Climate change glossary

arid  The arid and semi-arid areas of New South Wales are commonly referred to as rangelands. These lands generally lie to the west of the 500 mm average rainfall limit. The main enterprise is extensive grazing of predominantly native pastures. On the eastern and southern margins of the rangelands, extensive grazing occurs in conjunction with broadacre cropping and areas of intensive irrigated agriculture. Collectively, the semi-arid and arid zones occupy about 60 per cent of the state.

 

biomass  Refers to the amount of living material, or material that was once living, in a community. Plants and algae convert carbon dioxide and water, with energy from the sun, to create organic matter as part of the carbon cycle. Biomass can be a source of energy, or can be used as a fuel. For example, one animal can eat another for fuel, or wood can be burned to create heat energy.

blight  Refers to a specific symptom affecting plants in response to infection by a pathogenic organism. The plant cannot manufacture its own sugars through photosynthesis because not enough chlorophyll is produced. The plant browns, then death of plant tissues such as leaves, branches, twigs or floral organs occurs.

blooms  The circumstance where fresh, estuarine or marine waters contain very high numbers of algae cells. This can cause harmful or toxic effects and result in the discolouration of water to various colours from red to brown to green.

 

carbon cycle  Refers to the transfer of carbon, in various forms, through the atmosphere, oceans, plants, animals, soils and sediments. Read more about the carbon cycle.

carbon dioxide, CO₂  A naturally occurring gas; also a by-product of human activities such as the combustion of fossil fuels, biomass burning, land-use changes, and other industrial processes.

carbon dioxide equivalent, CO₂-e  A measure that allows for the comparison of different greenhouse gases in terms of their global warming potential. For example methane is 20 times more effective than carbon dioxide in trapping heat in the atmosphere, so less methane is required for the same warming effect as carbon dioxide.

carbon offsets  Credits purchased by a consumer, or a polluter, that results in an action that reduces carbon dioxide in the atmosphere. Recently companies have emerged which sell carbon credits so that consumers can voluntarily purchase enough credits to neutralise the carbon emissions from a particular activity such as using a car or making an aeroplane journey.

carbon sequestration  The process of removing and storing carbon from the atmosphere into a carbon sink, such as the ocean, forests or soil, through physical or biological processes, such as photosynthesis. Technological advances have allowed geosequestration to be achieved, whereby carbon dioxide is captured, compressed and injected as a liquid into deep geological formations. Research is continuing on a wider application of this technology.

cation exchange capacity (CEC)  A measure of the soil's ability to hold positively charged ions. It is a very important soil property influencing soil structure stability, nutrient availability, soil pH and the soil's reaction to fertilisers and other ameliorants.¹ Read more about cation exchange capacity.

clean coal  The name given to new technologies being researched and developed to lower the carbon dioxide emissions from coal-fired power stations. Find out more about low emission coal technologies here.

climate system  A highly complex system consisting of the atmosphere; the water cycle; ice, snow and frozen ground; the land surface; plants and animals; and the interactions between them (Garnaut, R (2008). 'The Garnaut Climate Change Review: Final Report', Commonwealth of Australia, Cambridge University Press, Port Melbourne. www.garnautreview.org.au).

coral bleaching  Occurs when microscopic algae, called zooxanthellae, inside a coral skeleton are expelled. Zooxanthellae are responsible for supplying nutrients via photosynthesis to the coral skeleton and this is the reason for the pretty colours in the coral. Zooxanthellae can be expelled in certain ocean conditions, such as higher water temperatures (e.g. during hot summer months in shallow waters), or due to disease or pollutants. Without the colour pigments of the zooxanthellae, the coral appears white or 'bleached'. Read more about coral bleaching.

crustacean  A large group of animals living in the sea or fresh water with a type of shell amour called a carapace. Crustaceans include crabs, lobsters, prawns and barnacles.

cultivation  Working the soil with implements to prepare it for sowing crops.

