2019 may be the warmest year on record as a result of an El Niño event exacerbated by global warming

Climate scientists warn that 2019 may be the warmest year on record largely as the result of a possible El Niño event exacerbated by man-made global warming.

There is a 90 percent chance that El Niño will form and continue through the Northern Hemisphere winter of 2018-19 and a 60 percent chance that it will continue into the spring of 2019, according to the Climate Prediction Center at the National Oceanic and Atmospheric Administration (NOAA).

El Niño is a part of a routine climate pattern that occurs when sea-surface temperatures in the tropical Pacific Ocean rise to above-normal levels for an extended period of time. It can last anywhere from 4 to 16 months and it typically has a warming influence on the global temperature.

The opposite of El Niño, La Niña, is when sea-surface temperatures in the central Pacific drop to lower-than-normal levels.

These warm and cool phases are part of a recurring climate pattern that occurs across this section of the Pacific, known as the El Nino-Southern Oscillation (ENSO), according to the National Oceanic and Atmospheric Administration (NOAA).



The strong El Niño of late 2015 to early 2016 helped boost global temperatures to their warmest on record in 2016, according to AccuWeather Senior Meteorologist Brett Anderson.

"However, if there was no El Niño during that period, I still suspect that 2016 would have still ranked as the second warmest year on record globally due to the steady increase in greenhouse gases into the atmosphere, which trap heat closer to the surface," Anderson said.

So far, 2018 is on pace to likely be the third warmest year on record, behind 2016 and 2017.

"What's interesting is that 2018 started out under La Niña conditions, which usually has a cooling influence on global temperatures, but it was not nearly enough to cancel out the warming from the release of man-made greenhouse gases," Anderson said.

However, since late April 2018, sea-surface temperatures across much of the east-central tropical Pacific returned to neutral levels following the La Niña of 2017-18, meaning neither La Niña or El Niño present.

"Looking back at the data, years with moderate to strong El Niño's continue to trend warmer. If this upcoming El Niño reaches at least moderate strength and persists at least 9 months, then I think that 2019 can end up in the top two warmest on record globally," Anderson said.

The global temperature impacts of El Niño are sometimes delayed. Therefore, 2020 may end up warmer than 2019 even though this upcoming El Niño may be well over by that time.

Global ocean water temperatures in October 2018 ranked as the second warmest on record for October. Oceans can store a lot of heat, thus the world's oceans may remain near or at record warmth through 2019, which will further add to the warming influence of the global air temperature.

It is certainly possible that 2019 may be the warmest year on record, Anderson said.

"I am not ready to say it will be the warmest on record yet. Though I am fairly confident that it will at least rank in the top three regardless of the strength of the El Niño," Anderson said. "Ask me again in March."

The impacts of El Niño have been more severe in recent years due to global warming, and these impacts may be worse as temperatures continue to rise, according to a recent study in the journal Geophysical Research Letters, published on Aug. 22.

Emerging research suggests that the typical atmospheric responses to La Niña and El Niño are changing and that the expected weather in the United States may not follow the traditional ENSO pattern.

The AccuWeather Long-Range Team closely follows the on-going research linking climate change to the long-term trends in ENSO patterns, according to AccuWeather Long-Range Meteorologist Max Vido.

"When creating our seasonal forecasts for the U.S., we take into account the long-term climate trends when predicting temperature and precipitation anomalies compared to the 30-year normal (1981-2010)," Vido said.

The team has become increasingly vigilant of how the global weather pattern during more recent El Niño and La Niña events can differ from the traditional expected patterns.

"So, instead of assuming a certain ENSO phase will lead to a particular seasonal weather pattern to areas of the U.S., we acknowledge how the once traditional impacts could be different. This is all factored into our seasonal forecasts," Vido said.

As of November 2018, El Niño has not officially begun and questions remain about the strength and longevity of this El Niño.

The years 2014, 2015 2016 and 2017 all rank in the top four warmest years on record globally, ocean and land combined, with data going back to 1880, according to the National Aeronautics and Space Administration (NASA).

"It's not hard to see that with the potential added boost from another El Niño that 2019, or even 2020, is a pretty good bet to take out some of those years from the top four list," Anderson said.

Seventeen of the 18 warmest years in the 136-year record all have occurred since 2001, with the exception of 1998, which was a strong El Niño year, according to Anderson.

Research shows that the warming climate will have a profound affect on extreme weather events, such as heat waves, wildfires, droughts, flooding and violent storms.

The U.S. government released a report in November 2018 that highlights these impacts. The report examines the effects that climate change will have on health, local communities, the economy and infrastructure.

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