Some not directly available for use: petroleum
Perpetual resource
Solar energy

11. Some Sources Are Renewable and Some Are Not
Renewable resource
Several days to several hundred years to renew
E.g., forests, grasslands, fresh air, fertile soil
Sustainable yield
Highest rate at which we can use a renewable resource without reducing available supply 11

12. Some Sources Are Renewable and Some Are Not
Nonrenewable resources
Energy resources
Metallic mineral resources
Nonmetallic mineral resources
Reuse
Recycle

14. Reuse
Figure 1.7: Reuse: This child and his family in Katmandu, Nepal, collect beer bottles and sell them for cash to a brewery that will reuse them.
Fig. 1-7, p. 11

15. Recycle
Figure 1.8: Recycling: This family is carrying out items for recycling. Scientists estimate that we could recycle and reuse 80–90% of the resources that we now use and thus come closer to mimicking the way nature recycles essentially everything. Recycling is important but it involves dealing with wastes we have produced. Ideally, we should focus more on using less, reusing items, and reducing our unnecessary waste of resources.
Fig. 1-8, p. 12