Why is it not surprising that 2016 was the third year in a row to have record-high surface temperatures

If you guess long-term climate change—Yes! If you guess El Niño—Yes! Also correct. If you guess supermoons—umm, sorry, not so much.

The Background
First, Earth’s temperature has been rising at an average rate of 0.13°F each decade since the start of the record in 1880 and more than twice that rate (0.31°F) if you consider the past half century alone. That increase is due to long-term warming.

Second, natural climate cycles, the biggest player being the El Niño-Southern Oscillation (ENSO), cause global temperatures to temporarily rise (El Niño) or fall (La Niña). Generally, the stronger the El Niño or La Niña, the greater the impact will be on the average global temperature. Over time, the effects of El Niños and La Niñas balance each other out, so the net effect on long-term warming is negligible.

Because of its strength and lingering effects, the 2016 annual global temperature was influenced more by El Niño than by La Niña. And so, with the global temperature already elevated at the beginning of the year, 2016 set yet another annual global temperature record, albeit by a slimmer margin of 0.07°F.