 

deforestation  The process that results in the removal of forests by cutting down or burning trees to convert the land use for other purposes. Examples include the cutting down of a forest to change the land use for agricultural purposes; or harvesting the trees for the production of building materials or for fuel without replanting the trees. By reducing the amount of forest area that would otherwise convert CO₂ to O₂ during photosynthesis, deforestation can be likened to carbon emission.

drip irrigation system  A watering system for crops which applies accurately metered quantities of water to the root systems of plants across a paddock. It requires a system of pumps and pipes and must be well managed for success.²

 

East Australian and Leeuwin currents  Both influential ocean currents carrying warmer tropical waters from the north to the south and beyond, on both east and west coasts of Australia.

The East Australian Current flows south from the Coral Sea to Tasmania, it is the largest ocean current close to Australia, moving as much as 30 million cubic metres of water per second in a broad ribbon that covers as much as 100 kilometres in width and 500 metres in depth.

At 5500 km the Leeuwin current is the longest continuous coastal current system in the world, linking Western Australia's North West Shelf to South Cape in southern Tasmania. The current speeds are about 1 knot (50 cm/s), although speeds of 2 knots (1 m/s) are common.

ecologically sustainable  Describes a theory or practice which aims to meet the needs of Australians today, while conserving ecosystems for the benefit of future generations - to develop ways of using those environmental resources which form the basis of our economy in a way which maintains and, where possible, improves their range, variety and quality.

El Niño events  Refers to the extensive warming of the central and eastern Pacific that leads to a major shift in weather patterns across the Pacific. In Australia (particularly eastern Australia), El Niño events are associated with an increased probability of drier conditions. Find out more about El Niño (Bureau of Meteorology).

emissions trading scheme  Sometimes referred to as 'cap and trade' - a pollution control tool Australia's government is working towards establishing as part of a framework to reduce Australia's carbon emissions. The 'cap' refers to setting an overall environmental limit by issuing a set number of permits, and the scheme will allow entities who create carbon emissions to trade permits, thereby putting a price on carbon. The issuing of permits is designed to place Australia on a low emissions path.

enteric fermentation  A digestive process by which carbohydrates are broken down by microorganisms into simple molecules for absorption into the bloodstream of an animal.

extensive agriculture  Usually refers to farming over a large land area and is the term used to describe the raising of stock or crops, excluding intensive agriculture.

 

feedlot  A confined area for the controlled feeding of animals. Animals are given feed rather than allowing them to graze. Used in intensive agriculture.

flood and furrow irrigation  Both are types of surface irrigation, where farmers flow water across a field or down small trenches, channels or furrows running through their crops. This method of irrigation uses a large amount of water, and if the water is applied at a rate faster than the rate at which water can soak into the soil, surface runoff water flows off the area.

foliage wires  A 'wire and post' system of support for grape vines in the viticulture industry to promote better fruit quality.

forest management plans   The plans according to which NSW state forests are managed. Plans are developed for a region, and all plans guide forest management practices. Forest management includes considerations to the following: natural heritage, Aboriginal cultural heritage, non-Aboriginal cultural heritage, nature conservation, forest health, sustainable timber supply, economic development, social development, forestry operations, consultation, monitoring and reporting. Find out more about forest management plans.

forestry values  The collection of values that describe what the forest means to a community. These include social, environmental, economic and sustainability values of the forest.

• Social values - what the forest can contribute to the social wellbeing of a regional community, such as providing employment in the industry, tourism, recreational or educational opportunities.
• Environmental values - maintaining and enhancing biodiversity and forest health, for example by reducing the impact of invasive species while managing healthy forests through methods such as fire prevention and pest animal and weed control programs. It also includes environmental services such as the carbon sequestration role that forests provide.
• Economic values - the revenue that timber products provide.
• Sustainability values - the ability of native forests and plantations together to provide timber and all of the other forest values for the future.

fossil fuels  Refers to the coal, oil and natural gas found in rock formations under the earth's surface. They were formed approximately 50 to 350 million years ago and are derived from the decaying remains of ancient plant and animal life that were buried by sediment. Because these fuels took millions of years to form, they are considered a non-renewable energy source, because once they have all been used they cannot be replaced within human time scales.  These fossil fuels are burned to produce energy.

For example, to produce electrical energy from coal:

• The coal is crushed to a fine dust and burned.
• The heat released from the burning heats water to make steam.
• The steam then turns turbines.
• The turbines turn generators, and it is these generators which produce the electrical power.

