GREEN HOUSE EFFECT

The greenhouse effect is a process by which radiative energy leaving a planetary surface is absorbed by some atmospheric gases, called greenhouse gases. They transfer this energy to other components of the atmosphere, and it is re-radiated in all directions, including back down towards the surface. This transfers energy to the surface and lower atmosphere, so the temperature there is higher than it would be if direct heating by solar radiation were the only warming mechanism

This mechanism is fundamentally different from that of an actual greenhouse, which works by isolating warm air inside the structure so that heat is not lost by convection.

The greenhouse effect was discovered by Joseph Fourier in 1824, first reliably experimented on by John Tyndall in 1858, and first reported quantitatively by Svante Arrhenius in 1896.

If an ideal thermally conductive blackbody was the same distance from the Sun as the Earth, it would have an expected blackbody temperature of 5.3 °C. However, since the Earth reflects about 30% (or 28%) of the incoming sunlight, the planet's actual blackbody temperature is about -18 or -19 °C , about 33°C below the actual surface temperature of about 14 °C or 15 °C. The mechanism that produces this difference between the actual temperature and the blackbody temperature is due to the atmosphere and is known as the greenhouse effect.

Global warming, a recent warming of the Earth's surface and lower atmosphere, is believed to be the result of a strengthening of the greenhouse effect mostly due to human-produced increases in atmospheric greenhouse gases.

Values Of Biodiversity

"Biological diversity" or "biodiversity" can have many interpretations and it is most commonly used to replace the more clearly defined and long established terms, species diversity and species richness. Biologists most often define biodiversity as the "totality of genes, species, and ecosystems of a region". An advantage of this definition is that it seems to describe most circumstances and present a unified view of the traditional three levels at which biological variety has been identified:

• species diversity
• ecosystem diversity
• morphological diversity
• genetic diversity

But Professor Anthony Campbell at Cardiff University, UK and the Darwin Centre, Pembrokeshire, has defined a fourth, and critical one: Molecular Diversity (see Campbell, AK J Applied Ecology 2003,40,193-203; Save those molecules: molecular biodiversity and life).

This multilevel conception is consistent with the early use of "biological diversity" in Washington, D.C. and international conservation organizations in the late 1960s through 1970's, by Raymond F. Dasmann who apparently coined the term and Thomas E. Lovejoy who later introduced it to the wider conservation and science communities. An explicit definition consistent with this interpretation was first given in a paper by Bruce A. Wilcox commissioned by the International Union for the Conservation of Nature and Natural Resources (IUCN) for the 1982 World National Parks Conference in Bali^[8] The definition Wilcox gave is "Biological diversity is the variety of life forms...at all levels of biological systems (i.e., molecular, organismic, population, species and ecosystem)..." Subsequently, the 1992 United Nations Earth Summit in Rio de Janeiro defined "biological diversity" as "the variability among living organisms from all sources, including, 'inter alia', terrestrial, marine, and other aquatic ecosystems, and the ecological complexes of which they are part: this includes diversity within species, between species and of ecosystems". This is, in fact, the closest thing to a single legally accepted definition of biodiversity, since it is the definition adopted by the United Nations Convention on Biological Diversity.

The current textbook definition of "biodiversity" is "variation of life at all levels of biological organization".^[9]

For geneticists, biodiversity is the diversity of genes and organisms. They study processes such as mutations, gene exchanges, and genome dynamics that occur at the DNA level and generate evolution. Consistent with this, along with the above definition the Wilcox paper stated "genes are the ultimate source of biological organization at all levels of biological systems..."

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NON RENEWABLE RESOURCES

A non-renewable resource is a natural resource which cannot be produced, re-grown, regenerated, or reused on a scale which can sustain its consumption rate. These resources often exist in a fixed amount, or are consumed much faster than nature can recreate them. Fossil fuel (such as coal, petroleum and natural gas) and nuclear power are examples. In contrast, resources such as timber (when harvested sustainably) or metals (which can be recycled) are considered renewable resources

Fossil fuel

A temporary oil drilling rig in Western Australia

Further information: Oil depletion

Natural resources such as coal, petroleum, oil and natural gas take thousands of years to form naturally and cannot be replaced as fast as they are being consumed. Eventually natural resources will become too costly to harvest and humanity will need to find other sources of energy. At present, the main energy sources used by humans are non-renewable as they are cheap to produce natural resources, called renewable resources, are replaced by natural processes given a reasonable amount of time. Soil, water, forests, plants, and animals are all renewable resources as long as they are properly conserved. Solar, wind, wave, and geothermal energies are based on renewable resources. Renewable resources such as the movement of water (hydropower, including tidal power; ocean surface waves used for wave power), wind (used for wind power), geothermal heat (used for geothermal power); and radiant energy (used for solar power) are practically infinite and cannot be depleted, unlike their non-renewable counterparts, which are likely to run out if not used wisely. Still, these technologies are not fully utilized.^[2]

Economic models

Hotelling's rule is a 1931 economic model of non-renewable resource management by Harold Hotelling. It shows that efficient exploitation of a nonrenewable and nonaugmentable resource would, under otherwise stable economic conditions, lead to a depletion of the resource. The rule states that this would lead to a net price or "Hotelling rent" for it that rose annually at a rate equal to the rate of interest, reflecting the increasing scarcity of the resources. The Hartwick's rule provides an important result about the sustainability of welfare in an economy that uses non-renewable resources.

COAL

Coal is the most abundant fossil fuel in the world with an estimated reserve of one trillion metric tons. Most of the world's coal reserves exist in Eastern Europe and Asia, but the United States also has considerable reserves. Coal formed slowly over millions of years from the buried remains of ancient swamp plants. During the formation of coal, carbonaceous matter was first compressed into a spongy material called "peat," which is about 90% water. As the peat became more deeply buried, the increased pressure and temperature turned it into coal.

Different types of coal resulted from differences in the pressure and temperature that prevailed during formation. The softest coal (about 50% carbon), which also has the lowest energy output, is called lignite. Lignite has the highest water content (about 50%) and relatively low amounts of smog-causing sulfur. With increasing temperature and pressure, lignite is transformed into bituminous coal (about 85% carbon and 3% water). Anthracite (almost 100% carbon) is the hardest coal and also produces the greatest energy when burned. Less than 1% of the coal found in the United States is anthracite. Most of the coal found in the United States is bituminous. Unfortunately, bituminous coal has the highest sulfur content of all the coal types. When the coal is burned, the pollutant sulfur dioxide is released into the atmosphere.

