The Irish Potato Famine

The Irish potato famine has been called the "last great European natural disaster." The famine was caused by a blight that wiped out Ireland's potato crop during the summer of 1846. An estimated one-half million died from starvation and another one million from epidemics during the harsh winter of 1846-47.

The tragedy of the famine was rooted in the unique conditions that gradually developed in Ireland as a result of the introduction of the New World potato many years earlier. The bulk of the Irish people were confined to relatively small and marginally productive lands by the English. But, the potato, yielding enough protein to sustain a family of six and their animals, permitted population growth, which in turn, dictated that more lands be devoted to the potato, allowing more population growth. On the eve of the famine, this cycle had resulted in virtually all lands available to the Irish being in full production. But, the population had grown so large that it was finding it increasingly difficult to meet minimum calorie requirements. Thus, when the potato crop failed, the Irish were unprepared with food or land reserves with which to respond.

Lacking adequate food and vulnerable to disease, 1.5 million Irish died, while another 1.6 million assembled their meager belongings and, in the eight years between 1846 and 1854, departed Ireland to find new homes abroad (the vast majority destined for North America).

In 1854, many historians suggest, the effects of the famine upon the Irish had subsided. But are the historians correct? Or, were there longer-term effects that historians have overlooked?

To address this question, use a system dynamics model to examine whether or not two major developments associated with the famine (1.5 million deaths and 1.6 million emigrants) produce the pattern of actual population levels presented in the table below. If so, historians are correct and the effects of the famine were over by 1854. If not, modify the model to better reflect the actual pattern of population.

    Population of Ireland
       (in millions)

    1791        4.753
    1821        6.802
    1831        7.767
    1841        8.175
    1851        6.552
    1861        5.799
    1871        5.412
    1881        5.175
    1891        4.705
    1901        4.459

You will produce two models. The first assumes that emigration ceases after 1854. When the results of the first model are compared to historical data, you will see that the model does not recreate actual population behavior after 1854 (see below). You will then modify the model to better match the historical data.