Watch this YouTube video on how a coal power station works: http://au.youtube.com/watch?v=SeXG8K5_UvU

 

geosequestration  Carbon dioxide is captured, compressed and injected as a liquid into deep geological formations. See also carbon sequestration.

gigalitre  A measure of volume, equivalent to one billion litres.

gigawatt  A measure of power, equivalent to one billion watts.

global warming potential  An index measure of the insulating ability of the various greenhouse gases. An index is used to translate the level of emissions of greenhouse gases into a common measure. This allows the comparison of the relative radiative forcing of different gases without directly calculating the changes in atmospheric concentrations.

greenhouse gases  The earth's atmosphere acts like the roof of a greenhouse, allowing short-wavelength (visible) solar radiation from the sun to reach the surface, but absorbing the long-wavelength heat that is emitted back. This process is referred to as 'the greenhouse effect', and the gases that absorb the emitted heat are known as greenhouse gases. The main naturally occurring greenhouse gases are water vapour (H₂O ), carbon dioxide (CO₂), methane (CH₄), nitrous oxide (N₂O) and ozone (O₃). Find out more about greenhouse gases.

groundwater  Water in the lower layers of the soil that supplies wells, bores and springs. It usually drains into creeks and rivers, and carries leached nutrients and dissolved salts.

 

hazard reduction burn activities  These activities reduce the amount of fuel in an area with an aim to significantly reduce fire behaviour and assist in fire suppression activities. Called a 'prescribed burn', a purposely lit fire is managed for a specific purpose and conducted according to a specific plan. A prescribed burn plan will define the control lines to contain the burn, the required fire intensity to achieve objectives, the weather and seasonal conditions required during the burning operation, and the light-up methods and sequences. The use of prescribed burning is essential to:

• reduce overall fuel hazard to assist in the protection of life, property and community assets;
• manage biodiversity to maintain the reproductive viability of a species or a community of species;
• manage introduced species, their spread and impact on native fauna and flora; and
• research fire behaviour and ecological response to fire.

humus  The final product of the decaying process. Humus is important for binding soil particles together and improves the water and nutrient-holding capacity of soils making these resources available to the plant. Humus is also where carbon may be stored or sequestered for decades or even centuries.

 

incident solar radiation  The actual amount of solar radiation penetrating the earth's atmosphere. This can be measured from the earth's surface.

intensive agriculture  Usually refers to farming over a smaller land area relative to the amount of product it produces, compared with extensive agriculture. Intensive agriculture requires high inputs of food, water and labour.

 

kilowatt  Measure of power. 1000 kilowatts is equivalent to 1 megawatt.

Kyoto Protocol  The international agreement signed at the United Nations Framework Convention on Climate Change (UNFCCC) in Kyoto, Japan in 1997. Industrialised countries who signed the treaty agreed to reduce their greenhouse gas emissions by at least 5% below 1990 levels in the commitment period 2008 to 2012.

 

land degradation  The reduction in the ability of landscapes to produce vegetation cover from rainfall.

 

medium chain fatty acids  A type of fat that is able to restrict the activity of microbes found in the rumen of ruminants. This means less methane would be produced during digestion.

megawatt  A measure of power, equivalent to one million watts. 1000 megawatts is equivalent to 1 gigawatt.

merchandise  Refers to goods and commodities, especially manufactured goods.

methane, CH₄  A principal component of natural gas. It is also formed and released to the atmosphere by biological processes occurring in anaerobic environments (meaning environments where there is no oxygen). Its presence in the atmosphere affects the earth's temperature and climate system. Methane is twenty times more effective than carbon dioxide in trapping heat in the atmosphere.

methanogen  A type of microbe that can survive without oxygen, for example in an animal's intestinal tract. A methanogen, like other microbes, feeds off other organisms and decaying organic matter, producing methane as a by-product during this breaking-down process.

microbe  A microbe is any living organism that is too tiny to be seen with the naked eye. The term 'microbe' is short for microorganism, which means 'small organism'.

