GLOBAL WARMING
© 2007 Paul Billiet ODWS
Sunlight energy in the atmosphere
© Windows to the Universe
The layers of the atmosphereThe 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
© Windows to the Universe© Text 2007 Paul Billiet ODWS
The Greenhouse Effect
© Oceanworld 2005 Robert R Stewart
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
The Greenhouse Gases
H2O vapour
CO2
CH4
NOx
CFC
© Oceanworld 2005 Robert R Stewart
© Text 2007 Paul Billiet ODWS
Infrared Absorption Spectra
© Oceanworld 2005 Robert R Stewart
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
Mauna Loa Observatory
© Mauna Loa Observatory Site
© Earth System Research Laboratory
© Earth System Research Laboratory
Carbon dioxide a greenhouse gas
© Mauna Loa Observatory Site
South Pole Data
Samoa data
© Australian Antarctic Division
© New Scientist : Environment
Levels during the last ice age
© Dennis Hartmann: Universoty of Washington: Department of Atmospheric Sciences
Out of the ice age
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)
The oceanic conveyor belt
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
Is it really getting warmer
1979 2003
© NASA
The consequences
Sea level riseFlooding coastal areasReduced agricultural landDisplacement of populations
Climate changeDisplacement of ecosystemsChange in range of insect vectors of pathogensReduced biodiversity
© 2007 Paul Billiet ODWS
The consequences
Increased rates of photosynthesis Increased agricultural production at high
latitudes BUT faster growth means:
less protein in cerealstrees taller and more exposed to storm damage
© 2007 Paul Billiet ODWS
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
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 foodHydroelectric dams disrupt river ecosystems
Nuclear powerBUT problems of nuclear waste treatment/storage
© 2007 Paul Billiet ODWS
What can be done?
Increase natural CO2 sequestering Reduce deforestation Increase reforestation
© 2007 Paul Billiet ODWS
What can be done?
Artificial CO2 sequestering
Filter CO2 sources using hydroxide scrubbers
Injection of CO2 into deep ocean layersForms CO2 reservoirsImpact on sea life unknown
Injecting CO2 into disused oil wells Mineral deposition as carbonates
© 2007 Paul Billiet ODWS
The bottom lineTwo 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 humanHigher standards of living usually means higher consumption of fossil fuels
The planet will look after itself in the endThere are plenty of examples where human
communities have disappeared because they outstripped the environmental resources
© 2007 Paul Billiet ODWS
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
© Text 2007 Paul Billiet ODWS
The Moai statues, Easter Island © Martin Gray, World Mysteries
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
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
© Text 2007 Paul Billiet ODWS
© Asociación Cultural Nueva Acrópolis en Barcelona
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
forumpolitics.com/pics/earth-photo.jpg
Who’s next?
© NASA
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