SECTION 2CHANGING POPULATION TRENDS

Chapter 9

Environmental ScienceSpring 2011

Objectives

Describe 3 problems caused by rapid human population growth

Compare population growth problems in more-developed countries and less developed countries

Analyze strategies countries may use to reduce their population growth

Describe worldwide population projections into the next century

Infrastructure

Infrastructure: basic facilities and services that support a community Public water supplies, sewer lines, power plants,

roads, subways, schools, hospitals

Infrastructure

Populations with high rates of growth create environmental and infrastructure problems

Symptoms of overwhelming population growth include suburban sprawl, overcrowded schools, polluted rivers, barren land, inadequate housing

Mumbai, India

Problems of Rapid Growth

Rapidly growing population uses resources faster than the environment can renew them

Problems of Rapid Growth

Shortage of Fuel-wood: In many of poorest countries wood is main fuel source When populations stable people use fallen tree limbs In rapid population growth deadwood does not

accumulate fast enough to provide enough fuel People begin to cut down trees and vegetation

resources are cleared Lack of fuel- cannot cook food, boil water (often

unsafe), leads to people suffering from disease and malnutrition

Problems of Rapid Growth

Unsafe Water: In places that lack

infrastructure local water supply may be used for drinking, washing, sewage disposal

Water supply becomes breeding ground for organisms that cause diseases such as dysentery, typhoid, cholera

With expanding populations, water systems cannot expand fast enough to keep up with growth

Problems of Rapid Growth

Impacts on Land: Arable land: land that can be used to grow crops Increasing populations may have a shortage Need to make tradeoff between competing uses for

lands such as agriculture, housing, natural habitats Urbanization: movement of people from rural areas

to cities

A Demographically Diverse World

Not every country is progressing through each stage of the demographic transition according to the model

Ex. Modern industries, incomes remain low Ex. Stable and educated populations, little

industriesEx. Remain in second stage of model

A Demographically Diverse World

Least developed countries: show few signs of development and in some cases have increasing death rates, while birth rates remain high

Managing Development and Population Growth

Countries are realizing that continued population growth can limit their economic development

Many countries favor stabilizing population growth through investments in development, especially through improvements in women’s status

Growth Is Slowing

World population = 6 billion Still growing

Fertility rates are declining world wide If these rates continue most countries will

have replacement level fertility rates by 2050If so world population growth would

eventually stop

Review

1. Describe 3 problems caused by population growth

2. Compare population growth in more developed countries to population growth in less developed countries

3. Describe worldwide population projections for the next 50 years

4. Do you think that simply changing birthrates will cause a nation to undergo further development?