Chapter 5: Natural Systems Under Stress Daniel Burton Geoff Koegler

Overview Chapter Summary Chapter Summary Fact Check Fact Check

Natural Systems Under Stress “Mercilessly expanding human demands are putting stresses on forests, rangelands, and fisheries that they cannot withstand. We are also destroying many of the plant and animal species with which we share the planet”.

Shrinking Forests Effects of Deforestation Effects of Deforestation Pressures on Deforestation Pressures on Deforestation The importance of the world’s forests The importance of the world’s forests

Losing Soil Topsoil and soil erosion Topsoil and soil erosion Dust Bowl Examples Dust Bowl Examples Global effects of Dust Bowls Global effects of Dust Bowls

Grassland to Desert Grass-based livestock economies Grass-based livestock economies Livestock Vs. Carrying Capacity Livestock Vs. Carrying Capacity Land Degradation Land Degradation

Advancing Deserts Desertification Desertification Stages of Desertification Stages of Desertification Effects of Desertification Effects of Desertification

Collapsing Fisheries Demand increase for seafood Demand increase for seafood Effects of over-fishing Effects of over-fishing Canadian Cod Canadian Cod EU Solution EU Solution Dead Zones Dead Zones

Disappearing Plants and Animals The sixth great extinction The sixth great extinction Habitat Destruction Habitat Destruction Bird Population Bird Population Bee Population Bee Population Non-native Species Non-native Species

Fact Check: Natural Systems Under Stress Loss of Forests Loss of Forests Desertification Desertification Collapsing Fisheries Collapsing Fisheries Extinction Extinction

Loss of Forests Brown: Forests make up 4 billion hectares today, down from 5 billion in 1900 Brown: Forests make up 4 billion hectares today, down from 5 billion in 1900 U.N. FAO: U.N. FAO:

Loss of Forests Forest cover is growing in developed countries Forest cover is growing in developed countries (U.N. FAO)

Loss of Forests Forest cover is declining in developing countries Forest cover is declining in developing countries (U.N. FAO)

Loss of Forests The Amazon The Amazon –Brown: Brazil has lost 20% of the Amazon since 1970 –U.N. FAO:

Desertification Brown: Sahara Desert is growing rapidly Brown: Sahara Desert is growing rapidly –Nigeria: losing 351,000 hectares of land each year Center for International Earth Science Information: Center for International Earth Science Information: –Lack of rain is the largest cause

Desertification Brown: China losing 3,600 square km per year, up from 2,100 in the 1970s and 80s, Brown: China losing 3,600 square km per year, up from 2,100 in the 1970s and 80s, –Resulted in the loss of over 24,000 villages during the past 50 years China is indeed losing China is indeed losing this much land (China Environmental Science Presses) –Disputes as to how many villages have been lost (4,000 according to the Boston Globe)

Collapse of Fisheries Brown: World-wide fish catch at a historic high of 96 million tons in 2000, 75% of fisheries are over fished Brown: World-wide fish catch at a historic high of 96 million tons in 2000, 75% of fisheries are over fished U.N. FAO: U.N. FAO: 80% of Fisheries 80% of Fisheries are over fished (Oceana)

Collapse of Fisheries Brown: Canadian Cod Fishery collapsed in 1990 as a result of overfishing Brown: Canadian Cod Fishery collapsed in 1990 as a result of overfishing U.N. FAO: U.N. FAO:

Collapse of Fisheries Brown: Chesapeake Bay oyster catches have decreased rapidly Brown: Chesapeake Bay oyster catches have decreased rapidly Chesapeake Bay Program: Chesapeake Bay Program:

Collapse of Fisheries Brown: Gulf of Mexico “Dead Zone” (size of New Jersey) kill fish due to algae blooms Brown: Gulf of Mexico “Dead Zone” (size of New Jersey) kill fish due to algae blooms Sierra Club: 4,565 square miles, roughly the size of Connecticut Sierra Club: 4,565 square miles, roughly the size of Connecticut (NASA) (NASA)

Extinction Brown: An alarming amount of species are vulnerable or in immediate danger of extinction Brown: An alarming amount of species are vulnerable or in immediate danger of extinction –12% of birds –20% of mammals –39% of fish Conservation Conservation International Study –36% of land mammals –61% of ocean mammals

Summary Lester Brown clearly depicts how several of earth’s natural systems are under stress Lester Brown clearly depicts how several of earth’s natural systems are under stress Uses accurate and interesting information to convey issues regarding: Uses accurate and interesting information to convey issues regarding: –Loss of Forests –Desertification –Collapsing Fisheries –Extinction

“On the plus side, we now have more information on the state of the earth and the life on it than ever before. While knowledge is not a substitute for action, it is a prerequisite for saving the earth’s natural systems- and the civilization that they support”.

Questions?

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