GEF

244 Glossary PARIS AGREEMENT  An agreement within the United Nations Framework Convention on Climate Change, intended to control greenhouse gas emis- sions beginning in the year 2020. PARTS PER MILLION (PPM)  A measurement of concentration used for atmospheric gases such as carbon dioxide. PASSIVE HEATING AND COOLING  Using building design principles to heat and cool structures without relying on additional energy inputs. PASSIVE HOUSE DESIGN  A set of building design standards that radically reduce energy use over conventional structures. PEAK OIL DATE  The point in time when global oil production reaches its maximum rate, after which oil production will decline. PER CAPITA ECOLOGICAL FOOTPRINT  A measure of average ecological footprint per person, usually by country. PER CAPITA ENERGY USE  The average amount of energy used per person, usually by country. PH  A measure of the acidity or basicity of a liquid, like seawater. Lowered pH in the oceans has nega- tive effects on marine organisms. PHOTOSYNTHESIS  The production of carbohy- drates from carbon dioxide and hydrogen in the chlorophyll-containing tissues of plants in the pres- ence of light. PHOTOVOLTAIC CELLS  Solid electrical devices used in solar panels that convert energy from the sun directly into electricity; specifically, they capture photons passing through the Earth’s atmosphere and convert them in to electrons. PHOTOVOLTAIC ENERGY  Electricity gener- ated from sunlight using silicon-based panels or similar components. PHYTOPLANKTON  Tiny photosynthesizing organ- isms that inhabit the upper layers of the ocean where sunlight is able to penetrate; they are integral to the carbon and oxygen cycles of planet Earth. PLUG-IN HYBRIDS  Hybrid vehicles that can recharge their batteries directly from the electrical grid. POACHING  Illegal hunting of wildlife. POLITICIZED  Turned into something that relates to the ideas or strategies of a particular party or group in politics. POLLUTER PAYS PRINCIPLE  A legal concept in which the party responsible for pollution or environ- mental damage pays the cost. POLYCHLORINATED BIPHENYLS (PCBs)  A class of highly toxic chemicals that were used in elec- trical components and have been found even in remote ecosystems. POPULATION GROWTH  The increase in the number of individuals in a population over a period of time. POTABLE WATER  Fresh water that is safe to drink. PRECAUTIONARY PRINCIPLE  A decision-making standard which states that actions which could potentially harm the environment or people should not be carried out if scientific understanding is incomplete. PROTECTED AREAS  Land or marine areas that prohibit or restrict human activity in order to protect species, habitats, or ecosystems. PUBLIC GOODS  Publicly owned goods or services to which everyone has equal access. PUBLICLY-TRADED COMPANIES  Companies that sell and trade ownership shares to the public through a stock exchange.