mineral carbonation  The reaction of captured carbon dioxide with materials containing metal oxides, resulting in the formation of a carbonate (a mineral containing the carbonate ion, CO₃^2-)  and a solid by-product, such as silica, that can be stored and disposed of, or reused in construction. When CO₂ reacts with metal oxides (indicated here as MO, where M is a divalent metal, e.g. calcium, magnesium or iron), the corresponding carbonate is formed and heat is released according to the following chemical reaction:
MO + CO₂ → MCO₃ + heat

mixed layer depth  The area in the ocean usually between the depths of 25 m and 200 m, where the density of the water is generally the same as at the surface. Waves and wind turbulence cause mixing of surface layers with the water beneath it to maintain this uniformity of sea conditions. This mixed-layer zone responds most quickly to changes in atmospheric conditions and further transmits these changes to the whole ocean.

ms^-1 or m/s  Metres per second, a measurement for wind speed.

Mt  Megatonnes. One megatonne is equivalent to one million tonnes.

 

nitrous oxide (N₂O)  An important greenhouse gas, as it does not easily break down. It has an atmospheric lifetime of more than a century. Present concentrations of the gas have not been exceeded for at least the past 1000 years. Nitrous oxide concentrations increase due to land use changes, biomass burning, fertiliser use and some industrial processes.

 

ocean pH  When carbon dioxide dissolves in water, there is a reaction between the H₂O and CO₂ to form carbonic acid:
CO₂ + H₂O <=> H₂CO₃
Carbonic acid is a weak acid and can readily release a proton (H⁺) and a negatively charged inorganic carbon ion. The release of H⁺ into the water makes it more acidic and is what can reduce ocean pH (i.e. higher acidity). As concentrations of CO₂ in the earth's atmosphere increase, so does the amount of CO₂ that the oceans absorb, increasing concentrations of H⁺ in the ocean, making them more acidic. This is what is called 'ocean acidification'.³

 

parasitoid  An organism that spends most of its life attached to or within a single host organism, which it ultimately kills in the process.

perennial   Plants that do not die after flowering but live from year to year.

pheromone  A sex-attractant hormone or scent produced by animals or insects.

photosynthesis  The process by which plants, some bacteria, and another type of organism called a protist, use the energy from sunlight to produce sugar as its energy source so that it can grow and reproduce. All photosynthesising organisms use a light-absorbing pigment called chlorophyll to absorb the energy from light, and use carbon dioxide and water to produce sugar, oxygen and water.
Carbon dioxide + water + energy from the sun → sugars, oxygen and water.
In symbols: 6CO₂ + 12H₂O + light → C₆H₁₂O₆ + 6O₂ + 6H₂O
Watch this animation which explains photosynthesis on land and in the oceans: http://earthguide.ucsd.edu/earthguide/diagrams/photosynthesis/photosynthesis.html

 

radiative forcing  A measure of the influence that a factor has on the energy balance of the climate system. Positive forcing tends to warm the surface, while negative forcing tends to cool it.

renewable energy

• energy from biomass  The burning of vegetative material or of biogas (methane) releases stored energy from the sun. Methane from rotting organic material (material that was once living) can be captured and used to generate electricity. Some landfills and rubbish dumps capture the gas created from its waste stores and create power to run operations at waste disposal centres. The gas is captured and burned, releasing heat energy which drives a generator to create electricity. Carbon dioxide is released in this process, but because it has a lower global warming potential than methane, it traps less heat in the earth's atmosphere. Energy from biomass can also be generated from animal manure, or vegetation can be specifically grown for the purpose of generating electricity or making fuel.
• geothermal energy  Uses the natural heat found within the earth's core. Heat increases with depth at a rate of around 10-50ºC/km. This heat is generated from the radioactive decay of naturally occurring potassium, thorium and uranium isotopes.⁴ Hot fractured rock geothermal energy is one example of geothermal energy whereby energy is produced by circulating water through heat-producing granite rocks located some 3 km below the earth's surface. The heat energy is extracted via pumped circulating water which brings the superheated water back to the surface. A geothermal power station converts the extracted heat into electricity for consumers. One cubic kilometre of hot granite at 250ºC has the stored energy equivalent of 40 million barrels of oil.
• hydropower  The energy harnessed from the force of running water. Energy can be captured from waterfalls or from the vertical drop of water from a dam wall. The fast-moving flow of the water pushes turbine blades which turn the rotor part of an electric generator. The generator produces electricity inside a hydroelectric power station located close to the water source. Australia has about 100 hydroelectric power stations, and these create 16 000 gigawatts of energy each year.
• ocean energy  Can be either thermal energy or mechanical energy.
  
