Anthropogenic Changes: Resources

POSTED: 4 December 2018

• Energy Resources

The most widely used energy resources are fossil fuels (oil, gas, coal), nuclear power (nuclear fission) and moving water. The first two are nonrenewable energy resources, while moving water, wind and Earth's internal heat are renewable energy resource.

• Fossil fuels: oil and coal are made of organisms that lived a long time ago. Burning fossil fuels has the same effects as burning plants.
• non-renewable resources: resources that take long to be replaced relative to the human life span
• download 2013 key world energy statistics published by the International Energy Agency
• petroleum is made of plankton, i.e. it formed in ancient oceans (see also page on energy resources)
• petroleum is raw material for many chemical products, including solvents, fertilizers, pesticides and plastics
• 84% (37 out of 42 gallons in a typical barrel) of petroleum is processed as fuel, incl. gasoline, diesel and kerosene
• at the current rate of consumption, oil reserves will be depleted within a few decades



Consumption of Energy in the U.S.

Energy Resource	Fraction 1997	Fraction 2002	Fraction 2012(10)
Petroleum	41%	41%	36%
Natural Gas	24%	22%	27%
Coal	22%	24%	18%
Nuclear	7%	9%	8%
renewable total			9%
Hydroelectric	5%	3%
others	1%	1%




Consumption of Energy in the U.S. by sector⁽¹⁰⁾

Sector	Fraction 2012
Transportation	28%
Industrial	22%
Residential and Commercial	10%
Electric Power	40%



• OIL AND NATURAL GAS
• industrialized societies today rely primarily on oil and natural gas for their energy needs
• Oil and gas are hydrocarbons, ring or chainlike molecules of C and H, and are organic chemicals
• Hydrocarbons have varying viscosity and the volatility depends on the molecule size
• form primarily from dead algae and plankton
• require a long (geologic times) process to form, involving burial and increase in T and P
• oil window: oil and natural gas exist only under certain T and P conditions. At T>160^oC, any remaining oil breaks down to form gas and at T>250^o the remaining organic matter transforms into graphite. Under normal conditions, oil exists at depths only down to 6.5km.
• oil reserves: oil can be found in sedimentary deposits. Large oil fields can be found in the Canadian Arctic Ocean, Gulf of Mexico, North Sea, Kara Sea/Northern Russia and the Persian Gulf (largest oil fields)
• Huge natural gas reserves can be found in Siberia (1/3 of the world's reserves)
• Two oil reserves that are very important U.S. domestic resources are the Gulf of Mexico and off-shore Alaska. The latter currently provides up to 20% of U.S. domestic oil and there are plans to expand oil production into the Arctic National Wildlife Refuge ( see more).
• With 7 Mio barrels per day (1 barrel = 42 Gallons), the U.S. is the largest consumer worldwide, using about 25% of the produced oil (and contributing 25% of the world's CO₂ production)
• In the 1970ies, when the U.S. oil production passed its peak (Hubbert's Peak, the U.S. lost its position as largest producer
• U.S. oil reserves now account for only 4% of the world's reserves
• the U.S. must now import more than 50% of its used oil.
• The world consumption now exceeds the rate of discovery of oil (by factor 3)
• at the current rate of consumption, know oil resources will be depleted within a few decades
• predictions place Hubbert's Peak of world oil production around 2005
• natural gas is more abundant than oil
• Gas burns more cleanly than oil. Burning gas produces only CO₂ (the least amount of C of all fossil fuels) and water, while burning oil produces more complex organic pollutants.
• Gas transportation requires expensive high-pressure pipelines and containers making gas less attractive as energy source than oil


• COAL
• Coal forms from plant material (wood, stems, leaves) in swamps and adjacent forests
• Most coal was formed in the late Carboniferous and Permian Periods (320-245 Mio years ago) when the continents were locked together to form Pangaea
• Coal is the most polluting fossil fuel but reserves will last 3 times as long as the oil reserves (300 years).
• The U.S. burn 1 Billion tons of coal per year, mostly at electrical power plants that generate ~23% of U.S. electricity.
• classification of coal:
• Peat: 50% Carbon (C); not yet coal
• Lignite: from peat (soft dark-brown coal) (70% carbon)
• Bituminous Coal: from lignite at higher T (100-200^oC) (85% C)
• Anthracite Coal: from bituminous coal at even higher T (200-300^oC); formed at 8-10 km depth (95% C); burns most efficiently and clean
• Graphite: at even higher T and P
• anthracite coalis the rarest type of coal. In the US, it is found at two places in Pennsylvania and Arizona
• More than half of the world's coal can be found in the United States and Former Soviet Union.