Coal mining creates several environmental problems. Coal is most cheaply mined from near-surface deposits using strip mining techniques. Strip-mining causes considerable environmental damage in the forms of erosion and habitat destruction. Sub-surface mining of coal is less damaging to the surface environment, but is much more hazardous for the miners due to tunnel collapses and gas explosions. Currently, the world is consuming coal at a rate of about 5 billion metric tons per year. The main use of coal is for power generation, because it is a relatively inexpensive way to produce power.

Coal is used to produce over 50% of the electricity in the United States. In addition to electricity production, coal is sometimes used for heating and cooking in less developed countries and in rural areas of developed countries. If consumption continues at the same rate, the current reserves will last for more than 200 years. The burning of coal results in significant atmospheric pollution. The sulfur contained in coal forms sulfur dioxide when burned. Harmful nitrogen oxides, heavy metals, and carbon dioxide are also released into the air during coal burning. The harmful emissions can be reduced by installing scrubbers and electrostatic precipitators in the smokestacks of power plants. The toxic ash remaining after coal burning is also an environmental concern and is usually disposed into landfills.

OIL
Crude oil or liquid petroleum, is a fossil fuel that is refined into many different energy products (e.g., gasoline, diesel fuel, jet fuel, heating oil). Oil forms underground in rock such as shale, which is rich in organic materials. After the oil forms, it migrates upward into porous reservoir rock such as sandstone or limestone, where it can become trapped by an overlying impermeable cap rock. Wells are drilled into these oil reservoirs to remove the gas and oil. Over 70 percent of oil fields are found near tectonic plate boundaries, because the conditions there are conducive to oil formation.

Oil recovery can involve more than one stage. The primary stage involves pumping oil from reservoirs under the normal reservoir pressure. About 25 percent of the oil in a reservoir can be removed during this stage. The secondary recovery stage involves injecting hot water into the reservoir around the well. This water forces the remaining oil toward the area of the well from which it can be recovered. Sometimes a tertiary method of recovery is used in order to remove as much oil as possible. This involves pumping steam, carbon dioxide gas or nitrogen gas into the reservoir to force the remaining oil toward the well. Tertiary recovery is very expensive and can cost up to half of the value of oil removed. Carbon dioxide used in this method remains sequestered in the deep reservoir, thus mitigating its potential greenhouse effect on the atmosphere. The refining process required to convert crude oil into useable hydrocarbon compounds involves boiling the crude and separating the gases in a process known as fractional distillation. Besides its use as a source of energy, oil also provides base material for plastics, provides asphalt for roads and is a source of industrial chemicals.

Over 50 percent of the world's oil is found in the Middle East; sizeable additional reserves occur in North America. Most known oil reserves are already being exploited, and oil is being used at a rate that exceeds the rate of discovery of new sources. If the consumption rate continues to increase and no significant new sources are found, oil supplies may be exhausted in another 30 years or so.

Despite its limited supply, oil is a relatively inexpensive fuel source. It is a preferred fuel source over coal. An equivalent amount of oil produces more kilowatts of energy than coal. It also burns cleaner, producing about 50 percent less sulfur dioxide.

Oil, however, does cause environmental problems. The burning of oil releases atmospheric pollutants such as sulfur dioxide, nitrogen oxides, carbon dioxide and carbon monoxide. These gases are smog-precursors that pollute the air and greenhouse gases that contribute to global warming. Another environmental issue associated with the use of oil is the impact of oil drilling. Substantial oil reserves lie under the ocean. Oil spill accidents involving drilling platforms kill marine organisms and birds. Some reserves such as those in northern Alaska occur in wilderness areas. The building of roads, structures and pipelines to support oil recovery operations can severely impact the wildlife in those natural areas.

NATURAL GAS

Natural gas production is often a by-product of oil recovery, as the two commonly share underground reservoirs. Natural gas is a mixture of gases, the most common being methane (CH4). It also contains some ethane (C2H5), propane (C3H8), and butane (C4H10). Natural gas is usually not contaminated with sulfur and is therefore the cleanest burning fossil fuel. After recovery, propane and butane are removed from the natural gas and made into liquefied petroleum gas (LPG). LPG is shipped in special pressurized tanks as a fuel source for areas not directly served by natural gas pipelines (e.g., rural communities). The remaining natural gas is further refined to remove impurities and water vapor, and then transported in pressurized pipelines. The United States has over 300,000 miles of natural gas pipelines. Natural gas is highly flammable and is odorless. The characteristic smell associated with natural gas is actually that of minute quantities of a smelly sulfur compound (ethyl mercaptan) which is added during refining to warn consumers of gas leaks.

The use of natural gas is growing rapidly. Besides being a clean burning fuel source, natural gas is easy and inexpensive to transport once pipelines are in place. In developed countries, natural gas is used primarily for heating, cooking, and powering vehicles. It is also used in a process for making ammonia fertilizer. The current estimate of natural gas reserves is about 100 million metric tons. At current usage levels, this supply will last an estimated 100 years. Most of the world's natural gas reserves are found in Eastern Europe and the Middle East.

OIL SHALE AND TAR SANDS

Oil shale and tar sands are the least utilized fossil fuel sources. Oil shale is sedimentary rock with very fine pores that contain kerogen, a carbon-based, waxy substance. If shale is heated to 490º C, the kerogen vaporizes and can then be condensed as shale oil, a thick viscous liquid. This shale oil is generally further refined into usable oil products. Production of shale oil requires large amounts of energy for mining and processing the shale. Indeed about a half barrel of oil is required to extract every barrel of shale oil. Oil shale is plentiful, with estimated reserves totaling 3 trillion barrels of recoverable shale oil. These reserves alone could satisfy the world's oil needs for about 100 years. Environmental problems associated with oil shale recovery include: large amounts of water needed for processing, disposal of toxic waste water, and disruption of large areas of surface lands.

Tar sand is a type of sedimentary rock that is impregnated with a very thick crude oil. This thick crude does not flow easily and thus normal oil recovery methods cannot be used to mine it. If tar sands are near the surface, they can be mined directly. In order to extract the oil from deep-seated tar sands, however, steam must be injected into the reservoir to make the oil flow better and push it toward the recovery well. The energy cost for producing a barrel of tar sand is similar to that for oil shale. The largest tar-sand deposit in the world is in Canada and contains enough material (about 500 billion barrels) to supply the world with oil for about 15 years. However, because of environmental concerns and high production costs these tar sand fields are not being fully utilized.

NUCLEAR POWER

In most electric power plants, water is heated and converted into steam, which drives a turbine-generator to produce electricity. Fossil-fueled power plants produce heat by burning coal, oil, or natural gas. In a nuclear power plant, the fission of uranium atoms in the reactor provides the heat to produce steam for generating electricity.