  Ocean thermal energy: The sun's heat warms the surface water to a greater temperature than the deeper ocean water, and this temperature difference creates thermal energy. Warm ocean surface waters can heat and vaporise (i.e. turn a liquid into a gas) a working fluid which has a low boiling point, such as ammonia. When the vapour expands, it turns a turbine that drives a generator to produce electricity.⁵
  
  Ocean mechanical energy refers to the tides and waves providing energy by the gravitational pull of the moon and due to the wind. Water is forced through a turbine which activates a generator. For wave energy conversion, there are three basic systems: channel systems that funnel the waves into reservoirs; float systems that drive hydraulic pumps; and oscillating water column systems that use the waves to compress air within a container. The mechanical power created from these systems either directly activates a generator or transfers to a working fluid.
• solar power - photovoltaics  The sun provides energy in the form of light and heat. Solar panels or 'solar photovoltaics', usually mounted on the roofs of houses, capture the sun's light energy and turn it into electricity. Chemicals inside layers of silicon contain electrons which are charged by sunlight, move through the cell and flow into a wire, creating an electric current. The electricity is provided directly to a home or where the infrastructure allows, or is fed into the grid for wider use by the community. In Singleton NSW, a 2.75 hectare solar farm, the size of about five football fields, produces enough electricity each year to power around 100 homes.⁶
• solar power - solar thermal  The most popular use of solar thermal energy is through solar hot water services used for our hot showers. The sun's heat energy is absorbed and used to heat water. The heated water can be stored and used directly, or it can be used to create steam to drive a small turbine to generate electricity.
• tidal energy  Produced through the use of tidal energy generators. These large underwater turbines are placed in areas with high tidal movements, and are designed to capture the kinetic motion of the ebbing and surging of ocean tides in order to produce electricity.⁷
• wind energy  A wind farm is a place where many wind turbines are clustered together in a very windy area. A wind turbine is a tall pole with two or three propeller blades attached to the top which are driven by the wind. The blades rotate in the wind, and the energy of this movement provides power to a generator. The generator produces electricity which is provided to the community via the electricity grid.

reporting of gas emissions by sector

• stationary energy sector emissions  Mainly greenhouse gas emissions from the production of electricity and other direct combustion of fossil fuels in industry, such as manufacturing and construction.
• transport sector emissions  Greenhouse gas emissions from air, road, rail and shipping transportation.
• fugitive emissions from fuels sector  Greenhouse gas emissions from the extraction and distribution of coal, oil and natural gas.
• agriculture sector emissions  Emissions of methane and nitrous oxide only (i.e. non carbon dioxide gases) from livestock, crops, agricultural and forest soils, and agricultural burning.⁸ These emissions result from the decay or burning of biomass, feed digestion by ruminant livestock, the addition of nitrogen fertiliser and animal manure, crop residues returned to the soil, nitrogen fixation, nitrogen leaching and runoff, atmospheric deposition, and the anaerobic decomposition of organic matter during flood irrigation.⁹
  - land use change sub-sector emissions  Includes greenhouse gas emissions from the conversion of forests to grassland and cropland.
  - forestry sub-sector emissions Refers to the amount of carbon dioxide removed from the atmosphere via plantations established on agricultural land since 1990, referred to as afforestation and reforestation' in the Kyoto Protocol. While not an emission, recognition of the carbon storage potential during inventory is important for greenhouse gas accounting. See the Department of Climate Change website at http://www.climatechange.gov.au for more detail.¹⁰
• waste emissions  Predominantly methane. Small amounts of carbon dioxide and nitrous oxide are generated through the incineration of solvents and the decomposition of human wastes respectively. The main source of waste emissions are:
  - solid waste  Emissions resulting from anaerobic (without oxygen) decomposition of organic matter in landfills;
  - waste water  Emissions resulting from anaerobic decomposition of organic matter in sewerage facilities (including on-site systems such as septic tanks) during treatment and disposal of wastewater;
  - incineration  Emissions resulting from the incineration of solvents and clinical waste.¹¹

residue  1. Refers to the remains of crop plants after a harvest has been completed.
2. Refers to the quantity of an agricultural chemical either in or on plants or animals at the time of testing (in the past, expressed in parts per million (ppm), but now milligrams per kilogram (mg/kg) is favoured).

