Global dimming
A web-based activity exploring this recently identified phemomenon

created by Kaye Placing
UniServe Science

Introduction | Task and Resources | Glossary | Follow-up |


We hear and read a great deal about climate change and in particular "global warming". But it is only in recent years that we have been alerted to another man-made feature of climate change - "global dimming".

In this WebSheet, you will investigate the phenomenon known as "global dimming", how it was discovered, its cause and effect and what are the consequences if we do, or do not, act to slow or stop "global dimming".

Task and resources

Construct answers for the following questions from the information to be found in the web sites list below.

In constructing your answers, note the web site from which the information was obtained.

  1. Examine the observations that have led some scientists to propose the phenonemon termed "global dimming" or "solar dimming"
  2. Define "global dimming"
  3. Account for the fact that the theory of "global dimming" was ignored for over 30 years
  4. Outline the suggested causes of "global dimming"
  5. Discuss the possible effects of "global dimming" and some events that have been attributed to "global dimming"
  6. Describe two experiments or observations that support the theory of "global dimming"
  7. Compare "global dimming" and "global warming"
  8. Deduce the effect on "global warming" if "global dimming" is rectified
  9. Which is the more accurate term for this phenomenon, "global dimming" or "solar dimming"? Can you suggest an alternative term? Justify your answer.

Useful web sites

  • Goodbye sunshine
    - from The Guardian newspaper
  • Global dimming
    - summary of Horizon program on BBC (also screened on ABC 4 Corners) with link to transcript
  • Why the Sun seems to be 'dimming'
    - from BBC
  • Global Dimming
    - from Global Issues that Affect Everyone
  • Global Dimming
    - from 4 Corners, ABC
  • Could Global Warming Mean Less Sunshine and Less Rainfall?
    - from Earth Observatory, NASA
  • Global Dimming: A Hot Climate Topic
    - from US Department of Energy's Atmospheric Radiation Measurement (ARM)


    Here are some words that you may come across in your research. Find meanings for them by entering "define" and the word in the Google search engine.
    1. Pan evaporation
    2. aerosols
    3. anthropogenic
    4. contrail
    5. effective rainfall
    6. evapotranspiration
    7. particulates
    8. insolation


    Summarise the usefulness of each of the web sites used in order to complete the questions above. Consider such issues as:
    • Was the information presented in each web site comprehensive?
    • Was the information presented in a web site biased?
    • Was the information from a identified, reputable source?
    • Was the information referenced?

    [an error occurred while processing this directive]

    Page Maintained By:
    Last Update: Monday, 30-Apr-2012 15:05:55 AEST