EQ3: How are the carbon and water cycles linked to the global climate system?
- The biosphere is responsible for sequesting around 1/4 of global CO2 emissions from
fossil fuels.
- This directly slows down global warming.
- Change in demand has caused land conversion
Land conversion: any change from natural ecosystems to alternative use, reducing soil
health and reducing carbon and water stores.
Deforestation
- Main increase of deforestation is the demand for food.
- 50%+ of global deforestation has happened to clear space for the production of soy,
palm oil, beef, and paper
- Land conversion has also occurred due to the construction of dams and reservoirs,
infrastructure and mining.
Deforestation in Madagascar
- Deforestation has increased since the 1950s.
- Land has been cleared to increase the
production of hardwoods; the government
were in debt and needed to boost their
income.
- Madagascan hardwood is highly valuable and
can retail for over $2,000 per tonne.
- Before 1950 there were 11.6 million hectares
of forest; by 1985 the amount had been
reduced to 3.8 million hectares.
Impacts
- Biodiversity in Madagascar is under threat due
to a loss of forest cover.
- This includes the famous baobab trees.
- Deforestation affects rivers, landscapes, and
soil health.
- The waters of the river have turned red as a
result of soil erosion.
- Soil erosion has increased.
- Extensive logging also adds to soil erosion.
- Deforestation has a major impact on the size of terrestrial carbon stores.
- Overall size of the carbon sink has decreased.
Actions/players/futures
- Conservation international are working to implement strategies to keep the forest
healthy.
- They are offsetting carbon emissions with carbon credits, supporting communities
Impacts on the water cycle
- Infiltration is decreased.
- Runoff and erosion are increased.
- Flood peaks are higher and lag time is shorter.