A level 2020 Flashcards
Outline the process of decomposition in the carbon cycle. (4 marks)
- Decomposition is the breakdown of organic matter by bacteria/fungi
- Animals, bacteria and fungi are decomposers
- During decomposition carbon dioxide is released
- Most of the carbon released in the atmosphere Is as a result of decomposition
Analyse the data shown in Figure 1. (6 marks)
- P - Both graphs show fluctuation in annual rainfall and moving 5-year average
- E - Royal Observatory has a range from 350 to 950 (range of 600 mm). In 2009-2011 the range and variation is strong.
- D - Range is higher for Dwarsberg station. Range from 1800 to 4500 (range of 2700 mm)
- A - 2003 to 2009. The variation on the 5-year moving average is narrowed
- L - Rainfall at the Dwarsberg Observatory is higher than the Royal Observatory.
Using Figure 2 and your own knowledge, assess the predicted impact of climate change upon life in this region. (6 marks)
AO1:
* Changes to water cycle: natural variation (e.g. storm events), human impact (e.g. farming practices)
* Role of water in supporting life on Earth
AO2:
* The west is set to experience an increase in area where plant growth days are low
* Lower no. of precipitation days impact on farming yields, affecting crop growth but also livestock
* Less rainfall will impact reservoirs and water storage for human consumption
Assess the impact of farming practices on the carbon budget. (20 marks)
Introduction
- The carbon budget is how much carbon is absorbed compared to how much is released into different stores but mainly in the atmosphere due to its importance in climate control
- Population growth and increased demand has caused agriculture to increase
- The carbon cycle is in dynamic equilibrium but farming practices are disrupting this
Assess the impact of farming practices on the carbon budget. (20 marks)
Para 1 - Impacts of deforestation and slash/burn
- Deforestation is happening at a rate of 20,000km which has caused 20% of the Amazon rainforest to be lost over the last 50 years
- Pastoral cattle ranching directly covers 15% of this deforestation
- Slash and burn - high temp increases decomposition, soil is unsustainable
- Slash and burn is sustainable on small scale but lead to positive feedback (e.g. droughts)
Assess the impact of farming practices on the carbon budget. (20 marks)
Para 2 - Deforestation and agriculture
- Deforestation for agriculture decreases carbon sequestration as there is less organic matter from decomposition of vegetation
- Less organic matter from decomposition, less humus to bind soil, soil erosion
- Deforestation contributes to greenhouse effect, global impact
Assess the impact of farming practices on the carbon budget. (20 marks)
Para 3 - Ploughing
- Ploughing is a farming practice
- Disrupt carbon cycle as disturbs topsoil containing carbon so carbon stored in lithosphere decreases
- Mitigation strategy: low conservation tillage
- Allow fields to follow instead of cultivating them, replenish, humus binds soil, reduce soil erosion
Assess the impact of farming practices on the carbon budget. (20 marks)
Para 4 - cattle ranching disrupt carbon budget
- Ranching is the practice of raising herds of animals on large tracts of land
- Ranching raises cattle and methane
- More energy inputs (e.g. fossil fuels to transport)
Assess the impact of farming practices on the carbon budget. (20 marks)
Conclusion
- Farming practices contribute to carbon budget
- Impact: local/global scale
- Deforestation main driver from carbon sink to source due to ranching and less sequestration
- Damages may reduce if shift to environmentally friendly farming (e.g. agriculture)
- Mitigation strategies also reduce carbon budget
Outline the process of sub-aerial weathering in the development of coastal landscapes. (4 marks)
- Sub-aerial weathring is the action of rainwater nad insolation on landforms in coastal landscape
- Material broke in situ, rocks weakene and large-scale movements
- Chemical weathering occurs when weak carbonic acid in rainwater attacks limstone cliffs.
- Mechanical weathering occurs when repeated freezing and thawing of water absorbed in rocks leads to breakdown of rocks and cracks in strata
Analyse the relationship between isostatic adjustment and the 2010 melting day anomaly in Greenland as shown in Figure 5. (6 marks)
- P - There is a correlation between 2010 melting day anomaly and uplift
- E - Melting is higher than 1979-2009 average, more uplight in 2010
- D - Southwest, melt anomaly is strongest, with ice having more than 60 days above average melting
- A - At grok, small variation from 1979-2009 average (20 days), 9-10 mm of uplift
- L - South has more uplift than north
Using Figure 6 and your own knowledge, assess the view that rock type is the most important factor in the development of this landscape. (6 marks)
AO1:
* Coastal processes (e.g. erosion)
* High-energy coast
* Caves, arches, stacks
AO2:
* Rock type is a significant factor in the formation of an arch. This forms as a result of a discordant coastline experiencing differential erosion, causing a headland formed of more resistant rock (limestone) to stick out into the sea. This leads to wave refraction occurring, bending the waves around the headland and leading to a crack and then cave forming. Erosion, in this case hydraulic action, wave quarrying and abrasion will break through the headland leaving an arch as seen in the figure.
Overall, rock type determines the ability for a headland and then arch to form, however, other factors such as erosion and weathering are also needed for their development
