The planet’s warm streak has continued: 2018 was the fourth-hottest year on record since our measurements began, in the 1880s.
According to an analysis released today by NASA and the National Oceanic and Atmospheric Administration (NOAA), 2018 ranked just behind 2016, 2017, and 2015 as the hottest year on record. Taken together, the past 5 years have been the warmest, keeping up with a record-scorching decade. A respite from the baking temperatures doesn’t appear to be in sight: 2019 may be warmer than 2018, given the El Niño that’s sluggishly developing this year.
“The long-term trends are extremely robust,” said Gavin Schmidt from NASA in a press conference. He said that the reason for the warming is clear: “It’s because of the increases of greenhouse gases that we’ve put into the atmosphere over the last 100 years.”
NOAA also released its annual billion-dollar disasters tally. The agency keeps track of weather disasters in the United States that account for more than $1 billion in direct losses. Since the tally began in 1980, the average number of billion-dollar disasters per year has been 6.2. In 2018, however, there were 14 events topping $1 billion. Western wildfires amounted to the majority of the losses, costing $73 billion of the $91 billion total.
Some countries, particularly in Europe, had their hottest years yet. France, Germany, and Switzerland all topped their previous records for warmest year on average.
In the United States, temperatures were more forgiving. The past year placed fourteenth-hottest for the country. One of the clearest signals in the data is the warming of mornings in the United States, said Deke Arndt of NOAA. “This is one of the most significant and emergent themes in the 21st century that we’ve seen in U.S. temperatures,” Arndt noted. He explained that mornings are particularly sensitive to warming because the atmosphere compresses at night and intensifies the warming effect.
Both sides of the United States were racked by disparate problems in 2018: The West saw persistent drought in the Pacific Northwest and the Southwest. Warmer temperatures can exacerbate drought by limiting water stored in soil. On the other side of the country, the Mid-Atlantic and the upper Midwest had record-breaking precipitation. Warmer air carries more moisture, leading to storms that can deliver more water, said Arndt.
The planetwide warming trend “resembles riding up an escalator over time,” said Arndt. Although there are small wiggles in the upward climb, some caused by the El Niño–Southern Oscillation, the overall trend is still rising.
President Donald Trump delivered his second State of the Union address last night and did not mention climate in his speech. Trump claimed that the United States ranks as “the number one producer of oil and natural gas in the world” and praised the “revolution in American energy.”
The Trump administration released the Fourth National Climate Assessment late last year that states that rising temperatures will exacerbate power generation, leading to lower efficiency and higher costs. The report predicted that if greenhouse gas emissions continue without intervention, the annual losses in profits for the United States may rise to hundreds of billions of dollars by the end of the century, topping the gross domestic product (GDP) of many U.S. states.
Although the percentage of North American emissions in greenhouse gases has dipped slightly, Schmidt said that emissions show no sign of slowing.
“We still collectively have our foot on the accelerator,” he said.
—Jenessa Duncombe (@jrdscience), News Writing and Production Intern
Duncombe, J. (2019), 2018 is the fourth-hottest year on record, Eos, 100, https://doi.org/10.1029/2019EO115671. Published on 06 February 2019.
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