Several commercial reactor designs are currently in use in the United States. The most widely used design consists of a heavy steel pressure vessel surrounding a reactor core. The reactor core contains the uranium fuel, which is formed into cylindrical ceramic pellets and sealed in long metal tubes called fuel rods. Thousands of fuel rods form the reactor core. Heat is produced in a nuclear reactor when neutrons strike uranium atoms, causing them to split in a continuous chain reaction. Control rods, which are made of a material such as boron that absorbs neutrons, are placed among the fuel assemblies.

When the neutron-absorbing control rods are pulled out of the core, more neutrons become available for fission and the chain reaction speeds up, producing more heat. When they are inserted into the core, fewer neutrons are available for fission, and the chain reaction slows or stops, reducing the heat generated. Heat is removed from the reactor core area by water flowing through it in a closed pressurized loop. The heat is transferred to a second water loop through a heat exchanger. The water also serves to slow down, or "moderate" the neutrons which is necessary for sustaining the fission reactions. The second loop is kept at a lower pressure, allowing the water to boil and create steam, which is used to power the turbine-generator and produce electricity.

Originally, nuclear energy was expected to be a clean and cheap source of energy. Nuclear fission does not produce atmospheric pollution or greenhouse gases and it proponents expected that nuclear energy would be cheaper and last longer than fossil fuels. Unfortunately, because of construction cost overruns, poor management, and numerous regulations, nuclear power ended up being much more expensive than predicted. The nuclear accidents at Three Mile Island in Pennsylvania and the Chernobyl Nuclear Plant in the Ukraine raised concerns about the safety of nuclear power. Furthermore, the problem of safely disposing spent nuclear fuel remains unresolved. The United States has not built a new nuclear facility in over twenty years, but with continued energy crises across the country that situation may change.

RENEWABLE RESOURCES

A natural resource is a renewable resource if it is replaced by natural processes at a rate comparable or faster than its rate of consumption by humans. Solar radiation, tides, winds and hydroelectricity are perpetual resources that are in no danger of a lack of long-term availability. Renewable resources may also mean commodities such as wood, paper, and leather, if harvesting is performed in a sustainable manner.

Some natural renewable resources such as geothermal power, fresh water, timber, and biomass must be carefully managed to avoid exceeding the world's capacity to replenish them. A life cycle assessment provides a systematic means of evaluating renewability.

The term has a connotation of sustainability of the natural environment. Gasoline, coal, natural gas, diesel, and other commodities derived from fossil fuels are non-renewable. Unlike fossil fuels, a renewable resource can have a sustain

Solar energy is the energy derived directly from the Sun. Along with nuclear energy, it is the most abundant source of energy on Earth. The fastest growing type of alternative energy^[1], increasing at 50 percent a year, is the photovoltaic cell, which converts sunlight directly into electricity. ^[2] The Sun yearly delivers more than 10,000 times the energy that humans currently use. ^[3]

Wind power is derived from uneven heating of the Earth's surface from the Sun and the warm core. Most modern wind power is generated in the form of electricity by converting the rotation of turbine blades into electrical current by means of an electrical generator. In windmills (a much older technology) wind energy is used to turn mechanical machinery to do physical work, like crushing grain or pumping water.

Hydropower is energy derived from the movement of water in rivers and oceans (or other energy differentials), can likewise be used to generate electricity using turbines, or can be used mechanically to do useful work. It is a very common resource.

Geothermal power directly harnesses the natural flow of heat from the ground. The available energy from natural decay of radioactive elements in the Earth's crust and mantle is approximately equal to that of incoming solar energy.

Alcohol derived from corn, sugar cane, switchgrass, etc. is also a renewable source of energy. Similarly, oils from plants and seeds can be used as a substitute for non-renewable diesel. Methane is also considered as a renewable source of energy.

able yield.

ECOSYSTEM EVOLUTION

Before Human Transformation (Map)

When Chicago's first human inhabitants arrived at the end of the last ice age, they encountered a landscape much different from what the Europeans observed 11,000 years later. Mastodons and woolly mammoths inhabited an evergreen spruce forest similar to what can be found in Alaska today. Over the succeeding millennia, the climate warmed, the spruce forest gave way to deciduous forest and then to prairie, and the large Pleistocene mammals went extinct.

Climate, never constant, drove these changes. Cyclic variations in the Earth's orbit around the Sun, affecting the amount of solar radiation reaching the Earth, are a primary driver of climate change and of the glacial-interglacial cycle. Because of the constantly changing climate, ecosystems are in continual flux, as plants, animals, and other organisms must continually adjust their ranges to regions of suitable climate.

Geologists refer to the last 1.8 million years as the Quaternary period, a time when great continental glaciers advanced and then retreated 20 or more times. Rather arbitrarily, the Quaternary period is divided into the Pleistocene and Holocene epochs. The old idea was that the Pleistocene was the time of the ice ages, and the Holocene was the “postglacial” period; actually, the Holocene is but one of many interglacial periods that have characterized the Quaternary. The Holocene began approximately 11,500 years ago, when the last continental glaciers very rapidly began to melt away. The glaciers left behind characteristic deposits from which geologists can interpret the glacial history. Glacial ice is always flowing forward and always melting backward. The flowing ice continually transports rocks, pebbles, sand, and other material forward. Whenever a glacier stabilizes for a time at the same position, the transported material accumulates into hilly moraines, several of which occur in the Chicago region.

The starting point for the development of ecosystems in the Chicago region is the retreat of the glaciers at the end of the last ice age, the Wisconsin glaciation. During the maximum of the Wisconsin glaciation, the Lake Michigan lobe of the great Laurentide ice sheet, which covered much of Canada and the northern United States, advanced over the entire Chicago region. The ice sheet entered northeastern Illinois about 30,000 years ago during the Marengo Phase of the Wisconsin glaciation, and it reached its southernmost extent near Shelbyville in central Illinois about 24,000 years ago. At this time, glacial ice covered the entire Chicago region. The outer edge of the ice sheet advanced and retreated several times before finally disappearing from Illinois. By about 18,000 years ago, the active ice sheet retreated into the Lake Michigan basin, although stagnant, melting ice remained behind. The ice then rapidly readvanced to the prominent Valparaiso moraine in the western Chicago region. After retreating from the Valparaiso moraine, the ice margin made a series of minor advances and retreats, building the Lake Border moraines just north of Chicago about 17,000 years ago, after which the Wisconsin glacier finally retreated from Illinois. Thus, time zero for development of post-Pleistocene ecosystems in the Chicago region is about 17,000 years ago.

