Date | May 2021 | Marks available | 2 | Reference code | 21M.2.bp.2 |
Level | SL and HL | Paper | 2 | Time zone | |
Command term | Outline | Question number | 2 | Adapted from | N/A |
Question
The map shows the land surface temperature anomalies for February 2017.
[Source: NASA Earth Observatory. Land Surface Temperature Anomaly. [online] Available at: https://earthobservatory.nasa.gov/global-maps/MOD_LSTAD_M [accessed 16 April 2019].]
Identify one region showing an extensive positive anomaly of +12 °C.
Identify one region showing an extensive negative anomaly of −12 °C.
Outline how extreme warming can affect the albedo of a region.
Outline how extreme warming can affect the operation of a feedback loop.
Explain two ways in which climate change impacts upon ocean transport routes.
Way 1:
Way 2:
Markscheme
South/South East Greenland
central/eastern/N/NE USA
central North America
central Asia
E/NE Australia
southern Africa
western/NW Australia
western USA
SW Asia
In each case, award [1] for a valid comment on effects of extreme warming and [1] for the impact on albedo.
Valid effects may include:
- Decrease in the amount of ice, decrease in albedo less energy reflected.
- Increases amount of cloud through increased evaporation, increases albedo.
- Increased heat causes wildfires which destroy vegetation, increases albedo.
- Expansion of deserts due to water loss decreases vegetation, increases albedo.
For example: Extreme warming is going to melt ice in the polar regions [1] and therefore the surface will reflect less solar radiation and decrease albedo [1].
OR
Extreme warming may increase evaporation in tropical areas [1], which can reduce vegetation cover and increase albedo [1].
In each case, award [1] for the valid identification and description of a loop and [1] for development linked to impact.
Valid loops may include:
Positive loops
- Release of methane from frozen ground, causes increase in greenhouse gases which gives more warming.
- Warming of atmosphere leads to more evaporation, causes more water vapour which traps heat and amplifies initial warming.
- Warming melts ice which decreases albedo so absorbed heat warms atmosphere which melts more ice.
- Warming gives conditions perfect for wildfires, causes release of more GHG/shrink forests as a carbon sink.
- Warming causes the oceans to increase in temperature and become less efficient as a carbon sink, this increases the CO2 in the atmosphere which further increases warming.
Negative loops
- Increase in temperature increases the amount of cloud cover, decrease incoming solar radiation and decrease warming.
For example: Melting of frozen ground releases methane/greenhouse gas [1] so there is more warming and more melting [1].
In each case, allow [1] for a valid way and [1] for development/exemplification of impacts on ocean transport routes.
Valid possibilities include:
- Warming may decrease the amount of sea ice and so ice-bound ports may be more accessible all year round.
- Warming may increase the occurrence of natural hazards, such as hurricanes/storms, these would make some routes more dangerous and hazardous to navigation.
- Increased natural hazards (storms and storm surges) may damage infrastructure, interrupt operations at terminals.
- Climate change may result in sea level rise which leads to more frequent flooding of port facilities.
- Existing routes may no longer be safe due to icebergs/increased sedimentation due to worsening coastal erosion, re-routing becomes more common.
For example: New sea routes opening up as sea ice melts [1] and allows passage through areas previously ice bound for large parts of the year [1].
Examiners report
The main issue with both (i) and (ii) was the recognition of what constituted a region rather than the ability to interpret the patterns shown on the world map. The geography guide outlines the scales with which candidates should be familiar and examiners were given guidance to cover major interpretations of regional; an area within a country or an area that crosses international boundaries. Many answers were given at the national scale which the resource did not identify.
The main issue with both (i) and (ii) was the recognition of what constituted a region rather than the ability to interpret the patterns shown on the world map. The geography guide outlines the scales with which candidates should be familiar and examiners were given guidance to cover major interpretations of regional; an area within a country or an area that crosses international boundaries. Many answers were given at the national scale which the resource did not identify.
Virtually all answers referred to the impact of extreme warming in Arctic environments and were generally well done. The loss of ice and snow due to warming was understood by the majority and most went on to outline how this caused a decrease in the albedo. In a minority of cases the second element of the answer was omitted, and the sole focus was a description of changes in the cryosphere. There were some instances where candidates were confused and suggested that warming would increase albedo, but these were not significant in number.
This question proved to be more of a challenge but, as with 2(b)(i) many candidates were well prepared and gave a developed outline of the operation of a feedback loop. The most popular ways of answering involved a development of the albedo theme or the melting of permafrost and the release of methane. Encouragingly a significant number addressed negative loops and the self-regulatory systems that slow down the warming trend. Where marks were lost was usually in the outlining of the link between the stimulating factor and the increasing or slowing of the trend.
This question was accessible to most candidates with most of the successful answers making reference to a decrease in the amount of sea ice and the increase in extreme weather conditions, usually with reference to hurricanes/storms. The better answers were able to link these with observed impacts on transport routes such as the opening up of new routes in the Arctic Ocean. Some answers lacked precision and referred to the melting of ice in polar regions conflating sea ice and land ice and some drifted into possible impact in the future when the question was directed to present impacts. As a result some candidates identified sea level change as an element of climate change but linked this with the opening up of new routes rather than the more frequent flooding of port facilities.