WHAT IS CLIMATE CHANGE?
1.Are humans responsible for most of the global temperature rise of the past century or so, or is the increase just a typical fluctuation in global temperature?
2. If most of the temperature rise can be attributed to increases in anthropogenic CO2 emissions, what are the likely consequences if no action is taken to curb these emissions?
What is the evidence? Is it compelling?
§What is the scientific consensus?
§Climate models and their predictions
§Consequences of the predictions
§Strategies for change
Chemistry we need to learn
§The Earth’s energy balance - the greenhouse effect
§The shapes of molecules - valence shell electron pair repulsion (VSEPR) theory
§Molecular vibrations – how they absorb IR radiation
§Masses and moles - weighing to count molecules
a) The Earth is about 33OC warmer than
expected if we consider only the amount of solar energy received and reflected.
b) Trace atmospheric gases, H2O and CO2, trap
infrared radiation that would otherwise be re-
emitted into space.
c) This effect is known as the Greenhouse Effect the mechanism that keeps greenhouses hotter than we might expect.