The Knowledge
2025 was hotter than it should have been – 5 influences and a dirty surprise offer clues to what’s ahead
The past three years recorded unprecedented global heat, with 2025 being particularly warm. Factors such as greenhouse gas emissions and a decline in solar activity influenced temperatures and extreme weather patterns.
Michael Wysession, Washington University in St. Louis
The past three years have been the world’s hottest on record by far, with 2025 almost tied with 2023 for second place. With that energy came extreme weather, from flash flooding to powerful hurricanes and severe droughts. Yet, by most indicators, the planet should have been cooler in 2025 than it was.
So, what happened, and what does that say about the year ahead?
As an earth and environmental scientist, I study influences that affect global temperatures year to year, such as El Niño, wildfires and solar cycles. Some make Earth hotter. Some make it cooler. And one particularly unhealthy influence has been quietly hiding a large amount of global warming – until now.
Factors that made 2025 cooler than 2024
The Earth’s climate is the result of many factors that change from year to year. Some that helped make 2025 cooler than 2024 include:
La Niña’s arrival: La Niña is part of the El Niño-Southern Oscillation, a natural climate pattern that fluctuates between warm El Niño conditions and cooler La Niña conditions. During El Niño, the Pacific Ocean heats up along the equator, influencing the atmosphere in ways that can cause intense storms, droughts and heat waves around the planet. La Niña does the opposite; it’s like putting an ice pack on the atmosphere.
Both 2023 and 2024 were El Niño years, but in 2025 conditions shifted to neutral and then to La Niña starting in September.
The solar cycle: The Sun reached its solar maximum near the end of 2024, the peak of its energy output in an approximately 11-year cycle, and began declining in 2025. So, while the sun’s output was still stronger than average in 2025, it was less than in 2024.
Fewer wildfires: Despite some destructive blazes, the world also saw fewer wildfires during 2025 than 2024, which put less carbon dioxide – a planet-warming greenhouse gas – into the atmosphere.
Despite those points, 2025 still ended up as the third-hottest year in over 175 years of record-keeping and likely one of the warmest in at least several thousand years. It was nearly as warm as 2023, at 2.6 degrees Fahrenheit (1.47 Celsius) above the 1850-1900 average, according to the European Union’s Copernicus Climate Change Service. It also had the second-highest average land temperature recorded, up 3.6 F (2 C) compared to preindustrial years, with more than 10% of the land experiencing record-high temperatures.
Factors that made 2025 warmer than expected
Several other factors made 2025 warmer than expected, and some are likely to continue to increase in 2026. They include:
Greenhouse gas emissions: The big driver of global warming is excess greenhouse gas emissions, largely from burning fossil fuels, and 2025 had plenty.
Greenhouse gases trap heat near Earth’s surface like a blanket, raising the temperature. They also linger in the atmosphere for years to centuries, meaning gases released today will continue to warm the planet well into the future. The levels of carbon dioxide, methane and nitrous oxide in the atmosphere all increased in 2025.
Rising energy demand drove an increase in fossil fuel use. About 80% of the increasing electric power demand came from emerging economies, largely for rising air conditioning demands as the world gets hotter. In the U.S., the rapid growth of data centers for AI and cryptocurrency mining helped boost U.S. carbon dioxide emissions by 2.4%.
Earth’s energy imbalance: Other sources can disrupt the natural balance between the amount of sunlight that reaches Earth and the lesser amount radiated back to space. A recent study found that Earth’s energy uptake surged and temperatures rose quickly when a rare three-year La Niña in 2020-2022 shifted to El Niño in 2023-2024.
Declining polar ice, which efficiently reflects sunlight back into space, also affects the energy balance. As sea ice declines, it leaves dark ocean water that absorbs most of the sunlight that reaches it. In a spiraling feedback, warmer water melts sea ice, allowing more sunlight into the ocean, warming it faster; 2025 had the lowest winter peak of Arctic sea ice on record and the third-lowest minimum extent of Antarctic ice.
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Air pollution: Sulfate aerosol pollution from coal combustion and burning heavy fuel oil in shipping has also been affecting Earth’s energy balance. It has been masking the full effects of human-caused greenhouse gases for years by reflecting sunlight back into space, creating a cooling effect. But sulfate aerosol pollution is also a serious health hazard, blamed for about 8 million human deaths per year from lung diseases.
Recent reductions in sulfate pollution – now 40% less than 20 years ago – have meant about a 0.2 F (0.13 C) increase in global temperatures. Much of the reduction was from China’s efforts to reduce its notoriously bad air pollution in recent years and international shipping rules in effect since 2020 that have reduced sulfur emissions from large ships by 85%.
Taking all factors together, humans are now warming the planet at a faster rate than at any point in human history: at about 0.5 F (0.27 C) per decade. That extra heat can fuel extreme weather, including flash floods, heat waves, extended droughts, wildfires and coastal flooding, affecting human lives and economies.