The Global Distribution of Coal Reserves

Country	Fraction
United States	28%
Former Soviet Union	26%
China	11%
Western Europe	10%
Australia	10%
Eastern Europe	6%
other	9%




• Air Pollution due to the Burning of Fossil Fuels

(see also Lectures 22, 24)


Primary Pollutants from Burning Fossil Fuels

Pollutant	Fraction
Carbon Monoxide	49.1%
Sulfur Oxides	16.4%
Nitrogen Oxides	14.8%
Volatile Organics	13.6%
Particulates	6.0%

NB: the greenhouse gas CO₂ is not considered a pollutant and is therefore not included in this table! CO₂ in the atmosphere has increased from 290 ppm in 1850 to 370 ppm in 2000.

Sources of the Primary Pollutants

Process	Fraction
Transportation	46.2%
Stationary Source Fuel Combustion	27.3%
Industrial Processes	15.0%
Miscellaneous	9.0%
Solid Waste Disposal	2.5%

The pollution per car was even greater before catalytic converters were introduced in the 1970ies (see more).


• The Carbon Footprint

• the net amount of greenhouse gases (amount emitted minus amount consumed) a process, product or entity releases to the environment
• serves as a measure to estimate the net contribution of a process or production to global warming
• a carbon-neutral process produced as much greenhouse gases as it consumes
Some companies try to reduce their overall carbon footprint by adding processes that emit less greenhouse gases. E.g.
• electricity-generating companies adding renewable energy to their portfolio
• some airlines offer a surcharge to customers that goes toward regrowing rainforest to reduce the carbon footprint of an airline passenger
• the carbon footprint of individually bottled water is much higher than that of tap drinking water (transportation!)

• Cap and Trade

A market-based approach of emission trading of pollutants and greenhouse gases to control net pollution of a company or entity. Typically, some economic incentives (such as reduced taxes) are provided to make this approach attractive.
• a central authority (state or country) sets emission limits (cap) on emission
• a company can buy permits (carbon credits) for higher emissions
• the total number of carbon credits cannot exceed the cap
• companies with higher emissions must buy credits from company with lower emissions, so that total cap is not exceeded (trade)
• in theory, this should reduce the pollution at the lowest cost to society, as companies who can reduce their emission cheaply will do so

• Summary on Fossil Fuels and Consumption

• global energy demand doubled in last 30 years
• hydrocarbons now account for > 50% world's energy production
• fossil fuels account for nearly 80%
• fossil fuels are non-renewable
• U.S. oil production peaked in 1970ies
• U.S. has to import 50% of its oil
• peak in global oil production by 2005
• oil consumption now exeeds rate of discovery by factor 3


• oil reserves exhausted within 50 years
• gas reserves probably within 100 years
• coal reserves probably within 300 years
• burning fossil fuels pollutes the environment
• burning fossil fuels accelerates the greenhouse effects
• burning coal causes acid rain



• Metallic Resources

Metallic resources come in native form and as ore.
Native metals are easy to mine because they occur in pure form (e.g. gold nuggets, copper lumps). Examples for native metals: gold, copper, silver
In ores the metals occur in metallic compounds such as oxides. The extraction of the metals require elaborate techniques that use high temperature smelting (e.g. iron ore) or toxic chemicals (e.g. need mercury for some gold compounds) to extract the metal from the compound.
Many metals are not found in native form, e.g. iron.
• some metals are not found in native form, e.g. iron
• a rock qualifies as an ore, if:
  • the metal content is high
  • and the process to extract this metal is cost-effective

dependent on the market value we distinguish between base and precious metals:
• base metals: e.g. copper, iron, lead, zinc, tin
• precious metals: e.g. gold, silver, platinum
• of the 63 metals in use today, only 9 were known before 1700 (Gold, Silver, Copper, Mercury, Lead, Tin, Antimon, Iron, Arsenic), typically the metals found in native form



• Non-Metallic Mineral Resources

E.g. building stone, gravel, sand, gypsum, phosphate (for fertilizer), salt.
• dimension stone: intact slabs and blocks of rock (e.g. granite or marble) cut out in a quarry (a quarry provides stone, a mine provides ore).
• crushed stone: for concrete, cement and asphalt.
cement forms by precipitation of minerals out of slurry of water, lime (CaO) (66%), silica (SiO2) (25%), alumimun oxide (Al2O3) and iron oxide (Fe2O3). CaO comes from the calcite in limestone that is roasted in a furnace at high temperature. The other elements come from shale and sandstone. Concrete is a mixture of cement with sand and gravel. Bricks are made from dried and bakes clay (this process is a metamorphic process that recrystallize the clay and make it relatively impermeable). Glass comes from the melting of quartz and quartz sand. Drywall is made from a slurry of water and gypsum (CaSO4.H2O); asbestos is made from serpentine; plastics from oil; fertilizers such as phophate (PO₄^3-) and potash (K2CO3) come from evaporites.

