hottest months on record

The study found that in 170 countries, mean temperatures over the hottest months on record exceeded 30-year norms, exposing 7.8 billion people — 99% of humanity — to above-average warmth.

Climate change makes the last 12 months hottest on record : Study

The period between November 2022-October 2023 was the hottest 12 consecutive months ever recorded and the Global Mean Temperature (GMT) was around 1.3°C hotter than the pre-industrial climate, the study says

The past 12 months have been the hottest ever recorded, 1.3°C above the pre-industrial climate, according to an analysis published by Climate Central. This marks the hottest year-long period in recorded history, driven by climate change that is the result of burning fossil fuels and other human activities. 

The analysis using the Climate Shift Index (CSI) — Climate Central’s daily local temperature attribution system — indicated that human-caused climate change significantly elevated temperatures over the past 12 months. The analysis looked at daily average temperatures and heat waves and included data for 175 countries, 154 states/provinces, and 920 major cities.

The study found that in 170 countries, mean temperatures over the span exceeded 30-year norms, exposing 7.8 billion people — 99% of humanity — to above-average warmth. That exposure included nearly every resident of Japan, Indonesia, the Philippines, Vietnam, Bangladesh, Iran, Egypt, Ethiopia, Nigeria, Italy, France, Spain, the United Kingdom, Brazil, Mexico, and every Caribbean and Central American nation.

Key global findings on hottest months on record

According to the study, the period between November 2022-October 2023 was the hottest 12 consecutive months ever recorded and the Global Mean Temperature (GMT) was around 1.3°C hotter than the pre-industrial climate. This 12-month period data is very consistent with the long-term global warming trend. 

In India, 1.2 billion residents — 86% of the population — experienced Climate Shift Index level-three temperatures on 30 or more days. In China that figure was 513 million residents — 35% of the population; and in the United States, 88 million — 26% of the population experienced at least 30 days of temperatures made at least three times more likely by climate change.

During this span more than 500 million people in 200 cities experienced streaks of extreme heat, with at least five days of daily temperatures in the 99th percentile compared to 30-year norms.  1 in 4 people worldwide (1.9 billion people) faced extreme and dangerous heatwaves driven by climate change over the past 12 months. Over the year, 90% of people experienced at least 10 days of high temperatures that climate change made significantly more likely. 

New Orleans and two Indonesian cities — Jakarta and Tangerang — followed with 17 straight days of extreme heat. Austin (16 days), San Antonio (15 days), and Dallas (14 days) were also among the cities with the longest extreme heat streaks. In each of these cities, on every day of these streaks, the Climate Shift Index reached the maximum level-five, indicating that climate change made this extreme heat at least five times more likely. 

Number of days with locally extreme temperatures. The circles indicate cities with at least one 5+ day streak of extreme temperatures that is attributable (CSI>=2). The size of the circles reflects the length of the longest heat streak.  Source

El Niño and reductions in shipping pollution, along with other factors, have likely had a small influence on increasing temperatures over the last 12 months – but this is very small compared with the influence of human-caused greenhouse gas emissions.

Only Iceland and Lesotho recorded cooler-than-normal temperatures. Weather attribution analysis reveals that during the span, 5.7 billion people were exposed to at least 30 days of above-average temperatures made at least three times more likely by the influence of climate change, or level-three on Climate Central’s Climate Shift Index.

“This 12-month record is exactly what we expect from a global climate fueled by carbon pollution,” Dr. Andrew Pershing, vice president for science at Climate Central said. “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-fueled streaks of extreme heat in the U.S., India, Japan, and Europe underscores that no one is safe from climate change.” 

Devastating impacts of hottest months on record

In India, the report analysed 70 cities across 32 states and union territories. The analysis found that about 12 cities experienced more than 100 days last year with a CSI index score of 5, including Bengaluru (124), Visakhapatnam (109), Thane (101) and Guwahati (112). Also, other than the population in Punjab, Haryana and Rajasthan, 100% of the population across the 30 states/UTs were exposed to Climate Shift Index level-three-plus for more than five days.

Human-induced climate change impacted large parts of South America, with the entire continent much warmer than normal for at least the first six months of the year. The drought in Argentina led to an estimated 3% GDP reduction, while in the Amazon River region, the water level reached its lowest point ever recorded, affecting water and food distribution to half a million people in October alone. 

Human-induced climate change brought record rainfall, increasing the severity and frequency of fatal flooding events. Across the world, millions were displaced with thousands killed in storms that included New Zealand during Cyclone Gabrielle, in Malawi, Mozambique and Madagascar during Cyclone Freddy, in China during Typhoon Haikui and in Libya, Greece, Bulgaria and Turkey during Storm Daniel –Africa’s deadliest storm ever with over 4,000 victims. A recent investigation shows that extreme weather has killed at least 15,700 people in Africa this year so far.  In April, unprecedented flooding in Rwanda and the Democratic Republic of the Congo killed over 400 people; by September, flooding washed away farmlands in Ghana and displaced nearly 26,000 people – most of whom are women and children. Meanwhile, the drought in the Horn of Africa continues to make new victims, having left over 23 million people acutely food insecure while displacing another 2.7 million. Record-breaking rains and bursting of glacial lakes wreaked havoc in Northern India, washing away towns. 

In the US, 24 extreme weather events killed at least 373 people and led to financial losses exceeding U$67 billion to date. 93 died in what is now considered the deadliest US fire of the century in Hawaii. In Canada, 1 out of every 200 people were forced to evacuate their homes due to wildfires that burnt over 45 million acres and lasted for months. Heatwaves that breached the human survivability threshold stretched from East and South Asia to Europe and North Africa, killing at least 264 people in India and over 2,000 people in Spain, at a time when parts of the country also faced their driest period in 500 years. In Italy, as temperatures surpassed 40 Cs in August and September, hospitals were unable to accommodate the number of people seeking care for heat-related illnesses, with Covid-era admission levels reported in emergency units.

The study warned that temperatures will continue to increase and extreme weather will get worse until world leaders act to end net greenhouse gas emissions. CarbonCopy earlier reported that governments around the world are currently on track to produce 110% more fossil fuels by 2030 than would be consistent with limiting warming to 1.5°C, and 69% more than consistent with 2°C, according to the Production Gap report. The oversupply of fossil fuels will worsen extreme weather and continue to increase temperatures around the world.

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