Population & Population & Environment IIEnvironment II

ES 118 Spring ES 118 Spring 20082008

Life expectancyLife expectancy

2020thth Century saw global Century saw global transformation of human healthtransformation of human health– Worldwide, Worldwide, average life expectancyaverage life expectancy

rose from 40 to 65.5 years (projected rose from 40 to 65.5 years (projected to reach 74 by 2050)to reach 74 by 2050)

– In India in 1900, average life In India in 1900, average life expectancy around 23 years; by 2000 expectancy around 23 years; by 2000 this had tripledthis had tripled

– In US increased from 47 to 77 yearsIn US increased from 47 to 77 years

Life expectancyLife expectancy

Factors influencing include:Factors influencing include:– Better nutritionBetter nutrition– Improved sanitationImproved sanitation– Clean waterClean water– EducationEducation– Access to health and medical servicesAccess to health and medical services

Strongly correlated with income to about Strongly correlated with income to about $4,000/person, then level out at about $4,000/person, then level out at about 75 years for men and 85 for women75 years for men and 85 for women

www.gapminder.org

Contraceptive Contraceptive revolutionrevolution

For many, the concept of planning the For many, the concept of planning the number and timing of their children number and timing of their children revolutionaryrevolutionary

By 2000, more than half of the world’s By 2000, more than half of the world’s women of reproductive age using a women of reproductive age using a modern family planning methodmodern family planning method

Early attempts to influence fertility Early attempts to influence fertility focused on smaller family size and focused on smaller family size and family planningfamily planning

……but access still but access still limitedlimited ½ billion people live in countries where ½ billion people live in countries where

<10% of women use an effective <10% of women use an effective contraceptioncontraception– Largely rural and agriculture-basedLargely rural and agriculture-based– Low per capita incomeLow per capita income– Economic crisesEconomic crises– Waning international supportWaning international support

Examples: Nigeria (8%), Afghanistan, Examples: Nigeria (8%), Afghanistan, Ethiopia, Mali, Democratic Republic of Ethiopia, Mali, Democratic Republic of CongoCongo

Social and political Social and political factors influencing factors influencing fertilityfertility

Some countries used restrictive Some countries used restrictive policies, penalizing families with policies, penalizing families with “too many” children“too many” children

Policy response shifting to Policy response shifting to broader issues (“social broader issues (“social determinants of health”):determinants of health”):– Maternal and child healthMaternal and child health– Recognition of importance of Recognition of importance of

gender and links between gender and links between poverty, gender roles, inequality, poverty, gender roles, inequality, and healthand health

– Education, sanitation, Education, sanitation, transportation, clean watertransportation, clean water

UN Millennium Goals target UN Millennium Goals target many of these issuesmany of these issues

EducationEducation

Kerala, India Kerala, India – One of poorer One of poorer

states in India, but states in India, but India's highest life India's highest life expectancy and expectancy and lowest infant lowest infant mortality ratesmortality rates

– High literacy High literacy rates, especially rates, especially among womenamong women

www.gapminder.org

MortalityMortality

Rapid growth in world’s population Rapid growth in world’s population in last century caused largely be in last century caused largely be decline in crude death ratesdecline in crude death rates

Time

Maternal healthMaternal health

HIV/AIDSHIV/AIDS

Between 2000-2050, AIDS projected to cause premature deaths of 278 million people in 53 countries—38 in Africa

MalariaMalaria

Why is Malaria getting worse?Why is Malaria getting worse?– Drug resistanceDrug resistance– Environmental and social change Environmental and social change

(poverty, dams, irrigation, (poverty, dams, irrigation, deforestation, war, lack of basic deforestation, war, lack of basic sanitation…)sanitation…)

– Cost of controlCost of control

Case StudiesCase Studies

The case of citiesThe case of cities

We are now an urban planetWe are now an urban planet– 1900: 10% of global population1900: 10% of global population– 2008: >50% of world’s 6.6b 2008: >50% of world’s 6.6b

people and growingpeople and growing

Growing citiesGrowing cities

By 2030,~ 5 billion By 2030,~ 5 billion people will live in citiespeople will live in cities