• Global Mineral Needs and Reserves

• Mineral resources are non-renewable resources (i.e. the lifetime is limited). Combined with energy resources, the U.S. mine, quarry and pump 18 billion tons/year. For comparison, the Mississippi transports 190 million tons of sediments into the Gulf of Mexico.
• How Much Do We Need?
In "Physical Geology", Carlson et al., refer to the Mineral Information Intitute to estimate per capita/year needs in the U.S.:
• 18,000 kg total are mined, not including energy resources
• 4,400 kg stone
• 3,500 kg sand and gravel
• 325 kg limestone for cement
• 160 kg clays
• 165 kg salt
• 760 kg other nonmetals
• 545 kg iron
• 19 kg aluminum
• 9 kg copper
• 5 kg lead
• 5 kg zinc
• 3 kg manganese
• 11 kg other metals
for comparison, some numbers for energy resources⁶:
• 3050 kg petroleum
• 2650 kg coal
• 1900 kg natural gas



• The Dependence on Importing Minerals

• 99% of gemstones are imported (e.g. from Israel, Belgium and India)
• Strategic metals: metals that are alloyed with iron to make special-purpose steels needed in the aerospace industry; many need to be imported⁶: e.g. manganese (100%), cobalt (95%), chromium (73%) and platinum (92%).
• many other raw materials are 100% imported



Metals used in the U.S. and Where They Come From

metal	Metal's Origin
arsenic trioxide	China, Chile, Mexico
bauxite and alumina	Australia, Jamaica, Brazil
bismuth	Belgium, Mexico, China
strontium	Mexico, Germany
thallium	Mexico, Belgium, Germany
thorium	UK, France




Lifetime (in years) of Currently Known Ore Resources

metal	World Resources	U.S. Resources
Iron	120	40
Aluminum	330	2
Copper	65	40
Lead	20	40
Zinc	30	25
Gold	30	20
Platinum	45	1
Nickel	75	<1
Cobalt	50	<1
Manganese	70	0
Chromium	75	0


THE BOTTOM LINE: mineral resources are non-renewable and many global resources will last a few more decades. The U.S. has to import large fractions of the metals used.

• Recycling

Estimates in the 1960ies and 1970ies predicted a shortfall of available minerals. But mineral consumption has slowed in the meantime and current estimates predict that resources will last about 100 years. The rate of mineral consumption has slowed especially in industrialized nations due to a shift of economics from construction and manufacturing to service and technology. The demand for raw minerals has decreased because of recycling and substitution by low-cost ceramics, composites and plastics.



Fraction of Recycled Metals
Metal	Fraction
Au (Gold)	45%
Pt (Platinum)	45%
Al (Aluminum)	45%
Pb (Lead)	73%
Cu (Copper)	60%
Fe (Iron), Steel	56%



Issues that determine whether a mineral is to be recycled or not: costs, environmental impact, availability.


• Flourescent Light Bulbs and Compact Fluorescent Light Bulbs (CFL)
Disposal is problematic because such bulbs contain mercury (Hg) vapor. The amount of Hg varies between 3 and 46 mg. A typical 2006-era 4-ft tube contains about 12 mg, CFLs that use 25-40 W of electricity have about 6 mg or less. Users are supposed to bring old CFL and fluorescent tubes to a recycling center (or hazardous waste disposal place. The San Diego/Miramar landfill is said to collect bulbs but only quantities that are consistent with "single household usage". Home Depot is said to have just started a take-back program.



• Plastic ²

• made from oil; many different kinds (e.g. from clear plastic bottles to styrofoam)
• plastics are durable, lightweight, and can be made into virtually anything
• plastics are not biodegradeable
• only 3.5% of plastics are recycled in any way
• in the U.S., 63 pounds of plastic packaging goes into landfills per person per year
• broken, degraded plastic pieces outweigh surface zooplankton in the Central North Pacific by 6 to 1

SOME PLASTIC MILESTONES
• 1869: John Wesley Hyatt invents celluloid, the first plastic product given a trade name
• 1909: Bakelite introduced as the "first thermoset plastic" (once set it is set for life)
• 1939:Nylon stockings debut at the World's Fair
• 1946: Earl S. Tupper produced a 7-ounce polyethylene tumbler, the first Tupperware product
• 1955: the Corvette is the first car to use plastic for body panels
• 1957: the Hula Hoop creates a surge in demand for polyehtylene
• 1983: microwave ovens open up a new market for plastic packaging
• 2000: in the U.S., pre-production plastics reaches 100 billion pounds of virgin resin pellets per year



• Recommended Reading

• "Coal" by Barbara Freese, 2004, Penguin Books, ISBN: 01-42000981:a good book on coal, its history and how it changed mankind

