Environmental Problems, Their Causes, and Sustainability 1

Age Distribution (%)40353025201510501950 1970 1990 2010 2030 2050 2070 2090 2110 2130 2150YearUnder age 15 Age 60 or over Age 80 or overFigure 10-19 Global aging. Projected percentage of worldpopulation under age 15, age 60 or over, and age 80 or over,1950–2150, assuming the medium fertility projection shown inFigure 10-6. Between 1998 and 2050 the number of peopleover age 80 is projected to increase from 66 million to 370 million.The cost of supporting a much larger elderly population willplace enormous strains on the world’s economy. (Data from theUnited Nations)sharp rise in the proportion of older people. They consumean increasingly larger share of medical care, socialsecurity funds, and other costly public servicesfunded by a decreasing number of working taxpayers.Such countries can also face labor shortages unlessthey rely more on greatly increased automation or immigrationof foreign workers.Without babies to replenish the labor force andpay taxes, governments of countries such as Japan andsome European countries facing rapid population declinewill have a hard time funding the pensions ofpeople who are living longer. To keep their finances inthe black they will probably need to take unpopularsteps, such as raising the retirement age, cutting retirementbenefits, raising taxes, and increasing legalimmigration.What Are Some Effects of PopulationDecline from a Rise in Death Rates? TheAIDS TragedyLarge numbers of deaths from AIDS disrupt acountry’s social and economic structure by removingmany young adults from its age structure.Globally between 2000 and 2050, AIDS is projected tocause the premature deaths of 278 million people in 53countries—38 of them in Africa. These prematuredeaths are almost equal to the entire current populationof the United States. Read this paragraph againand think about the enormity of this tragedy.Hunger and malnutrition kill mostly infants andchildren, but AIDS kills many young adults. Thischange in the age structure of a country has a numberof harmful effects. One is a sharp drop in average lifeexpectancy. In 16 African countries where up to a thirdof the adult population is infected with HIV, life expectancycould drop to 35–40 years of age.Another effect is a loss of a country’s most productiveyoung adult workers and trained personnel suchas scientists, farmers, engineers, teachers, and government,business, and health-care workers. This causes asignificant increase in the number of orphans whoseparents have died from AIDS—with 40 million orphansprojected in Africa by 2010. It also causes a sharpdrop in the number of productive adults available tosupport the young and elderly and to grow food.Analysts call for the international community—especially developed countries—to develop and funda massive program to help countries ravaged by AIDSin Africa and elsewhere. The program would have twomajor goals. One is to reduce the spread of HIVthrough a combination of improved education andhealth care. The other is to provide financial assistancefor education and health care and volunteer teachersand health-care and social workers to help compensatefor the missing young adult generation.10-3 SOLUTIONS: INFLUENCINGPOPULATION SIZEWhat Are the Advantages and Disadvantagesof Reducing Births? An ImportantControversyThere is disagreement over whether the worldshould encourage or discourage populationgrowth.The projected increase of the human population from6.4 to 8.9 billion or more between 2004 and 2050 (Figure10-6) raises an important question: Can the worldprovide an adequate standard of living for 2.5 billion morepeople without causing widespread environmental damage?Controversy surrounds this and two related questions:whether the earth is overpopulated, and whatmeasures, if any, should be taken to slow populationgrowth. To some the planet is already overpopulated.To others we should encourage population growthto help stimulate economic growth by having moreconsumers.Some analysts believe that asking how many peoplethe world can support is the wrong question. Theyliken it to asking how many cigarettes one can smokebefore getting lung cancer. Instead, they say, we shouldbe asking what the optimum sustainable population of theearth might be, based on the planet’s cultural carryingcapacity See the Guest Essay by Garrett Hardin on thishttp://biology.brookscole.com/miller14187