Classroom Questions

Questions for ‘Are major ocean currents moving to turn Earth into a snowball?’ 

The Atlantic Meridional Overturning Circulation, or AMOC, ferries warm waters from the tropics northward toward Europe. Recent analyses say the current could weaken by half within 75 years.

Goddard Space Flight Center Scientific Visualization Studio/NASA

By Science News Explores

To accompany ‘Are major ocean currents moving to turn Earth into a snowball?’  

SCIENCE

Before Reading:

  1. Describe density in one sentence. Use the concept of density to explain why air bubbles rise through water rather than sink or remain stationary.
  2. Not all liquid water has the same density. What is one factor that can increase the density of water? Predict what might happen if you poured water of higher density into an aquarium of lower density water.

During Reading:

  1. What does AMOC stand for?
  2. Briefly describe the AMOC’s role in transferring heat from one place to another.
  3. What 2004 film explored the potential consequences of an AMOC shutdown?
  4. As the salinity (saltiness) of seawater increases, does density increase, decrease or remain the same?
  5. What changes cause the AMOC’s surface waters to sink at its northernmost reach?
  6. How will the AMOC change by 2100, according to current computer models?
  7. After a heavy rain, does the density of surface water increase, decrease or remain the same? Explain your answer.
  8. Explain how evaporation affects salinity. Give one example of how a weather change might contribute to increased evaporation.
  9. What does NOC stand for?
  10.  Some climate scientists have proposed an engineering project in the Bering Strait to help manage ocean currents. Briefly describe what this project might look like.

After Reading:

  1. Experts in this story say that predicting future changes to the AMOC is even more complicated than predicting future changes in global temperature. One particularly difficult variable to model is salinity. For accurate predictions of salinity, scientists say they must get “salinity all over the Atlantic Ocean right.”  In your own words, explain what scientists mean by saying this.
  2. List three physical processes, weather events or other factors mentioned in this story that can alter salinity. For one of these factors, explain how climate change or human activity might affect this factor and how that change might, in turn, affect the salinity in a particular region.
  3. Imagine that, in a particular region of the ocean, salinity values for surface water become higher than models predicted. This surface water’s salinity is greater than that of the water below it. How might this unexpected high surface salinity cause water to move in ways that computer models did not predict? Consider how this single error in the computer model’s prediction might lead to errors in salinity predictions for other parts of the ocean. Describe one specific example.