• References

• ⁽¹⁾"The Penguin State of the World Atlas" by Dan Smith, 2003. Penguin Books, ISBN: 0-14.200318-2
  
• ⁽²⁾Flyer from the Algalita Marine Research Foundation
• ⁽³⁾United Nations Environmental Programme (UNEP) web site
• ⁴"State of the World 2003" by Chris Bright et al., 2003, The Worldwatch Institute, Norton & Company, ISBN: 0-393-32386-2
• ⁵"State of the World 2004" by Erik Assadourian et al., 2004, The Worldwatch Institute, Norton & Company, ISBN: 0-393-32539-3
• ⁶Earth, Portrait of a Planet, 2001. Stephen Marshak, Norton & Company Ltd., New York, ISBN: 0-393-97423-5
• ⁷Earth, An Introduction to Physical Geology, 2005. E.J. Tarbuck and F.K. Lutgens, 8th ed., Prentice Hall, Upper Saddle River, N.J., ISBN: 0-13-114865-6
• ⁸"Earthshock" by Andrew Robinson, 1993, Thames and Hudson, ISBN: 0-500-27738-9
• ⁹ Wikipedia web page on petroleum
• ¹⁰ U.S. Energy Information Administration Energy in Brief (2012)



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• Five Random Review Questions (not a complete review!)

1) Which of these is not a fossil fuel?
1. coal
2. oil
3. natural gas
4. nuclear power
2) Which of these is NOT a renewable energy resource?
1. wind
2. nuclear
3. solar
4. hydro-electric
3) About how much of the produced petroleum is used as fuel?
1. 100%
2. 85%
3. 50%
4. 15%
4) About how much longer will current oil reserves last, at the current level of consumption?
1. 1000s of years
2. 100s of years
3. 10s of years
4. forever
5) Which of these is the least recycled item?
1. aluminum
2. paper
3. lead
4. copper
5. plastic
6) Petroleum is made of which of these?
1. plant material
2. plankton
3. fish bones
4. dinosaur fossils
5. wood


Answers: 1d; 2b; 3b; 4c; 5e; 6b

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• APPENDIX A: The Special Role of Traffic

• transportation takes up 1/3 of the world's energy consumption
• transportation is responsible for almost half of the pollution produced
• finding alternatives current transportation is therefore essential!
• public transportation effective alternative in densely populated areas
• cars need to be made more fuel efficient (technology exists since the 1980s!)
• finding alternatives is crucial. Hybrid-automobiles and biodiesel are only temporary alternatives as hybrid cars still use fossil fuels and biodiesels contribute to greenhouse effect



• APPENDIX B: Where do Metallic Resources Come From?

• magmatic deposits: bottom of a magma chamber
• hydrothermal deposits: circulation of hot-water solutions
• disseminated deposit: deposit throughout an intrusion
• vein deposit: deposit in a preexisting crack
• copper porphyry deposit: copper in a two-stage melted igneous rock
• black smoker: precipitated nearly pure metal sulfides around black smokers
• secondary-enrichment deposits: transport and re-deposition of ore minerals, typically at higher concentrations
• sedimentary deposits: for example
  • banded-iron formation (BIF) in deep ocean, when environment suddenly became oxygen-rich
  • manganese nodules (manganese-oxide, typically about 10 cm diameter) on the ocean floor. Rich in manganese and copper (20% Mn + Fe, Cu, Ni). Technology to mine vast deposits underway (e.g. copper supply would last 720 years).
• residual mineral deposits:tropical environments, iron and aluminum-rich soil residuum in the soil as consequence of severe leaching (E.g. bauxite is a aluminum-bearing residual from extreme leaching of granite).
• placer deposits: native metals eroded from original deposit and settled as flakes in rivers (recovery similar to what happens during panning).



• APPENDIX C: Resource Exploration and Production

in the past, prospectors looked for "shows" of ore (exposures of ore minerals at the surface). They looked out for quartz veins or stained rock (green or red by oxidizing metal-containing minerals).

Today's geologists look at tectonic settings and measure the magnetic and gravity fields to find ore bodies (they are typically denser and more magnetic than ordinary rock).


• open-pit mines: explosions separate blocks from bedrock; waste rock is separated from ore and brought to a "tailings pile". The ore is crushed, ore minerals extracted and smelted or treated with acidic solutions to separate the metal. The metal is then melted and poured into molds to make ingots (brick-shaped blocks).
• underground mines: drive vertical shafts and horizontal adits into the ore-bearing rock. The deepest mine currently reaches 3.5 km where the temperature exceeds 55^oC.



• APPENDIX D: Mining and the Environment

• open-pit mining leaves landscape scars
• mining leaves waste rock in tailings piles (artificial hills)
• acid mine runoff (sulfides released in ore-mining)
• smelting in ore-processing creates acidic air and rain