Here are a couple of helpful graphics looking at global warming in relation to ENSO events. During La Nina years, we expect the earth to cool(ish). During El Nino years we expect the earth to warm(ish). This pattern sort of cycles over several years, with neutral years in between (it isn’t a very regular cycle). The influences of the tropical Pacific, manifest as La Nina and El Nino periods is then, of course, superimposed over the longer term warming trend caused by increase of greenhouse gases in the atmosphere. Technically, 2014, which was the warmest year during the instrumental record beginning in the 19th century, was a neutral year, though there were some El Nino tendencies.
This graph, from Climate Central, helps show this relationship:
Dana Nuccitelli is the master of animated climate change graphs. He has produced a graph that shows the surface temperature record for only La Nina years, only El Nino years, and all the years together, in a way that makes the point. The original graphic can be found here, and further discussion of it can be found here. Here is the moving GIF … but if it doesn’t move for you go to one of the provided links and get to the original version.