Download Global Warming Definitions Global Warming – An increase in global

Global Warming
Definitions
Global Warming – An increase in global surface temperatures due to natural
or anthropogenic (due to human activity) climate change.
Greenhouse Effect - The phenomenon whereby the earth's atmosphere traps
solar radiation from the Sun, caused by the presence of gases such as carbon
dioxide, water vapour, and methane in the atmosphere that allow incoming
sunlight to pass through but absorb heat radiated back from the earth's
surface. The greenhouse effect is a natural process without which life on
Earth would not be possible.
Enhanced Greenhouse Effect – The concept that the greenhouse effect has
been increased by the anthropogenic emissions of greenhouse gases. This
means it is the increase in greenhouse gases caused by human activity such
as the combustion of fossil fuels.
Climate Change - Any change in global temperatures and weather patterns
over time due to natural variability or to human activity.
What Causes Global Warming?
 Volcanic Eruptions
 Burning of Fossils Fuels
e.g. coal
 Agriculture e.g. cows
produce Methane
 Deforestation
Natural Reduction
The diagram above show some sources of greenhouse gases. The diagram also
shows some natural methods through which atmospheric carbon can be “locked up”.
 Trees and Plankton (photosynthesis)
 Sedimentary Rocks (the shells of organisms)
What can we do?
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Be Energy Efficiency – reducing how much energy you use
Use Renewable Energy Resources – geothermal, wind and hydroelectric
Use Nuclear Power – Does not produce greenhouse gases and produces
more energy than the combustion of fossil fuels. However the mining of
uranium and dangers of nuclear safety also have negative environmental
consequences.
Carbon Capture and Storage – The Future?
It is possible that in the future some of the carbon dioxide produced by power
stations may be sequestered by old oil/gas fields. This means that we may be able
to injects carbon dioxide into geological structures and trap it there to stop it entering
the atmosphere as a method of mitigating the damage we case by burning fossil
fuels.
Evidence & Consequences
Jacabamba Glacier, Peru, in 1980 (left) and 2002 (right)
The observed sea ice in 1979 and 2003
The concentration of carbon dioxide in the atmosphere from 1958-2004
Graph showing the rise in global temperatures
The projected sea level increase in the 21st century.
Comparison between temperature and quantity of carbon dioxide in the atmosphere.
Previous Periods of Warming
Ice cores can be used as evidence of previous global temperature change/climate change
because they can be analysed for their concentration of greenhouse gases such as carbon
dioxide and methane.
Previous Sea Level Change
There is evidence of previous global sea level change. An example is the Pleistocene.
Evidence for this includes; raised beaches, submerged forests and drowned valleys.
Raised beaches show that sea level has changed. A raised beach is an elevated area of sloping
ground, sitting above the present tide line. In the past this area was at sea level. There are many
examples of this feature throughout Britain, particularly along the West coast - this is because the
area experienced the greatest weight of ice during the last Ice Age (about 10,000 years ago).
Submerged forests are Areas of peat bed, sometimes with in situ broken or uprooted tree
stumps, that are exposed in the inter-tidal zone at low water. These are the remains of terrestrial
landscapes that have become covered during periods of sea level rise.
Drowned valleys are valleys that have been submerged by the advance of the sea or a lake.
Reduced Albedo
As shown melting ice caps and glaciers are consequences of climate change. The melting of
the ice caps in turn result in further warming due to an effect known as albedo. Albedo is
the proportion of the suns solar energy that is reflected by the Earth’s surface. The higher
the albedo the more of the suns solar energy a surface reflects. White surfaces such as ice
absorb very little solar energy from the sun, instead they reflect it. Dark surfaces such as
oceans absorb far more solar energy. This means that as the ice caps melt then there is a
decrease in light surfaces (ice) and an increase in dark surfaces (ocean) and so more solar
energy from the Sun is absorbed. This leads to a warming of the Earths surface and thus
further melting of the ice caps, in turn decreasing albedo further and leading to greater
warming.
Other Consequences
Climate change is also believed to cause an increase in the frequency of extreme weather
events e.g. tornadoes and drought.