ESR102 - Lecture 7

http://web.pdx.edu/~rueterj/courses/esr102-201001/lecture7.html

Lecture 7: Impact of Agriculture February 18, 2010 at end quiz I=PAT and Importance of agriculture energy and society humans harnessed ecology for agriculture types of farming - uses of capital and labor the Green Revolution the food people choose to eat has environmental impact scenarios for the future need to deal with global food production transition to sustainable and secure food food vs. fuel high touch food production examples
1. return at end of lecture and go over the quiz
2. I=PAT equation agriculture has a big impact water - largest user energy - 17% of all commercial energy in the US emissions - 20% of CO2 emissions, 55% of methane
3. energy and society progression around agriculture helped structure society link
4. Humans harnessed ecosystems for agriculture primary and secondary succession traditional view of ecosystem succession
5. Types of agriculture trade-offs between: machine capital, human labor, energy, chemical costs, and land low-technology farming smaller less productive subsistence or local market only intensive agriculture high human labor maybe fertilizer costs low to none traction small land use industrial agriculture low human labor high traction and fertilizer costs and machinery can use lower grade soil but needs lots of it another description (Pollan) industrial industrial organic artisan - smaller scale
6. "Green Revolution" Brought together: plant genetics higher yield grains and rice less stalk more grain hardier for harvesting availability of irrigation higher water demand use of petrochemicals fertilizers (N and P) herbicides and pesticides traction benefits: meeting food demand for many developing countries avoiding famines food security excess food for income disadvantages: moving toward fewer varieties - depleting natural range of crops dependence on irrigation, more severe impact when there is a drought dependence on energy subsidies indirect effects of these process water consumption lake eutrophication from runoff - case study
7. impacts from food choices not in the food itself but in the embodied or life-cycle energy people may consume more goods, but bulk food consumption stays the same however, different foods may require more or less water or energy examples from last week on the embedded water in foods (water embedded in food) energy in foods (about 10 * as much as nutritional) 68 kcal of fossil fuel energy to make 1 kcal worth of pork 35 kcal of fossil fuel energy to make 1 kcal worth of beef references - link high and low life cycle energy input for food can result in 5 fold difference animal products range over about 4 fold range, so the particular recommendation for saving energy needs to take that into account clams 27 MJ per portion, down to fresh cooked local cow at 3.2 MJ per portion 27 MJ = 6480 kCal of embodied or life-cycle energy link Ecotrust calculations show that air transported fresh salmon costs 57 times more CO2 than frozen ref
8. scenarios for the future Millenium Ecosytem Assessment 4 scenarios powerpoint MEA - from lab
9. transition to a sustainable and secure food system sustainable food production details next lecture food security amount of food types of food available vs. nutrition economics fuel fertilizer land ownership issues risks in the distribution system sensitivity to disruption from climate
10. Food vs. Fuel controversy bio-fuels are competing with food production water land environmental choice, economic incentives and policies play a big role tax credits carbon incentives rules that require proportion of fuel to be biodiesel of ethanol impact on land use and biodiversity
11. High touch food production Examples to consider for next lecture: Polyface Farms in NC - mentioned in Michael Pollan's book Zena Farms here in Willamette Valley - summer program Tryon Creek community Portland Urban Growth Bounty WWOOF example in Spain