Maps, Graphs, and Data

Global Land Use for Years 1900 and 2100

Proportion of landcover projected for year 2100

Examine data to evaluate the primary land cover in 1900 versus the projected primary land cover in 2100. Discuss the implications of the differences.

Mini Lesson

These data represent the percent of landcover which is considered to be primary landcover for the years 1900 and 2100 at a spatial resolution of approximately 50 km. The data for 1900 are historical. The data for 2100 are projections from 2006-2100 using four Integrated Assessment Model (IAM) scenarios with different levels of incoming solar energy and outgoing energy, or radiative forcing. Radiative forcing is computed by subtracting the outgoing energy from the incoming energy. 

Primary land cover is natural vegetation that has never been disturbed by human activities such as agriculture or wood harvesting. Secondary land cover is also natural vegetation that is recovering from human activities. It can be very young or as mature as primary land cover. Even if it is mature, it is not considered primary because it has been disturbed and has recovered.

The images below show the percent of landcover which is primary. Examine the images to see the projected differences between 1900 and 2100.

What differences do you see?

Primary Landcover 1900Primary Landcover 2100

Examine the images of Africa and answer the questions.

Primary Land Cover 1900 and 2100 Africa



  1. Use the i-squared writing technique to write a caption for the images of Africa.
    • What do you observe in Africa for 1900?
    • What do you observe in Africa for 2100?
    • What are the differences? 
    • What do these differences signify?
    • Write the caption.
  2. The images show primary landcover only. Using the information provided about secondary cover, what might this mean about the areas shown in white?


Chini, L.P., G.C. Hurtt, and S. Frolking. 2014. Harmonized Global Land Use for Years 1500 – 2100, V1. Data set. Available on-line [] from Oak Ridge National Laboratory Distributed Active Archive Center, Oak Ridge, Tennessee, USA.


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