Paper 2019 A Level

Question 1

To what extent does an understanding of feedback systems in the carbon cycle helps with attempts to mitigate the impacts of climate change?

Answer 1

Point 1 - yes
2- yes
3 - no

Question 2

Feedback system

Answer 2

Feedback systems are systems where a chain of reactions occurs, where one process leads to another process. In the negative feedback loop systems initial change is nullified while in the positive change is amplified

Question 3

Point 1 _ negative feedback loop of afforestation

Answer 3

Understanding of negative feedback loop of afforestation will help to reduce CO2 emissions and mitigate climate change . As more trees are planted - more photosynthesis is performed - more CO2 is sequestered in trees - less CO2 is emitted to the atmosphere - reduced greenhouse gas effect

Evaluation: It will take up to 30 years to bring the forest back to its initial state

Question 4

Point 1 - AO1 on deforestation (How much of co2 def. Accounts for + how much of tree cover was lost as well as co2 released)

Answer 4

-deforestation accounts for 30% of anthropogenic CO2 emissions

-361 Mha of three cover was lost globally between 2001-2018, releasing an estimated 987 GtC of CO2 emissions

Question 5

Point 2 - negative feedback of reduced overgrazing

Answer 5

Reduced overgrazing will lead to less methane being emitted as a result of enteric fermentation - reduced greenhouse gas concentrations in the atmosphere - reduced warming effect
Over time with lowering rates of overgrazing and possibly lower demand (unlikely to occur)- reduced demand for pastoral land- reduced deforestation - reduced CO2 emissions
Evaluation - over time lowering demand for meat products is unlikely to occur due to the growing population

Question 6

Point 2 - AO1- (livestock emissions and deforestation for pastoral land)

Answer 6

• livestock account for 14,5 % of all anthropogenic emissions
• amazon rainforest has lost approximately 17% of its primary rainforest in the last 50 years, 80% is due to cattle ranching

Question 7

Point 3 - no need of the knowledge of the feedback systems

Answer 7

• if carbon emissions increases are linked to global warming and it is damaging to the environment than irrespective of an understanding of feedback systems, human endeavor should be geared towards reducing the amount of carbon produced as a result of human activity
• evaluation - mainly has only small-scale local impacts, while in order to mitigate occurring climate change global scale mitigation strategies should be implemented

Question 8

Point 3 - AO1 (emissions of electric vehicles and level of emissions from transport in US)

Answer 8

• electric vehicles emissions are up to 43% lower than diesel vehicles
• in the US GHG emissions from transportation account for about 27% of total emissions

Question 9

Conclusion

Answer 9

-understanding of the feedback systems in the carbon cycle to a significant extent help in both understanding of the occurring climate change and help in mitigating the impacts of the occurring climate change on the global scale
-some of the mitigation strategies such as use of electric vehicles does not necessarily requires and understanding of feedback systems and implementation of them can be driven rather by the human endeavor, but they have rather a local impact