History of Lake Michigan

Much of the city of Chicago lies on beach and lake sediments deposited by Lake Michigan and its predecessor glacial Lake Chicago. After the Wisconsin glacier retreated from the Chicago region, it still occupied and dammed the northern end of the Lake Michigan basin, forming glacial Lake Chicago. This lake, which covered most of present-day Chicago, was higher than modern Lake Michigan. Its outlet was westward across the Valparaiso moraine via the modern Des Plaines and Illinois River valleys. The Chicago outlet consisted of the southern Calumet Sag Channel and the northern Des Plaines channel, now occupied by the Des Plaines River and the Chicago Sanitary and Ship Canal. As the glacier repeatedly advanced and retreated in the Lake Michigan basin north of Chicago, the level of glacial Lake Chicago fluctuated as different outlets to the east were opened and closed. The Glenwood and Calumet beaches were formed during this time. When glacial ice finally melted completely from the basin about 12,000 years ago, the lake fell because the heavy weight of the ice had depressed the land surface in the northern part of the basin, producing a northern outlet lower than today's. This outlet was located in northeastern Lake Huron, where water drained through Lake Nipissing and into the Ottawa River. The land depressed by the glacial ice gradually uplifted, a process called isostatic rebound. As the northern outlet isostatically rose, the level of the confluent Lakes Michigan and Huron rose to a level higher than today, until the lake eventually spilled out southern outlets at Chicago and southern Lake Huron. This high lake level, called the Nipissing stage, was reached about 5,500 years ago and lasted about 1,000 years. The Toleston beach formed during this time. The outlet at the southern end of Lake Huron eroded downward more rapidly than the outlet at Chicago, so that by about 4,500 years ago, the Chicago outlet was no longer active. Lake and beach sediments from the Nipissing high stage cover much of the city of Chicago, and terrestrial ecosystems developed on these sediments after the Nipissing stage.

Ecosystem Development

Following the retreat of the glaciers, vegetation invaded the newly ice-free terrain. From about 18,000 to 16,000 years ago, open tundra-like vegetation with scattered spruce (Picea) trees covered the landscape. Both white spruce (Picea glauca) and black spruce (Picea mariana) were present, as was larch (Larix laricina). These trees are all common today in the boreal forest or taiga of Canada. Although the glaciers had retreated, the climate was still quite cold. About 16,000 years ago, the spruce forest became denser, and closed forest developed. This spruce forest lasted for about 1,000 years, until about 15,000 years ago, when climate warmed and deciduous trees became more abundant, including balsam poplar (Populus balsamifera), black ash (Fraxinus nigra), and ironwood (Ostrya virginiana or Carpinus caroliniana). Balsam fir (Abies balsamea) also was present, as was spruce, although not as abundantly as before.

This late-Pleistocene forest of spruce and deciduous trees is unusual in that a forest of similar composition does not occur anywhere today. The implication is that the climate was unlike any climate in North America today. The presence of spruce suggests cool summers, whereas the deciduous trees imply relatively warm winters. Thus, the climate may have been more equable than it is now. Although the Laurentide ice sheet, which still existed to the north, may have kept the summers cool, it may also have blocked arctic air masses from extending into the Midwest during winter.

About 13,000 years ago climate apparently cooled again, and spruce became more abundant and black ash less common. During this time birch (Betula) and alder (Alnus) were also important components of the vegetation. Then from about 12,000 to 11,500 years ago, the vegetation changed very rapidly as climate suddenly warmed at the transition from the Pleistocene to the Holocene.

In the earliest Holocene, the conifers— spruce, fir, and larch—disappeared, and a deciduous forest dominated by black ash, elm (Ulmus), and oak prevailed. Other deciduous trees also occurred, including sugar maple, basswood, ironwood, hickory, and walnut ( Juglans). The abundance of elm and ash, trees that favor wet soils, implies a very wet climate. After about 10,000 years ago, the climate became drier, and some limited areas of prairie developed in the Chicago region. This dry period may have lasted about 1,000 years, but conditions apparently became wetter again, because elm increased after about 9,000 years ago. About 6,000 years ago, the climate again became drier, and the modern mosaic of prairie and woodland began to develop. Elm and other fire-sensitive trees decreased in abundance, and oak became the predominate tree on the landscape. The driest time of the Holocene was from about 6,000 years ago to about 3,000 years ago, after which the climate again became somewhat cooler and wetter, although not as wet as in the early Holocene. However, prairie persisted because of its great propensity for burning and because the Native Americans provided a constant source of ignition. Some evidence of cooler climate is evident in the wetlands of the Chicago region. Larch reappeared in the region within the last 1,000 years, for example, at Volo Bog.

Vegetation

At the time when the first Europeans entered the Chicago region, the predominant vegetation was a mosaic of prairie, oak woodland, and savanna, with distinctive vegetation on sand dunes adjacent to Lake Michigan. Soils, topography, and firebreaks strongly controlled the vegetation pattern. Before European settlement, fire was a major influence. Every year the copious prairie vegetation dried in late summer, becoming highly flammable, and fires, mostly set by Native Americans either accidentally or purposefully, occurred annually. These fires carried easily through the prairie and burned into adjacent woodlands. As a result, the woodland vegetation was dominated by fire-resistant trees and occurred in areas protected from fire by rougher topography or water bodies—rivers and lakes.

Native Americans had many reasons to burn the prairie vegetation, including making the prairie easier to walk through, removing cover that might hide enemies, lighting backfires to remove the immediate danger of wildfires, and especially for hunting. “Tall-grass” prairie occurred in Illinois and in the Chicago region. The dominant grasses were big bluestem (Andropogon gerardii ), Indian grass (Sorghastrum nutans), and prairie dropseed (Sporobolus heterolepis), with large forbs such as prairie dock (Silphium terebinthinaceum) and rattlesnake master (Eryngium yuccifolium). Wet prairie with grasses such as prairie cordgrass (Spartina pectinata) occurred in more poorly drained areas.

On the loamy glacial moraines that cover most of the Chicago region, bur oak (Quercus macrocarpa) was the most common tree in woodlands, with lesser amounts of white oak (Quercus alba) and black oak (Quercus velutina). Bur oak has thick bark that makes it resistant to fire, and it resprouts if burned. Groves of bur oak occurred in more protected areas throughout the Chicago region. The early land surveyors described much of this vegetation as “scattered” or “scattering” timber or as “oak openings.” The trees tended to be scrubby. In some places they might have been widely spaced with a grassy understory, but they often occurred in clumps with shrubby undergrowth of oaks and hazel (Corylus americana).

