1. GLOBAL WARMING
© 2007 Paul Billiet ODWS

2. Sunlight energy in the atmosphere
© Windows to the Universe
Sunlight energy in the atmosphere

3. The layers of the atmosphere
© Windows to the Universe
The troposphere is the part of the atmosphere in the biosphere
The stratosphere contains the ozone layer
The stratosphere is also a zone of warm air that keeps a lid on the troposphere. It does not mix with the upper atmosphere
© Text 2007 Paul Billiet ODWS

4. The Greenhouse Effect
© Oceanworld 2005 Robert R Stewart

5. The Greenhouse Effect
The molecules of some gases in the atmosphere absorb heat energy and retain it
This can be a good thing
Without an atmosphere the Earth would have same temperature as the moon
Moon mean surface temperature -46°C
Moon temperature range: -233 to +123°C
© 2007 Paul Billiet ODWS

6. The Greenhouse Gases H2O vapour CO2 CH4 NOx CFC
© Oceanworld 2005 Robert R Stewart
© Text 2007 Paul Billiet ODWS

7. Infrared Absorption Spectra
© Oceanworld 2005 Robert R Stewart

8. The Greenhouse Gases Water vapour in the atmosphere is stable
The atmosphere is saturated
CO2 levels are currently rising
They have varied in the past
Methane levels are increasing: as more cattle are farmed, as more paddy fields are planted, as permafrost melts
NOx levels increase due to increased circulation of motor vehicles
© 2007 Paul Billiet ODWS

9. Mauna Loa Observatory © Mauna Loa Observatory Site
© Earth System Research Laboratory
© Earth System Research Laboratory

10. Carbon dioxide a greenhouse gas
© Mauna Loa Observatory Site

11. South Pole Data

12. Samoa data

13. © Australian Antarctic Division
© New Scientist : Environment

14. Levels during the last ice age
© Dennis Hartmann: Universoty of Washington: Department of Atmospheric Sciences

15. Out of the ice age

16. Since the Industrial Revolution
Concentration of Carbon Dioxide from trapped air measurements for the DE08 ice core near the summit
of Law Dome, Antarctica. (Data measured by CSIRO Division of Atmospheric Research from ice cores supplied by
Australian Antarctic Division)

17. The oceanic conveyor belt

18. The melting Arctic ice
The length of the melt season inferred from surface temperature weekly data has been increasing by 9, 12, 12, and 17 days per decade in sea ice covered areas
© NASA

19. Is it really getting warmer
1979
2003
© NASA

20. The consequences
Sea level rise Flooding coastal areas Reduced agricultural land Displacement of populations
Climate change Displacement of ecosystems Change in range of insect vectors of pathogens Reduced biodiversity
© 2007 Paul Billiet ODWS

21. The consequences Increased rates of photosynthesis
Increased agricultural production at high latitudes
BUT faster growth means: less protein in cereals trees taller and more exposed to storm damage
© 2007 Paul Billiet ODWS

22. Knock-on effects Increased temperature melts the permafrost
Frozen plant remains decompose
More methane released
Similarly soils will lose organic carbon (humus) more rapidly in a warmer climate
Ice caps melt more sea exposed
Snow reflects light (high albedo)
Water absorbs light, increases warming
More CO2 dissolving in water lowers pH
Currently this is buffered and remains stable
Eventually pH will drop sea life will die CO2 produced as organisms decompose
© 2007 Paul Billiet ODWS

23. What can be done? Reduce carbon emissions
Improve mass transport systems (public transport)
Design more efficient motors
Design alternative power sources
Hydrogen powered motors
BUT problems of fuel reservoir, delivery, fabrication
Renewable energy (wind, tidal, hydro, geothermal, biomass)
BUT growing crops for biofuel reduces farmland available for food Hydroelectric dams disrupt river ecosystems
Nuclear power
BUT problems of nuclear waste treatment/storage
© 2007 Paul Billiet ODWS

24. What can be done? Increase natural CO2 sequestering
Reduce deforestation
Increase reforestation
© 2007 Paul Billiet ODWS

25. What can be done? Artificial CO2 sequestering
Filter CO2 sources using hydroxide scrubbers
Injection of CO2 into deep ocean layers Forms CO2 reservoirs Impact on sea life unknown
Injecting CO2 into disused oil wells
Mineral deposition as carbonates
© 2007 Paul Billiet ODWS

26. The bottom line Two factors will ultimately govern what happens:
1. Human population growth
More people means greater demand for non-renewable resources
2. The ecological footprint of each individual human
Higher standards of living usually means higher consumption of fossil fuels
The planet will look after itself in the end
There are plenty of examples where human communities have disappeared because they outstripped the environmental resources
© 2007 Paul Billiet ODWS

27. The planet will look after itself in the end
Easter Island (Rapanui) in the Pacific
Settled between AD900 and 1200
Community in severe decline AD 1700
Cause: excessive deforestation
The Moai statues, Easter Island © Martin Gray, World Mysteries
© Text 2007 Paul Billiet ODWS

28. The planet will look after itself in the end
Chaco Canyon, New Mexico
Anasazi culture
AD 850 – 1250
Cause: Deforestation combined with a decline in rainfall
© New Mexico Tourism Department
© Text 2007 Paul Billiet ODWS

29. The planet will look after itself in the end
Mesopotamia
Sumerian civilization
3100 – 1200 BC
Increased salt levels in soil due to irrigation systems & arid environment
Reduced food yield
© Asociación Cultural Nueva Acrópolis en Barcelona
© Text 2007 Paul Billiet ODWS

30. The planet will look after itself in the end
Greenland
Viking colony
AD982 – 1350
Cause: Deforestation, soil degradation & cooling of the climate
© Emporia State University
© Text 2007 Paul Billiet ODWS

31. Who’s next?
forumpolitics.com/pics/earth-photo.jpg
© NASA