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When Hurricane Melissa roared ashore in Jamaica in late October 2025 as a Category 5 monster, it became one of the most powerful landfalling Atlantic hurricanes ever recorded. With sustained winds around 185 mph and an exceptionally low central pressure, it wiped out infrastructure, battered tourism-dependent economies, and displaced tens of thousands of people.New York Post+3Wikipedia+3AP News+3
Melissa didn’t happen in a vacuum. It formed over record-warm Atlantic waters and developed against the backdrop of a rapidly evolving El Niño–Southern Oscillation (ENSO) pattern in the Pacific. As the world heads into 2026 under a La Niña advisory, Melissa is less a “freak event” and more a preview of the climate risks we’ll be juggling in the near future.
This article unpacks how La Niña, Hurricane Melissa and broader climate change fit together — drawing on insights from NOAA, the World Meteorological Organization (WMO), the World Health Organization (WHO), and the UK’s National Centre for Atmospheric Science (NCAS).
Hurricane Melissa: A brutal signal from a hotter ocean
Hurricane Melissa intensified with startling speed, jumping from a weaker system to a Category 5 hurricane in roughly a day — a textbook case of rapid intensification. Scientists and meteorological agencies have been warning that warmer oceans are making this kind of explosive strengthening more likely. Sea surface temperatures near Melissa’s track were around 2–3°C above average, providing huge amounts of latent heat to fuel the storm.The Guardian+1
By landfall in Jamaica, Melissa:
- Tied the record for strongest Atlantic landfall in terms of sustained winds and central pressure
- Produced catastrophic flooding, storm surge, and wind damage
- Triggered mass evacuations and long-term disruptions to power, health care, and transport systemsThe Washington Post+1
Events like Melissa don’t “prove” climate change by themselves — hurricanes have always existed — but they are increasingly consistent with the trends that agencies such as NOAA and WMO have been documenting: warmer seas, higher sea levels, and a rising share of the most intense storms in total hurricane activity. The Guardian+1
ENSO 101: Why La Niña matters for 2026
To understand what 2026 might hold, we need to talk about ENSO — the El Niño–Southern Oscillation. ENSO is a natural swing in Pacific Ocean temperatures and atmospheric circulation with two main phases:
- El Niño: unusually warm waters in the central/eastern tropical Pacific
- La Niña: unusually cool waters in the same region
These shifts may sound distant, but they have global knock-on effects on rainfall, storm tracks, and temperature patterns.
As of October 2025, NOAA’s Climate Prediction Center has issued a La Niña advisory, with cool-phase conditions expected to persist through the 2025–26 winter and then fade toward neutral in early 2026.Climate Prediction Center+2iri.columbia.edu+2
This means that for at least part of 2026, the world will likely be transitioning from a La Niña-influenced climate back toward ENSO-neutral, with some models hinting at a possible swing back towards El Niño later on. That transition period can be especially volatile, as atmospheric circulation “rebalances” to new temperature patterns.
La Niña in a warming world: stacking the odds for extremes
Historically, La Niña years have certain typical fingerprints:
- More Atlantic hurricanes and sometimes stronger ones
- Drier conditions in parts of South America, East Africa and the southern U.S.
- Wetter conditions in parts of Southeast Asia and northern Australia
- Shifts in jet streams that influence storminess over North America and Europe
But here’s the crucial piece: ENSO today is operating on top of a planet that is already around 1.1–1.3°C warmer than pre-industrial levels, with greenhouse gases at record highs according to the WMO.Reuters+2World Meteorological Organization+2
That combination — a natural cycle plus human-driven warming — is what shapes climate risk in 2026. In practice, this can look like:
- More intense rainfall events in regions where La Niña already tends to bring storms
- Hotter heatwaves, even in areas that are typically cooler during La Niña
- Higher storm surges because sea level is now several centimetres higher than a few decades ago
- Greater drought-fire interactions, as dry periods coincide with hotter temperatures
Hurricane Melissa, intensified by abnormally warm Atlantic waters at the tail end of the 2025 hurricane season, is a vivid demonstration of how natural variability and global warming can interact to produce outsized extremes.The Guardian+2Severe Weather Europe+2
Climate change is loading the dice, not writing the script
It’s important to be clear on how climate change affects hurricanes and ENSO-related extremes:
- Climate change does not create ENSO — ENSO is a natural oscillation.
