| Date | November 2020 | Marks available | 2 | Reference code | 20N.1.SL.TZ0.3 |
| Level | Standard Level | Paper | Paper 1 | Time zone | Time zone 0 |
| Command term | Describe | Question number | 3 | Adapted from | N/A |
Question
Figure 3(a): Hurricane history of Dominica since 1900
[Source: Adapted from Dominica’s history with tropical storms. Available at: http://www.hurricanecity.com/city/dominica.htm.]
Figure 3(b): Average global sea surface temperature, 1900–2015
[Source: NOAA.]
Figure 3(c): Impacts of Hurricane Maria
- 100 % of food crops were destroyed.
- 90 % of housing was damaged.
- Almost 10 000 landslides occurred.
- Extreme damage to tropical rainforest: all leaves removed from trees and large numbers of trees knocked down.
- Major damage to coral reef systems caused by waves and soil erosion from the island.
- Contamination of freshwater by oil spills and chemicals.
[text] Adapted from ACAPS, 2018. Dominica: The impact of Hurricane Maria. Available at:
https://www.acaps.org/sites/acaps/files/products/files/20180131_acaps_disaster_profile_dominica_v2.pdf.
[left image] Photo credit: Marica Honychurch.
[right image] Photo courtesy of CARICOM, September 21, 2017,
https://caricom.org/carpha-ready-to-assist-dominica/.
Figure 3(d): Landslide caused by heavy rains after a hurricane
[Source: Photo courtesy of Jodie Dangleben.]
Using Figure 3(a), identify why Hurricane Maria was so destructive.
Describe the relationship between sea surface temperature in Figure 3(b) and hurricane wind speed in Figure 3(a).
With reference to Figures 3(c) and 3(d), outline how Hurricane Maria has reduced Dominica’s food availability.
With reference to Figure 3(c), explain three ways in which Hurricane Maria has affected ecosystem services provided by Dominica’s forests.
Markscheme
strongest hurricane in Dominica’s history / fastest (maximum) wind speeds/wind speed of over 250 km/hr and therefore most destructive;
has been many/22 years since the last hurricane, so people were not prepared;
last hurricane had much lower maximum wind speeds, so people were not expecting such a damaging storm;
Note: Do not accept only ‘very high wind speed’.
rising sea temperatures result in greater hurricane strength/stronger maximum wind speeds;
the two largest hurricanes occurred after 1979, when sea temperatures increased above the 1971–2000 average;
there is no relationship/no clear relationship;
the relationship is not consistent as smaller storms occur even after sea surface temperatures exceed the 1971–2000 average/higher sea temperature in the early1940s did not result in a hurricane;
100% of food crops were destroyed in the hurricane (reducing food availability);
damage to coral reef ecosystems reduced fish catch;
wild food sources within the forest (eg nuts, fruits) destroyed;
delays to food supply due to time needed to regrow local crops;
food transportation disrupted due to loss of/damage to roads/bridges/airports/ports;
soil erosion/landslides reduced soil fertility/area available for cultivation;
heavy rains leached soil nutrients/reduced soil fertility;
contamination of freshwater with oil/chemicals reduces water available for irrigation;
disruption to electricity supply resulted in spoilage / unable to store food due to lack of refrigeration;
Note: Do not accept only ‘hurricane damages food crops’.
reduction in photosynthesis so less oxygen produced;
reduction in trees results in loss of carbon sink / reduction in trees/photosynthesis reduces carbon dioxide uptake;
loss of leaves means more precipitation reaches the ground causing surface runoff/causing more soil erosion/loss of soil nutrients;
less uptake of water by plants resulting in increased flooding;
loss of plants/trees reduces water infiltration into aquifers/groundwater;
loss of habitat for species (reducing biodiversity);
loss of habitat reduces food supply / loss of trees reduces food sources;
loss of trees reduces available timber/wood for human use;
loss of trees means reduced transpiration, reducing atmospheric moisture, reducing precipitation and thereby affecting local climate/microclimate;
loss of shade means hotter ground temperatures/loss of cooling effect of forest on local climate/microclimate;
Note: Accept other reasonable responses which are specific to ecosystem services provided by forests. Hence, do not accept ‘contamination of freshwater by oil/chemicals reduces water/fish supplies / erosion of soils reduces nitrogen cycling/nutrient availability’.
Examiners report
Most candidates answered this question well. A few responses such as 'increased or high wind speed' were too vague for credit.
Most students achieved one mark for this question with most identifying a positive correlation between sea surface temperature and hurricane wind speed. Few candidates gave examples that supported this relationship or recognised that it was not a strong relationship with a number of anomalous periods.
This question was answered well by most candidates. Some responses lacked the necessary detail required for full marks.
Responses varied widely for this question. Many candidates did not focus on ecosystem services provided by the forest as required and included non-relevant material e.g. contamination of freshwater with oil and chemicals or damage to the coral reefs.
