GLOBAL WARMING

© 2013 by iqbal1313

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© 2013 by iqbal1313

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

© 2013 by iqbal1313

The Greenhouse Gases

H2O vapour

CO2

CH4

NOx

CFC

© Oceanworld 2005 Robert R Stewart

© 2013 by iqbal1313

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

© 2013 by iqbal1313

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

© 2013 by iqbal1313

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

© 2013 by iqbal1313

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© 2013 by iqbal1313

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

© 2013 by iqbal1313

What can be done?

Increase natural CO2 sequestering Reduce deforestation Increase reforestation

© 2013 by iqbal1313

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

© 2013 by iqbal1313

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

© 2013 by iqbal1313

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

© 2013 by iqbal1313

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

© 2013 by iqbal1313

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

© 2013 by iqbal1313

© 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

© 2013 by iqbal1313

forumpolitics.com/pics/earth-photo.jpg

Who’s next?

© NASA