Human changes: Land use changes

Question 1

overview

Answer 1

The Intergovernmental Panel on Climate Change (IPCC) estimates that land use change contributes a net 1.6 GtC per year to the atmosphere. Changes include the conversion of natural ecosystems to plantations/ croplands/ shifting cultivation and wetland clearance, afforestation and urbanisation.

Question 2

Urbanisation

Answer 2

Urbanisation, the replacing of countryside with concrete and tarmac means that stores are replaced (vegetation) or are covered up (soils) with impermeable surfaces. Urban areas occupy 2% of total land area but account for 97% of all anthropogenic CO2 emissions. The sources include transport, industry and cement production.

Question 3

cement

Answer 3

Cement manufacturing contributes CO2 when calcium carbonate is heated, producing lime and CO2. It is also produced by burning fossil fuels that provide the heat in the manufacturing process. The cement industry produces 5% of global anthropogenic CO2.

Question 4

afforestation

Answer 4

Afforestation, the planting of new forests or reforestation- regrowth of forest after an alternative land use, may increase absorption of CO2 – one form of carbon offsetting scheme (a deliberate scheme to reduce atmospheric CO2 through absorption- tree planting, or reducing emissions- moving to green energy use).

Plantations such as rubber or oil palm are much poorer carbon sinks than the primary rainforest and the peatlands they replace.