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Resource Basis - Potato Famine in Ireland


This model simulates the potato famine with events starting in 1842. Somewhat earlier the development of potato agriculture caused Ireland's population to explode. Then there were two rainy and cloudy summers. Without enough solar energy the potatos didn't grow. A potato blight developed so that there was little food. People began to starve and human diseases started. A million people died and three million emigrated.


  • Interface between humans and their environmental resource base.
  • Cold summer in New England which followed the eruption of the Krakatoa volcano in 1883. Volcanic dust floated around the world, cutting down sunlight.
  • Diagram


    S = sunlight
    N = population (density per hectare)
    Q = potato stock (tons per hectare)


    R = S/(1 + K0*N)
    P = K1*R*N/(1 + Y*K4)
    DQ = P - K2*Q - K3*(Q/N)*N
    DN = W*K5*(Q/N)*N - K6*R*N - K7*N - X*K8*N*N + Z*K9*(Q/N)*N


    The graph shows the changes of S(red), N(green) and Q(blue) over a time period.
    Source code:

    "What if" Experiments:

  • What would have happened to the population of Ireland if the weather had not changed? When C=3, the sun is cut to 1/3, so type C=10. And what would have happened to the population if the climate had changed permanently to 1/3 the sun? What statement or statements would you change to keep C=3?
  • Does the pattern you found in the previous question continue after 30 years? Change T0 to 26 to give you 30 years across the plotting.