2023 was the warmest year recorded in 173 years of record-keeping, the European Union’s Copernicus Climate Change Service (CCCS) confirmed Tuesday, Jan. 9, 2024. The global average temperature for 2023 was 14.98 degrees Celsius (58.96 F). The previous record was 14.81 degrees Celsius (58.66 F) set in 2016. The record-breaking year, wrapped up with another new record. December 2023 was the warmest December on record globally.
An astonishing seven consecutive months of record-breaking warmth has culminated a grim milestone for humanity: 2023 was, officially, Earth’s hottest year on record.
That assessment follows a year in which extreme heat smothered multiple continents simultaneously pushed ocean temperatures to alarming highs and spurred dire warnings about the worsening effects of climate change.
“2023 was an exceptional year with climate records tumbling like dominoes,” read a statement from Samantha Burgess, deputy director of CCCS. “Not only is 2023 the warmest year on record, it is also the first year with all days over 1 degree Celsius warmer than the preindustrial period. Temperatures during 2023 likely exceed those of any period in at least the last 100,000 years.”
According to CCCS, 2023 saw global average temperatures of 14.98 degrees Celsius, 0.6 degrees warmer than the last 30 years and 1.48 degrees warmer than the pre-industrial period, the second half of the 19th century. It surpassed the previous hottest year on record, 2016, by 0.17 degrees.
Every Day Of A Year
The CCCS found that 2023 marked the first instance recorded in which every day of a year was at least 1 degree hotter than pre-industrial levels. It additionally determined that nearly half of the days in the past year surpassed the temperature threshold of 1.5 degrees Celsius over pre-industrial levels that was set as a limit in the Paris Climate Agreement, while two days in November surpassed 2 degrees above pre-industrial levels, the first time on record that has happened.
The CCCS also said it is “likely” the 12-month period ending in either January or February will surpass 1.5 degrees above those levels.
July And August
The year also saw the warmest two individual months on record in July and August, in keeping with earlier reports that summer 2023 was the hottest summer recorded.
In July, Earth’s hottest month on record, 81% of people on the planet experienced soaring temperatures made more likely by climate change, according to an analysis from Climate Central, a nonprofit news organization that reports on the effects of climate change. Heat waves roiled parts of China, Europe, North Africa, South America and South Asia.
“The extremes we have observed over the last few months provide a dramatic testimony of how far we now are from the climate in which our civilization developed. This has profound consequences for the Paris Agreement and all human endeavors,” Copernicus Director Carlo Buontempo said in a statement. “If we want to successfully manage our climate risk portfolio, we need to urgently decarbonize our economy whilst using climate data and knowledge to prepare for the future.”
Copernicus scientists said as early as November that 2023 was “virtually certain” to be the warmest year on record. That followed reports that October was the hottest October in records dating back to 1940. Copernicus said Tuesday that December was also the warmest December ever recorded, with average temperatures 1.78 degrees above the pre-industrial average for the month.
With a global average temperature of 58.96 degrees, last year was about 0.31 of a degree warmer than the previous hottest year on record, 2016, according to data from Copernicus. December was also the warmest on record globally, as were all the months from June through November.
Official record-keeping of global temperatures began in 1850, or shortly after the end of the Industrial Revolution. Analysis of those records reveal that 2023 was 2.67 degrees warmer than the preindustrial period — or just shy of the 2.7-degree limit (1.5 degrees Celsius) established under the 2015 Paris climate agreement, an internationally recognized tipping point for the worst effects of climate change.
Nearly half the days last year reached at least 2.7 degrees over preindustrial levels, Burgess said.
While global average temperature is an abstract concept for many people — nobody actually lives in a climate that is constantly 59 degrees — the effects of extreme heat were felt by the vast majority of Earth’s inhabitants last year.
Experts say much of the heat was supercharged by the June arrival of El Niño, a climate pattern associated with warmer global temperatures.
Still, the primary cause of increasing global temperatures remains human-caused climate change driven by fossil fuel emissions. The 10 warmest years on record have all occurred since 2010.
“We know for sure that the two main reasons 2023 was warm were an El Niño event on top of long-term climate change,” said Zeke Hausfather, a climate scientist with Berkeley Earth. “The long-term warming is the basis on which any of these records are set, necessarily.”
The latest El Niño arrived on the heels of a rare three consecutive years of La Niña, its cooler counterpart, which may have had a masking effect on the heat, Hausfather said.
“When you flip from temperatures being suppressed to temperatures being enhanced, you might see a bigger effect this year than, say, comparable El Niño events where you went from neutral conditions,” he said.
There are other variables that may have contributed to 2023’s runaway warmth, including the eruption of the Hunga Tonga volcano in the South Pacific the year prior, which shot record amounts of heat-trapping water vapor into the stratosphere.
