Relationship between the 1997/98 El Niño and 1999/2001 La Niña events and oil palm tree production in Tumaco, Southwestern Colombia

Abstract. Although the relationship between ENSO events and oceanographic and meteorological conditions of Southwestern Colombia is well-known, very little work has been done to assess the related socio-economic impacts. This is the first effort made to determine the effect of such events on local climate and the impact of this variability on oil palm tree (Elaeis guineensis) production in the Tumaco municipality, which is located on Colombia's Pacific coast. First, we studied the correlation between sea surface temperature anomalies (SSTA) in the various El Niño regions and those observed off Tumaco. Next, we scrutinized the ENSO impact on regional climatic indicators, e.g. active solar radiation (hrs/day), air temperature (°C), and rain (mm). Finally, we analyzed the relationship between ENSO, Tumaco climate variability, and oil palm production (tons/hectare-month). Hours of active radiation increased (decreased) under El Niño (La Niña) conditions, as did average monthly precipitation rates and air temperature. ENSO-related climatic variability also had an important effect on the different developmental stages of the oil palm tree, thereby affecting its production. The worst scenario was found during La Niña, when reduced intensity of the rainy season (second semester) caused severe droughts in the region.