1AnnouncementsMidterm #1 on Thursday (Midterm study guide posted on the website: http://www.geo.arizona.edu/geo4xx/geos478/GC10.ExamReview.html)Graduate assignment #2 out later todayGlobal Change Drivers: POPULATION & CONSUMPTIONGlobal Change Lecture #8, S. Saleska, 21-Sept-2010I. Population Growth *II. Population & Food ConsumptionIII. Population & Energy Consumption* With thanks to Joel Cohen for slides from: “Human Population: History, Status, Trends,” seminar at Columbia Earth InstituteUltimate long-term question:Is the human enterprise sustainable?CComponents:- How many people will there be?(and will we be able to feed them all?)- What level of consumption will these people sustain?(what lifestyles, and with what technologies?)- With what impact on the world’s resources and the global environment?(many aspects, but focus on energy)I. Global population growth212,000 years of population growth600070006.1 billionin 20005th billion in 1987 AD(after13more yrs)2000300040005000population (millions)1stbilli i 1800 AD2ndbillion in 1930 AD(after 130 more yrs)3rd billion in 1960 AD(after 30 more yrs)4th billion in 1974 AD(after 14 more yrs)(after 13more yrs)01000-10000 -8000 -6000 -4000 -2000 0 2000year1stbillion in 1800 AD(after ~120,000 yrs)New peak: ¼ billion in year 0Source: Cohen, 2005leastdevelopedLDCsPopulation growth rateWorld population worldLDCs%/yeargrowth rate peaked at 2.1 percent per year in 1965-70 ― the most important change in humanmoredevelopedchange in human demographic history.20th century was unique demographically• Highest population growth rate in human history• Only century in which global population doubled (& tripled)• Largest voluntary decline in fertility•Last century with more young peopleLast century with more young people than old people• Last century with more rural people than urban peopleDemographic situation 2005 • 6.5 billion people in 2005 (±0.2 billion).•~75 millionpeople (1 2%) added per•~75 millionpeople (1.2%) added per year.• Average 2.6-2.7 children per woman in lifetime at current birth rates (total fertility rate, TFR).fertility rate, TFR).– TFR varies widely: Europe TFR = 1.4, Africa TFR = 5.0– Replacement level TFR is 2.1 children.3Two worlds: 2003 rich poorGNP PPP/person $22,030 $3,660population (billion) 1.2 5.1%i /0116(note: PPP = Purchasing Power Parity: $ adjusted for the non-monetized economy)% increase/year0.11.6% with HIV/AIDS 0.4 1.4infant mortality rate 7/1000 61 /1000children/woman 1.5 3.1life expectancy 76 65% urban 75 40people/km223 59Source: Population Reference Bureau World Population Data Sheet 2003Population from now to 2050Bigger: 2-4 billion more people by 2050Growth in poor countries, not rich. Slower: population growth could end beforeSlower: population growth could end before doubling, depending on choices made now.Older: people 60+ years will outnumber children 0-4 years.More urban: virtually all population growth will ypp gbe in cities of poor countries.Rural population will hold steady at 3 billion.Unpredictable: migration, families11.710.691World population 1950-2050(billions): Bigger but slower growing9.17.7Aging results from 2 successes1. Lower fertility, worldwideCame later and slower in some regions2. Longer life, worldwideCame later and slower in some regionsWith significant reversals in Eastern Europe and sub-Saharan AfricafFall in fertility contributes more to population aging than increasing length of life.4World-wide age structureLess-developed countries: have broad “pyramid” structureMore-developedMore-developed countries: have a “column” structure (lower fertility and longer survival)Source: Cohen, 2005China’s age-structure looks more like a developed countryU.S. age structure over time19001970203020002000Urban population surpassed rural in 2007-2008ruralruralurbanurbanurbanUrban & rural people have different food habits in developing countries• Rural residents eat more cereals, tubers and roots.• Urban residents eat more meat, fruits, vegetables. • Urbanization will increase average meat, fruit, vegetable consumption/person, reduce average cereal, root, tuber consumption/person. • Diets rich in meats require feedgrains & meals, so demand more cereal than diets based on direct cereal consumption.• Changes in consumption patterns brought about by urbanization can significantly affect global food supply, markets, and trade.5II. Population & Food consumption(or, will we be able feed everone?)Supply of Calories per day for human consumption (per capita)Developing Countries WorldFood supply, relative to the population, has increasedHOW?Carbo-hydrates1965 1975 1985 19951965 1975 1985 1995Source: UN FAOFatProteinNorman Borlaug, 1914-2009Father of the “Green Revolution”- Developed hybrid strains of wheat and rice that could, with heavy fertilization give 3-4timesheavy fertilization, give 3-4 times the yield of previous varieties.- Methods also later criticized as strengthening an input-intensive and environmentally unsustainable agribusiness model for food production.“More than any other single person of this age, he has helped provide bread for a hungry world.” - Nobel Committee, 1970 (Peace Prize)- Is there a basis for a next “green revolution”? (e.g., Genetically modified organisms?)6Improvements in nutritional status of populations in poor countries made possible by continuing increases in crop yieldWe produce1980s1990sWe produce enough food right now to feed 10+ billion people a vegetarian 1970sgdiet!But the question is…7Improvements in nutritional status of populations in poor countries made possible by continuing increases in crop yieldCthibkt tCan this be kept up to support a population that is:- 50% larger (9+ in 2050 vs 6 billion today)- Eating higher on the food chain1980s1990sfood chain- expanding its cities into surrounding “breadbaskets”?1970sCurrent trends are worrisome (?)20032004 200520062008International Food Policy Research Institute20072009Current trends are worrisomeMain reasons for global food price increases:1. Growth in Income and food demand (dietary composition shifts towards meat and milk -- e.g. in India and China)2. Increased energy prices (increases input costs, but also direct competition from diversion of agricultural land tobiofuels)International Food Policy Research Institutefrom diversion of agricultural land to biofuels)3. Underinvestment in agricultural productivity and technologyIs