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Sea Level Rise - Why are sea levels rising?



Introduction film exploring how quickly sea levels are rising, and why this is happening.

Key Issues

- The causes of sea level rise.
- Sea level rise over time (future and historic predictions).
- How scientists measure sea level rise and predict future changes.
- Variations in sea level rise around the world.


There are two main causes of sea level rise:

1. As air temperatures rise (due to climate change) the water in the oceans is warmed and expands. This process is called thermal expansion.

2. As ice sheets and glaciers melt, they increase the amount of water in the oceans.

Scientists have shown that in the past there have been periods of significant sea level change due to natural factors. However, current measurements and predictions indicate that human activity is now the main driving force.

Sea level rise is not a uniform process. Increases vary widely by region, with prevailing winds, ocean currents, and land rebound or subsidence being important considerations. This means that while Scotland might not see any significant sea level rise in the near future, somewhere like the The Chesapeake Bay, USA may see an above average rise.




Starter Activities

  Show a number of photos of well known places around the world and ask how at risk from sea level rise they are. Show pictures from coastal places in MEDCs and LEDCs and ask which is best prepared to adapt.  Download.
  Show a picture of people skiing on a glacier and an area being flooded by coastal flooding and ask how the two pictures are connected.  Download.


Enquiry Questions

 - Why is the sea level rising? (see worksheet for exercise)
 - Will the sea rise the same amount everywhere in world at the same time?
 - Which places do you think will be most vulnerable to sea level rise? (see worksheet for activities on this)
 - What do you think are the risks of sea level rise to your local area?
 - What impacts could climate change have on the oceans beyond sea level rise (e.g. ocean acidification and changes in ocean currents)?

Lesson Activities

The video throws up a number of different issues and could be incorporated into a variety of main lesson activities. Here are a few examples:

  • What factors cause sea level to change (Image 7 in diagram pack)? What is the evidence for sea level rise at present?
  • What are the biggest contributors to recent and future sea level change, what does this tell us about the causes of sea level rise? (Image 8 in diagram pack)
  • Which areas of the world are most vulnerable to see level rise. Compare coastal locations and look at the potential impact on each? (Image 2-6 and 10 in the diagram pack)
  • A practical exercise highlighting the different effects of land locked ice and sea ice on sea levels can be found here.


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