The bottom-line is that it is very difficult to convince Americans that the planet is facingan impending environmental crisis. As the world’s greatest consumer & polluter, the U.S.will have to lead the international community to a consensus.
EL NINOEl Nino is a Pacific Ocean current with worldwide climatic effects. Next to the seasons, El Nino is themost powerful force driving global weather. Normally the Humboldt Current, an extensive cold oceancurrent, provides the coast from southern Ecuador to northern Chile with a cool, misty, virtually rain-free climate.
In normal years, the flow of the Humboldt Current is strongly maintained by the counterclockwisewind flow around the South Pacific. These winds blow northward along the coast, inducing a flow ofcold water originating off the coast of Antarctica. The winds, as they approach Peru’s latitude,gradually are redirected westward as they are incorporated into the southeast trade winds. Thewestward movement of the surface water causes large volumes of cold water to well up from greatdepths. The water level drops along the S. American coast and rises in the tropical west Pacific.
For reasons still mysterious toscientists, wind direction shifts,causing the Humboldt Current toreverse its flow to a clockwisedirection every 5-7 years.The warm water that hasaccumulated in the western Pacificno longer is pressed against Asiaand surges eastward in a series ofwaves.It crosses the Pacific to produce asouthward flow of tropical waterdown the S. American coast andnorthward along the Central &North American westerncoastlines.Sea levels rise & temperaturesrise as much as 14.5 degrees. Thisis El Nino.On average, an El Nino occursapprox. every 5-7 years.
The most recent El Nino occurred in the late 1990’s. Throughout the years,they have varied in strength and length, although they generally endure fortwo years. The consequences of each have been widespread and locallydisastrous. The effects are generally felt most strongly in the immediatevicinity. In the U.S., the effects range from severe storms along the westcoast to drought conditions in the northeastern and mid-western portions ofthe country.
For the southeastern U.S. and Central America, an El Nino will magnify hurricane season,meaning more hurricanes that are more powerful.The other major effect of an El Nino includes a disruption of the food chain for fish andtheir predators (commercial fishing is effected). Associated weather calamities affectevery continent except Antarctica & Europe. The more recent El Ninos cause thousandsof deaths and billions of dollars in damage.
LAND & CLIMATE FACTORS AFFECTING CLIMATELatitude is the most prominent factor affecting climate. The Earth’s shape and tiltaffects the angle of the sun’s rays, thus affecting climate.
ELEVATION Even in the tropics, elevation can create a frigid climate. For every 1,000 feet above sea level, the temperature drops approx. 3 degrees.
WIND & OCEAN CURRENTSThe source and direction of wind influences the climate of a given region. An excellentexample of this phenomenon is the monsoon seasons of South Asia.
Cold and warm currents of seawater greatly influence the climate of coastal areas. Whatis the biggest impact of these ocean currents?
LANDFORMSProminent mountain ranges greatly impact climate, especially rainfall amounts. Examplesinclude the Atlas Mountains in North Africa and the Rocky Mountains in the U.S.
NATURAL PHENOMENON & HUMAN ACTIVITYIn the short term, natural phenomenon, such as volcanic eruptions, can alter climate.Human activities, including recreational and economic, can have longer-term consequenceson climate.
LOW LATITUDE CLIMATES The first type of low latitude climate is humid tropical, better known as tropical rainforest. Provide the geographic distribution, major weather characteristics, and vegetation.
The other low latitude climate is tropical savanna. Provide the geographic distribution,weather characteristics, and vegetation. Identify the major differences betweenthe two tropical climates.
DRY/SEMI-ARID CLIMATESThe first climate type in this category is desert. Provide the geographic distribution,major weather characteristics, and vegetation.
The second climate type in this category is steppe. Provide geographic distribution,major weather characteristics, and vegetation.
Causing growing concern among geographers is the phenomenon of desertification, wheresteppe areas are growing and desert areas are moving into steppe areas. Causes includenatural phenomenon (drought/global warming) and human activity (deforestation & over-grazing).
MIDDLE LATITUDE CLIMATESThe Mediterranean climate is one of four climates found in this category. Providegeographic distribution, major weather characteristics, and vegetation.
Another middle latitude climate is the humid-subtropical. Provide the geographicdistribution, major weather characteristics, and vegetation.
The humid continental climate zone encompasses the area in which we live. Provide thegeographic distribution, major weather characteristics, and vegetation.The marine west coast climate zone rounds out the middle latitude climates. Provide thesame characteristics for this climate zone.
HIGH LATITUDE CLIMATESThe three climate zones included in this category include subarctic, tundra, and ice cap.Provide the geographic distribution for each, major weather characteristics, andvegetation.
The climate zone that is unique because it can be found at most latitudes is the highlandclimate zone. Provide the geographic distribution, major weather characteristics, andvegetation.