Faculty of Engineering, Environment and Computing Geosystems
Activity Brief 3: Climate Review
Module Learning Outcome Assessed:
3. Review the scientific argument for climate change and the influence of both natural and anthropogenic forcing agents in this process
Portfolio Task – Climate Review
Background
Climate change predictions suggest that global sea levels will rise, but uncertainty remains regarding the magnitude of the increase. Providing a specific prediction for sea level rise for the end of the current century (AD 2100) is a difficult task, and often relies on intensive numerical modelling experiments that are beyond our ability to perform in this module. However, we can evaluate how much sea level rise is POSSIBLE, based on our understanding of the different sources and mechanisms of sea level rise.
In this assignment, you will calculate the potential sea level rise from various sources, critically review this in comparison to the Intergovernmental Panel on Climate Change (IPCC)’s sea level projection for 2100, and use your findings in combination with published literature to suggest, and justify, what you believe to be a reasonable projection for sea level rise by 2100.
Preparation
Thermal Expansion
The first mechanism to consider is thermal expansion of the seawater itself. All materials expand when they heat up, and water is no different. Although we are talking about a volume change, the ocean will have to expand laterally (by flooding land) as it rises, which poses a complicated problem.
For simplicity, we will consider the expansion to be a linear rise in the surface of the ocean:
(Equation 1)
where
ΔH is the change in height of the ocean,
H is the coefficient of thermal expansion of seawater (6.9 x 10-5 oC-1),
ΔT is the temperature change and
H is the average depth of water in the ocean (we will assume 5000 m).
For this assessment, answer:
Question 1:
Calculate how much sea level will rise by due to thermal expansion, assuming a 2oC temperature rise from global warming.
Ice Sheets
The second major way of causing sea levels to rise is by putting more water into the oceans. The biggest reservoirs of freshwater are those locked up in ice sheets. You can assume that 361 km3 of ice or snow is the equivalent of 1 mm of sea level change. Using this value, estimate the amount of sea level change that would occur if the snow / ice masses in Table 1 melted completely. Note the different units used for different measurements in the table!
Table 1. Ice and Snow Calculations.
Ice / Snow mass Area (106 km2) Average Thickness (m) Volume (km3) Sea Level Equivalent (mm)
All Snow – – 50,000
All Mountain Glaciers 0.54 241
Greenland Ice Sheet 0.996 1706
West Antarctic Ice Sheet 1.2 1800
East Antarctic Ice Sheet 11.2 2010
Now that you have completed your calculations, for this assessment, answer:
Question 2. Which reservoir of freshwater is the largest potential contributor to global sea level rise?
Question 3. Assuming no thermal expansion of the oceans, what is the LARGEST sea level change that is possible?
Question 4. What is the LARGEST possible sea level change with the inclusion of thermal expansion?
The Write-Up
The review should consist of at least the four sections specified below and an Appendix. It should be written in a professional and consistent manner, in the third person. It should include references using the CU APA referencing style and appropriate table and figure captions. The review should contain the answers to the four questions in Section B.
Introduction and Background
Introduce the purpose, content and structure of the review.
Results: Sources and Mechanisms of Sea Level Rise
Summarise your calculations and results for Questions 1-4 (detailed workings for your calculations should be included in an Appendix). You may wish to present your analysis in a manner similar to table 1.
Remember to include an explanation of your results – it is not appropriate to present a series of calculations with no context or explanation. Do not simply present your results as a series of questions and answers – provide an integrated, clearly written summary of your findings.
Discussion: a review in comparison to the IPCC predictions
The Intergovernmental Panel on Climate Change (IPCC) state that there could be a global sea level rise of up to 1.01 m by 2100, depending on future emissions trajectories. You should now review and discuss your results in comparison to the IPCC and any other predictions of future sea level rise you have found in reputable sources such as peer reviewed journal articles.
Whilst writing this section you should think about the following additional questions:
How do your results compare to other predictions? If they are consistent, what is the main source of global sea level rise? If they are different, can you explain why? What assumptions have you made in your calculations that may have influenced your results?
In this section you should attempt to answer these questions, supporting your arguments with evidence of additional reading and information from other sources. You should use this reading and information to suggest, and justify, a value that you believe is appropriate for global sea level rise by 2100.
All sources of information should be referenced.
Conclusion
End with a brief conclusion summarising your findings. No new information should be presented in the conclusion.
Appendix
Detailed calculations that show your workings for the results in section 2.
Submission
You should submit this coursework using the appropriate link on Aula. You should submit it as a Word or PDF document. You should include the standard coursework cover page available in the guidance document on Aula.
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