The Cryosphere
i.e those areas of the Earth covered in ice or show such as ice sheets, glaciers, permafrost, and snow fields.
Most of the world's ice is contained in the Antarctic and Greenland icesheets. These are so big that, were they to melt completely, sea levels would rise by 65 metres. If you want to get an idea of what that would mean to your part of the world try here.
Unfortunately, the Greenland sheet is losing mass at an accelerating rate and parts of western Antarctica are showing signs of vulnerability too. We learnt about some of the things that influence this including how melt water can accelerate the rate of flow of glaciers and buttressing (which can slow mass loss down).
Ocean Acidification
The oceans act as a CO2 sink, absorbing around half of our carbon emissions. Unfortunately, this is leading to the oceans becoming more acidic. The pH has decreased by 30% since pre-industrial times. This could seriously compromise the ability of marine organisms to build and retain shells and skeletons. They may even have problems getting rid of CO2 from their bodies leading to acidosis.
These problems may result in the extinction of many shell forming organisms. If any of these are near the bottom of food chains it may lead to the collapse of the whole food chain. Mass extinction anyone?
Why should we care? Because the sea provides us with a significant part of our diet. For many of us, fish and shellfish is a nice-to-have not an essential, but for some populations, it is a staple part of their diet.
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