Part A: Mass Balance
The term "land ice" can be used to describe any ice that formed over land primarily from freezing precipitation (as opposed to sea ice, which forms by the freezing of seawater). This includes glaciers, ice sheets, ice shelves, icebergs, and frozen ground. Read this excerpt about land ice (Acrobat (PDF) 305kB Jul2 11) from the NSIDC page "All About the Cryosphere" to familiarize yourself with the different types of land ice or click here to read the full article. In this part of the lab, we'll be focusing on glaciers.
Scientists are interested in studying these thermodynamic processes in glaciers because of the potential impacts for both humans and wildlife. More than two billion people around the world (primarily in China, India, Pakistan, and Bolivia) rely on glacial melt water for drinking and agriculture, but if glaciers melt too fast, there can be catastrophic flooding followed by a fresh water shortage. Melting ice sheets could result in loss of habitat for many species of birds and mammals, rising sea level, and increased global warming.
In this part of the investigation, you will explore glacial accumulation and ablation processes using an online interactive produced by ThinkTV. By studying these processes, scientists are able to determine whether a glacier is growing or shrinking and whether changes in the glacier's mass balance are related to climate change.
- Roll over each icon on the glacier in the interactive below to learn about the clues scientists look for to determine whether glaciers are experiencing possible climate-driven changes. Click on the icons to reveal additional information.
Courtesy Teachers Domain.
Stop and Think
1: Explain what it means for a glacier to be in equilibrium.
2: Describe how scientists determine glacial mass balance.