Each vertical bar in this plot represents NASA’s estimate of the the annual average temperature compared to the 1951 to 1980 baseline. Each horizontal rule represents 0.1 °C. Orange bars are El Niño years, blue bars are La Niña years, and gray bars are neutral years. During El Niño, currents in the South Pacific prevent upwelling of deep, cold water, and the surface waters get warmer than they would with upwelling. During La Niña years, currents create extra upwelling and make surface water cooler. The ocean area and amount of water involved in this phenomenon are so large that they have a pronounced effect on the atmosphere’s annual average temperature as seen in the plot.
2013 and 2014 were both neutral years, when the amount of upwelling was average. They are about as warm as the four earlier El Niño years (2010, 2007, 2005, and 2003).
2014’s anomaly map (below) indicates that the main land areas on the planet that were cooler than the average was the eastern U.S. and Canada.