Mini Lesson/Activity

Evaluating Natural and Human Activities Effects on Earth's Climate (Student Activity)

Mini Lesson

What happens when the amount of energy entering into the Earth system does not equal the amount that exits?  This is a simple question with a complicated answer.

Imbalances in the Earth's Energy Budget, called radiative forcings, cause chemical and physical changes in the Earth system that impact the climate. An example of this imbalance is the current trend in Earth's energy budget; the Earth system has more energy entering than leaving (called a "positive forcing"). Conversely, if more energy exits than enters the system, the planet would cool ("negative forcing"). 

Energy into Earth - Energy leaving Earth = Radiative Forcing Amount

Prior to the Industrial Revolution, the radiative forcing was nearly balanced and Earth's atmosphere was relatively stable.  Scientists use a year prior to this era, 1750, as a baseline to compare radiative forcings and measure the impact of anthropogenic activities of modern times that affect our climate. See the chart below to identify and analyze the warming or cooling effects of these forcings. Notice that there are two main categories:  anthropogenic (human-caused) and natural. 

Radiative Forcing Caused by Human Activities Since 1750, Credit: EPA
Credit: EPA

Review the chart above and answer the following questions:

  1. What is the net total value of radiative forcing (in watts per square meter) of natural activities?  Anthropogenic (human) activities?
  2. Of the anthropogenic activities, which factor has the greatest value?  What category does this belong to?
  3. Which of the factors have both a cooling and warming effect on climate?  
  4. What is the overall radiative forcing effect on climate since 1750?
  5. Why is the year 1750 selected as a baseline?
  6. What are three questions that you can ask of this chart?

Teacher Note

Teachers, these mini-lessons/student activities are perfect "warm-up" tasks that can be used as a hook, bellringer, exit slip, etc.

Teachers who are interested in receiving the answer key, please contact MND from your school email address at  We verify that requestors are teachers prior to sending access to the answer keys as we’ve had many students try to pass as teachers to gain access. To receive the keys please provide the following:

  1. The link to the school/institution’s teacher directory where you are employed so we can verify that you are a teacher
  2. Ensure that the school email address is provided in your response as we are unable to send to personal email accounts

Related Mini Lessons

Grade Band

Crosscutting Concepts


Download this page