More than 95% of net More than 95% of net increase in the global increase in the global population will be in population will be in cities in developing cities in developing world, mostly in Asiaworld, mostly in Asia

Largest “mega-cities” Largest “mega-cities” are growing to are growing to unprecedented sizes, unprecedented sizes, but most do not live in but most do not live in mega-citiesmega-cities

R. Mace Science 319, 764 -766 (2008)

Environmental impact Environmental impact of citiesof cities Hot spots of production, consumption, Hot spots of production, consumption,

and waste generationand waste generation <3% of land surface but<3% of land surface but

– 78% of global carbon emissions78% of global carbon emissions– 60% of residential water use60% of residential water use– 76% of wood for industrial purposes76% of wood for industrial purposes– Huge “Huge “ecological footprintsecological footprints””

Cities thus present both problems and Cities thus present both problems and solutions to sustainability challenges in solutions to sustainability challenges in an increasingly urban worldan increasingly urban world

The case of AsiaThe case of Asia

Pace of economic change in India Pace of economic change in India and China is breathtakingand China is breathtaking– Fastest growing middle-classes in the Fastest growing middle-classes in the

worldworld These two countries will have a These two countries will have a

profound impact on the world’s profound impact on the world’s environmentenvironment

ChinaChina

China’s economy has averaged a China’s economy has averaged a 9.5% growth rate9.5% growth rate

Approximately 80% of Wal-Mart’s Approximately 80% of Wal-Mart’s suppliers are now located in suppliers are now located in ChinaChina

China is starting to build one of China is starting to build one of the world’s largest automobile the world’s largest automobile industriesindustries

http://www.earth-policy.org/Updates/Update45_data.htm

Steel consumption US and China Steel consumption US and China 1990-20031990-2003

http://www.earth-policy.org/Updates/Update45_data.htm

Meat consumption US and China Meat consumption US and China 1960-20041960-2004

The Challenge of FoodThe Challenge of Food People in poor countries typically eat at lower People in poor countries typically eat at lower

trophic levels than rich countriestrophic levels than rich countries– 90% of energy of plants lost when converted to 90% of energy of plants lost when converted to

protein from animalsprotein from animals People in countries like US eat too much People in countries like US eat too much

(“overnutrition”) (“overnutrition”) – 50% of North Americans overweight50% of North Americans overweight– 25% obese25% obese– Ecological impact of 1 person eating at carnivore Ecological impact of 1 person eating at carnivore

level = 10 people living at herbivore levellevel = 10 people living at herbivore level What happens as countries like China become What happens as countries like China become

wealthier and want more meat? wealthier and want more meat?

Environmental impactEnvironmental impact

Extreme pollutionExtreme pollution– 16 of 20 cities in the world with most 16 of 20 cities in the world with most

polluted air in Chinapolluted air in China Access to resourcesAccess to resources

– China: Just 8% of world’s fresh water China: Just 8% of world’s fresh water for 22% of world’s populationfor 22% of world’s population

– India: 17% of world’s population and India: 17% of world’s population and 2.3% of land resources2.3% of land resources

The FutureThe Future

Lessons of last ½ Century have Lessons of last ½ Century have shown that countries can undergo shown that countries can undergo rapid and radical social and rapid and radical social and demographic changedemographic change– Fertility rates can drop from 7 to 2 Fertility rates can drop from 7 to 2

children in less than 2 generationschildren in less than 2 generations– Birth rate remains single most potent Birth rate remains single most potent

determinant of global population growthdeterminant of global population growth– We know much more, but prediction We know much more, but prediction

difficultdifficult

How many people?How many people?

Key questions for Key questions for futurefuture Can the world provide an adequate Can the world provide an adequate

standard of living for 2.5 billion standard of living for 2.5 billion moremore people without causing widespread people without causing widespread environmental damage?environmental damage?

How do we address increased:How do we address increased:– WasteWaste– PollutionPollution– Competition with other organisms for spaceCompetition with other organisms for space– Energy and climate changeEnergy and climate change

What is the earth’s carrying capacity?What is the earth’s carrying capacity?