chapter 23 the atmosphere, climate, and global warming
TRANSCRIPT
Videos
• Layers of the atmosphere, sorry, a bit boring, but all the info you need here.
• Greenhouse effect
• Global Warming
The Atmosphere
• The thin layer of glass that envelops the Earth
• Chemical reactions
• Atmospheric circulation produces weather and climates
Climate
• Climate: – the representative or characteristic atmospheric
conditions for a region on Earth
• Microclimate– The climate of a very small local area
• Urban Dust Dome– Polluted urban air produced by the combination of
lingering air and abundance of particulates and other pollutants in the urban air mass
Climatic Change
• Major climatic changes have occurred during the past 2 million years
• Appearances and retreats of glaciers
• During the past 100 years, the mean global annual temperature ahs increased by .5 degrees Celsius
Global Warming
• A natural or human induced increase in the average global temperature of the atmosphere near the earth’s surface
• 4 factors– Amount of sunlight Earth receives– Amount of sunlight Earth reflects– Retention of heat by atmosphere– Evaporation and condensation of water vapor
Electromagnetic Radiation and Earth’s Energy Balance
• Electromagnetic spectrum– The collection of all possible wavelengths of
electromagnetic energy, considered a continuous range
The Greenhouse Effect
• Greenhouse Effect– The process of trapping heat in the atmosphere– Water vapor and several other gases warm the
Earth’s atmosphere because they absorb and emit radiation
• Greenhouse Gasses– Gasses that have a greenhouse effect– Water vapor, carbon dioxide, methane, CFCs
Global Warming
• Negative and Positive feedback cycles affect the atmosphere
• Increase in emission of greenhouse gasses
• Solar Forcing, Natural Cycles, Aerosols (global dimming), Volcanic Eruptions, El Nino
Global Climate Patterns• Earth’s global climate patterns
– Are determined largely by the input of solar energy and the planet’s movement in space
• Sunlight intensity– Plays a major part in determining the Earth’s climate
patterns
Figure 50.10
Low angle of incoming sunlight
Sunlight directly overhead
Low angle of incoming sunlight
North Pole60N
30NTropic ofCancer
0 (equator)
30S
60S
Atmosphere
LALITUDINAL VARIATION IN SUNLIGHT INTENSITY
Tropic ofCapricorn
South pole
Figure 50.10
June solstice: NorthernHemisphere tilts toward sun; summer begins in Northern Hemisphere; winter begins inSouthern Hemisphere.
March equinox: Equator faces sun directly;neither pole tilts toward sun; all regions on Earthexperience 12 hours of daylight and 12 hours ofdarkness.
60N30N
0 (equator)
30S
Constant tiltof 23.5
September equinox: Equator faces sun directly; neither pole tilts toward sun; all regions on Earth experience 12 hours ofdaylight and 12 hours of darkness.
December solstice: NorthernHemisphere tilts away from sun; winter begins in Northern Hemisphere; summer begins in Southern Hemisphere.
SEASONAL VARIATION IN SUNLIGHT INTENSITY
Descendingdry airabsorbsmoisture
Ascendingmoist airreleasesmoisture
Descendingdry airabsorbsmoisture
30 23.5 0 23.5 30Aridzone Tropics
Aridzone
60N
30N
0 (equator)
30S
60S
GLOBAL AIR CIRCULATION AND PRECIPITATION PATTERNS
• Air circulation and wind patterns– Play major parts in determining the Earth’s climate
patterns
Figure 50.10
GLOBAL WIND PATTERNS
Westerlies
Northeast trades
Doldrums
Southeast trades
Westerlies
AntarcticCircle
60S
30S
0(equator)
30N
60N
ArcticCircle
Figure 50.10
Adjustments to Global Warming
• Evidence based decision-making???
• Mitigate warming through reduction of greenhouse gasses
• Energy conservation
• Alternative energy sources
• Danger: rapid climatic change