Annual fluctuations in production are a major feature of the food situation. Often they tend to offset one another to some extent at the regional or global level, but when there are simultaneous drops in production (or increases below the trend rate) in a large number of major countries and regions, the implications for the world food situation are serious. In assessing the longer-term trends in food production, it is therefore necessary to examine the annual fluctuations above and below this trend, and to attempt to determine whether there has been any cyclical pattern in their magnitude or frequency that has affected the longer-term trend itself.
Variations in seasonal rainfall, temperature, and other climatic factors are generally the principal causes of the fluctuations, although the isolation of their effects from those of the other factors involved is difficult and has been accomplished for only a few crops in some developed countries. Fluctuations in production lead to changes in prices, employment, incomes and demand which in turn influence the course of production, generally accentuating the fluctuations caused by the weather. Changes in price and other agricultural policies can cause production to vary sharply from the trend. Civil disturbance, hostilities, natural disasters unrelated to the weather, and pests and diseases (sometimes linked with weather) are other powerful contributors.
[Developing countries] Variable and unreliable national food production is particularly marked in certain developing countries, affected by such destabilizing factors as the drug trade, cash cropping and the economic effects of managing burgeoning foreign debt.