Predictions for 2026
Most climate models predict 2026 will be about as hot as 2025, depending on whether a Pacific El Niño develops, which forecasters give about a 60% chance of happening. The planet is already starting the year out warm, even if it doesn’t feel like that everywhere. While January was very cold in parts of the U.S., globally, Earth saw its fifth-warmest January on record, and much of the western U.S. saw one of its warmest winters on record.
Solar output will continue to decrease slowly in 2026. However, the International Monetary Fund projects strong global economic growth at about 3.3%, suggesting electricity demand will also continue to grow. The International Energy Agency expects global electricity demand to increase by 3.6% per year through at least 2030.
Even though global renewable energy use is growing quickly, it isn’t growing fast enough to meet rising demand, meaning more fossil fuel use in the coming years. More fossil fuels burned means more emissions and more warming, while the ability of the ocean and land to absorb carbon dioxide continues to decrease. As a result, the atmosphere and oceans heat up, increasing the risks of passing tipping points – glaciers disappear, Atlantic Ocean circulation shuts down, permafrost thaws, coral reefs die.
If greenhouse gas emissions continue at a high rate, humanity may look back at 2025 as one the coolest years globally in the rest of our lives.
Michael Wysession, Professor of Earth, Environmental, and Planetary Sciences, Washington University in St. Louis
This article is republished from The Conversation under a Creative Commons license. Read the original article.
Dive into “The Knowledge,” where curiosity meets clarity. This playlist, in collaboration with STMDailyNews.com, is designed for viewers who value historical accuracy and insightful learning. Our short videos, ranging from 30 seconds to a minute and a half, make complex subjects easy to grasp in no time. Covering everything from historical events to contemporary processes and entertainment, “The Knowledge” bridges the past with the present. In a world where information is abundant yet often misused, our series aims to guide you through the noise, preserving vital knowledge and truths that shape our lives today. Perfect for curious minds eager to discover the ‘why’ and ‘how’ of everything around us. Subscribe and join in as we explore the facts that matter. https://stmdailynews.com/the-knowledge/
Forgotten Genius Fridays
Forgotten Genius Friday: Granville T. Woods — The Inventor Who Helped Keep America’s Railroads Safe
Discover how Granville T. Woods, known as the “Black Edison,” revolutionized railroad communication and safety with inventions that helped shape modern transportation.
When America was expanding westward and railroads connected cities like never before, safety and communication remained major challenges. Trains often operated with limited information about where other locomotives were located, creating dangerous conditions on busy rail lines.
One inventor helped change that.
His name was Granville T. Woods, a prolific engineer and inventor whose innovations transformed railroad communication and earned him the nickname “The Black Edison.”
A Self-Taught Innovator
Born in 1856 in Columbus, Ohio, Woods displayed a remarkable aptitude for mechanics and engineering from an early age. Although he received limited formal education, he dedicated himself to learning about machinery, electricity, and industrial systems.
As a young man, Woods worked on railroads and steamships, gaining firsthand experience with the transportation technologies that powered the Industrial Age. These experiences helped him identify problems that needed solving.
Revolutionizing Railroad Safety
One of Woods’ most important inventions was the Synchronous Multiplex Railway Telegraph, patented in 1887.
This groundbreaking system allowed moving trains to communicate with stations and other trains using telegraph technology. Prior to this innovation, communication between trains was limited, increasing the risk of accidents and delays.
Woods’ system helped railroad operators track train locations more effectively and improve safety along busy routes.
More Than Fifty Patents
Throughout his career, Woods earned more than 50 patents covering electrical and mechanical devices. His inventions improved:
- Railroad communication systems
- Electric railway technology
- Power distribution systems
- Telegraph and telephone equipment
- Transportation safety mechanisms
His innovations became increasingly important as cities adopted electric transit systems and rail networks expanded across the United States.
A Rivalry with Thomas Edison
Woods’ achievements attracted the attention of some of the biggest names in technology, including Thomas Edison.
At one point, Edison challenged Woods’ claim to one of his inventions in court. Woods successfully defended his patent rights, proving that the innovation was indeed his own.
Impressed by Woods’ talent, Edison later offered him a position with the Edison Electric Light Company. Woods declined, choosing instead to continue his independent work as an inventor.
Why Granville T. Woods Still Matters
Today, transportation systems depend heavily on communication, signaling, and safety technologies. While modern systems use computers, wireless networks, and satellites, the underlying goal remains the same: ensuring that vehicles can communicate and operate safely.
Granville T. Woods helped establish that foundation.
His work contributed to safer rail travel, more efficient transportation networks, and advancements in electrical engineering that continue to influence modern infrastructure.
Final Word
As part of STM Daily News’ Forgotten Genius Friday series, Granville T. Woods reminds us that some of history’s most important innovators remain largely unknown.
His inventions helped move America forward—one railway signal at a time.