riparian vegetation  The plants growing on the water's edge, the banks of rivers and creeks, and along the edges of wetlands. Riparian vegetation can include trees, shrubs, grasses and vines in a complex structure of groundcovers, understorey and canopy. Native riparian vegetation forms an important part of a healthy functioning ecosystem and has many important ecological benefits.

rumen  The first compartment of the stomach of a ruminant animal. Food is collected here and returned to the mouth as cud for chewing. Cud comprises the separated clumps of solid food material.

ruminant  A hooved animal that digests its food in a multi-step process using a stomach with four chambers - first by eating the raw material and then regurgitating it as a semi-digested form called 'cud', and chewing that cud again to further break down the plant matter and stimulate digestion.

 

saline aquifer  An underground reservoir of salt water.

salinisation  The build-up of salt within the soil to an extent which causes degradation of soils and vegetation.

Changes in water movement patterns across the landscape (see water cycle), as during the wet and dry periods, can alter the height of the underlying water table. Land management practices such as land clearing can affect the soil moisture, sometimes resulting in more rainfall reaching the groundwater recharge. Rising water tables can bring dissolved salts to within two metres of the soil surface; capillary action then carries the salts to the soil surface, usually on lower slopes. There, the salts are concentrated by evaporation, killing vegetation cover and forming scalds, and may be discharged by runoff into surface waters where they affect water quality. Erosion of affected areas causes further problems and salt mobilisation. Salt export to downstream waterways may place water resources, aquatic ecosystems, farm dams, riparian vegetation and wetland areas at risk.¹²

sediments  Soil, sand and minerals which are suspended in water, or are being transported, or which settle in loose layers typically on a river or sea bed.

semi-arid  The arid and semi-arid areas of New South Wales are commonly referred to as rangelands. These lands generally lie to the west of the 500 mm average rainfall limit. The main enterprise is extensive grazing of predominantly native pastures. On the eastern and southern margins of the rangelands, extensive grazing occurs in conjunction with broadacre cropping and areas of intensive irrigated agriculture. Collectively, the semi-arid and arid zones occupy about 60 per cent of the state.

shale  A sedimentary rock that is made up of clay-size particles (less then 1/256 millimetre in diameter) from weathered debris. It typically breaks into thin flat pieces.¹³

soil microorganism  A microbe living in the soil. Microorganisms transfer nutrients within the soil by breaking down mineral components into a form able to be used by plants.

soil organic carbon  The major component of soil organic matter. It is extremely important in all soil processes. Organic carbon refers to decomposed compounds that were once living organisms, such as plants or animals.

soil organic matter  The fraction of the soil made up of anything that was once living, including plant and animal remains, cells and tissue, plant roots and soil microbes and their excretions.

stratification, ocean  The term used to describe different layers within a body of water, or the ocean. Physical variables such as salinity and temperature influence these layers. Warmer waters usually have a lower density and are generally found in the upper layers. Waters of lower temperatures have a higher density and are found in the deeper layers.

sustainable harvesting  Refers to forest harvest and management methods used to provide a supply of timber today and into the future, to protect the environmental values of the forest and provide community amenities.

 

temperature-humidity index (THI)  See http://www.coolcows.com.au/go-on-alert/thi.htm

tensile strength of soils  A soil aggregate is an assembly of organic and inorganic particles that stick to each other more than to neighbouring particles. Tensile strength of soil aggregates refers to the stress of a given amount of force required to break the aggregate. The ability of aggregates to resist some disturbance, such as when the soil is turned over during cultivation, against a backdrop of the wetting and drying cycle of the soil, is an indicator of soil tensile strength.

thinning  A forestry management technique whereby a proportion of trees in a given area are selectively harvested to reduce tree competition for light, nutrients and water.

tillage  The agricultural preparation of the soil by ploughing, ripping, or turning it. Tillage can also mean the land that is tilled.

