How Hot Was 2025, Really? || Climate Change || Year in Review || ProtectTheEarth

How Hot Was 2025, Really? || Climate Change || Year in Review || ProtectTheEarth

National Geographic

As a reflection of the final day of 2025, I've decided to write about what I think was the most important current event we faced this year: climate change, and just how hot this planet has been getting.

Search the topic online, and you'll quickly find people with strong opinions. The discussion usually falls into 3 categories: 

1. Scientists sounding the alarm with data most people never actually read
2. Politicians and commentators arguing about whether any of it is worth taking seriously 
3. Everyone else somewhere in between—vaguely aware that the summers feel longer and the storms feel worse, but not totally sure what to do with that feeling.

A Record Year, Again

"Vital Signs of the Planet" NASA, 31 December 2025

2025 was not the hottest year on record (That title still belongs to 2024) But scientists tracking global temperatures all year were saying 2025 was on pace to land in the top three warmest years since records began in the 1800s. In its December bulletin, the Copernicus Climate Change Service made it close to official, saying 2025 was "virtually certain" to finish as either the second- or third-warmest year on record. NASA's "Vital Signs of the Planet" page has essentially functioned as a running scoreboard all year, and the scoreboard hasn't been encouraging.

What stuck with me most is the pattern. 2023, then 2024, then 2025—three years in a row landing at or near the top of a 145-year record. One unusually hot year could be written off as an outlier. Three in a row is harder to explain away.

What made 2025 particularly notable, based on what I read this year, is that all of this happened during a La Niña pattern—the ocean cycle that typically cools global temperatures down somewhat. Even with one of nature's own regulating mechanisms working against the heat, 2025 still came in near-record hot. Carbon Brief's tracking data from earlier in the year showed the same story played out month after month, with January 2025 alone recorded as the warmest January ever measured.

What the Ocean tells us

The statistic that stopped me longest this year was about the ocean. Oceans absorb more than 90% of the excess heat trapped by greenhouse gases, which makes ocean heat one of the most honest indicators of what's actually happening to the climate. 2025 wasn't just warm at the surface—it was a record-setting year for ocean heat content, continuing a streak of new highs that, according to the World Meteorological Organization, has now stretched for eight consecutive years.

That's not a minor detail. That's the planet's largest heat reservoir filling up more than it ever has before, year after year.

What it actually looked like

The numbers are one thing. What made this year different for me was how often the abstract statistics turned into something visible. Heatwaves and storms hit Europe, Asia, and North America hard this year. Wildfires tore through Spain, Canada, and southern California, including the Palisades Fire in January, which was hard to look away from in the news coverage at the time. Later in the year, back-to-back tropical cyclones struck Indonesia and Malaysia, triggering floods that killed more than a thousand people and displaced over a million more. Climate scientists said the storms were "supercharged" by climate change. That was the story that made this feel less like a statistic and more like something real.

So what do we do with all of this?

I'm not writing this to be alarmist, and I don't think fear is a particularly useful way to end the year. But I do think there's something worth naming about being a teenager right now, watching "one of the hottest years on record" become close to an annual headline. That shouldn't be a normal thing to expect every December. And I think it's worth writing down, honestly, before this year ends and the next one starts.

If someone asked me whether 2025 should change how we think about the years ahead, I wouldn't answer with a simple yes or no. I'd answer with another question:

How many more years like this one are we willing to let become routine?

Because that, more than any single number in this article, is what I think the next year—and the years after it—will actually come down to.

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Sources

• "Vital Signs of the Planet." NASA, 31 Dec. 2025.
• "Global Temperature — Earth Indicator." NASA Science, science.nasa.gov/earth/explore/earth-indicators/global-temperature.
• Earth.Org. "Year in Review: The Biggest Climate Headlines of 2025." Earth.Org, earth.org/year-in-review-the-biggest-climate-headlines-of-2025.
• Ward, Kevin, and Kevin Ward. "Climate Change - NASA Science." NASA Science, science.nasa.gov/climate-change.
• Hausfather, Zeke, et al. "State of the Climate: 2025 On Track to Be Second or Third Warmest Year on Record." Carbon Brief, carbonbrief.org/state-of-the-climate-2025-on-track-to-be-second-or-third-warmest-year-on-record.