The next time you see a train safely navigating a busy rail corridor, remember the inventor whose ideas helped make modern rail communication possible.
Related Links for Further Information
- National Inventors Hall of Fame – Granville Woods
- National Inventors Hall of Fame – How Granville Woods Helped Trains Communicate
- Biography.com – Granville T. Woods Biography
- Granville Woods – Wikipedia
- U.S. Energy Information Administration – Granville Woods
- Texas Railroad Hall of Fame – Granville T. Woods
- Coney Island History Project – Granville T. Woods
- Scholastic – African American Inventors: Granville T. Woods
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Last Updated on June 12, 2026 by Rod Washington
Valerie Thomas is a true pioneer in the world of science and technology. A NASA engineer and physicist, she is best known for inventing the illusion transmitter, a groundbreaking device that creates 3D images using concave mirrors. This invention laid the foundation for modern 3D imaging and virtual reality technologies.
Beyond her inventions, Thomas broke barriers as an African American woman in STEM, mentoring countless young scientists and advocating for diversity in science and engineering. Her work at NASA’s Goddard Space Flight Center helped advance satellite technology and data visualization, making her contributions both innovative and enduring.
In our latest short video, we highlight Valerie Thomas’ remarkable journey—from her early passion for science to her groundbreaking work at NASA. Watch and be inspired by a true STEM pioneer whose legacy continues to shape the future of space and technology.
🎥 Watch the video here: https://youtu.be/P5XTgpcAoHw
Dive into “The Knowledge,” where curiosity meets clarity. This playlist, in collaboration with STMDailyNews.com, is designed for viewers who value historical accuracy and insightful learning. Our short videos, ranging from 30 seconds to a minute and a half, make complex subjects easy to grasp in no time. Covering everything from historical events to contemporary processes and entertainment, “The Knowledge” bridges the past with the present. In a world where information is abundant yet often misused, our series aims to guide you through the noise, preserving vital knowledge and truths that shape our lives today. Perfect for curious minds eager to discover the ‘why’ and ‘how’ of everything around us. Subscribe and join in as we explore the facts that matter. https://stmdailynews.com/the-knowledge/
Forgotten Genius Fridays
https://stmdailynews.com/the-knowledge-2/forgotten-genius-fridays/
🧠 Forgotten Genius Fridays
A Short-Form Series from The Knowledge by STM Daily News
Every Friday, STM Daily News shines a light on brilliant minds history overlooked.
Forgotten Genius Fridays is a weekly collection of short videos and articles dedicated to inventors, innovators, scientists, and creators whose impact changed the world—but whose names were often left out of the textbooks.
From life-saving inventions and cultural breakthroughs to game-changing ideas buried by bias, our series digs up the truth behind the minds that mattered.
Each episode of The Knowledge runs 30–90 seconds, designed for curious minds on the go—perfect for YouTube Shorts, TikTok, Reels, and quick reads.
Because remembering these stories isn’t just about the past—it’s about restoring credit where it’s long overdue.
🔔 New episodes every Friday
📺 Watch now at: stmdailynews.com/the-knowledge
🧠 Now you know.
The Knowledge
Dr. Charles R. Drew: The Father of the Blood Bank
Dr. Charles R. Drew revolutionized blood storage and stood against racial injustice, earning the title “Father of the Blood Bank.”
AI generated image
Dr. Charles R. Drew: The Father of the Blood Bank
In the 1930s and 40s, one man’s groundbreaking medical research transformed how we save lives — and his legacy still flows through hospitals around the world.
Dr. Charles R. Drew (1904–1950), an African American physician and surgeon, discovered a better way to store and transport blood plasma. Plasma, the liquid component of blood, can be preserved longer than whole blood and safely shipped over great distances — a game changer for emergency medicine.
@stmblog He revolutionized how we store blood, saved thousands in WWII, and stood up to injustice. 🩸 Meet Dr. Charles R. Drew — the Father of the Blood Bank. History BlackHistory WWII MedicalBreakthrough STMDailyNews DidYouKnow ScienceHistory BloodBank InspiringStories LearnOnTikTok ♬ original sound – STMDailyNews – STMDailyNews
During World War II, Drew’s expertise powered the “Blood for Britain” program, which sent vital plasma to soldiers and civilians injured in the Blitz. Later, as the first director of the American Red Cross blood bank, he helped establish modern blood collection and distribution systems.
But Drew was more than a scientist — he was a man of principle. He resigned from the Red Cross in protest over its policy of segregating blood by race, a practice he condemned as scientifically baseless and morally wrong.
Known today as the “Father of the Blood Bank,” Dr. Drew’s innovations continue to save millions of lives every year. His story is a testament to the power of science, dedication, and courage to challenge injustice.
Related Links:
Link: https://stmdailynews.com/the-woman-who-invented-the-home-security-system/
Moments in History: Dr. Charles R Drew
Link: https://stmdailynews.com/moments-in-history-dr-charles-r-drew/