The vegetation pattern clearly shows the effects of fires emanating predominantly from the west. Strips of woodland were wider on the east sides of lakes and rivers. Broad bands of woodland occurred east of the Fox River from Aurora to the Wisconsin border and east of the Des Plaines River in Lake County. Much of the area in Lake County on rolling moraines and east of the larger lakes was forested. In areas more protected from fire, especially immediately east of the larger rivers, forests of oak and hickory (Carya) predominated. In the areas best protected from fires, trees quite sensitive to fire such as sugar maple (Acer saccharum) and basswood (Tilia americana) occurred. Particularly notable was the “Big Woods” east of the Fox River where the city of Aurora is now located. Early pioneers used this term for forests of large trees with a continuous canopy, in contrast to the scrubby, open, frequently burned woodlands that were more common in the region. Depending on exposure to fire, a continuum existed from bur oak savanna or scrub to oak-hickory forest to maple-basswood forest.

The plain of glacial Lake Chicago on which much of the city lies was prairie, but paralleling Lake Michigan were sand dunes with black oak scrub having an understory of hazel, blueberry (Vaccinium), and other shrubs. Cottonwood (Populus deltoides) and jack pine (Pinus banksiana) also occurred on the dunes, and a few white pine (Pinus strobus) occurred in Lake County. The dunes are still preserved at Illinois Beach State Park in Lake County and Indiana Dunes National Lakeshore in northern Indiana.

Henry Chandler Cowles of the University of Chicago was one of the first plant ecologists in North America, and his research published in the Botanical Gazette in 1899 and 1901 on the succession of vegetation on the Lake Michigan dunes was seminal to the embryonic science of ecology. He documented a succession that begins with dune-forming plants such as beach grass (Ammophila breviligulata), sand cherry (Prunus pumila), willows (Salix), and cottonwood; followed by dune capture, with such plants as red-osier dogwood (Cornus sericea) and choke cherry (Prunus virginiana); and finally dune stabilization, with either black oak or jack pine. With long-term suppression of fires, Cowles noted an eventual succession to forest with shade-tolerant, fire-sensitive trees, particularly sugar maple. In contrast to sugar maples, oak seedlings do not survive in dense forest shade. In the past, occasional ground fires kept the forest more open and encouraged reproduction of oaks and hickories. Large oaks have thick bark and are quite resistant to ground fires, whereas sugar maples are much more sensitive. With fire exclusion, sugar maple is increasing at the expense of oak throughout Illinois.

Not only was the vegetation of the late Pleistocene much different from that of the present, so was the fauna. Arctic animals of today such as lemmings (e.g., Synaptomys borealis), caribou (Rangifer tarandus), and musk ox (Ovibos moschatus) occurred in the Midwest in the tundra-like vegetation that existed immediately after the glaciers retreated. Other large animals, the megafauna, went extinct at the end of the Pleistocene. American mastodon (Mammut americanum), woolly mammoth (Mammuthus primigenius), giant beaver (Castoroides ohioensis), Harlan's musk ox (Bootherium bombifrons), and stag-moose (Cervalces scotti ) all occurred in the Chicago region. According to fossil finds, mastodon was particularly common. After the extinction of these animals, white-tailed deer (Odocoileus virginianus), elk (Cervus elaphus), and bison (Bison) survived. Large predators—wolves, cougars, and bears—also inhabited the region. Although early explorers described “large” herds of bison, these herds generally contained a few hundred animals, nowhere near the size of the populations of millions in the Great Plains to the west. The tall-grass prairie habitat was probably not ideal for bison, and hunting pressure from the relatively large Native American population was probably intense. Scientists are divided as to the degree to which hunting by early Americans or rapid environmental change at the end of the Pleistocene were the causes for the extinction of the megafauna.

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You should all be aware by now of just how serious the facts on global warming really are and how detrimental an issue this is to all of us who live here on planet Earth.

Facts on Global Warming: What You Should Know

There are some very important facts on global warming that you need to be aware of, especially in today’s day and age where it has become more of an issue than ever before,

Some Interesting Facts on Global Warming

There are some very interesting facts on global warming out there, which we should all be aware of. Especially in today’s day and age where we are facing more environmental issues than ever before,

Good Fast Facts on Global Warming

When it comes to the fast facts on global warming, there are a few in particular that are going to be really important for you to learn about.

Some Fun Facts on Global Warming

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There are not really any fun facts on global warming. This is because global warming is a very serious issue, one that we all need to understand and learn as much as we can about.

TO AVOID EARTHUAKE

The devastating earthquake in Haiti has brought the "people" who try to profit illegally from the suffering of others out in force and the Federal Trade Commission (FTC) is urging consumers to "to choose carefully" when responding to urgent appeals for Haiti earthquake aid.

LANDRESOURCE MANAGEMENT

The Land Tenure and Management Unit undertakes the following activities in land resources:

• Promotes the development of cost-effective methods for land and soil survey and classification including testing and identification of soil constraints, criteria and methods for assessment of land degradation and sustainable land management and monitoring trends.
• Promotes and provides documentation, information and technical guidance for the assessment, conservation and productive management of land resources.
• Promotes the development and harmonisation of land evaluation methodology, land use analysis, land degradation assessments, agro-ecological zoning, indicators of land quality and criteria for monitoring land use systems and works towards their application through participatory land use planning approaches.
• Promotes soil and land use classification and correlation methodologies and mapping.
• Maintains a database and web-based information system on land resources and land use at national and regional level for comparative studies and analysis.
• Advises governments and other stakeholders in the formulation and implementation of appropriate land use and land management policies, strategies and action plans.
• Co-operates with UN and specialised agencies, international and national bodies, non-governmental organisations and the private sector to support sustainable and productive land use and land management practices.
• Contributes to the implementation of Agenda 21 and the Rio Conventions and assists member countries in the preparation of National Action Plans that address sustainable use of land resources use and food security goals.
• Supports member countries in the formulation and implementation of sustainable land and ecosystems management programmes/projects, with attention to land productivity, degradation, problem soils, biodiversity and climate change issues as well as emergency and relief operations.

GLOBAL WARMING SOLUTIONS

TheGlobalWarming Solutions Act of 2006 is an environmental law in California, signed into law by Governor of California Arnold Schwarzenegger on September 27, 2006. The bill establishes a timetable to bring California into near compliance with the provisions of the Kyoto Protocol. In signing the bill, Schwarzenegger declared, "We simply must do everything we can in power to slow down global warming before it is too late... "I say the debate is over. We know the science. We see the threat

The evidence that humans are causing global warming is strong, but the question of what to do about it remains controversial. Economics, sociology, and politics are all important factors in planning for the future.

Even if we stopped emitting greenhouse gases (GHGs) today, the Earth would still warm by another degree Fahrenheit or so. But what we do from today forward makes a big difference. Depending on our choices, scientists predict that the Earth could eventually warm by as little as 2.5 degrees or as much as 10 degrees Fahrenheit.

