## Stability and Change: Currents of Change

The Earth's system exemplifies stability and change. Change and rates of change can be observed and quantified over very short or long periods of time and at various spatial scales (e.g., from landscape level to global processes). Understanding stability and change in Earth processes contribute to a more complete understanding of the Earth system.

Warm ocean currents circulating off the coast of Antarctica are indirectly contributing to rising global sea levels. As these twisting flows meander around the continent's frozen edges and beneath the underside of floating ice shelves, they're slowly melting the ice from below. Using surface elevation measurements collected during NASA's ICESat mission, scientists have found that this melting is driving most of Antarctica's recent ice losses-particularly in West Antarctica, where inland glaciers that feed into the ice shelves are moving at an accelerated rate. The visualization shows the interaction of modeled ocean currents and Antarctic ice shelves, where red areas represent ice thicker than about 1,800 feet (about 550 meters) and blue areas represent ice thinner than about 650 feet (about 200 meters). Notice how the ice shelves generally become thinner- a rainbow of colors indicates intermediate thicknesses- as they extend farther from land.

Credit: NASA Scientific Visualization Studio

### Mini Lesson

Step 1:  Project the video on your screen and queue to the beginning. Before playing the video or providing background information, ask your students, “where is this map?” Have students write down their guess on a whiteboard or sheet of paper. After everyone has written something down, have them share l their answers. Answer: Antarctica located on the South Pole.

Step 2: Ask your students, “what do you think the zones of red and blue represent?” They should again write their answers down on a whiteboard or sheet of paper. Instruct your students to flip their whiteboards over at the same time or share their responses orally. You are likely to receive a range of answers. Instead of going over the answers then, provide them with some background information to encourage them to think critically.

Background Information: Accessibility Option 1

“Warm ocean currents circulating off the coast of Antarctica are indirectly contributing to rising global sea levels. As these twisting flows meander around the continent's frozen edges and beneath the underside of floating ice shelves, they're slowly melting the ice from below. Using surface elevation measurements collected during NASA's ICESat mission, scientists have found that this melting is driving most of Antarctica's recent ice losses-particularly in West Antarctica, where inland glaciers that feed into the ice shelves are moving at an accelerated rate.”

Background Information: Accessibility Option 2

“There are warm ocean currents moving around the coast of Antarctica. These currently are indirectly increasing global sea levels. These currents flow around the continent's frozen edges and beneath the floating ice shelves. They are slowly melting the ice from below. NASA scientists have found that ocean currents are influencing Antarctica's recent ice melting. In West Antarctica, inland glaciers are moving quickly.”

Step 3:  Now, play the video.

Step 4:  With the additional information, ask your students again,  “what do you think the zones of red and blue represent?” Hopefully, more of the students are able to apply the background information to understand the red area is thicker and blue is thinner areas of the ice.

Connect the background information provided about oceans to the visualization model. Explain how it shows the interaction of modeled ocean currents and Antarctic ice shelves, where red areas represent ice thicker than about 1,800 feet (about 550 meters) and blue areas represent ice thinner than about 650 feet (about 200 meters). Point out how the ice shelves generally become thinner- a rainbow of colors indicates intermediate thicknesses- as they extend farther from land.

Supplies:

• Whiteboards with markers

• Or paper and pencil

• Projector