PalaearcticOne of the eight ecozones into which the world is divided. This ecozone includes the terrestrial ecoregions of Europe, Asia north of the Himalaya foothills, northern Africa, and the northern and central parts of the Arabian Peninsula.
Panchromatic imageryImagery taken of all wavelengths within the visible spectrum (though not uniformly).
Parameciuma single-celled, microscopic aquatic organism with hairlike appendages (cilia) around its body used to move around and capture bacteria.
ParticipationA process that enables a wide range of stakeholders from the public and private spheres to participate in and influence decision-making processes, especially at the local level.
Participatory planningA planning approach in which all stakeholders, and in particular the envisaged beneficiaries are part of the decision process.
PastoralismA livelihood in which people living in the semi-arid areas support themselves by tending domesticated animals that feed on grass and other available plant foods and water sources, usually in areas characterized as semi-arid to semi-desert.
PathogenMicroscopic parasite organism that causes disease in a host. Disease causes the host to be less fit and may eventually cause premature death.
Per capitaUsually used in the field of statistics to indicate the average per person for any given concern, such as income, crime rate, etc.
PercolationFlow of a liquid through an unsaturated porous medium, e.g. of water in soil, under the action of gravity.
PerennialA plant in which the vegetative structures live year after year (some definitions say at least 3 years).
Perennial RiverA river that flows in at least parts all year round.
PeriphytonThe layer of algae, microorganisms and organic material coating the surface of stones, plants, and hard objects on the beds of streams, rivers, and reservoirs. See also biofilm.
Persistent Organic Pollutants (POPs)Organic compounds that are resistant to environmental degradation through chemical, biological, and photolytic processes.
PesticideChemical agent used to kill insects, usually associated with agriculture, but also associated with insect pest control in tourist areas, such as game parks.
pHScale used to measure the alkalinity or acidity of a substance through the determination of the concentration of hydrogen ions in solution. A pH of 7.0 is neutral. Values below 7.0, to a minimum of 0.0, indicate increasing acidity. Values above 7.0, to a maximum of 14.0, indicate increasing alkalinity.
PhotosynthesisThe process by which plants use energy from the sun to transform carbon dioxide (CO2) and water into carbohydrates and other compounds.
Physical Water ScarcityA physical lack of water available
PhysiochemicalA term used to denote something influenced by physical and chemical characteristics.
PhysiographicAdjective from "physiography" (or, Physical geography) – one of the three major subfields of geography. Physical geography focuses on understanding the processes and patterns in the natural environment, as opposed to the cultural or built environment, the domain of human geography.
PhytoplanktonMicroscopic plants suspended in the open water.
Pioneer speciesPlant species that dominate a community in the early stages of ecological succession.
Pixel"Picture element" is the ground area corresponding to a single element of a digital image data set. A two-dimensional ensemble of pixels forms the geometric grid on which an image is built.
PJTCPermanent Joint Technical Commission of the Kunene River.
PolicyA plan or course of action intended to influence and determine decisions, actions, and other matters.
Policy coordinationA voluntary and largely unenforceable alignments of national policies and measures in particular fields.
Policy harmonizationAn agreement on the manner in which each Member State will exercise or use a particular instrument over which it retains control.
Political insecurity (in terms of water transfers)The insecurity of a country when a water-scarce country depends on a water-abundant country for critical water supply and when the water-abundant country depends on the water-scarce country for its export revenue.
PollutantGenerally, any substance introduced into the environment that adversely affects the usefulness of a resource or the health of humans, animals, or ecosystems.
PopulationIn biology, a population is the collection of inter-breeding organisms of a particular species; in sociology, a collection of human beings.
PorosityRatio of the volume of the interstices in a given sample of a porous medium, e.g. soil, to the gross volume of the porous medium, inclusive of voids.
PotableWater of a quality that is fit for consumption by humans or animals.
Potential evaporationThe amount of evaporation that would occur if there was sufficient water available.
PovertyThe situation facing those in society whose material needs are least satisfied. Inability to afford an adequate standard of consumption because of low income is referred to as income poverty. If, apart from low income, a country is characterised by malnutrition, poor health, low survival rates, low literacy levels, inadequate housing and living conditions, etc., then there is human poverty.
Poverty alliviationReduction of poverty through public policies.
Poverty LineA measure of the money income required to attain a basic minimal standard of living – enough to purchase a nutritionally adequate food supply and to provide for other essential requirements
Poverty Reduction Strategy PapersThe anti-poverty strategy depends heavily on reducing poverty through the promotion of economic growth.
Precipitation(1) Liquid or solid products of the condensation of water vapour falling from clouds or deposited from air on the ground.(2) Amount of precipitation (as defined under (1) ) on a unit of horizontal surface per unit time.
PredatorAn animal that kills and eats other animals.
Prevalence of HIVThe AIDS / HIV prevalence rate in selected populations refers to the percentage of people tested in each group who were found to be infected with HIV.
Primary aquifersAquifers with intergranular porosities and permeabilities occur which produce the water-bearing characteristics.
Primary consumerAn animal that eats autotrophs.
Primary producerProduces the first form of organic carbon from inorganic compounds. See also autotroph.
Primary productionThe production of organic matter, such as new cells, mainly by photosynthetic plants.
Private resourcesResources for which consumption is subtractive and to which access can be controlled (access is exclusive).
PrivatisationThe sale of public assets to individuals or private business interests.
ProducerSee autotroph.
ProductionThe amount of organic matter produced by an organism over a period of time.
Protected areaAn area in which resource use and access is managed to protect valued environmental and natural resources.
ProtistsA collective term for eukaryotes that are not considered true animals, plants, or fungi; or, members of the kingdom Protista.
ProtocolAn instrument of implementation of the SADC Treaty, having the same legal force as the Treaty.
Protocol on Shared Watercourseshe protocol on Shared Watercourses in the Southern African Development Community (SADC) Region, was concluded as a legally binding document, in order to ensure equitable sharing of water and efficient conservation of the scarce resource. It established the River Basin Management Institutions and its financial and regulatory framework.
ProtozoaA large group of single-celled eukaryotic and often microscopic organisms.
Public goodA resource with non-subtractive consumption and unlimited access. Protection from UV radiation by the ozone layer is an example of a public good.
PulaThe currency of Botswana. Pula literally means "rain" in Setswana language, because rain is very scarce in Botswana and therefore valuable. Pula also means "blessing" as rain is considered a blessing.
Purification PlantA facility that treats raw water and removes its impurities, making the water safe.