Transcript Document

Climate Change
Prof Dudley Shallcross and Tim Harrison, Bristol ChemLabS, University of Bristol, UK
The Earth’s 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 Earth’s 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
o
temperature should be about 10 C. 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 Sun’s energy.
This would make the Earth’s average temperature to
o
be -18 C. Water would be a solid so very little life on
Earth!
Earth
Clouds and Ice
Earth
Clouds and Ice
(Greenhouse gases)
Sun
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
o
warms up the Earth to ~16 C. Water is liquid so life
can exist. A natural level of greenhouse gases is
essential but adding more will change the climate.
The Evidence For Climate Change
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.
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,
Bristol ChemLabS is the project name for the UK’s 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