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 a billion people around the world (primarily in China, India, Pakistan, and Bolivia) rely on glacial melt water for drinking and agriculture (Qiu, 2010), 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 and using an interactive produced by the National Park Service, you will learn more about glaciers. 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.
- Read the Introduction to Glaciers text on the opening page of the About Glaciers interactive.
- Click on What Glaciers Are in the left menu. Then read the front page and click the photo boxes on the bottom right of the interactive window for more information. Clicking these boxes will cause a popup window to appear with the information. When you have finished reading all the information in the boxes, close the popup window.
- Continue to click through all six of the menu options in the left menu. Be sure to read all the photo boxes on each new page's bottom right to get additional information about that topic. Take notes as needed.
Stop and Think1: Explain what it means for a glacier to be in equilibrium.
2: What evidence could scientists use to show whether or not a glacier is in equilibrium?