In addition, there is some potential that we will see a new global surface temperature record in 2014 or 2015. It is looking increasingly likely that El Nino will develop this summer or fall, with some indicators suggesting that it could be a moderate or strong event.
El Nino is characterized by relatively warm sea surface temperatures in the tropical Pacific Ocean which, along with other accompanying changes in atmospheric and oceanic circulations, typically leads to an increase in global temperatures. Conversely, La Nina is associated with relatively cool sea surface temperatures in the tropical Pacific Ocean and a decrease in global temperatures. This can be seen in the graphic below, which categorizes years based on El Nino (red), La Nina (blue), or neutral/other conditions (a.k.a., "No Nino").
That categorization doesn't distinguish, however, between weak and strong El Nino events. 1998 was characterized by a very strong El Nino and it remains one of the warmest years on record. Note what an outlier it was compared to the period in which it is embedded. There has subsequently been only one El Nino Year (2010) and it was a weak one. However, the most recent 10-year period is clearly the warmest decade in the instrumented record so it is quite likely that a moderate to strong El Nino will likely yield record global surface temperatures.
In the above analysis, NCDC classifies a year as El Nino or La Nina based on the first three months of the calendar year. This reflects that fact that El Nino and La Nina typically reach their peak strength during the Northern Hemisphere winter. However, this also makes the categorization a bit more difficult since the peak El Nino/La Nina conditions often straddle the start/end of the calendar year. For example, some classify 2010 as a La Nina year since there was a rapid transition from El Nino to La Nina conditions during the Northern Hemisphere spring and summer.
On the other hand, there is often a lag of a few months between peak El Nino/La Nina conditions and the accompanying increase/decrease in global temperature anomalies. This is why we might need to wait for 2015 for a record. Alternatively, we could bag this calendar year crap and instead look at a 12-month period encompassing the peak El Nino/La Nina period. Here's what the global temperature trend looks like for July-June average temperatures.
All of this suggests that if we can get a moderate to strong El Nino to develop, we will probably see record setting global temperatures for some 12-month period if not the calendar year. Perhaps even a weak El Nino will do the job. We'll have to see how things come together in the coming months and see if there are any surprises, like a huge volcanic eruption to cool things off.