GLOBAL WARMING © 2007 Paul Billiet ODWS

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

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

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 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

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

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 food Hydroelectric dams disrupt river ecosystems Nuclear power BUT 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 layers Forms CO2 reservoirs Impact on sea life unknown Injecting CO2 into disused oil wells Mineral deposition as carbonates © 2007 Paul Billiet ODWS

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

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

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 © Asociación Cultural Nueva Acrópolis en Barcelona © Text 2007 Paul Billiet ODWS

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

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