2024: The warmest year in the history, first to breach 1.5 degrees threshold

The year 2024 has set a historic benchmark, officially becoming the warmest year on global temperature records dating back to 1850, according to the World Meteorological Organization (WMO) and Copernicus Climate Change Service (C3S), an European weather agency.

According to ERA5 dataset by C3S, the global average temperature reached 15.10°C, which is 0.72°C above the 1991-2020 average and 0.12°C higher than 2023, the previous record-holder. This unprecedented rise equates to a staggering 1.60°C above the estimated 1850-1900 pre-industrial temperature levels. With this, this is the first time in the history that a calendar year has surpassed the critical 1.5°C threshold above pre-industrial levels.

This surge highlights the alarming pace at which global temperatures are rising. Monthly global averages in 2024 exceeded the 1.5°C mark for 11 months of the year. Notably, every month since July 2023, except for July 2024, has consistently stayed above this level.

According to researchers, human-induced climate change remains the primary driver of extreme air and sea surface temperatures, while other factors, such as the El Niño Southern Oscillation (ENSO), also contributed to the unusual temperatures observed during the year.

“Climate history is playing out before our eyes. We’ve had not just one or two record-breaking years, but a full ten-year series. This has been accompanied by devastating and extreme weather, rising sea levels and melting ice, all powered by record-breaking greenhouse gas levels due to human activities,” said Celeste Saulo, Secretary-General, WMO.  

“Each year in the last decade is one of the ten warmest on record. We are now teetering on the edge of passing the 1.5ºC level defined in the Paris Agreement and the average of the last two years is already above this level. These high global temperatures, coupled with record global atmospheric water vapour levels in 2024, meant unprecedented heatwaves and heavy rainfall events, causing misery for millions of people,” said Samantha Burgess, Strategic Lead for Climate, European Commission by the European Centre for Medium-Range Weather Forecasts (ECMWF).

Dr Friederike Otto, Senior Lecturer at the Centre for Environmental Policy, Imperial College London, added, “This record needs to be a reality check. The climate is heating to levels we’ve spent years trying to avoid because countries are still burning huge amounts of oil, gas and coal. A year of extreme weather showed just how dangerous life is at 1.5°C. The Valencia floods, US hurricanes, Philippines typhoons and Amazon drought are just four disasters last year that were worsened by climate change.”

A Decade of Extremes

The last 10 years (2015–2024) now stand as the warmest decade on record. This consistent trend highlights the long-term impacts of climate change, with each year in this period ranking among the ten warmest ever recorded.

Record-Breaking Moments of 2024

• Daily Record: On July 22, 2024, a new daily global temperature record was set at 17.16°C.

• Seasonal Highs: The year witnessed three record-warm seasons:    

                           o  Boreal Winter (December 2023-February 2024): 0.78°C above the 1991-2020 average

                            o Boreal Spring (March-May 2024): 0.68°C above the average

                            o Boreal Summer (June-August 2024): 0.69°C above the average

• Monthly Record: Each month from January to June 2024 was warmer than the corresponding month in any previous year on record. Each month from July to December, except August, was each the second warmest, after 2023, for the time of year. August 2024 was tied with August 2023 as the warmest on record.
• Continental Impact: 2024 was the warmest year for all continental regions except Antarctica and Australasia. 
• The atmospheric concentrations of carbon dioxide and methane continued to increase and reached record annual levels in 2024, at 422 parts per million (ppm) and 1897 parts per billion (ppb), respectively. Carbon dioxide concentrations in 2024 were 2.9 ppm higher than in 2023, whereas methane concentrations were 3 ppb higher.

Ocean surface temperature shatters record

Ocean warming is another key contributor in the growing climate impacts across the world. About 90% of the excess heat from global warming is stored in the ocean, making ocean heat content a critical indicator of climate change. Significant warming was observed in major oceanic regions, including the North Atlantic Ocean, the Indian Ocean, and the western Pacific Ocean.

In 2024, the annual average sea surface temperature (SST) over the extra-polar ocean reached a record high of 20.87°C, which is 0.51°C above the 1991–2020 average, the C3S report noted. The average extra-polar SST was at record high levels for the time of year from January to June 2024. From July to December 2024, the SST was the second warmest on record for the time of year, after 2023.

The total amount of water vapor in the atmosphere reached a record value in 2024, at about 5% above the 1991–2020 average, according to ERA5, more than 1% higher than in 2016 and 2023, the years with the previous highest and second highest values, respectively. This was visible in form of record extreme weather events witnessed across the world.

Extreme temperatures and high humidity contributed to increased levels of heat stress. Much of the Northern Hemisphere, which also includes India, experienced more days than average with at least ‘strong heat stress’ during 2024, and some areas saw more days than average with ‘extreme heat stress’.

Implications and the Path Forward

The record-breaking warmth of 2024 underscores the urgent need for global action to mitigate climate change. These unprecedented temperature levels are a stark reminder of the rapidly closing window to limit global warming and avoid the most catastrophic impacts of climate change. Policymakers, scientists, and communities must collectively to implement sustainable solutions and transition to a low-carbon future.

Dr Paulo Ceppi, Senior Lecturer in Climate Science at the Department of Physics, Imperial College London, said, “Countries have the power to bring global warming to a halt by reducing greenhouse gas emissions to net zero. This must happen as quickly as possible to give us some hope of preventing further global climate change catastrophes.”

“The world doesn’t need to come up with a magical solution to stop things from getting worse in 2025. We know exactly what we need to do to transition away from fossil fuels, halt deforestation and make societies more resilient to the changes in the climate we see in so clearly in this report,” added Dr Otto.

"It is imperative to recognise the profound impact of rising global temperatures on our region. With 2024 marking a critical threshold, we face heightened risks, including intensified heatwaves, flooding, and agricultural disruption. These climatic changes disproportionately affect vulnerable communities, magnifying existing socio-economic disparities. Immediate, evidence-based action is essential to mitigate these effects, embracing sustainable practices and policies prioritising climate resilience. The future of South Asia and the world hinges on our collective response to this stark reality—our time to act is now," said Professor Anjal Prakash, Clinical Associate Professor (Research) and Research Director, Bharti Institute of Public Policy, Indian School of Business, Hyderabad, India. Prof Prakash has contributed to the 6th Assessment Report of IPCC as lead author.