A commonly cited goal is to stabilize GHG concentrations around 450-550 parts per million (ppm), or about twice pre-industrial levels. This is the point at which many believe the most damaging impacts of climate change can be avoided. Current concentrations are about 380 ppm, which means there isn't much time to lose. According to the IPCC, we'd have to reduce GHG emissions by 50% to 80% of what they're on track to be in the next century to reach this level.

Is this possible?

Many people and governments are already working hard to cut greenhouse gases, and everyone can help.

Researchers Stephen Pacala and Robert Socolow at Princeton University have suggested one approach that they call "stabilization wedges." This means reducing GHG emissions from a variety of sources with technologies available in the next few decades, rather than relying on an enormous change in a single area. They suggest 7 wedges that could each reduce emissions, and all of them together could hold emissions at approximately current levels for the next 50 years, putting us on a potential path to stabilize around 500 ppm.

There are many possible wedges, including improvements to energy efficiency and vehicle fuel economy (so less energy has to be produced), and increases in wind and solar power, hydrogen produced from renewable sources, biofuels (produced from crops), natural gas, and nuclear power. There is also the potential to capture the carbon dioxide emitted from fossil fuels and store it underground—a process called "carbon sequestration."

In addition to reducing the gases we emit to the atmosphere, we can also increase the amount of gases we take out of the atmosphere. Plants and trees absorb CO2 as they grow, "sequestering" carbon naturally. Increasing forestlands and making changes to the way we farm could increase the amount of carbon we're storing.

Some of these technologies have drawbacks, and different communities will make different decisions about how to power their lives, but the good news is that there are a variety of options to put us on a path toward a stable clim

ENERGY CRISIS

Causes

Market failure is possible when monopoly manipulation of markets occurs. A crisis can develop due to industrial actions like union organized strikes and government embargoes. The cause may be over-consumption, aging infrastructure, choke point disruption or bottlenecks at oil refineries and port facilities that restrict fuel supply. An emergency may emerge during unusually cold winters due to increased consumption of energy.

Pipeline failures and other accidents may cause minor interruptions to energy supplies. A crisis could possibly emerge after infrastructure damage from severe weather. Attacks by terrorists or militia on important infrastructure are a possible problem for energy consumers, with a successful strike on a Middle East facility potentially causing global shortages. Political events, for example, when governments change due to regime change, monarchy collapse, military occupation, and coup may disrupt oil and gas production and create shortages.

[edit] Historical crises

• 1970s Energy Crisis - Cause: peaking of oil production in major industrial nations (Germany, U.S., Canada, etc.) and embargoes from other producers

• 1973 oil crisis - Cause: an OPEC oil export embargo by many of the major Arab oil-producing states, in response to western support of Israel during the Yom Kippur War
• 1979 oil crisis - Cause: the Iranian revolution

• 1990 spike in the price of oil - Cause: the Gulf War
• The 2000–2001 California electricity crisis - Cause: failed deregulation, and business corruption.
• The UK fuel protest of 2000 - Cause: Raise in the price of crude oil combined with already relatively high taxation on road fuel in the UK.
• North American natural gas crisis
• Argentine energy crisis of 2004
• North Korea has had energy shortages for many years.
• Zimbabwe has experienced a shortage of energy supplies for many years due to financial mismanagement.
• Political riots occurring during the 2007 Burmese anti-government protests were sparked by rising energy prices.

[edit] Emerging shortages

Kuwait's Al Burqan Oil Field, the world's second largest oil field, will be depleted within 40 years.^[1]

Crises that exist as of 2008 include:

• Oil price increases since 2003 - Caused by continued global increases in petroleum demand coupled with production stagnation, the falling value of the U.S. dollar, and a myriad of other secondary causes.
• 2008 Central Asia energy crisis, caused by abnormally cold temperatures and low water levels in an area dependent on hydroelectric power. Despite having significant hydrocarbon reserves, in February 2008 the President of Pakistan announced plans to tackle energy shortages that were reaching crisis stage.^[2] At the same time the South African President was appeasing fears of a prolonged electricity crisis in South Africa.^[3]
• South African electrical crisis. The South African crisis, which may last to 2012, lead to large price rises for platinum in February 2008^[4] and reduced gold production.
• China experienced severe energy shortages towards the end of 2005 and again in early 2008. During the latter crisis they suffered severe damage to power networks along with diesel and coal shortages.^[5] Supplies of electricity in Guangdong province, the manufacturing hub of China, are predicted to fall short by an estimated 10 GW.^[6]
• It has been predicted that in the coming years after 2009 that the United Kingdom will suffer an energy crisis due to its commitments to reduce coal fired power stations, its politician's unwillingness to set up new nuclear power stations to replaces those that will be de-commissioned in a few years (even though they will not be running in time to stop a full blown crisis) and unreliable sources and sources that are running out of oil and gas. It is therefore predicted that the UK may have regular blackouts like South Africa.^[7]

[edit] Social and economic effects

Main article: Energy economics

The macroeconomic implications of a supply shock-induced energy crisis are large, because energy is the resource used to exploit all other resources. When energy markets fail, an energy shortage develops. Electricity consumers may experience intentionally-engineered rolling blackouts which are released during periods of insufficient supply or unexpected power outages, regardless of the cause.

Industrialized nations are dependent on oil, and efforts to restrict the supply of oil would have an adverse effect on the economies of oil producers. For the consumer, the price of natural gas, gasoline (petrol) and diesel for cars and other vehicles rises. An early response from stakeholders is the call for reports, investigations and commissions into the price of fuels. There are also movements towards the development of more sustainable urban infrastructure.

In 2006, US survey respondents were willing to pay more for a plug-in hybrid car

In the market, new technology and energy efficiency measures become desirable for consumers seeking to decrease transport costs.^[8] Examples include:

• In 1980 Briggs & Stratton developed the first gasoline hybrid electric automobile; also are appearing plug-in hybrids.
• the growth of advanced biofuels.
• innovations like the Dahon, a folding bicycle
• modernized and electrifying passenger transport
• Railway electrification systems and new engines such as the Ganz-Mavag locomotive
• variable compression ratio for vehicles

Other responses include the development of unconventional oil sources such as synthetic fuel from places like the Athabasca Oil Sands, more renewable energy commercialization and use of alternative propulsion. There may be a Relocation trend towards local foods and possibly microgeneration, solar thermal collectors and other green energy sources.

Tourism trends change and ownership of gas-guzzlers vary, both because of increases to fuel costs which are passed on to customers. Items which were not so popular gain favour, such as nuclear power plants and the blanket sleeper, a garment to keep children warm. Building construction techniques change to reduce heating costs, potentially through increased insulation.

