2. The Changing Global Environment Geological Base; Climate & Climate Change; Water; Human Impacts on Plants & Animals; Food Resources.

2. The Changing Global Environment

Geological Base; Climate & Climate Change; Water; Human Impacts on Plants & Animals; Food Resources

Figure 2.2, Plate Tectonics

Figure 2.3, Global Tectonic Plates

Geology & Human Settlement: A Restless Earth

• Plate Tectonics/Continental Drift• Break-up of Africa centered supercontinent Pangaea c. 250

million yrs Before Present (BP)• Formation of Tethys Sea• Removal of Australia from main evolutionary line in Pangaea

and around Tethys Sea• Removal and return of India to create Himalayan Mountain

Range• Formation of major fold mountain ranges along leading edges

of North and South American Plates• At human scale, problems of earthquakes and volcanic

activity along plate boundaries• Plate Tectonic Theory confirms Evolutionary Theory• Collapse of Reptiles as dominant species c. 65 million years

BP, probably because of impact of asteroid in Yucatan peninsula

Figure 2.3, Global Tectonic Plates

Figure 2.7, Global Earthquakes and Volcanoes

Climate Change• Climate change: natural, anthropogenic, or both?• Glacial, interglacial, & interstadial climates• Natural change--a historic pattern of 400 to 600 years

interval for the past 2,000 years?• Evidence for change (the church & wine production in

Europe).• Shift in North Atlantic Drift• Rice cultivation in China• Deforestation in Europe• Recent anthropogenic change• Burning hydrocarbons produces carbon dioxide. CO2 main

contributor to Global Warming (Table 2.1)• Large scale CO2 production began late 1770s w/Industrial

Revolution & coal burning• Modern CO2 production largely from automobile fleet• Only EU has attempted to mitigate automobile CO2 output

Figure 2.11: Global Pressure Systems

Climate• Planetary heat transfer from Equatorial to Polar regions

• Planet takes in more solar radiation between Tropics of Cancer and Capricorn than it loses, loses more from Polar regions than is coming in (see Fig. 2.1)

• Hot air and water masses move polewards, cold air and water returns toward Equator

• Planetary heat transfer & us• Warms west coasts of continental masses• W. Europe main beneficiary• Provided main power source (wind) for planetary movement (ships) from late 1400s to mid-1800s

Table 2.1 (3rd edn): the World’s Major CO2 Polluters

Table 2.1 (4th edn): the World’s Major CO2 Polluters

Water on Earth: A Scarce & Polluted Resource

• Only 3% of world’s water is fresh water, most of it is ice, & there is rarely enough where humans want it!

• Except when it floods. Floods cause more fatalities than any other natural disaster. Too many people live in flood prone regions (e.g. Bangladesh)

• Much water is polluted & runoff has been increased by deforestation

• Water more valuable than oil• Most destructive use of water is in agriculture (evaporation)

• Use in closed systems (water for sewage disposal, washing etc.) allows recycling (tho at some cost)

• When there is water policy it tends to underprice water

• Texas had no comprehensive water plan until Senate Bill 2 took effect 9/1/2001

Human Impacts on Plants & Animals

• For most of human history we collected and hunted food• C. 20,000 BP Agricultural Revolution (AR) improved food supply, but still erratic. Protein, inputs dropped. AR encouraged human crowding (bad for health-poor waste disposal etc.) Food surplus made urban life & civilization possible, allowed division of labor, elites

• Population rose rapidly, then leveled off• AR Plants chosen for productivity, ease of cultivation• Animal resources added later to do work, for protein, & for fiber

• Organic Society marked by 3Fs. Food, Fiber, Fuel all grown in Organic Society

• Land resources allocated between 3Fs according to population pressure, environmental needs etc.

• Humans lived on, at best, c. 3 million cals. each per year

Figure 2.19: World Bioregions

Food resources: environment, diversity, globalization

• Industrial Revolution c. 200 years BP transformed human societies and economies

• Better transport made food supply much more reliable• Better public health began inexorable increase in human life

expectancy• Fossil fuel inputs took fuel out of 3F equation, then fiber, thus more

land for food• Population skyrocketed, in part because of more reliable food supply

(remember that deaths drop before births in classical version of Demographic Transition-DR)

• Global population currently showing signs of reduced rates of increase (i.e. reaching stage 3 of DR)

• Fossil fuel inputs to food now immense in developed world (10 calories in, 1 cal vegetable energy out: 10 cals vegetable energy in, 1 cal beef protein out)

• Calorie consumption per head in America now c. 100 million calories per year

• Rest of developed world much lower (Germany c. 40, Japan below 30)• LDCs starting to catch up very quickly in consumption (remember

increase in China’s CO2 output)

World Population & Grain Production

Grain for people vs grain for biofuels

• World grain supply only just keeping pace w/world population growth

• North America and EU are world’s only large scale exporters of grain

• Grain in NA, EU requires high fossil energy inputs

• Public policy in US has reduced world grain supply by diverting corn to biofuel production, causing sharp rises in grain prices

• Biofuels from food grains actually have negative impact (more calories in than calories out) as well as other negatives (increase in greenhouse gasses)

The next 50 years in energy (“this is your life” part 1)

• Serious and accelerating climate change (now looks fundamentally irreversible, although better public policy could reduce impact)

• “Short” term energy crisis (likely to see 30 years of steadily rising prices and accelerating demands for efficiencies in usage of fossil fuels and electricity, most of which still comes from fossil fuels)

• Some solutions unlikely if examined closely-clean coal for example. World has coal in abundance but generating electricity with coal results in much higher CO2 output per unit energy generated than using natural gas. China, India, building huge # new coal plants

• Long term energy stability, assuming renewed investments in nuclear power, substantial investment in wind power, ramped up research into alternate fuels

• Main shortfalls will be in liquid hydrocarbons for air transport and as raw materials for plastics

The next 50 years in the environment (“this is your life” part 2)

• Global warming, global warming, global warming• Plausible rise in hurricane/cyclone frequency• Massive rise in flood related deaths in LDCs• Serious threats to coastal cities around world• What is currently happening to New Orleans will become commonplace

• Capital cost of defending coastal cities will necessitate huge increases in public spending or abandonment of such cities

• Potable water will become substantially more expensive, not least as salt water from rising sea levels penetrates coastal aquifers

Books worth reading• Kenneth S. Deffeyes, 2005. Beyond Oil: the View from Hubbert’s Peak. NY: Hill & Wang

• Bruce Podobnik, 2006. Global Energy Shifts: Fostering Sustainability in a Turbulent Age. Philadelphia: Temple University Press

• Spencer W. Weart, 2003. The Discovery of Global Warming. Cambridge: Harvard University Press