3.1.1.4 Water, Carbon, Climate and life on Earth

Question 1

The Enhanced Greenhouse Effect

Answer 1

The process that is currently causing global warming as abnormally high levels of greenhouse gases are being produced by humans, trapping radiation from the sun, causing global warming and leading to climate change.

Question 2

Relationships between the two cycles (rainforests, two)

Answer 2

• Rain that forms over intact tropical rainforest may fall over deforested land, causing soil erosion. If soil and ash flows into rivers it increases the carbon content of rivers. The water leaves the rainforest cycle as an output through streamflow due to reduced interception and increased surface runoff.
• Reduced rainfall in the intact forest as there is less evapotranspiration in the deforested area. This causes drought periods and the intact rainforest to deteriorate.

Question 3

Relationships between the two cycles (peatlands, two)

Answer 3

• Deforestation on peatlands and the digging of drainage channels reduces water storage. The organic peat matter is no longer preserved underwater and decomposes quickly, releasing CO₂ into the atmosphere. Weathering and erosion increase speeding up decomposition. There is a greater wildfire risk from the hotter temperatures.
• Blocking drainage ditches in peatland rainforests, helps restore the natural environment by increasing soil water storage and decreasing runoff. This can raise the water table and decrease the flood risk.

Question 4

Mitigating Climate change - global intervention (example)

Answer 4

Paris Climate Deal (COP21):

• Aim to limit global temperatures to 2°C above pre-industrial levels
• Support for developing countries
• Public interaction and awareness schemes
• Meet every 5 years to review and improve goals

Question 5

Mitigating Climate change - regional intervention (example)

Answer 5

EU 20-20-20:

• 20% reduction in GHG emissions and commitment to 20% of energy coming from renewable sources and 20% increase in energy efficiency by 2020
• EU has suggested it will increase its emissions reduction to 30% if major GHG producing countries also improve their targets

Question 6

Mitigating Climate change - national intervention (example)

Answer 6

Climate Change Act 2008 UK:

• Legally binding target for the UK to reduce GHG emissions by 80% of 1990 levels by 2050 with a target of 26% by 2020 which has recently increased to 34%
• Created national carbon budgets and the Independent Committee on Climate Change to help the government and report on progress that is being made

Question 7

Mitigating Climate change - local intervention (example)

Answer 7

• Improving home insulation
• Recycling
• Using energy more wisely and use of smart meters and using public transport or car sharing schemes and calculating personal carbon footprints