Vi dykker lidt ned i jordens varmestrømme. Hvad er det der sker lige denne sommer?
Her er Karina’s noter til dagens afsnit.
1) Heat Dome, eller hvad DMI kalder det - Omega-Blokering
2) Hvad er El Niño
3) Hvad er El Niña
4) Hvordan er 2026 El Niño anderledes?
5) Is-kappe re-generering
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1) Heat Dome, eller hvad DMI kalder det - Omega-Blokering
Omegablokering lagde låg på vejret og løftede Danmark til 37 grader
En fastlåst bølge i atmosfæren sendte varm luft fra Nordafrika mod Danmark og var med til at udløse sidste uges hedebølge. Klimaforandringer skaber ikke omegablokeringen, men gør den varme, som følger med, mere intens. En ny blokering er ved at sætte sig fast.
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2) Hvad er El Niño:
El Niño is a naturally occurring climate pattern characterized by the unusual warming of surface waters in the central and eastern tropical Pacific Ocean. It represents the "warm phase" of a larger, global ocean-atmosphere cycle called the El Niño-Southern Oscillation (ENSO).
Under normal conditions, equatorial trade winds blow steadily from east to west (from South America toward Asia), pushing warm surface water into the western Pacific. During an El Niño event, these trade winds weaken or completely reverse. This allows the massive pool of warm water to slosh backward across the ocean toward the Americas.
By shifting where vast amounts of ocean heat are released into the atmosphere, El Niño disrupts weather patterns worldwide:
The Americas: Warmer coastal waters suppress the normal upwelling of cold, nutrient-rich deep sea water, severely disrupting local marine ecosystems and fishing industries. The shifting Pacific jet stream brings heavy rainfall, storms, and increased flood risks to the southern United States and western South America.
Asia and Australia: Because the warm pool of water moves away from the western Pacific, places like Southeast Asia, Indonesia, and Australia experience decreased rainfall, resulting in severe droughts and heightened wildfire risks.
Global Temperatures: El Niño acts as a temporary booster for global heat, often pushing global average temperatures to record-breaking levels.
Imagine a giant, shallow bathtub. Normally, the wind blows hard across the tub, pushing all the warm surface water to one side (Asia) while cold water wells up at the back (South America). During El Niño, the wind suddenly stops blowing. That massive wall of hot water sloshes straight back across the tub toward the Americas.
Right now, in July 2026, the Pacific Ocean is sloshing backwards, and it's unleashing an unbelievable amount of heat into our global weather system.
Frequency: Occurs irregularly every two to seven years.
Duration: Typically lasts 9 to 12 months, usually developing in the northern hemisphere's spring/summer, peaking around December (hence its Spanish name, "the Christ Child" or "little boy"), and fading by the following spring
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3) Hvad er El Niña
Opposite Phase: Its cool-phase counterpart is La Niña, which features unusually cold ocean temperatures in the exact same region of the Pacific.
If El Niño is the "slosh" where warm water rushes eastward, La Niña is the "super-charge" of normal conditions. During a La Niña event, the easterly trade winds blow much stronger than usual. This acts like a giant broom, aggressively sweeping warm surface water westward toward Asia and Australia. As that warm water is pushed away, deep, icy-cold, and nutrient-rich water is pulled up to the ocean surface off the coast of South America—a process known as intense upwelling.
How La Niña Flips Global Weather
Because the vast pool of ocean heat is pinned far over in the western Pacific, the global jet stream shifts dramatically:
The United States and Canada: The polar jet stream moves farther north. This pushes freezing, moisture-heavy arctic air directly into western Canada and the northern U.S., creating severe, snow-heavy winters. Conversely, the southern U.S. gets left high and dry, suffering through warmer, severe drought conditions. [1, 2, 3, 4, 5]
Australia and Southeast Asia: With an overwhelming amount of hot water packed right against their coastlines, the atmosphere goes into hyperdrive. This brings heavy rainfall, intense monsoons, and devastating flood risks to eastern Australia, Indonesia, and India. [1, 2, 3, 4, 5]
The Hurricane Engine: Unlike El Niño, which tears Atlantic storms apart with high-altitude winds, La Niña reduces wind shear. This acts like premium fuel for tropical systems, typically triggering intense, highly destructive Atlantic hurricane seasons
Duration: La Niña events are notoriously stubborn. While El Niño usually fades in under a year, La Niña can easily persist for two or three consecutive years (often referred to as a "triple-dip")
The Current 2026 Situation: The planet just finished a multi-year weak La Niña cycle that officially faded away in early 2026. The Pacific has completely flipped, and we are currently in an active, rapidly intensifying El Niño phase moving through the summer of 2026.
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4) Hvordan er 2026 El Niño anderledes?
El Niño and La Niña have existed for thousands—and likely millions—of years, long before human-induced climate change began. They are foundational, ancient components of Earth's natural climate system.
Paleoclimate researchers have found chemical signatures of alternating warm and cold Pacific cycles in ancient coral samples, lake sediments, and ice cores dating all the way back to the last Ice Age and beyond. There is even evidence of active ENSO cycles during the Early Eocene period roughly 50 million years ago, a prehistoric era when the Earth was naturally up to 15°C warmer than it is today.
Climate change did not create these phases; climate change is supercharging them. This breakdown outlines how they behaved in the past versus how they are behaving now.
While the engine behind El Niño and La Niña is entirely natural, human-driven global warming has fundamentally changed the environment in which these cycles operate.
25% Stronger Swings: A landmark study published in Geophysical Research Letters noted that industrial-age ENSO fluctuations are roughly 25% more intense than pre-industrial baselines. The peaks are hotter, and the dry spells are drier.
The "Super" El Niño Phenomenon: Truly catastrophic, extreme El Niño events used to be incredibly rare historical anomalies. However, in our modern era, we are seeing "Super El Niños" strike with far greater frequency (such as the massive 1982–83, 1997–98, and 2015–16 cycles).
Multi-Year Stubbornness: La Niña has also shown a modern tendency to get "stuck." We have recently witnessed prolonged "triple-dip" La Niñas (like the event stretching from 2020 to 2023) that refuse to break, causing relentless multi-year droughts in some areas and endless flooding in others.
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5) Is-kappe re-generering
https://aria.org.uk/exploring-climate-cooling-rethickening-arctic-sea-ice
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