2024 was officially the hottest year on Earth
by Elissa Tennant
It’s official: 2024 was officially the hottest year on Earth, surpassing the previous record-holder, 2023.
For the first time, the National Oceanic and Atmospheric Administration (NOAA), NASA, Berkeley Earth, and other leading climate research organizations agreed to synchronize the release of their temperature data to emphasize the urgency of the situation. And it worked—things definitely feel urgent to us!
A tumultuous 2024
The story of 2024’s record-breaking heat began long before January 1. By the end of the summer, it was clear that this year would likely claim the top spot as the hottest on record. Here’s a timeline:
- June: Sixty-three countries experienced their warmest June ever. Prior to that, from July 2023 to June 2024, a staggering 138 countries broke all-time high temperature records.
- July: The two hottest days on record occurred back-to-back on July 22 and 23.
- August: The National Oceanic and Atmospheric Administration publicly stated there was a 77% chance that 2024 would be warmest on record, and nearly 100% certainty it would land in the top five. August went on to become the hottest in 175 years of NOAA’s records and NASA’s 145-year record, with temperatures 2.34°F above any other August, according to NASA.
This wrapped up the hottest summer to date (about 0.2 degrees Fahrenheit hotter than any other summer’s average on NASA’s record), which then took us into the warmest fall on record according to NOAA.
Which brings us here. So yeah, we probably saw this announcement coming, but it doesn’t make it any easier to contend with. Extreme heat is one of the deadliest effects of climate change, but one of the least studied. Around 429,000 heat-related deaths occur globally each year, with heat waves leading to more fatalities within shorter periods of time. Heat exacerbates underlying conditions and impacts the health of vulnerable populations, particularly older folks.
However, the hottest temperatures on Earth have disproportionately occurred on small islands and in developing nations, which are on the frontlines of climate change. Unfortunately, this means the impacts of climate-fueled heat tend to go underreported and are not fully understood.
Why 2024 Was So Hot
Several factors converged to make 2024 a record-breaking year, but two primary drivers stand out.
Fossil Fuels
It’s old news, but fossil fuels are the main cause of warmer temperatures worldwide. Greenhouse gas emissions increased in 2024, further exacerbating the problem. Atmospheric carbon dioxide concentrations reach about 422.5 parts per million (ppm), an increase of more than 50% since 1750. Without decisive action to curb fossil fuel use, these emissions will continue to rise, driving global temperatures higher.
El Niño Climate Pattern
This natural weather pattern raised global surface temperatures this year, especially at the start of the year. The El Niño phenomenon occurs when warm water rises to the surface of the Eastern Pacific, raising global surface temperatures. As surface-dwellers, those are the temperatures that humans care about the most. Though El Niño faded midyear, its effects lingered, keeping us sweating through autumn.
The last major El Niño event in 2016 also resulted in record temperatures, but 2024 surpassed those levels. 2024 was about 0.25°C warmer than 2016.
1985–2024 global average surface temperature categorized by years with a significant La Niña cooling influence (blue), El Niño warming influence (red), neutral conditions (black), and those with a cooling influence from a recent large volcanic eruption (orange triangles). (Data: NASA. Graphic: Dana Nuccitelli.)
Note that while El Niño did play a role in warmer weather, studies show it took a backseat to climate change. World Weather Attribution found that “the influence of climate change increasingly overrides other natural phenomena affecting the weather.”
Other Factors
Scientists generally agree these two main drivers worked in tandem to make sure 2024 was officially the hottest year on Earth, but there are a number of other factors that contribute to rising temperatures, including changes in cloud cover allowing more solar energy to reach Earth’s surface, potentially influenced by cleaner shipping. All of these things are significant, but can’t truly compare to the impacts of fossil fuels.
Weather Disasters in 2024
Rising temperatures aren’t just numbers on a chart—they translate into real-world consequences that affect lives and livelihoods. The World Meteorological Organization reported that the U.S. experienced 41 days of dangerous heat in 2024. But we didn’t just experience extreme heat as a consequence of this year’s warming. We also saw:
- Hurricanes: In the Atlantic and Gulf of Mexico, hurricanes worsened by climate change caused devastation. Five hurricanes made landfall, killing 200 people, with countless others affected by the lingering impacts. Heat waves often followed hurricanes, compounding suffering for those without power to cool their homes.
- Flooding: A warmer atmosphere tends to hold more water. Record-breaking rainfalls this year led to catastrophic floods worldwide, including the Appalachian region of the U.S. Out of 16 floods examined by World Weather Attribution, 15 were intensified by climate change.
- Tornadoes: We saw the worst tornado season on record since 2011.
- Wildfires: Fires continued to rage in North America, fueled by dry conditions and soaring temperatures.
Scientists estimated the human influence of many of the year’s extreme weather events. The UN reported that climate change intensified 26 out of 29 major weather disasters this year, and that these disasters killed more than 3,700 people and displaced millions more. It was… maybe not the best year for humanity.
What Will Happen in 2025?
2024 was officially the hottest year on Earth. So what’s next? Well, the good news is global temperatures in 2025 might cool slightly, especially if El Niño transitions into its counterpart, La Niña. That’s a possibility, although neutral conditions in the Pacific Ocean are more likely, according to recent model forecasts.
However, a slight drop in annual temperatures doesn’t mean the problem is solved. Until we address the root cause—greenhouse gas emissions from fossil fuels—we risk repeating and exceeding 2024’s record-breaking heat.
Can We Fix Things?
You may have read in the news that this year’s average temperatures reached or exceeded the 1.5°C threshold identified as a critical danger zone in the 2015 Paris Agreement. While this is alarming, the 1.5°C target refers to a 20-year global average, not a single year. Temperatures are prone to variations, especially in years affected by El Niño and La Niña so we need to look at a long period of time to keep track of our goals.
We still have time to get well below 2°C above pre industrial levels and stay close to the 1.5°C goal, but not enough time to sit back and relax. Every fraction of a degree brings us closer to dangerous and irreversible impacts. We need to act now.
What Can We Do?
While the challenges of climate change may seem overwhelming, there are steps we can take to make a difference.
- Contact Congress: Your voice matters. Our tool makes it easy to write to your members of Congress on behalf of the climate. Help us advocate for policies that reduce greenhouse gas emissions, promote clean energy, and protect vulnerable communities.
- Talk to Friends and Family: Encourage others to join you in contacting elected officials or making changes in their own lives. We can’t solve climate change alone, and collective action is powerful.
- Join Citizens’ Climate Lobby: Speaking of collective action! CCL empowers individuals to work toward effective climate solutions. Whether you excel at lobbying, community engagement, or education, there’s a role here for everyone interested in solving climate change.
Above all, don’t give up. This is a setback, not a defeat. Every effort counts, and giving up means forfeiting the opportunity to create meaningful change. Together, we can transition to a future free of fossil fuels and ensure that years like 2024 become a thing of the past.
2024 was officially the hottest year on Earth. Let’s turn the lessons of 2024 into momentum for change in 2025 and beyond. Join Citizens’ Climate Lobby today and be part of the solution.
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