Changes in the Carbon Cycle Flashcards
What happened during the quaternary geological period?
Global climates fluctuated considerably between warm (interglacial) periodsand cold periods (glacial)
Higher temperatures are associated with…
Higher carbon dioxide levels in the air
An increase in the level of carbon dioxide in the air leads to..
Enhanced global warming and subsequent temperature increase
Lower levels of carbon dioxide…
Reduces the effectiveness of the greenhouse effect
What is the impact of cold conditions on carbon stores and transfers?
- chemical WEATHERING processes would have been more ACTIVE as cold water can hold more CO2
- DECOMPOSERS would have been LESS active, so carbon transfer to soils would be reduced
- SOIL would be FROZEN OVER vast areas of land. This would have stopped transfers of carbon
- less water would FLOW into oceans because it would be LOCKED UP on the land, therefore less BUILDUP of SEDIMENTS on the ocean floor
- FOREST COVERAGE would be different (geographically and its total area). This would affect the distribution of processes such as photosynthesis and respiration
What are the impacts of warmer temperatures on carbon stores and transfers?
Carbon stored in permafrost (along with other gases eg methane) are now being released into the atmosphere when it melts which further enhances the greenhouse effect, leading to increased warming.
This positive feedback system leads to a further destabilisation of the system.
Where is the melting of permafrost prevalent?
In tundra regions such as Russia and Siberia
How do wildfires affect the carbon cycle?
Even though forests only cover a small surface of the Earth, wildfires (started by lightening, or deliberately by people) turn forests from being a carbon sink into a carbon source because combustion returns huge quantities of carbon back into the atmosphere.
Example of a wildfire?
In 2013, the Indonesian wildfires burned out of control for months and their smoke spread to South-East Asia.
How does volcanic activity affect the carbon cycle?
Eruptions return to the atmosphere that has been trapped for millions of years in rocks stored deep within the Earth’s crust.
When were volcanoes most active?
In the polaeozoic period
How much carbon dioxide do volcanoes emit in comparison to human activity per year?
Volcanoes = between 130 and 380million tonnes of CO2
Humans = 30 billion tonnes of CO2
How does lava affect the carbon cycle?
Lava contains silicates which slowly weather. This converts CO2 in the air into carbonates in solution. In this way, carbon is absorbed very slowly from the atmosphere.
What do scientists believe the trigger is for the delay between temperature and carbon dioxide levels in the Vostock ice core?
Orbital change - the Milancovitch cycles.
These regular cycles of orbital eccentricity cause slight variations in the amount of suns radiation that warms up the Earth.
So, as temperatures start to rise at the end of a glacial period (triggered by orbital change), there is a surge of carbon dioxide released into the atmosphere by the warming of the oceans and unlocking of land surface that had previously been frozen.
This surge of CO2 enhances the greenhouse effect, amplifying the warming trend.
Interglacial periods?
Warm periods
Glacial periods?
Cold periods
What is the IPCC?
Intergovernmental Panel on Climate Change
What does anthropogenic mean?
Human caused