Climate Change

1
Climate Change
Prof Dudley Shallcross and Tim Harrison, Bristol
ChemLabS, University of Bristol, UK
The Earths climate is changing due to increases
in Greenhouse gases such as carbon dioxide,
methane and nitrous oxide in the atmosphere.
The increase in greenhouse gases is causing an
increase in the Earths average temperature. This
has many potential consequences, including
rising sea levels, the change in rainfall
patterns and its impact on food production.
The Granny Model of the Climate
The Sun warms the Earth. Based on the distance
between the Earth and the Sun the average Earth
temperature should be about 10 oC. Water will be
a liquid so life can exist.
Earth Sun
However, clouds and ice sheets reflect back to
space 30 of the incoming energy from the Sun. So
the Earth is only warmed by 70 of the Suns
energy. This would make the Earths average
temperature to be -18 oC. Water would be a solid
so very little life on Earth!
Earth Clouds and Ice Sun
Natural levels of greenhouse gases such as carbon
dioxide act as a blanket, trapping heat from the
Earth and stopping it from escaping. retain
energy in the atmosphere. This blanket of
greenhouse gases warms up the Earth to 16oC.
Water is liquid so life can exist. A natural
level of greenhouse gases is essential but adding
more will change the climate.
Earth Clouds and Ice Sun (Greenhouse gases)
The Evidence For Climate Change
The graph shows a plot of 60 million surface
temperature readings since 1860. The temperature
is increasing with an increase in carbon dioxide
levels, due to burning fossil fuels in the main.
To reduce any potential warming alternatives to
the use of fossil fuels need to be adopted
widely, These include solar power, wind power,
bio fuels, nuclear energy and more efficient cars,
Carbon dioxide levels have been monitored at
Mauna Loa, Hawaii, USA for many, many years.
These data show that carbon dioxide levels have
been rising steadily for some time.
Bristol ChemLabS is the project name for the UKs
Centre for Excellence in Teaching Learning
(CETL) in practical Chemistry. Bristol ChemLabS
stands for 'Bristol Chemical Laboratory
Sciences'. For more information please see
www.chemlabs.bris.ac.uk/overview.htm