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Climate & Terrestrial Biodiversity
Climate & Terrestrial Biodiversity
Ch. 7Ch. 7
What is Climate? What is Climate?
◊ Weather - short term; today◊ Climate - general atmospheric or
weather conditions over time
◊ Weather - short term; today◊ Climate - general atmospheric or
weather conditions over time
Climate is what we expect; weather is what we get.
Climate varies over the surface of the earthClimate varies over the surface of the earth◊ 2 main factors:
• Wind - air circulation
• Ocean currents
◊ 2 main factors:• Wind - air
circulation• Ocean currents
◊ Move warm & cold moisture from one place to another, but unevenly
◊ Move warm & cold moisture from one place to another, but unevenly
Focus on AIRFocus on AIR◊ Air
circulates warmth & moisture from the tropics to other places
◊ Air circulates warmth & moisture from the tropics to other places
Focus on AIR 3 forces responsible:Focus on AIR 3 forces responsible:1. Tilt of the earth - Earth is heated
unevenly1. Tilt of the earth - Earth is heated
unevenly
Focus on AIR 3 forces responsible
Focus on AIR 3 forces responsible2. Rotation of the Earth on its axis◊ equator spins faster than
poles◊ Warm air rising over equator
goes N or S then deflected E or W◊ creates “prevailing winds” -
major surface winds that blow almost continuously
2. Rotation of the Earth on its axis◊ equator spins faster than
poles◊ Warm air rising over equator
goes N or S then deflected E or W◊ creates “prevailing winds” -
major surface winds that blow almost continuously
Quick DemoQuick Demo
◊ What happened to the line as you rotated the whiteboard?
◊ What happens to the line as you get further toward the edge?
◊ What happened to the line as you rotated the whiteboard?
◊ What happens to the line as you get further toward the edge?
Focus on AIR3 forces responsibleFocus on AIR3 forces responsible3. The water cycle ◊ heat from the sun
evaporates ocean water and transfers it to air
◊ this creates convection cells that circulate heat, air, and moisture
3. The water cycle ◊ heat from the sun
evaporates ocean water and transfers it to air
◊ this creates convection cells that circulate heat, air, and moisture
Focus on OCEAN CURRENTSFocus on OCEAN CURRENTS◊ Prevailing winds blow over ocean &
move surface water --> currents◊ Prevailing winds blow over ocean &
move surface water --> currents
Focus on OCEAN CURRENTSFocus on OCEAN CURRENTS◊ Currents move warm water to
other places • Changes vegetation & climate of the
area, especially near the coastline
◊ Currents move warm water to other places • Changes vegetation & climate of the
area, especially near the coastline
Focus on OCEAN CURRENTS Focus on OCEAN CURRENTS ◊ Continents and wind currents
shape path of ocean currents◊ Continents and wind currents
shape path of ocean currents
Focus on OCEAN CURRENTSFocus on OCEAN CURRENTS◊ Currents go clockwise in Northern
Hemisphere◊ Currents go counterclockwise in
Southern Hemisphere
◊ Currents go clockwise in Northern Hemisphere
◊ Currents go counterclockwise in Southern Hemisphere
Focus on OCEAN CURRENTSFocus on OCEAN CURRENTS◊ Also vertical mixing of water
• Cold water sinks - more dense, saltier• Warm water rises - less dense, less
salty
◊ Also vertical mixing of water• Cold water sinks - more dense, saltier• Warm water rises - less dense, less
salty
OCEAN CURRENTS + AIR CURRENTS 4EVEROCEAN CURRENTS + AIR CURRENTS 4EVER◊ Ocean currents
affected by wind◊ Heat from ocean
affects air circulation patterns
◊ Ocean currents affected by wind
◊ Heat from ocean affects air circulation patterns
For ExampleFor Example◊ El Niño Southern
Oscillation (ENSO)◊ Changes global weather
over 2/3 of the planet due to a relatively small change in wind speed
◊ El Niño Southern Oscillation (ENSO)
◊ Changes global weather over 2/3 of the planet due to a relatively small change in wind speed
So…So…◊ Air circulation + winds
+ ocean currents + continents in the way = 6 giant convection cells that shape climate
◊ (3 in north, 3 in south)◊ Warm wet air rises◊ Cool dry air sinks
◊ Air circulation + winds + ocean currents + continents in the way = 6 giant convection cells that shape climate
◊ (3 in north, 3 in south)◊ Warm wet air rises◊ Cool dry air sinks
The AtmosphereThe Atmosphere◊ Greenhouse gases warm the Earth
• H2O, CO2, CH4, N2O
◊ Greenhouse gases warm the Earth• H2O, CO2, CH4, N2O
How they workHow they work◊ Light from sun passes
through atmosphere◊ Surface absorbs heat◊ Heat radiates back up◊ Some escapes to
space◊ Some absorbed by
greenhouse gases - its good! :)
◊ Light from sun passes through atmosphere
◊ Surface absorbs heat◊ Heat radiates back up◊ Some escapes to
space◊ Some absorbed by
greenhouse gases - its good! :)
Climate Change (global warming)Climate Change (global warming)◊ LOTS and LOTS of
evidence supports the hypothesis that humans are contributing excess greenhouse gases to the atmosphere - altering earth’s climate
◊ 90-99% sure of this◊ Why not 100%◊ Precautionary Principle
◊ LOTS and LOTS of evidence supports the hypothesis that humans are contributing excess greenhouse gases to the atmosphere - altering earth’s climate
◊ 90-99% sure of this◊ Why not 100%◊ Precautionary Principle
Earth’s Surface Features also affect climateEarth’s Surface Features also affect climate◊ Rain shadow effect
• Windward side wet• Leeward side dry
◊ Rain shadow effect• Windward side wet• Leeward side dry
All of this creates BIOMESAll of this creates BIOMESHigh Mountains Polar Ice Arctic Tundra Temperate
GrasslandTropical grassland (savanna)
Chaparral Temperate Coniferous forest
Temperate deciduous forest
Tropical rainforest Tropical dry forest
Tropical Desert Temperate rain forest
Temperate desert Cold desert Taiga
Tropical and subtropical coniferous forest
Pond Inland wetlands (swamps, marshes, prarie potholes)
Mangrove forest Riparian (rivers and surrounding area)
All of this creates BIOMESAll of this creates BIOMESHigh Mountains Polar Ice Arctic Tundra Temperate
GrasslandTropical grassland (savanna)
Chaparral Temperate Coniferous forest
Temperate deciduous forest
Tropical rainforest Tropical dry forest
Tropical Desert Temperate rain forest
Temperate desert Cold desert Taiga
Tropical and subtropical coniferous forest
Pond Littoral, intertidal zone
Mangrove forest Kelp forest
Coral reef Neritic zone (coastal waters)
Continental shelf Pelagic zone (open sea)
Benthic zone (bottom of lakes and oceans)
Hydrothermal vents Cold seeps Estuaries Riparian (rivers and surrounding area)
Inland wetlands (swamps, marshes, prarie potholes)