Penn State NASA

Module Summary and Final Tasks


Module Summary and Final Tasks

End of Module Recap:

In this module, you should have mastered the following concepts:

  • the difference between weather and climate; the importance of averaging over a long enough time period to remove the "noise" of weather;
  • how temperature records are analyzed to reveal meaningful information about climate change;
  • many different groups have used different approaches to estimate the history of global temperature, and they all reach similar conclusions — the Earth is warming;
  • looking further back in time, we see that recent warming is unusually abrupt and is not part of a natural cycle — but natural variation in climate is important, and it is superimposed on the warming trend;
  • virtually everything we can think of measuring that records the temperature at the surface and the near sub-surface tell us the same general story about the warming — there has been about 1.1°C warming over the past 70 or so years, with most of it in the last 50, and most of it concentrated in the high latitude regions of the Northern Hemisphere, where warming reduces the area and time period of coverage by snow and ice, and where, consequently, the snow-free ground absorbs much more solar energy;
  • glaciers are shrinking around the globe, and the shrinking coincides in time with the warming trend seen in the instrumental temperature record. Arctic sea ice is also shrinking, and at an alarming rate. The big ice sheets of Greenland and Antarctica are also melting, contributing to sea level rise.
  • sea level is on the rise during the same time period that the other records indicate warming. Seawater expands as it gets warmer, so it takes up more room, and so sea level must rise. Melting glaciers and ice sheets (but not sea ice) contribute to sea level rise as well.
  • along with a warming climate comes increased water vapor in the atmosphere, which means more energy in the atmosphere, thus increasing the chances for extreme weather events; The evidence indicates that heat waves and extreme rainfall events are increasing along a trajectory that is similar to the surface temperature warming; in contrast, the total amount of precipitation does not appear to be changing in a significant way for the Earth as a whole (although various regions have been getting drier or wetter).


You should have read the contents of this module carefully, completed and submitted any labs, the Yellowdig Entry and Reply and taken the Module Quiz. If you have not done so already, please do so before moving on to the next module. Incomplete assignments will negatively impact your final grade.


  • Lab 2: Hurricanes