Chapter 5

Climate & Biodiversity

Weather

• Short term physical properties of the troposphere at a particular time and place– Temperature– Pressure– Humidity– Precipitation– Cloud cover– Wind speed and directions

Data Collection of Weather

• Meteorologists are the scientists that evaluate data and predict weather based on cumulative information that defines the current physical conditions in the troposphere relative to a certain place on Earth. Weather prediction is based on information from the following sources:– Weather balloon– Aircraft equipped with sensors– Satellites– Computer modeling– Weather maps

Climate

• Climate is defined as the general atmospheric or weather conditions typical of an area over long periods of time. Some indicators are:– Average temperature– Average rainfall or snowfall

Global Air Circulation

Five major factors determine patterns:1. Uneven heating of the Earth’s surface

(more heat at the tropics) 2. Seasonal changes in temperature and

precipitation (tilting of the Earth) 3. Rotation of the Earth (convection cells)4. Long-term variations in solar energy5. Basic properties of water and air

Upwelling

• Oceans currents are driven by wind and heat from the sun.

• Winds blowing onto the western coasts push surface water away from land and is replaced with cold, nutrient rich bottom water.

• El-Nino-Southern Oscillation (ENSO) occurs when the westerly wind weaken, coastal waters remain warm and normal upwelling is suppressed. The ENSO affect can be devastating for many species.

Greenhouse Effect

• Greenhouse gases – allow IR/VIS/UV light in– Water vapor (H2O)

– Carbon dioxide (CO2)

– Methane (CH4)

– Nitrous oxide (N2O)

– Synthetic chlorofluorocarbons (CFC’s)

• Greenhouse Effect – natural warming effect of the troposphere (heat escapes and heat is absorbed)

Global Warming

• Global warming is explained as human factors that may cause the greenhouse effect to change in the direction of increased heat retention in the atmosphere.– Burning of fossil fuels– Release of carbon dioxide, methane and nitrous

oxide into the atmosphere– Precipitation patterns may shift– Many habitats could be affected

Ozone Layer

• A band of ozone (O3) exists in the stratosphere.– UV radiation causes O2 O3

– Filters about 95% of the harmful radiation from the sun

– Forms a thermal cap which helps maintain the average temperature of the troposphere

– Loss or destruction of the ozone layer would support global warming

Microclimates

• Small or local climate conditions– Mountains disrupt the flow of surface winds

and storms (rain shadow effect)• Surface air is cooled as it is forced to rise & expand)• Windward (wind-facing) slopes experience most of

the moisture• Leeward (away from the wind) slopes experience

drier air masses and draws moisture from plants

– Cities create microclimates due to the large amount of buildings, concrete and traffic

The Earths Major Biomes

• Result primarily from differences in climate• Biomes are not uniform but they offer different

communities• Latitude (distances from the equator) have biomes

that become colder toward the poles• Longitudes (distances from the prime meridian) go

from pole to pole – no effect• Altitude (elevation above sea level) becomes

colder with increased elevation

Deserts

• Evaporation exceeds precipitation• Sparse and widely dispersed vegetation• Low rainfall• Three classifications

– Tropical – hot & dry like the (Sahara)

– Temperate – high summer temps, low winter temps with species that have adapted to limited water like (Mojave)

– Cold – winter are cold, summers warm like (Gobi)

Grasslands• Grasslands have enough annual precipitation to

support grass & a few trees• Persist because of a combination of

– Seasonal drought– Grazing by large herbivores– Occasional fires

• Three types– Tropical (savanna) - warm temperatures, 2 prolonged

dry spells & abundant rain – Temperate - cold winters, hot/dry summers, sparse

precipitation – Polar (tundra) - south of artic polar ice cap, bitter cold

Forest

• Undisturbed areas of vegetation, moderate to high average precipitation

• Three types of forests– Tropical

• Tropical rain forest

• Tropical deciduous forest (monsoon or seasonal)

• Tropical scrub forest

– Temperate deciduous forest

– Polar (boreal) or Evergreen conifer forests

Mountains

• Dramatic changes in altitude, climate, soil & vegetation

• 20% of the Earth’s land surface

• Contain the majority of the world’s forest

• Help regulate climate

• Play a critical role in the hydrologic cycle

Saltwater Life Zone

• Types– Estuaries– Coastlines– Coral reefs– Coastal marshes– Swamps oceans

Estuaries

http://www.waikato.govt.nz/enviroinfo/coasts/coastalecosystems/estuaries/images/threats1.jpg

Coral Reefs

http://polarbearsmustnotdie.blogspot.com/2006/07/coral-reefs-are-dying-as-world-heats.html

Freshwater Life Zones

• Types– Lakes– Ponds– Streams– Rivers– Inland wetlands– Levees– Dredging canals

Inland Wetlands

Purpose of a Levee

How Levees Fail