Possible Impact on Agriculture Due to Climatic Change and Variability in South America

Abstract

Climatic fluctuations are a risk factor in agriculture. They hinder agricultural development in extensive and and semi-arid tropical areas of South America. The main uncertainty factors in the tropics are the amount and distribution of rainfall in dryland-farming areas and, in the subtropics, possible spring frost where temperate and subtropical species coexist. Economic losses, caused by these climatic phenomena, should not be underestimated. In Chile, annual losses in agriculture, due to frost, are estimated from 12 to 20 million US$, and due to droughts from 40 to 120 million US$ (Santibáñez 1983). To appreciate the magnitude of this problem at a South American level, these values would have to be multiplied by a factor of at least 8 to 10. Drought also affects irrigated areas, because streams and rivers depend on runoff water and/or the accumulation of snow in the upper Andes. The Brazilian northeastern arid zone, one of the agricultural areas with most variable precipitation in South America, is almost entirely dependent on rain for crop production. However, in the last few years underground water has been tapped for irrigation. Livestock production is especially uncertain in areas with less than 300 mm rainfall per year. In spite of this, there is an important segment of the population who depend on the rain to survive in the Chilean mediterranean climates and and steppes of Tierra del Fuego.