State the year in which total oil stocks were at their peak.

Referring to the graph, describe the trend in total oil stocks since the year 2000.

Suggest three reasons why total oil stocks may change from one year to the next.

1.

2.

3.

1998

Generally upwards [1] though with numerous peaks and troughs [1], with [1] for some attempt at quantification of the overall trend or of the fluctuation from the y axis.

Oil stocks (barrels of oil that have already been extracted and stored for future use) change due to changes in production and/or changes in demand/usage. Either approach, or both, is acceptable.

In each case, award [1] for a valid reason, and [1] for offering some expansion, detail or exemplification that is related to changing stocks (not reserves).

Possibilities include:
• geopolitical reasons eg Saudi Arabia over-extraction to flood the market and lower the price
• economic recession or boom could affect consumption of oil stocks
• stocks could increase due to new oil fields coming into production / decrease due to decline of existing fields
• increased demand because of extreme weather conditions (exceptionally cold or exceptionally hot year)
• economic growth in major economies leading to increase in demand
• substitution of oil by renewable resources
• stockpiling in case of conflict.

This presented no problems but candidates must not give a range of years when the question clearly asks ‘state the year’.  
 

This was answered well by most candidates who also included the necessary quantification.

This was generally well answered if the candidate had understood the meaning of ‘stocks’ as defined in the stem of the question. Answers varied from economic reasons such as a recession or boom impacting upon the demands of available stocks; weather-related answers explained how energy demands going up or down could impact upon the given stocks; and valid geopolitical reasons were often given as well. Weaker responses often failed to fully develop or exemplify their reasons.