Last 12 months were hottest ever recorded: Report

The last 12 months were the hottest ever recorded, with an estimated 7.8 billion people around the world experiencing above-average warmth, according to a new analysis from Climate Central.

The report, published Wednesday, analyzed temperatures between November 2022 and October 2023 and found global warming surpassed 1.3 degrees Celsius above pre-industrial levels, setting a new 12-month record.

Over the 12 months, the mean temperatures in 170 countries exceeded 30-year norms, meaning 99 percent of humanity experienced above-average warmth, Climate Central said.

Only Iceland and Lesotho experienced cooler-than-normal temperatures, according to the report.

Researchers found about 5.7 billion people from several countries — including Japan, Indonesia, the United Kingdom and Brazil — were exposed to at least 30 days of above-average temperatures during the 12-month span. Using Climate Central’s temperature attribution system, the nonprofit found that these temperatures were made at least three times more likely by the influence of climate change.

Across 200 cities, more than 500 million people experienced streaks of extreme heat, defined by the report as at least five days of daily temperatures in the 99th percentile when compared to the 30-year norms.

Houston experienced the most extreme heat, with 22 consecutive days between July 31 and Aug. 21, while New Orleans and the Indonesian cities of Jakarta and Tangerang had 17 straight days of extreme heat.

In Texas, Austin, San Antonio and Dallas were among the cities with the longest extreme heat streaks. In those cities, Climate Central found climate change made this extreme heat at least five times more likely.

“This 12-month record is exactly what we expect from a global climate fueled by carbon pollution,” said Andrew Pershing, vice president for science at Climate Central. “Records will continue to fall next year, especially as the growing El Niño begins to take hold, exposing billions to unusual heat.”

El Niño conditions arrived early in June, ahead of its typical time frame in late summer or early fall. Forecasters predict El Niño will likely get warmer and cause even higher temperatures next year.

Researchers with Climate Central said the boost from El Niño conditions is “just the beginning.”

Climate Central said the intensity of the recent heat waves is consistent with carbon pollution. On Wednesday, a United Nations environmental agency reported several countries are continuing to expand fossil fuel production despite pledges to have net-zero emissions.

The report found governments around the world will produce double the amount of fossil fuels in 2030 than what is needed to limit global warming to 1.5 degrees Celsius.

Under the Paris Agreement in 2015, the world agreed to try to limit future warming to a threshold of 1.5 degrees Celsius — 2.7 degrees Fahrenheit — though this is for long-term temperature measurements rather than a single month or year. 

The Climate Central’s report follows the findings from the European Environmental Agency, which found 2023 is likely to be the hottest year on record by an estimated 1.4 degrees Celsius, or 2.5 degrees Fahrenheit, above pre-industrial temperatures.