October 2023 capped the hottest 12 months in recorded history

A new analysis of international data, released by Climate Central, reveals that global temperatures have broken records over the past 12 months.

From November 2022 to October 2023, the Earth's average temperature exceeded pre-industrial levels by a staggering 1.3 degrees Celsius. This period is now recognised as the hottest year-long stretch ever recorded in history.

In a concerning trend, temperatures in 170 countries surpassed the 30-year norms during this time frame, exposing a staggering 7.8bn people – representing 99% of the world's population – to above-average warmth.

Remarkably, only Iceland and Lesotho reported cooler-than-normal temperatures.

Between November 2022 and October 2023, a significant portion of the global population, totalling 5.7bn individuals, endured over 30 days where the impact of climate change made unusually warm temperatures at least three times more likely.

A comprehensive weather attribution analysis indicates that during this period, 5.7 billion people faced at least 30 days of above-average temperatures, which were made significantly more probable by the influence of climate change – reaching level-three on Climate Central's Climate Shift Index (CSI).

This widespread exposure extended to nearly all residents of countries such as Japan, Indonesia, the Philippines, Vietnam, Bangladesh, Iran, Egypt, Ethiopia, Nigeria, Italy, France, Spain, the United Kingdom, Brazil and Mexico, as well as every nation in the Caribbean and Central America.

In India, a striking 1.2bn individuals, equivalent to 86% of the population, encountered Climate Shift Index level-three temperatures on 30 or more days. In China, this figure amounted to 513mn residents, or 35% of the population, while in the United States, 88mn people – 26% of the population – experienced at least 30 days of temperatures that were made at least three times more likely by climate change.

Over the same period, more than 500mn people across 200 cities experienced extended periods of extreme heat, characterised by a minimum of five consecutive days with temperatures in the 99th percentile when compared with the 30-year norms.

Notably, no major city on Earth matched Houston's remarkable 22-day streak of extreme heat between July 31 and August 21. New Orleans, Jakarta and Tangerang in Indonesia followed closely with 17 consecutive days of extreme heat. Austin (16 days), San Antonio (15 days), and Dallas (14 days) also joined the list of cities with the longest stretches of extreme heat.

In each of these cities, the Climate Shift Index consistently reached the maximum level-five, signifying that climate change had made such extreme heat at least five times more likely.

Dr Andrew Pershing, the vice president for science at Climate Central, commented on this alarming situation, stating: "This 12-month record is exactly what we expect from a global climate fuelled by carbon pollution. Records will continue to fall next year, especially as the growing El Niño begins to take hold, exposing billions to unusual heat.

“While climate impacts are most acute in developing countries near the equator, seeing climate-fuelled streaks of extreme heat in the US, India, Japan and Europe underscores that no one is safe from climate change."