Reductions in aerosol emissions have also contributed about a tenth of a degree of warming over the last two decades, as sulfate and other aerosols in the atmosphere can reflect sunlight away from the Earth, Hausfather said.
Additionally, solar activity is ramping up as part of an 11-year oscillation known as the solar cycle, which periodically heightens the amount of energy reaching Earth from the sun and may have contributed a couple hundredths of a degree of warming last year.
Yet 2023’s heat came as a surprise even to some scientists. Historical patterns indicate that global temperatures reach peak warmth in the year after El Niño’s arrival, as was the case in 2016 and 2020, the two previous hottest years on record.
The year was so exceptional that dozens of records were broken, according to Copernicus. June through August marked the Northern Hemisphere’s hottest summer on record, while sea surface temperatures remained persistently and unusually high, reaching record levels from April through December. Marine heat waves struck parts of the Mediterranean, Gulf of Mexico, Caribbean, Indian Ocean, North Pacific and North Atlantic.
Last year also saw Antarctic sea ice extents reach record lows for the time of year in eight different months, including all-time daily and monthly lows in February. Arctic sea ice ranked among the four lowest on record at its peak in March.
2024
That means there is a chance 2024 could be even hotter.
The World Meteorological Organization says that the current El Niño event is expected to last through at least April and will fuel further temperature increases in the coming months. El Niño impacts on global temperatures typically play out in the year after its development, meaning 2024 will likely feature further spikes in temperatures on both land and in the ocean.
“I would still probably give slightly better than even odds of 2024 being warmer,” Hausfather said. “It’s going to be up there, but it’s less clear-cut because 2023 was so weird.”
Gavin Schmidt, director of NASA’s Goddard Institute for Space Studies, said similarly in a post on X that there is a 55% chance of another record-warm year in 2024 because of the ongoing El Niño event, but that less confidence is warranted “given the exceptional nature of 2023.”
“The extremes we have observed over the last few months provide a dramatic testimony of how far we now are from the climate in which our civilization developed,” read a statement from Carlo Buontempo, director of Copernicus. “This has profound consequences for the Paris Agreement and all human endeavors. If we want to successfully manage our climate risk portfolio, we need to urgently decarbonize our economy whilst using climate data and knowledge to prepare for the future.”
GHG Emission Soars
Globally, concentrations of two major greenhouse gases (GHG), carbon dioxide and methane hit record highs in 2023. Carbon dioxide levels in 2023 were 2.4 ppm higher than in 2022 with methane concentrations increasing 11 ppb year-over-year.
Despite warnings from scientists, GHG emissions continued to soar in 2023. Carbon dioxide concentrations climbed to a record 419 parts per million (ppm) — 2.4 ppm higher than in 2022, according to Copernicus. Methane concentrations rose to a record 1,902 parts per billion — 11 ppm higher than the year prior — although methane’s rate of increase was lower than in the last three years.
US
Experts say the changing climate is exacerbating extreme events across the globe, including worsening heat waves, floods, droughts and wildfires. Through Dec. 8, the US alone experienced a record 25 weather and climate disasters where damage estimates reached or exceeded $1 billion, according to the National Oceanic and Atmospheric Administration.
November 17 And 18
The data make it clear the 1.5 -degree Celsius benchmark is slipping away. In fact, the planet briefly surpassed 2 degrees Celsius of warming globally — the upper limit of the Paris agreement — for the first time ever on Nov. 17 and 18, according to data from Copernicus.
That same month, world leaders gathered in Dubai for COP28, an annual United Nations climate conference, where nearly 200 countries agreed for the first time to move away from planet-warming fossil fuels.
Climate researchers emphasize that temporarily exceeding limits set in the Paris Agreement do not constitute a failure to the agreement. The limit set forth in the agreement looks at the climate average over many years.
Air Temperature
Average air temperatures were either the warmest on record or close to the record on every continent except Australia.
According to NOAA of the US, the last time Earth recorded a colder-than-average year was in 1976.
Ocean Temperature
Marine heatwaves all over the globe, including the Gulf of Mexico and North Atlantic, contributed to unprecedented ocean temperatures that set even more records.
Analysis of Copernicus’ ERA5 dataset shows that global average sea surface temperatures reached record levels from April through December.
Record highs set both on land and in the ocean contributed to what researchers called a “remarkable” year for Antarctic sea ice. Both the daily and monthly sea ice extents reached all-time minima in February 2023 with 8 months of the year featuring record low extents.
An alarming number of extreme events were recorded across the globe last year, including record-breaking heatwaves, relentless droughts, catastrophic floods, and devastating wildfires. According to researchers, the unprecedented 2023 wildfire season in Canada was a major contributor to a 30% estimated increase in global wildfire carbon dioxide concentrations last year.
“The extremes we have observed over the last few months provide a dramatic testimony of how far we are now from the climate in which our civilization developed,” Carlo Buontempo, director of the CCCS said in a statement.
