Siltation - occurs when water channels and reservoirs become clotted with silt and mud, a side effect of deforestation and soil erosion.
Slash-and-burn agriculture - a rotating cultivation technique in which trees are cut down and burned in order to clear land for temporary agriculture; the land is used until its productivity declines at which point a new plot is selected and the process repeats; this practice is sustainable while population levels are low and time is permitted for regrowth of natural vegetation; conversely, where these conditions do not exist, the practice can have disastrous consequences for the environment.
Soil degradation - damage to the land's productive capacity because of poor agricultural practices such as the excessive use of pesticides or fertilizers, soil compaction from heavy equipment, or erosion of topsoil, eventually resulting in reduced ability to produce agricultural products.
Soil erosion - the removal of soil by the action of water or wind, compounded by poor agricultural practices, deforestation, overgrazing, and desertification.
Ultraviolet (UV) radiation - a portion of the electromagnetic energy emitted by the sun and naturally filtered in the upper atmosphere by the ozone layer; UV radiation can be harmful to living organisms and has been linked to increasing rates of skin cancer in humans. Water-born diseases - those in which bacteria survive in, and are transmitted through, water; always a serious threat in areas with an untreated water supply.
Environment - international agreements: This entry separates country participation in international environmental agreements into two levels - party to and signed, but not ratified. Agreements are listed in alphabetical order by the abbreviated form of the full name.
Environmental agreements: This information is presented in Appendix C: Selected International Environmental Agreements, which includes the name, abbreviation, date opened for signature, date entered into force, objective, and parties by category.
Ethnic groups: This entry provides an ordered listing of ethnic groups starting with the largest and normally includes the percent of total population.
Exchange rates: This entry provides the official value of a country's monetary unit at a given date or over a given period of time, as expressed in units of local currency per US dollar and as determined by international market forces or official fiat.
Executive branch: This entry includes several subfields. Chief of state includes the name and title of the titular leader of the country who represents the state at official and ceremonial functions but may not be involved with the day-to-day activities of the government. Head of government includes the name and title of the top administrative leader who is designated to manage the day-to-day activities of the government. For example, in the UK, the monarch is the chief of state, and the prime minister is the head of government. In the US, the president is both the chief of state and the head of government. Cabinet includes the official name for this body of high-ranking advisers and the method for selection of members. Elections includes the nature of election process or accession to power, date of the last election, and date of the next election. Election results includes the percent of vote for each candidate in the last election.