Practical 1, 2, 5, 6 and 7 include personal answers, marked in blue, as no template answer
sheets were provided. Key terms are bolded for emphasis. I’ve also included images where
necessary to aid visualization. Practical 2 includes my notes in green made during the end
discussion of the practical; these answers were provided by the student-assistants. Practical
3 and 4 include the responses provided by dr. P.R.N. (Pierre) Offre in green. Practical 8 and
9 include the responses provided by Sluijs in green.
Practical 1 | Week 1 | Carbon Cycle and Climate Change
Question 1.
Over the past decade, the combustion of fossil fuels produced about 35 gigatons of CO2
per year that was injected into the atmosphere (See Figure 1).
a) How much carbon is this?
Since 1 kg carbon = 3.664 kg CO2, 35 Gt divided by 3.664 = 9.552 gigaton of
carbon. Since 1 gigaton (Gt) is equal to 1 billion tonnes (1x1015 g = 1 petagram),
9.552 gigatons of carbon is equal to 9.552x1015 g.
b) How much CO2 was produced by land-use change?
The land-use change produced 5 (2-7) gigatons of CO2. Land-use change is also
called deforestation.
c) To how much additional atmospheric CO2 did these 2 sources lead annually?
These sources lead to an increase in stock of 19 gigatons of atmospheric CO2.
d) The biosphere and ocean sinks are approximately equally large. If CO2 emissions
continue unabated, how could this change in the distant future?
If CO2 emissions continue unabated, the atmosphere sink would have to take up
relatively more CO2, because the ocean and land sinks would be saturated. Thus,
the relative importance of the atmosphere sink would increase compared to the
ocean and land sinks.
Question 2.
You could argue that the CO2 input due to land-use change is irrelevant to the total increase
in atmospheric CO2 concentrations since the year 1850. Why?
The CO2 emissions from fossil fuel combustion are significantly higher (7 times greater)
and account for 35 Gt compared to those from land-use change, which account for 5 Gt.
sheets were provided. Key terms are bolded for emphasis. I’ve also included images where
necessary to aid visualization. Practical 2 includes my notes in green made during the end
discussion of the practical; these answers were provided by the student-assistants. Practical
3 and 4 include the responses provided by dr. P.R.N. (Pierre) Offre in green. Practical 8 and
9 include the responses provided by Sluijs in green.
Practical 1 | Week 1 | Carbon Cycle and Climate Change
Question 1.
Over the past decade, the combustion of fossil fuels produced about 35 gigatons of CO2
per year that was injected into the atmosphere (See Figure 1).
a) How much carbon is this?
Since 1 kg carbon = 3.664 kg CO2, 35 Gt divided by 3.664 = 9.552 gigaton of
carbon. Since 1 gigaton (Gt) is equal to 1 billion tonnes (1x1015 g = 1 petagram),
9.552 gigatons of carbon is equal to 9.552x1015 g.
b) How much CO2 was produced by land-use change?
The land-use change produced 5 (2-7) gigatons of CO2. Land-use change is also
called deforestation.
c) To how much additional atmospheric CO2 did these 2 sources lead annually?
These sources lead to an increase in stock of 19 gigatons of atmospheric CO2.
d) The biosphere and ocean sinks are approximately equally large. If CO2 emissions
continue unabated, how could this change in the distant future?
If CO2 emissions continue unabated, the atmosphere sink would have to take up
relatively more CO2, because the ocean and land sinks would be saturated. Thus,
the relative importance of the atmosphere sink would increase compared to the
ocean and land sinks.
Question 2.
You could argue that the CO2 input due to land-use change is irrelevant to the total increase
in atmospheric CO2 concentrations since the year 1850. Why?
The CO2 emissions from fossil fuel combustion are significantly higher (7 times greater)
and account for 35 Gt compared to those from land-use change, which account for 5 Gt.
