| Date | November 2017 | Marks available | 6 | Reference code | 17N.1.bp.03 |
| Level | SL and HL | Paper | 1 | Time zone | |
| Command term | Explain | Question number | 03 | Adapted from | N/A |
Question
The graph shows external forcings, such as greenhouse gases, causing changes in the Earth’s atmospheric system.
[Source: Figure SPM.2 from Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change [Solomon, S., D. Qin, M. Manning, Z. Chen, M. Marquis, K.B. Averyt, M. Tignor and H.L. Miller (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.]
State which external forcing shown on the graph has the greatest impact on temperature in the atmosphere.
Outline what is meant by “albedo”.
Briefly describe the difference between stratospheric ozone and tropospheric ozone.
Explain two environmental consequences of global climatic change (global warming).
Consequence 1:
Consequence 2:
Markscheme
CO2 / carbon dioxide / greenhouse gases [1]
Solar radiation/heat reflected by the surface [1].
Award [1] for further development such as:
- the idea of amount/proportion
- measures how reflective a surface is
- the more reflective a surface is the higher the albedo value
- link between low/high albedo and reflectivity
The difference can be addressed by using own knowledge or with reference to the graph.
Award [1] for valid difference and [1] for further development/detail.
Possibilities include:
- different location/elevation/zone/height within the atmosphere [1] with tropospheric ozone being lower/nearer the ground than stratospheric ozone [1]
- tropospheric ozone is mainly anthropogenic [1] stratospheric ozone is mainly natural [1]
- tropospheric ozone has a positive heating effect whereas stratospheric ozone has a negative effect [1], with quantification from graph [1]
- radiative forcing is less in stratosphere and more in troposphere [1], with quantification from graph [1]
- tropospheric ozone is harmful for breathing [1] whereas stratospheric ozone is protective as stops UV [1].
Award [1] for a valid consequence resulting from increased temperature of global warming and [2] for further development/exemplification related to the natural environment.
For example: Global warming is leading to melting of the ice caps [1]; the meltwater from this leads to a global rise in sea level [1], which will result in the loss of some low-lying islands (or provides relevant example, eg Kiribati) [1].
Other possibilities include:
- changes to ice caps/glaciers
- sea level rise
- drowning/flooding of low-lying islands
- impacts on precipitation patterns
- changes in disease distributions
- changes in the areas covered by different habitats, types of vegetation/fauna
- extreme weather events
- acidification of the oceans
- coral bleaching.
