Over 70% of the Earth's surface is covered with oceans. Over a third of the world's population lives within 100 km of the coast. The largest source of fresh water on Earth is stored as ice on Antarctica. This year, Antarctica is expected to lose around 150 000 000 000 000 kg of its ice. Having been stored as ice on the landmass, it joins the Earth's oceans, contributing to sea level rise.

(Image source: NASA, retrieved 2017)

Suggestions for Student Discussion and Further Investigation

• One cubic metre of sea water has a mass of approximately one thousand kilograms. What is the approximate volume of water added to the oceans from Antarctica each year?
• The surface area of the Earth is just over 500 000 000 km². 70% of the surface of the Earth is covered by ocean. What area, in km², do the oceans cover?
• Use the approximations you have calculated of total ocean area and the volume of water released from Antarctica each year to estimate the expected sea level rise from this additional water.
• If the Antarctic ice sheets continued to melt at the same rate, what would the total contribution to sea level rise be by the year 2100?
• Official projections from now until 2100 suggest up to one metre of global sea level rise. Compare this value with your estimate of the contribution made from the melting of Antarctica's ice sheet. What other contributors to global sea level rise can you think of?
• Global sea level rise is of much concern, even though a difference of around one metre does not sound very much. Suggest some of the possible consequences of such a sea level rise?
• Is sea level rise a certainty? Is it preventable? Find out more about what we can do to make a difference.

Curriculum Mapping

Mathematics and Science in the New Zealand Curriculum.