Environmental Sustainability Studies 111

INTRODUCTION TO THE ENVIRONMENT

Lecture 4 – The Earth’s Component: Atmosphere

The Atmosphere: structure

Source: http://www.theozonehole.com/images/atmosphere.gif

Functions of the atmosphere• Life sustaining functions in Troposhere:

– Oxygen: for respiration– Carbon dioxide for photosynthesis– Nitrogen for protein synthesis– Moisture for a variety of chemical reactions

• Protection functions: ozone (in stratosphere) blocking harmful UV rays; shield us from solar winds

• Create temperature balances• Troposhere plays host to all our climate

weather phenomena...water vapour & aerosols

Composition of the atmosphere

• Nitrogen: 78.02%

• Oxygen: 20. 95%

• Argon: 0.93%

• Carbon dioxide: 0.035%

• Neon: 0.0018%

• Helium: 0.0005%

• Methane, krypton, xenon, hydrogen....

The Atmosphere: temperature, altitude and air pressure variations

Source: www.wyckoffschools.org/.../earthatmosphere.htm

Climate and weather factors• Location: latitude, longitude & altitude

• Seasonal changes

• Land & water contrasts

• Ocean currents

• Air pressure & wind

• Humidity

• Precipitation & forms of precipitation

• Weather extremities: cyclones, hurricanes, El Nino, La Nina

• Air quality & human influences

Global Air Circulation

Source: www.mynasadata.larc.nasa,gov

El Nino

Source: www.junglephotos.com/.../othersatimages/elnino.jpg

Cycles in the atmosphere

Big Picture – Planetary context for earth-atmosphere energy-matter exchange

…Heat Budget

Carbon Cycle

Source: www. theresilientearth.com

Carbon sinks

• Geological sinks:– Vast amounts of carbon trapped in sedimentary

rocks like limestone, dolomite & chalk

– Also in fossil fuels deposits

• Biological sinks:– Oceans, atmosphere, soil & plants

– These sinks primarily responsible for current build-up of CO2

•

Oxygen Cycle

Source: http://www.acsa2000.net/sites/10ba/Photosynthesis.jpg

Some questions

• How can your understanding of the structure of the atmosphere help in assisting carbon reduction efforts?

• The atmosphere is an important carbon sink . Briefly explain how this function is/can be jeopardized if we continue emitting more CO2 into the atmosphere.

• Briefly explain how atmospheric processes cause and influence different natural environments on earth.

Diagrammes and animations

Please visit http://earthguide.ucsd.edu/earthguide/diagrams.html for explanatory notes, diagrammes and animations of the earth’s realms and processes!