1. Environmental Science 3.6 Providing Food for an Expanding Population

2. Population Connection World population expected to reach 8 billion by 2025 99% of world’s population growth occurs in less developed countries where >80% or world’s population lives 3 factors determine population growth rate: 1. Fertility rates – 75 countries is at or less than the replacement level of 2.1 children. 40 countries in Africa and Asia have fertility rate of 5 or more children per woman. 2. Death rates – improvements in health care and sanitation have caused decline in child mortality rate; however, spread of HIV/AIDS has increased mortality rates in some areas 3. Number of women of childbearing age

3. Why People Go to Bed Hungry 80 million people are added to world’s population each year Poverty is major cause of hunger 1 in every 5 people in developing world is chronically undernourished Chronic hunger increases susceptibility to disease Africa is most malnourished Prolonged drought Civil conflicts

4. World’s Tillable Land Only U.S. and Canada produce surplus of food China has 20% of world’s population, but only 5% of world’s tillable land Misuse of land Farming methods do not consider sustainability of tillable land, so it eventually becomes a desert

5. Japan Japanese farmers have highest yield due to 3 factors: 1. Development of seed varieties that produce high yields 2. Use of large quantities of fertilizer 3. Labor that does not depend on use of large equipment

6. Green Revolution During the 1960s new varieties of wheat and rice were developed to produce higher yields Disease-resistant varieties Has caused digestive problems for some people

7. China and India Populations of China and India are 1.3 billion and 1.1 billion, respectively Each year China adds another 8 million and India adds another 18 million As populations grow and cities expand there is less good land for farming Water is often pumped from aquifers at a rate that exceeds recharge rate

8. More Protein Needed Green Revolution reduced amount of protein available Fish raised in irrigation canals of rice fields were poisoned by fertilizers and pesticides Tilapia fish are fed garbage, cornmeal, and bran Soybean is world’s leading source of high-quality protein

9. U.S. – Always a Land of Plenty? Most of wheat imported by many countries comes from surplus produced by U.S. and Canada Animals in other countries are fed corn and soybeans grown in U.S. An increase in food production would result in loss of wood production, wildlife habitat, and grazing land, and possibly increased soil erosion

10. Sea as a Source of Food Many species of edible fish are being threatened by intense fishing practices Protecting marshlands and estuaries is essential to our food supply Pollution of ocean is another threat to our food supply