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This year is off to a record-breaking start for global temperatures.

It has been the hottest year to date, with January, February and March each passing marks set in 2015, according to new data from the National Oceanic and Atmospheric Administration.

March was also the 11th consecutive month to set a record high for temperatures, which agencies started tracking in the 1800s.

With the release on Tuesday of its global climate report, NOAA is the third independent agency — along with NASA and the Japan Meteorological Association — to reach similar findings, each using slightly different methods.

The reports add a sense of urgency at the United Nations, where world diplomats are gathered this week to sign the climate accord reached late last year in Paris, when 195 nations committed to lower greenhouse gas emissions and to stave off the worst effects of climate change.

Since the initial agreement was reached, other global anomalies have been reported that punctuate the threat of climate change, including troubling trends on Arctic sea ice, floods, drought and carbon dioxide levels in the atmosphere.

Some of these — warm temperatures and heavy rains in particular — can be explained in part by this year’s El Niño phenomenon, which scientists predicted would release large amounts of heat from the Pacific Ocean into the atmosphere, causing irregular weather patterns across the globe.

But the effects of the current El Niño have been exacerbated by global warming, a result of emissions of greenhouse gases by humans, said Jessica Blunden, a climate scientist with NOAA and lead author of the report.

El Niño is on its way out, and ocean temperatures in the tropical Pacific peaked in November, said Kevin Trenberth, a senior scientist at the National Center for Atmospheric Research.

But the heat the ocean had stored had to go somewhere: “It’s come out and been distributed around the world,” which helps explain record warm temperatures and wildfires in the Southern Hemisphere, Mr. Trenberth said.

To get an idea of how much of the record heat is caused by El Niño and how much by global warming, Dr. Blunden said that scientists at NOAA compared this El Niño to the last strong one, in 1997-98, which was also record-setting for its warmth. This one has pushed past those records by raising global temperatures an additional 0.8 degree or so, Dr. Blunden said.

The high temperatures in March probably signaled the last gasp of El Niño, and surface temperatures across the globe are likely to begin to fall this year. Often, El Niños are followed by La Niña storm systems, which can usher in cooler periods, Dr. Blunden said.

But after more than two record-setting hot years — 2014 and 2015 and an extremely warm few months in 2016 — many of the devastating effects of the one-two punch of global warming and El Niño may be inescapable, setting the world on a course for an extended period of rapid global warming, after a period of relatively slow warming that began in 1998 and lasted for about a decade.

Dr. Blunden said that the Arctic was seeing some of the most abnormal weather on earth, with temperatures about 6 degrees warmer than the average over all. These highs could lead to record melting of Arctic sea ice this summer; the ice cover is at its lowest since measurements began to be taken in the late 1970s.

Dr. Trenberth said that these conditions did not represent “a new normal” and that it was difficult to determine the long-term consequences of this El Niño on both global temperatures and Arctic sea ice cover.

He is not sure if 2016 will prove to be as warm as 2015 — “I’m betting it’s a tossup,” he said — but added that it’s not the record heat that comes as a shock.

The magnitude of the jump “is indeed surprising,” Dr. Trenberth said.

A central feature of the Paris climate agreement was to hold the increase in the global average temperature to less than 2 degrees Celsius (3.6 degrees Fahrenheit) warmer than preindustrial levels, and to try to limit the increase to about 1.5 degrees Celsius.

As global temperatures are already nearing the 1.5-degree threshold, and some months have been about 1 degree or more above average, this goal might be difficult to achieve, Dr. Trenberth said.

“I don’t see at all how we’re going to not go through the 1.5 degree-number in the next decade or so,” Dr. Trenberth added.