The warm weather you’re experiencing is part of a larger pattern driven primarily by rising greenhouse gas concentrations in the atmosphere. Global temperatures in 2024 exceeded pre-industrial averages by 2.63°F (1.46°C), making it one of the warmest years in recorded history. Several forces are working together to push temperatures higher, from the long-term buildup of heat-trapping gases to shorter-term shifts in ocean and atmospheric patterns.
More CO2 Means More Trapped Heat
The atmosphere now contains about 430 parts per million of carbon dioxide, a level far above anything in the past several hundred thousand years. Human activities, primarily burning coal, oil, and natural gas for electricity, transportation, and industry, release roughly 35 billion metric tons of CO2 into the atmosphere every year. That CO2 doesn’t just float around harmlessly. Its molecular structure (one carbon atom bonded to two oxygen atoms) allows it to absorb heat radiating from Earth’s surface. The atoms vibrate, then re-emit that energy in all directions, including back toward the ground. The effect is like adding insulation to a house: less heat escapes, and the interior warms up.
Methane, another major greenhouse gas, is even more effective at absorbing heat than CO2, molecule for molecule. Nitrous oxide and water vapor play roles too. Together, these gases have increased the warming influence of the atmosphere by about 40% since 1990. The more of them we add, the more heat gets recycled between the surface and the sky before it can escape to space.
Ocean Cycles Amplify the Warmth
On top of the long-term warming trend, natural ocean cycles can temporarily push temperatures even higher or pull them slightly lower. The most influential is the El Niño-Southern Oscillation, or ENSO, a periodic fluctuation in Pacific Ocean surface temperatures that shifts global weather patterns every two to seven years. A strong El Niño event in 2023-2024 helped push global temperatures to record levels by releasing stored ocean heat into the atmosphere.
As of early 2026, the tropical Pacific has been transitioning from a La Niña phase (which tends to cool things slightly) back toward neutral conditions. Even during cooler ENSO phases, though, the underlying warming trend keeps baseline temperatures elevated. Think of it as a rising escalator: natural cycles move you up and down a few steps, but the escalator itself keeps climbing.
The Jet Stream Is Getting Wavier
If you’re noticing an extended stretch of unusual warmth in a specific region, the jet stream may be partly responsible. This high-altitude river of wind normally flows in a relatively tight band from west to east, separating cold polar air from warmer air to the south. But the Arctic is warming roughly three times faster than the rest of the planet, and that shrinking temperature difference between north and south slows the jet stream’s winds. When the jet stream slows, its waves grow larger and move eastward more sluggishly.
These bigger, slower waves park over regions for days or even weeks. If you’re on the side of a wave pulling warm air up from the south, you get prolonged heat. If you’re on the other side, you might see unusual cold or storms. “The big swings of the jet stream tend to be very persistent and to stay in the same place for a long time,” explains atmospheric scientist Jennifer Francis of the Woodwell Climate Research Center. These stalled patterns are happening more frequently, which is why stretches of abnormally warm weather feel like they’re lasting longer than they used to.
Melting Ice Creates a Warming Feedback Loop
One reason warming accelerates over time is that it triggers chain reactions. The most significant involves Arctic sea ice. Ice and snow are bright, reflecting a large share of incoming sunlight back to space. Open ocean water is dark and absorbs that energy instead. Between 1979 and 2011, the Arctic’s reflectivity dropped measurably as ice cover shrank, allowing an additional 6.4 watts per square meter of solar energy to be absorbed over the Arctic Ocean.
Globally, that single change in Arctic reflectivity added a warming effect equal to 25% of the direct warming caused by rising CO2 over the same period. In other words, ice loss doesn’t just respond to warming. It actively accelerates it. Less ice means more absorbed heat, which means more ice melts, which means even more heat is absorbed. This self-reinforcing cycle helps explain why warming has picked up speed in recent decades.
How Close We Are to Key Thresholds
Climate scientists track warming relative to pre-industrial temperatures (roughly 1850-1900) because that baseline represents conditions before large-scale fossil fuel burning began. The Paris Agreement set a target of limiting warming to 1.5°C above that baseline, recognizing that beyond this level, certain climate risks grow substantially. In 2024, the global average hit 1.55°C above pre-industrial levels.
A single year above 1.5°C doesn’t technically breach the Paris threshold, which is assessed over a 20-year average to filter out year-to-year natural variability. But research published in Nature Climate Change found that crossing the 1.5°C mark in a single year is virtually certain (around 99% probability) to fall within the 20-year window that reaches that warming level as a long-term average. The practical meaning: the impacts scientists have projected at 1.5°C of warming, including more intense heatwaves, shifting rainfall patterns, and ecosystem stress, are not a distant future scenario. They’re the conditions beginning to emerge now.
Why It Feels Different Than Before
Warm days have always existed, but several things make today’s warmth qualitatively different. Nighttime temperatures are rising faster than daytime highs in many regions, meaning your body gets less overnight relief during warm spells. Humidity is increasing in many areas because a warmer atmosphere holds more water vapor, making the same air temperature feel hotter on your skin. And the frequency of unusually warm days has shifted: what counted as a rare hot day a few decades ago now occurs several times more often in most parts of the world.
The warmth you’re noticing isn’t one thing. It’s the greenhouse effect doing what physics predicts it will do, amplified by feedback loops, shaped by ocean cycles, and delivered to your specific location by atmospheric patterns that are themselves changing because of the same underlying warming. Each of these forces is well understood individually. Together, they explain why the weather keeps breaking records.