1. Changes in the carbon cycle over time, to include natural variation (including wild fires, volcanic activity) and human impact (including hydrocarbon fuel extraction and burning, farming practices, deforestation, land use changes).

2. Changes in the carbon cycle over time
In this section:
You must understand: The changes to carbon cycle over time, to include natural variation and human impact.
Student must be able to describe, explain, analyse and comment on factors leading to change including: wild fires, volcanic activity, hydrocarbon fuel extraction and land use changes

4. The graph shows a mirroring pattern
High temperatures are associated with higher levels of Co2
Recent rise in Co2 – Due to anthropogenic changes which means level surpass 400PPMV
An increase in Co2 in the atmosphere enhances the greenhouse effect which then increases the temperatures
Lower levels of Co2 reduces the effectiveness of the greenhouse effects which leads to global cooling
Both examples of positive feedback mechanisms
Carbon dioxide levels can trigger temperature change although temperature change also has massive impacts on Co2 levels in the atmosphere.

5. Wildfires Can be started naturally by lightening strikes
Despite being restricted to tiny parts of the surface, they can have regional impacts
and in 2003, Indonesia had lots of wild fires that burnt out of control for months
Smoke spread across south-east Asia
Released large amount of Co2 into the atmosphere – noticeable strike in carbon emissions
Turned forests into a carbon source (compared to a carbon sink) – combustion returns carbon back to the environment

6. Volcanic activity
Returns carbon that has been trapped in the lithosphere for millions of years
During Palaeozoic era ( million years ago), volcanoes were much more active than they were today
Carbon dioxide was therefore emitted into the atmosphere, where it remained for a very long time.
At present, volcanoes emit between 130 and 180 million tonnes of Co2 each year, by comparison, human activities release 30 billion tonnes as a result of burning fossil fuels
Volcanoes also erupt lava, which contains silicates that will slowly weather. This converts carbon dioxide in the air to carbonates in solution. In this way, carbon dioxide is absorbed very slowly from the atmosphere.

7. Assess the extent to which natural factors impact the carbon cycle over time. (20 marks)