Climate study: October 2023 bookends hottest 12 months in recorded history

A visitor cools off in a fountain from the Roman period in the Haniya Natural Spring in the Judean Mountains National Park in Israel on July 15 amid a severe heat stress warning. File Photo by Debbie Hill/UPI
A visitor cools off in a fountain from the Roman period in the Haniya Natural Spring in the Judean Mountains National Park in Israel on July 15 amid a severe heat stress warning. File Photo by Debbie Hill/UPI

Nov. 9 (UPI) -- Man-made climate change helped push global temperatures to a new 12-month high, making November 2022 through October 2023 the hottest year since records began, impacting 90% of Earth's population, U.S. climate scientists said Thursday.

The average warming recorded was more than 1.3 degrees Celsius but with the worst of the temperature-boosting effects of the El Nino oscillation likely to be felt next year, rapid annual reductions in carbon emissions are necessary to halt the trend, Climate Central said in a new report.

High temperatures resulting from climate change affected 7.8 billion people for at least 10 days during the year; 5.8 billion people experienced them for more than a month; and 1 in 4 were exposed to "dangerous, extreme" heatwaves that last for a minimum of five days.

Mean temperatures exceeded 30-year norms across all but two nations, exposing 99% of humanity to warmer-than-average temperatures. Iceland and Lesotho were the only states that saw temperatures that were below normal.

Scientists at the Princeton, N.J.-based climate project said their weather attribution analysis showed the 30 days of above-average temperatures that affected almost three-quarters of people on Earth during the year was made at least three times more likely by climate change.

A report published Thursday says man-made climate change helped push global temperatures to a new 12-month high in the year to October, the hottest since records began, and impacting 90% of Earth's population. File Photo by John Angelillo/UPI
A report published Thursday says man-made climate change helped push global temperatures to a new 12-month high in the year to October, the hottest since records began, and impacting 90% of Earth's population. File Photo by John Angelillo/UPI

India and China were impacted disproportionately -- in part due to their latitudes and larger populations -- but also affected were virtually everyone in Japan, Indonesia, the Philippines, Vietnam, Bangladesh, Iran, Egypt, Ethiopia, Nigeria, Italy, France, Spain, Britain, Brazil, Mexico and all Caribbean and Central American nations, Climate Central said.

"This 12-month record is exactly what we expect from a global climate fueled by carbon pollution," said Climate Central's Science Vice President Andrew Pershing.

Children cool off in a water fountain near Jerusalem's Old City on August 13 as temperatures reached 39 degrees Celsius, or 102 degrees Fahrenheit during a scorching heat wave. File Photo by Debbie Hill/UPI
Children cool off in a water fountain near Jerusalem's Old City on August 13 as temperatures reached 39 degrees Celsius, or 102 degrees Fahrenheit during a scorching heat wave. File Photo by Debbie Hill/UPI

"Records will continue to fall next year, especially as the growing El Nino begins to take hold, exposing billions to unusual heat. While climate impacts are most acute in developing countries near the equator, seeing climate-fueled streaks of extreme heat in the U.S., India, Japan and Europe underscores that no one is safe from climate change."

Metropolitan areas were hit particularly hard with more than 500 million people in 200 cities experiencing extreme heatwaves of at least five days when temperatures were in the 99th percentile, compared with 30-year norms.

Metropolitan areas were hit particularly hard by the past year's heat with more than 500 million people in 200 cities experiencing extreme heatwaves of at least five days when temperatures were in the 99th percentile, compared with 30-year norms. File Photo by John Angelillo/UPI
Metropolitan areas were hit particularly hard by the past year's heat with more than 500 million people in 200 cities experiencing extreme heatwaves of at least five days when temperatures were in the 99th percentile, compared with 30-year norms. File Photo by John Angelillo/UPI

Four Texas cities -- Houston, Austin, San Antonio and Dallas -- were among seven cities around the world that endured extreme heat events of up to three weeks. The other three were New Orleans and the Indonesian cities of Jakarta and Tangerang.

In those heat waves, Climate Central's "Climate Shift Index" reached its maximum "Level 5," indicating that climate change made the extreme heat at least five times more likely.

Beachgoers visit Coogee Beach in Sydney, Australia on September 19 as the country swelters through another day of spring heatwave conditions, with temperatures climbing into the mid to high 30s Celsius across several states. File Photo by Dan Himbrechts/EPA-EFE
Beachgoers visit Coogee Beach in Sydney, Australia on September 19 as the country swelters through another day of spring heatwave conditions, with temperatures climbing into the mid to high 30s Celsius across several states. File Photo by Dan Himbrechts/EPA-EFE

Climate Central's report comes a day after European Union scientists also said October was the warmest in recorded history and that global "surface air temperature anomalies" had placed 2023 on track to be Earth's warmest ever year.

With an average temperature of 15.3 degrees Celsius, almost one degree above the 1991-2020 average and 0.4 degrees Celsius above the previous warmest October in 2019, the EU's Copernicus Climate Change Service said October was the warmest since records began in 1850.