1 The State of Nature Assessing the trends: Population, Consumption and Technology The end of more?

2 Indicators of state of nature n n Population growth n n Food production n n Energy consumption n n Deforestation n n Species extinctions n n Desertification n n Fresh water shortage n n Ozone depletion n n Climate change

3 The State of Nature n n E = P x C x T (or I = PAT) – –Human population growth n n Agricultural revolution n n Industrial Revolution – –1 billion in 1800; 6.8 billion now n n The “Population Bomb” – –Rule of 72 – –Malthusians vs. Cornucopians n n UN prediction: ~10 billion by 2050 n n A note on population density n n Into the fray: Demographic transition theory – –Is affluence the solution?

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5 Consumption n n How much do we need? n n Hunter-gatherers compared to Americans – –2500 vs. 192,000 kcals. n n 40% of Earth's primary productivity supports humanity n n Have's & have-nots n n North compared to South – –Avg American footprint  20 Indians or 50 sub-Saharan Africans n n Analogy: Nora and Sam’s well n n Can affluence be globalized? n n Do ethics matter?

6 Technology n n Fossil fuel-based economy – –Coal, oil, natural gas – –Primacy of oil – –Environmental effects n n Atmospheric pollution n n Marine pollution n n Deforestation, destruction of local habitat n n Renewables: solar, wind, hydrogen n n Can technology save us?

7 Geoengineering: Climate change tech fixes n “Virgin Earth Challenge” ~ $25 million for techs to capture 1 billion tons carbon/year –Some candidates: n Iron fertilization of the oceans n Bioengineering bacteria to eat CO 2 n Land-based algae tanks n Large mirrors in orbit n Artificial clouds or snow

8 The end of more? n Overshoot & carrying capacity –Analogy: bacteria in a petri dish –Signs of overshoot n Mass extinction of species, climate instability, collapse of fisheries… –Earth’s carrying capacity? n I = PAT n Human exceptionalism –The mind factor –Green growth?