6.3 Climate change — mitigation and adaptationIB Environmental Systems and Societies HL: Subtopic test

1. 1
   Costa Rica generates about 98% of its electricity from renewable sources, mainly hydropower, geothermal, wind and solar, and aims to reach net-zero emissions by 2050. However, transport, which relies on imported petrol and diesel, is one of its largest sources of carbon dioxide emissions.

   (a)

   Which description fits the decarbonisation of Costa Rica's electricity supply?

   [1 mark]

   • AReplacing fossil fuel generation with hydropower, geothermal, wind and solar
   • BBuilding higher walls to protect coastal power stations from flooding
   • CCapturing carbon dioxide from the air and storing it underground
   • DPlanting trees to remove carbon dioxide from the air

   (b)

   Which action would best reduce Costa Rica's transport emissions?

   [1 mark]

   • ABuilding sea walls
   • BBuilding cyclone shelters
   • CReplacing petrol and diesel vehicles with electric vehicles powered by renewable electricity
   • DPlanting drought-resistant crops

   (c)

   Explain why decarbonising electricity alone will not be enough for Costa Rica to reach net zero.

   [2 marks]

   Total for question 1: 4 marks

2. 2
   In Vietnam's Mekong Delta, rising sea levels and reduced river flow let salt water move inland and damage rice fields. Farmers in some areas have switched to rice-shrimp rotation or salt-tolerant crops, and local authorities have replanted coastal mangrove forests and built sluice gates. The Vietnamese government has produced national plans for adapting to climate change.

   (a)

   Which of these is an adaptation strategy used in the Mekong Delta?

   [1 mark]

   • AReplacing coal with solar power
   • BBanning the use of CFCs
   • CCapturing methane from landfill
   • DSwitching from rice to a rice-shrimp rotation and salt-tolerant crops

   (b)

   What is the aim of resilience and adaptation plans developed by societies?

   [1 mark]

   • ATo reduce global emissions to zero
   • BTo build the capacity of people and systems to withstand and recover from climate impacts
   • CTo increase the use of fossil fuels
   • DTo stop climate change completely

   (c)

   Explain how restoring coastal mangrove forests helps communities in the Mekong Delta to adapt to climate change.

   [2 marks]

   Total for question 2: 4 marks

3. 3
   The IPCC's sixth assessment report gives best estimates of global mean temperature rise by 2081 to 2100, relative to 1850 to 1900, under three emissions scenarios: very low emissions (SSP1-2.6) 1.8 °C; intermediate emissions (SSP2-4.5) 2.7 °C; very high emissions (SSP5-8.5) 4.4 °C. In the 2015 Paris Agreement, countries agreed to hold warming well below 2 °C and to pursue efforts to limit it to 1.5 °C. Each country sets its own nationally determined contribution (NDC), and there is no binding penalty for missing it.

   (a)

   (HL) Calculate the difference in projected warming between the very high and the very low emissions scenarios, state which scenario keeps warming below 2 °C, and explain why the IPCC uses scenarios.

   [3 marks]

   (b)

   (HL) Discuss the challenges of implementing climate management strategies such as those in the Paris Agreement.

   [4 marks]

   Total for question 3: 7 marks

4. 4
   In 1991 the eruption of Mount Pinatubo put millions of tonnes of sulfur dioxide into the stratosphere, forming aerosols that reflected sunlight and cooled the Earth by about 0.5 °C for around two years. Some scientists propose copying this by spraying reflective particles into the stratosphere (stratospheric aerosol injection), while others warn that it would not stop carbon dioxide concentrations rising. Separately, an economist notes that the atmosphere is a shared resource: each country gains from burning fossil fuels, while the costs of climate change are shared by everyone.

   (a)

   (HL) Evaluate stratospheric aerosol injection as a response to climate change.

   [6 marks]

   (b)

   (HL) Discuss how the idea of the tragedy of the commons applies to climate change, and how different stakeholders can influence perspectives and action.

   [6 marks]

   Total for question 4: 12 marks

End of questions