Global effect

• Marking criteria


  • 1 mark for 1 detailed response or limited description of 2 factors
  • Max 3 marks for answers consisting entirely of limited descriptive points, with 2 such points required for 1 mark
  • Credit both positive and negative impacts
  • Credit any other valid responses
• Sea level rises, caused by an expansion of the sea as it becomes warmer and also by the melting of glaciers and ice caps in Greenland, Antarctica, etc
• Low-lying coastal areas, eg Bangladesh, affected with large-scale displacement of people and loss of land for farming and destruction of property
• More extreme and more variable weather, including floods, droughts, hurricanes and tornadoes becoming more frequent and intense
• Globally, an increase in precipitation, particularly in the winter in northern countries such as Scotland, but some areas like the USA Great Plains may experience drier conditions
• Increase in extent of tropical/vector borne diseases, eg yellow fever, as warmer areas expand, possibly up to 40 million more in Africa being exposed to risk of contracting malaria
• Longer growing seasons in many areas in northern Europe for example, increasing food production and range of crops being grown
• Habitat loss has largest impact on indigenous animals/plants, and in areas where migration to new habitats is more difficult, leading to estimates of 10% extinction rates for land species
• Increased sea temperatures have led to 80% coral bleaching. Extended periods of bleaching can kill the coral with knock on effects for other marine life
• Changes to ocean current circulation, eg in the Atlantic the thermohaline circulation starts to lose impact on north-western Europe, resulting in considerably colder winters
• Changes in atmospheric patterns linking to changes in the monsoon caused by El Niño and La Niña
• Increased risk of forest fires, for example in Australia and California due to change in surface temperatures and changes in rainfall patterns