VULNERABILITY OF THE GLOBAL AGRICULTURAL ECONOMY TO VOLCANIC ERUPTIONS: LESSONS FROM TAMBORA

In the past, agricultural products were consumed close to where they were grown, and what farmers planted was determined by the balance between what people wanted locally and what could be grown locally. As agriculture has become part of the global economy, the rules have changed and farmers can often maximize the return on their investment by growing high demand crops that can't be grown in those regions which have less favorable climatic conditions. In effect, the primary goal has become one of taking almost full advantage of the available growing season. However, the curve of mean daily temperature versus time is relatively flat during the summer. As a result, a slight reduction in actual daily temperatures caused by cooling associated with a volcanic eruption can significantly reduce the length of the growing season in a given year, leading to a major perturbation of the global agricultural economy. The eruption of Tambora volcano in Indonesia on April 10, 1815 produced significant atmospheric cooling and led to the designation of 1816 as the Year Without a Summer. Accounts of the impact of this eruption on climate and agriculture around the world can be used to assess the impact that a similar eruption might have on the current global agricultural economy.