The difference in chlorophyll concentration in the Galapagos Archipelago when comparing El Niño (top) to La Niña (bottom) © NASA Earth Observatory

A global weather even that is the counterpart of El Niño. During La Niña the ‘normal’ weather conditions intensifies and the low pressure over the western Pacific becomes even lower. This causes a drop in sea temperature around the west coast of South America of between 3 and 5°c. Furthermore, rainfall increases over South East Asia while South America experiences drought. Generally La Niña will follow El Niño although this is not always the case.