Examine the positive and negative impacts of La Niña events for different parts of the world.

Evaluate the relative importance of vegetation in the development of coastal sand dunes.

Marks should be allocated according to the Paper 1 markbands (available under the "Your tests" tab > supplemental materials).

La Niña is the positive and cold phase of El Niño, and is associated with below average sea surface temperatures in the central and eastern tropical Pacific Ocean. La Niña may have significant impacts on weather systems, with environmental and economic consequences. La Niña can have positive and negative effects on different places, including changes in storm frequencies and rainfall amounts, causing flooding and droughts, and modification of ocean currents, affecting fishing industries.

Possible applied themes (AO2) demonstrating knowledge and understanding (AO1):

• La Niña is the positive and cold phase of an El Niño event, associated with cooler than average sea surface temperatures in the central and eastern tropical Pacific Ocean.
• La Niña may have significant impacts on weather systems, with major environmental and economic consequences. It may lead to intense storms and flooding in some areas, and severe drought in others. For example, in Asia the formation of tropical cyclones causes heavy rainfall, flooding and landslides over SE Asia.
• Above average rainfall in NW India and Bangladesh is of benefit to agriculture, water supply and industry.
• La Niña may also increase the potential for tropical cyclones in the Atlantic Ocean.
• Drought also affects the coastal regions of California, Peru and Chile; while flooding affects the central Andes and Bolivia.
• La Niña has a positive impact on the fishing industry of western South America – upwelling of cold, nutrient-rich waters increase fish stocks, especially crustaceans and sea bass.
• The intensity and duration of La Niña cycles may increase with global climatic change.

Good answers may be well structured (AO4) and may additionally offer a critical evaluation (AO3) of the statement in a way that examines the positive and negative impacts of La Niña in different areas. Another approach might be to examine which areas gain greater benefits, and whether these outweigh the negative impacts.

For 5–6 marks, expect weakly evidenced outlining of one positive and/or negative impact of La Niña.

For 7–8 marks, expect a structured account which includes:

• either an evidenced explanation of at least one positive and one negative impact of La Niña in different parts of the world
• or a discursive conclusion (or ongoing evaluation) grounded in geographical concepts and/or perspectives, possibly examining whether benefits outweigh the negative impacts.

For 9–10 marks, expect both of these traits.

Marks should be allocated according to the Paper 1 markbands (available under the "Your tests" tab > supplemental materials).

Vegetation plays a vital role in the formation and development of coastal sand dunes, but wind and other coastal processes are also of importance. Sand dunes typically develop where there are strong onshore winds, and constructive wave action with the formation of wide, sandy beaches. There should also be a plentiful supply of sand, either from erosion of nearby cliffs or transported by ocean currents. Vegetation is important in trapping and stabilizing sand deposition to form dunes. A recognizable vegetation succession is evident from newer to older, more inland dunes. If vegetation is destroyed by human activity, sand dune erosion may occur.

Possible applied themes (AO2) demonstrating knowledge and understanding (AO1):

• Vegetation plays a vital role in the formation and development of coastal sand dune systems.
• Other factors are also important, including the role of wind, and the availability of a large expanse of sand which can be transported inland.
• Strong prevailing onshore winds transport sediment inland, by saltation, suspension and creep.
• Vegetation traps and colonises the sand at the back of the beach, where wind velocities are lower. The roots and stems of the vegetation anchor the shifting sand, creating protection from the wind and hence more sand accumulation. Over time, more dunes will form at the back of the beach and plant succession occurs on the older, inland dunes.
• Dunes are vulnerable to erosion by human activities such as trampling which destroys the vegetation.
• Vegetation is vital in stabilising the sand dunes: protection and re-planting of dune vegetation is important in dune stabilisation.

Good answers may be well structured (AO4) and may additionally offer a critical evaluation (AO3) of the statement in a way that examines the relative importance of vegetation in sand dune formation in relation to other factors such as wind and coastal processes that provide a wide expanse of sand. Another approach might be to examine the spatial variation in the role of vegetation, the way vegetation succession occurs over time scales, and the interaction of human activity.

For 5–6 marks, expect weakly evidenced outlining of the link between vegetation and coastal sand dune development.

For 7–8 marks, expect a structured account which includes:

• either an evidenced explanation of the importance of vegetation in coastal sand dune development
• or a discursive conclusion (or ongoing evaluation) which examines the relative importance of vegetation in relation to other factors, such as wind.

For 9–10 marks, expect both of these traits.

There were some good responses on La Niña, taking examples from different parts of the world showing a sound knowledge of positive and negative impacts. Weaker responses were confused about what happened where.

Vegetation was discussed but very few understood the relevant importance of vegetation in sand dune formation, so failed to discuss other factors like wind. Many responses dealt incorrectly with mangroves, and some focused on threats to sand dunes.