Glaciers are a hot topic these days and are a frequent subject of debate when discussing global climate change or the fate of polar bears. Do you ever find yourself asking what glaciers have to do with global warming? Have you ever wondered what exactly your friend meant when she told you that you moved at a glacial pace? Read Colin's thorough
overview of glaciers to learn all about these physical features that hold more than three-quarters of the earth's fresh water.

Comments
In Colin’s overview of glaciers, you used:
Most glaciers that form in a mountain are known as an alpine glaciers.
Why “an alpine glaciers”? Can we use indefinite article befor the plural?