2023 was the hottest year on record — by a long shot
Nicole Mortillaro | CBC News | Posted: January 9, 2024 12:00 PM | Last Updated: January 9
2023 'surprised all climate scientists,' says deputy director of EU's climate agency
After a year of record-breaking wildfires across Canada and the hottest temperature ever recorded on Earth, it likely comes as no surprise that 2023 was the hottest year on record.
According to the European Union's Copernicus Climate Change Service (C3S), 2023 was 1.48 C warmer than the pre-industrial average from 1850-1900, beating out 2016's record of 1.25 C.
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As we continue to burn fossil fuels and pump greenhouse gases into the atmosphere, the planet keeps getting warmer. According to the climate agency, global CO2 levels were 419 parts per million (ppm) in 2023, an increase of 2.4 ppm from the previous year.
To put that into perspective, in 1988, the year climate scientist James Hansen warned the U.S. Congress about global warming, it was 351 ppm. And it's currently increasing at a much faster rate than in the past.
But last year's rapid jump in global temperatures has taken even climate scientists by surprise.
Last year, "it's fair to say, surprised all climate scientists: the sheer number of records that were broken, and how they were broken. They were broken by very large amounts," said Samantha Burgess, deputy director of the C3S.
"Our expectation was with this transition to El Niño, that it would be warmer than [2022]. But we weren't sure, particularly at the beginning of the year ... until spring … we didn't think it would be as exceptional as it was," she said. "And then we saw these record-breaking global temperatures in the summer."
Here are just some of the unusual records Earth experienced in 2023, according to C3S:
- 2023 had a global average temperature of 14.98 C, which was 0.17 C higher than the previous highest average temperature in 2016.
- 2023 was 0.60 C warmer than the 1991-2020 average.
- C3S says it is likely that a 12-month period ending in January or February 2024 will see average temperatures exceed 1.5 C above pre-industrial levels.
- 2023 marks the first time on record that every day within a year has surpassed 1 C above the 1850-1900 pre-industrial average.
- Almost 50 per cent of those days were more than 1.5 C warmer than the 1850-1900 average.
- Two days in November were more than 2 C warmer than the pre-industrial average, the first time this has ever occurred.
- July and August 2023 were the warmest two months on record.
- The meteorological summer (June to August) was also the warmest season on record
NASA and NOAA will release their findings on the global climate on Friday. While there may be a slight variation in their numbers — as their methodology differs from that of C3S — it's likely they will be similar. And, ultimately, it's the continued upward trend that matters.
While the increase of CO2 in the atmosphere is the main driver of climate change, there were other factors involved in 2023, including the overall increase in ocean temperatures, which store roughly 90 per cent of our planet's heat.
"We saw record sea surface temperatures for the time of year from April all the way through to December, with sea surface temperatures about half a degree or more warmer than they normally are," Burgess said. "And because the ocean is 70 per cent of the surface of the planet, this has a huge impact on global temperatures."
Added to that was the presence of an El Niño, a cyclical and natural ocean variability in the Pacific Ocean which can cause a rise in global temperatures. However, the effects of an El Niño are typically felt in the subsequent year, so there is a chance that 2024 will be even warmer than 2023.
James Hansen, who is now the director of climate science, awareness and solutions at Columbia University, told CBC News in an email that it's likely Earth's average temperature increase will exceed 1.5 C over the coming 12-month period.
"By late spring, it will be in the range 1.6-1.7 C warmer than in 1880–1920, which is our best estimate for pre-industrial," he said.
Debate over a potential acceleration
But not everyone is surprised by last year's record warmth.
"The warming is within the range we expect from the combined effect of continued long-term warming plus a boost from a major El Niño event," Michael Mann, a climate scientist and professor of earth & environmental science at the University of Pennsylvania, told CBC News in an email.
And, he said, global warming is continuing at a steady rate of roughly 0.28 C per decade, which is what was observed in 2023.
However, NASA and NOAA both suggest that the warming has been closer to 0.20 C per decade.
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But Hansen, who has continued his research since that 1988 congressional hearing, believes the planet is seeing a rapid shift.
"It confirms our conclusion that global warming is accelerating," he said of 2023's record heat.
He said the UN's Intergovernmental Panel on Climate Change (IPCC), the leading international authority on the issue, has been assuming that global emissions are near their peak and will begin to decline, as will global warming.
Hansen rejects that perspective. "The observed record 2023 global temperature, the certainty that it is going still higher in 2024, and the unprecedented planetary energy imbalance (more energy coming in than going out) assure that their assumption is hogwash, to use a milder agricultural [term] than the one I usually use."
Pushing for change
Burgess said she hopes that people take notice of this year's record warmth
"The more conversations we have about climate, the more likely we are to see that political action and change," she said.
With more warming, we will see more severe climate impacts, she added, including wildfires, droughts, more intense hurricanes and floods.
Hansen, who has been speaking out about climate change for more than 40 years, said that he, too, would like to see more action.
"As long as money rules in our governments ... as long as special interests are allowed to buy our politicians, we cannot solve the climate problem," he said.
"My New Year's resolution is to make the story clear enough to young people and to make young people more aware of their political power, so that within this decade they will be able to take charge of their future instead of simply protesting against the failure of the older generation."
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