See also: Green building and Zero-energy building

[edit] Crisis management

An electricity shortage is felt most by those who depend on electricity for their heating, cooking and water supply. In these circumstances a sustained energy crisis may become a humanitarian crisis.

If an energy shortage is prolonged a crisis management phase is enforced by authorities. Energy audits may be conducted to monitor usage. Various curfews with the intention of increasing energy conservation may be initiated to reduce consumption. To conserve power during the Central Asia energy crisis, authorities in Tajikistan ordered bars and cafes to operate by candlelight.^[9] Warnings issued that peak demand power supply might not be sustained.

In the worst kind of energy crisis energy rationing and fuel rationing may be incurred. Panic buying may beset outlets as awareness of shortages spread. Facilities close down to save on heating oil; and factories cut production and lay off workers. The risk of stagflation increases.

[edit] Mitigation of an energy crisis

Nuclear power in Germany

Main article: Mitigation of peak oil

The Hirsch report made clear that an energy crisis is best averted by preparation. In 2008, solutions such as the Pickens Plan and the satirical in origin Paris Hilton energy plan suggest the growing public consciousness of the importance of mitigation.

Energy policy may be reformed leading to greater energy intensity, for example in Iran with the 2007 Gas Rationing Plan in Iran, Canada and the National Energy Program and in the USA with the Energy Independence and Security Act of 2007. In Europe the oil phase-out in Sweden is an initiative a government has taken to provide energy security. Another mitigation measure is the setup of a cache of secure fuel reserves like the United States Strategic Petroleum Reserve, in case of national emergency. Chinese energy policy includes specific targets within their 5 year plans.

World energy usage

Andrew McKillop has been a proponent of a contract and converge model or capping scheme, to mitigate both emissions of greenhouse gases and a peak oil crisis. The imposition of a carbon tax would have mitigating effects on an oil crisis.^{[citation needed]} The Oil Depletion Protocol has been developed by Richard Heinberg to implement a powerdown during a peak oil crisis. While many sustainable development and energy policy organisations have advocated reforms to energy development from the 1970s, some cater to a specific crisis in energy supply including Energy-Questand the International Association for Energy Economics. The Oil Depletion Analysis Centre and the Association for the Study of Peak Oil and Gas examine the timing and likely effects of peak oil.

Ecologist William Rees believes that

“

To avoid a serious energy crisis in coming decades, citizens in the industrial countries should actually be urging their governments to come to international agreement on a persistent, orderly, predictable, and steepening series of oil and natural gas price hikes over the next two decades.

”

Due to a lack of political viability on the issue, government mandated fuel prices hikes are unlikely and the unresolved dilemma of fossil fuel dependence is becoming a wicked problem. A global soft energy path seems improbable, due to the rebound effect. Conclusions that the world is heading towards an unprecedented large and potentially devastating global energy crisis due to a decline in the availability of cheap oil lead to calls for a decreasing dependency on fossil fuel.

Other ideas have been proposed which concentrate on improved, energy-efficient design and development of urban infrastructure in developing nations.^[10] Government funding for alternative energy is more likely to increase during an energy crisis, so too are incentives for oil exploration. For example funding for research into inertial confinement fusion technology increased during 1970's.

Energy economists theorize that declining energy availability will result in a higher price for energy and that this will attract investment to procure new sources of energy that may be substituted. However as Michael Lardelli and others have pointed out, this hypothesis does not include the concept of Energy Returned on Energy Invested, which is important for example, when considering biofuels as an alternative to conventional energy supplies. The theory also assumes that capital investment in the substitution sector will be available even if a financial downturn caused by higher energy prices happens.^[11] Nor does the theory account for the fact that the most easily obtainable energy is extracted from reserves first because it provides the most profit leaving the smaller, harder to reach and more expensive to produce reserves.^[12]

[edit] Future and alternative energy sources

In response to the petroleum crisis, the principles of green energy and sustainable living movements gain popularity. This has led to increasing interest in alternate power/fuel research such as fuel cell technology, liquid nitrogen economy, hydrogen fuel, methanol, biodiesel, Karrick process, solar energy, geothermal energy, tidal energy, wave power, and wind energy, and fusion power. To date, only hydroelectricity and nuclear power have been significant alternatives to fossil fuel.

Hydrogen gas is currently produced at a net energy loss from natural gas, which is also experiencing declining production in North America and elsewhere. When not produced from natural gas, hydrogen still needs another source of energy to create it, also at a loss during the process. This has led to hydrogen being regarded as a 'carrier' of energy, like electricity, rather than a 'source'. The unproven dehydrogenating process has also been suggested for the use water as an energy source.

Efficiency mechanisms such as Negawatt power can encourage significantly more effective use of current generating capacity. It is a term used to describe the trading of increased efficiency, using consumption efficiency to increase available market supply rather than by increasing plant generation capacity. As such, it is a demand-side as opposed to a supply-side measure.

See also: Strategic uranium reserves and Nuclear energy policy

[edit] Predictions

Although technology has made oil extraction more efficient, the world is having to struggle to provide oil by using increasingly costly and less productive methods such as deep sea drilling, and developing environmentally sensitive areas such as the Arctic National Wildlife Refuge.

The world's population continues to grow at a quarter of a million people per day, increasing the consumption of energy. Although far less from people in developing countries, especially USA, the per capita energy consumption of China, India and other developing nations continues to increase as the people living in these countries adopt more energy intensive lifestyles. At present a small part of the world's population consumes a large part of its resources, with the United States and its population of 300 million people consuming far more oil than China with its population of 1.3 billion people.

William Catton has emphasised the link between population size and energy supply, concluding that

“

The faster the present generation draws down the fossil energy legacy upon which persistently exuberant lifestyles now depend, the less opportunity posterity will have to live in anything like the same way or the same numbers. Yet most contemporary political proposals for solving problems of economic stagnation or inequity amount to plans for speeding up the rate of drawdown of non-renewable resources.

”

David Pimentel professor of ecology and agriculture at Cornell University, has called for massive reduction in world populations in order to avoid a permanent global energy crisis. The implication is that cheap oil has created a human overshoot beyond Earth's carrying capacity which inevitably lead to an energy crisis. David Price postulates that population growth occurs when a higher quality form of energy is commercialised.^[13]

See also: Energy balance and Tragedy of the Commons

For nearly 60 years the US dependence on imported oil has grown significantly.

Matthew Simmons and Julian Darley amongst others, have examined the economic effects of an energy crisis. Historian, and sociologist Franz Schurmann links an energy crisis with a deflating American dollar. He has stated that

“

If a dollar free-fall should take place, Americans will confront an energy crisis that will make the October 1973 oil shortage seem a mild nuisance.