 

upwelling  The rise of sea water from the depths to the surface, typically bringing nutrients to the surface.¹⁴

 

water cycle  Refers to the continuous movement of water between the ocean, rivers and creeks, the land and the atmosphere. As water moves through its cycle, it changes from liquid (salt water, rain water) to gas (water vapour) and also to a solid when it is cold enough, in the form of ice and snow. You can see how the water cycle works here: http://www.water.wa.gov.au/Tools/The+Water+Cycle/Interactive+Water+Cycle/default.aspx

water vapour (H₂O)  Water moves between the atmosphere, the surface of the earth and in the ground through processes such as condensation, precipitation, run-off, evaporation and plant transpiration as part of the earth's natural hydrological cycle. Radiation from the sun drives this cycle, causing evaporation of water on the earth's surface and transpiration from plants. The water vapour in the atmosphere resulting from this evaporation and transpiration cools and condenses to become cloud or dew. When conditions are suitable, precipitation falls from clouds to the surface of the earth, and soaks into the soil or flows to the ocean as run-off. And the cycle continues - surface water (e.g. lakes, streams, oceans etc.) evaporates, returning moisture to the atmosphere, and plants return water to the atmosphere by transpiration. Warmer air temperatures hold additional water vapour, and water vapour can trap more heat as a greenhouse gas.

watt  Unit measure of power. One watt is equivalent to 1 joule of energy per second. 1000 watts is equivalent to 1 kilowatt.

weeds  Referred to as 'opportunists', weeds have characteristics which can make them more successful than native species in particular areas or under specific circumstances in the landscape. They have short life cycles, high reproductive rates, show rapid response to rainfall events and are adapted to a wide range of environments and soils.

Wm^-2  or W/m²  Watts per metre squared, the unit used to measure solar radiation.

woody weed invasion  A woody weed is an invasive native shrub species with woody stems which has invaded formerly open lands. Invasive native plants are a nuisance to land managers because they are generally dominant over other regenerating natives, compete against preferred species, are generally less palatable than preferred species, and can regenerate profusely, often in response to disturbance of the land, such as clearing, fire or overgrazing.¹⁵

 

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¹Direct from 'Soil quality and soil health information for Australia'. http://www.soilquality.org.au/factsheets/cation-exchange-capacity

²NSW Department of Primary Industries, Technology and practice for irrigation in vegetables, Authors: Evan Christen1,2, Jim Ayars3, John Hornbuckle1,2, Mark Hickey4, 2006. 

³Geoscience Australia, Ozcoasts - Australian online coastal information. http://www.ozcoasts.org.au/indicators/ocean_acid.jsp, viewed 21-4-2009.

⁴Primary Industries and Resources SA, 'Geothermal energy', http://www.pir.sa.gov.au/geothermal.

⁵Renewable energy world, http://www.renewableenergyworld.com/rea/tech/oceanenergy

⁶Energy Australia website, http://www.energy.com.au/energy/ea.nsf/Content/Kids+Sun

⁷http://www.alternative-energy-news.info/technology/hydro/tidal-power/

⁸Australian Government Department of Climate Change, Australia's national greenhouse accounts: State and territory greenhouse gas inventories, 2006.

⁹Australian Government Department of Climate Change, National greenhouse accounts (NGA) factors, 2008.

¹⁰Australian Government Department of Climate Change, Australia's national greenhouse accounts: State and territory greenhouse gas inventories, 2006.

¹¹Australian National Greenhouse Accounts: National Greenhouse Gas Inventory accounting for the KYOTO target, May 2009.

^12'NSW State of the Environment Report 2006', Chapter 4 'Land', http://www.environment.nsw.gov.au/soe/soe2006/chapter4/chp_4.3.htm, viewed 20-4-2009.

¹³http://geology.com/rocks/sedimentary-rocks.shtml   

¹⁴Geoscience Australia, Ozcoasts - Australian online coastal information, http://www.ozcoasts.org.au/glossary/def_u-z.jsp, viewed 21-4-2009.

¹⁵NSW Government, Border Rivers - Gwydir Catchment Management Authority, 'Invasive native species', http://brg.cma.nsw.gov.au/index.php?page=invasive-native-species viewed 20-4-2009.