CLIMATE CHAPTER 14
14.1 • Climatology is the study of Earth’s climate and the factors that affect past, present, and future. • Climate describes the long term weather patterns of an area (30 yrs.).
Factors that affect climate: • Temperature • Precipitation • Wind • Other weather variables
Data is averaged monthly or annually for at least 30 years to determine the normals (standards). • Weather on any given day can vary greatly from the normals.
Causes of Climate • Latitude • Tropics • Temperate zones • Polar zones
Topographic effects • Water – heats and cools slowerthan land • Coastal regions • Mountains – leeward vs. windward
Air masses – form in distinct areas • Movement • Interactions
14.3 • Long term climate changes take place over a long period of time. • -ice ages – the average global temperatures drop by an average of 5 degrees celcius. The most recent ice age ended about 10,000 years ago.
Short term climate changes are caused by regular variations in daylight, temperature, and weather patterns. • Seasons – caused by the tilt in the axis and the revolution of the Earth around the Sun. • El Nino – a band of warm ocean temperatures that occasionally develops off the western coast of South America. (Watch video)
Natural causes of climatic changes • Solar activity – sun spot cycles • Earth’s orbit – becomes more elliptical about every 100,000 years. • Earth’s tilt – varies from 22.1o to 24.5o every 41,000 years (presently 23.5o). • Earth’s wobble – over a period of about 26,000 years, Earth wobbles as it spins around on its axis.
- volcanic activity – large or multiple volcanic eruptions can trigger a climate change.
14.4 • Influences on the Atmosphere • The greenhouse effect – the natural heating of the Earth’s surface caused by certain atmospheric gases. This can lead to Global Warming.
Global Warming – a rise in global temperatures • Burning of fossil fuels – auto’s, factories, homes, and businesses • Deforestation – trees use CO2 in photosynthesis, less trees means more CO2 remains in the atmosphere. • Environmental efforts – reduce the consumption of fossil fuels (Kyoto Treaty)