”

According to Christopher Falvin, geopolitical factors has resulted in current energy system, based on fossil fuels, to be a risk management issue that undermines global security.^{[citation needed]} Considering the significant source of greenhouse gas emissions accumulating in the atmosphere, fossil fuel energy is being viewed as increasingly socially irresponsible. Joseph Tainter is an expert on societal collapse and energy supply who draws attention to the complexity of modern society and our ability to problem solve the wider issue of environmental degradation.^[14]

National population suffering from undernourishment as percentage.

[edit] Agriculture

According to Kenneth S. Deffeyes agricultural production is heavily dependent on hydrocarbons for energy, in the form of petroleum to power machinery and transport goods to market. Another important input is fertilizer usage that is highly dependent on natural gas for its production and sometimes for fueled irrigation. Between the late 1940s and early 1980s, as the Green Revolution transformed agriculture around the globe, world grain production increased by 250%. The energy for the Green Revolution was provided almost always by fossil fuels.^{[citation needed]} The 20th century population explosion is strongly correlated with the discovery and extraction of hydrocarbons.

The decision to develop a biofuel industry through subsidies and tariffs in the USA has increased food costs globally. Lester R. Brown states ^[15] that by converting grains into fuel for cars

“

..the world is facing the most severe food price inflation in history as grain and soyabean prices climb to all-time highs,

”

World power usage, 1965–2005

See also: Food security and Food vs fuel

[edit] Catastrophe

Some experts including Howard Odum and David Holmgren have used the term energy descent to describe a post-peak oil period of transition. Ron Swenson has described a looming peak oil crisis as a calamity unparalleled in human history.^{[citation needed]} The peaking of world hydrocarbon production, known as peak oil may test Malthus critics. Michael C. Ruppert has discussed energy crises in relation to the petrodollar, oil imperialism and police states.

See also: Oil depletion and Doomer

[edit] Cultural references

Fictional scenarios have been explored in;

• Frontlines: Fuel of War, a first-person shooter game that depicts a global energy crisis in 2024 leading to war between Western Coalition (EU and USA) against Red Star Alliance (Russia and China) over the last remaining natural resources
• Ice, online comic
• Mad Max, depicts an energy starved post-apocalypse world.
• Oil Storm, a 2005 television docudrama portraying a future oil-shortage crisis in the United States
• Soylent Green, a film about a dystopian future in which overpopulation leads to depleted resources
• The Man Who Broke Britain, a BBC docudrama
• The Running Man, a fictional film depicts the effects of a global economic collapse

MINERAL RESOURCES

Mineral resource classification is the classification of mineral deposits based on their economic value.

Mineral deposits can be classified as:

• Mineral occurrences or prospects of geological interest but not necessarily of economic interest
• Mineral resources that are potentially valuable, and for which reasonable prospects exist for eventual economic extraction.
• Mineral reserves or Ore reserves that are valuable and economically and technically feasible to extract

In common mining terminology, an "ore deposit" by definition must have an 'ore reserve', and may or may not have additional 'resources'.

Classification, because it is an economic function, is governed by statutes, regulations and industry best practice norms. There are several classification schemes worldwide, however the Canadian CIM classification (see NI 43-101), the Australasian Joint Ore Reserves Committee Code (JORC Code), and the South African Code for the Reporting of Mineral Resources and Mineral Reserves (SAMREC)^[1] are the general standards.

Contents [hide] 1 Mineral occurrences, prospects 2 Mineral resources 3 Mineral reserves 4 Further information 5 See also 6 References

[edit] Mineral occurrences, prospects

Main article: mineral exploration

These classifications of mineral occurrences are generally the least important and least economic. They include all known occurrences of minerals of economic interest, including obviously uneconomic outcrops and manifestations. However, these are often mentioned in a company prospectus because of "proximity"; a concept that something valuable may be found near these occurrences because it has been in the past due to a similar geological environment. Often, such occurrences of mineralisation are the peripheral manifestations of nearby ore deposits. "Ore deposit" applies specifically to economic mineral occurrences that could be mined at a profit after consideration of all factors impacting a mining operation. Note that this distinction between amounts of raw material available as either a resource or reserve also applies to other materials considered to be minerals. This can include natural gas (legally defined as a mineral in some states of the United States) and hydrocarbons.

[edit] Mineral resources

Mineral resources are those economic mineral concentrations that have undergone enough scrutiny to quantify their contained metal to a certain degree. None of these resources are ore, because the economics of the mineral deposit may not have been fully evaluated.

Indicated resources are simply economic mineral occurrences that have been sampled (from locations such as outcrops, trenches, pits and drillholes) to a point where an estimate has been made, at a reasonable level of confidence, of their contained metal, grade, tonnage, shape, densities, physical characteristics^[2].

Measured resources are indicated resources that have undergone enough further sampling that a 'competent person' (defined by the norms of the relevant mining code; usually a geologist) has declared them to be an acceptable estimate, at a high degree of confidence, of the grade, tonnage, shape, densities, physical characteristics and mineral content of the mineral occurrence.

Resources may also make up portions of a mineral deposit classified as a mineral reserve, but:

• Have not been sufficiently drilled out to qualify for Reserve status; or
• Have yet to meet all criteria for Reserve status ^[2]

[edit] Mineral reserves

Mineral reserves are resources known to be economically feasible for extraction. Reserves are either Probable Reserves or Proven Reserves. Generally the conversion of resources into reserves requires the application of various modifying factors, including:

• mining and geological factors, such as knowledge of the geology of the deposit sufficient that it is predictable and verifiable; extraction and mine plans based on ore models; quantification of geotechnical risk—basically, managing the geological faults, joints, and ground fractures so the mine does not collapse; and consideration of technical risk—essentially, statistical and variography to ensure the ore is sampled properly:
• metallurgical factors, including scrutiny of assay data to ensure accuracy of the information supplied by the laboratory—required because ore reserves are bankable. Essentially, once a deposit is elevated to reserve status, it is an economic entity and an asset upon which loans and equity can be drawn—generally to pay for its extraction at (hopefully) a profit;
• economic factors;
• environmental factors;
• marketing factors;
• legal factors;
• governmental factors;and
• social factors ^[3].

[edit] Further information

• JORC Code
• University of Western Australia Mining Law Centre
• U.S. Geological Survey Circular 831, Principles of a Resource/Reserve Classification for Minerals
• Canadian Institute of Mining, Metallurgy and Petroleum - CIM Definition Standards - On Mineral Resources and Mineral Reserves (PDF Format)
• The Canadian Council of Professional Geoscientists CCPG
• NI 43-101 Guidelines
• The South African SAMVAL and SAMREC Codes