The chart below shows how in El Niño years (red), the temperature is above the trend, in La Niña years (blue) it is below, and in years when there is a big volcanic eruption (grey), it is below trend. Yellow shows years when there were neither volcanic eruptions nor ENSO (El Niño/La Niña) fluctuations. Note that the chart does not include 2016, which will also be an El Niño year, and is even hotter than 2015. 2017 may or may not be a La Niña year. If it is, there will be a temporary cooling before the longer term trend reasserts itself. But note how in the "normal" years after the last La Niña (2010) global temps have risen each year--even though they weren't El Niño years. It's a scary trend.
It is absolutely vital that we switch as rapidly as possible to renewables in electricity generation and to electric powered vehicles.