Glaciers and global warming

This task is about glaciers and global warming.

Question 1Change answer

The debate
Some people say glaciers worldwide are getting smaller and that this is a sign that global warming really is happening. But some glaciers, such as Franz Josef in New Zealand, have got bigger in the past.
So other people say this proves global warming is not happening!
a) To make an informed decision about something it is important to gather enough evidence. Use each piece of information about glaciers in the table below to write a question you would need to ask about Franz Josef before you could make an informed decision about whether its recent changes are evidence either for or against global warming.
Fact
Question
i) There are many glaciers in the South Island and elsewhere in the world. Is Franz Josef changing in the same way as other glaciers?
ii) Glaciers in steep, narrow valleys are less affected by small overall temperature changes than wider glaciers.
iii) Some glaciers have a layer of rubble on top. It makes them look dirty but also acts like a cooling layer of insulation that traps the cold.
iv) Changes to glaciers are related to weather that happened several years ago.
v) Glaciers have always gone through periods of retreat (shrinking) and advance (growing).

Question 1Change answer

b)  Why is it important to think about more than one piece of evidence before you make up your mind about something?