How much does El Niño contribute to climate change?
The year 2014 was remarkable to climate scientists because it was the warmest year on record. That is, until 2015, which replaced it as the warmest year on record. That is, until 2016, when the record was broken again.
“2016 is remarkably the third record year in a row in this series,” explains Gavin Schmidt, director of NASA’s Goddard Institute for Space Studies. “We don’t expect record years every year, but the ongoing long-term warming trend is clear.”
Even though El Niño conditions were in effect for significant portions of 2015 and 2016, Schmidt says the weather pattern only made minor contributions to overall global temperature changes. NASA attributes a 0.5˚C boost to El Niño in 2015 and a 0.12˚C boost in 2016—just a fraction of the total temperature change.
“Effectively, the modern trend is providing 90% of the signal, and El Niño is contributing 10% of the signal,” he says. “We’re only seeing these records because of greenhouse gases, not El Niño. We anticipate when we have an El Niño at the beginning of the year, we expect to have a slightly warmer-than-average year.”
And what—or who—is the cause of more greenhouse gases? “Pretty much all of the long-term trend can be attributed to human activity,” Schmidt says.
Earth’s oceans have played an interesting role in climate change, absorbing around 90% of the heat caused by greenhouse gases, according to Deke Arndt, chief of NOAA’s National Centers for Environmental Information’s monitoring branch.
“It’s something of a savings account,” he adds. 2016 ended up 1.69˚F warmer than the 20th century average. No land areas were cooler than average for the year and record-breaking warm temperatures happened in several areas, including far eastern Russia, Alaska, far western Canada, portions of the eastern U.S., much of Central America and northern South America. Every U.S. state saw warmer-than-average temperatures in 2016.
By continent, North America saw its warmest year on record in 2016, with the second-warmest year on record for Africa and South America, and the third-warmest year on record for Europe and Asia.