Severe droughts in the Philippines in AD 1700-1800

Thursday, 18 December 2014
Rhodelyn Saban1, Fernando Pascual Siringan2 and Cesar Villanoy2, (1)Marine Science Institute, University of the Philippines, Metro Manila, Philippines, (2)Marine Science Institute, University of the Philippines, Quezon City, Philippines
Large precipitation variability can lead to either flooding or droughts that can greatly impact the society. The more recent past can give us better insights on the possible range of precipitation changes in the coming years and needs to be investigated. A two-meter long sediment core acquired in a 300 m deep basin on the shelf off the eastern coast of northern Luzon Philippines was used to reconstruct changes in precipitation in the past millennia. Geochemical data generated using an XRF core scanner and grain size measured using a laser particle analyser were used as precipitation proxies. Trends of Ti and Al/Ti revealed an overall decreasing precipitation throughout the millennia. The period AD 1700 to 1800 is indicated to have experienced the lowest precipitation within the past millennia. This decrease in precipitation is also indicated by a decrease in silt fraction. Historical records list severe droughts leading to famine and crisis in the country. This period of lowest precipitation fall within a La Nina-dominated period shifting to an El Nino-dominated condition and is coincident with a negative Pacific Decadal Oscillation (PDO) phase.