- But it changes the baseline: warmer oceans, moister air, higher seas and altered jet streams.
- That baseline shift means the “dice” of weather are loaded toward more severe outcomes.
Attribution studies show that rapid intensification events like Melissa are becoming more frequent and more likely in the modern climate, as warm ocean layers extend deeper and provide more energy for storms.The Guardian+1
This is the kind of phenomenon NCAS and other research centres study: they investigate how background warming alters storm tracks, rainfall extremes, and the likelihood of compound events like “heat + drought + wildfire” or “storm + high tide + heavy rain”.NCAS+2NCAS+2
Heading into 2026, climate scientists are less focused on predicting one specific disaster and more on how the probabilities of extremes have shifted. That’s what matters for disaster planning, insurance, agriculture and health systems.
The human face of La Niña and Melissa: WHO and climate-health risks
If Hurricane Melissa was a meteorological record-breaker, it was also a public-health crisis. Storms of this scale damage hospitals, disrupt water and sanitation, and increase the spread of water-borne and vector-borne diseases in their wake.
The World Health Organization (WHO) has repeatedly warned that climate change is now one of the biggest health threats of the 21st century, affecting clean air, safe water, food security and shelter.World Health Organization+2World Health Organization+2
Recent analyses from WHO-linked initiatives and the Lancet Countdown show:
- Heat-related deaths have risen by around 23% since the 1990s, now causing hundreds of thousands of deaths each year.The Guardian+1
- Extreme events — storms, floods, heatwaves and wildfires — are driving millions into poverty and pushing health systems to breaking point.World Health Organization+1
In 2026, La Niña-related anomalies can amplify these health risks:
- Stronger storms and floods in some regions increase injuries, disease outbreaks and mental-health impacts.WHO+1
- Drought and crop failures in others worsen malnutrition and food insecurity.World Health Organization+1
- Repeated climate shocks erode the capacity of under-resourced health systems, exactly as WHO has been warning for years.World Health Organization+1
In other words, Melissa is a dramatic example of a broader pattern: extreme weather amplified by climate change is increasingly a health story, not just a “weather” story.
NCAS and the science of a changing atmosphere
The National Centre for Atmospheric Science (NCAS) in the UK is one of the key institutions researching how Earth’s atmosphere and climate are evolving. Its work spans climate modelling, severe weather, air quality and long-term climate projections that inform UK and global policy.NCAS+2NCAS+2
In the context of La Niña and Hurricane Melissa, research priorities that matter for 2026 include:
- Attribution science: quantifying how much climate change increased the likelihood or intensity of Melissa-type hurricanes.
- Jet stream and storm-track changes: crucial for understanding how La Niña will influence European and North Atlantic weather in 2026.
- Compound risks for the UK and Europe: NCAS is heavily involved in studying how heatwaves, floods and windstorms may coincide or occur back-to-back in a warmer climate.NCAS+2NCAS+2
These insights feed into national adaptation planning and into international collaborations coordinated through bodies like WMO.
WMO and NOAA: watching the global signals
The World Meteorological Organization (WMO), a UN specialised agency, coordinates global observation systems and synthesises data on weather and climate.World Meteorological Organization+1
In late 2025, WMO reported that CO₂, methane and nitrous oxide have all reached record concentrations, with CO₂ posting the largest annual jump on record.Reuters+1 These rising greenhouse gases underpin:
- The record-high ocean temperatures that helped fuel Melissa
- Increasingly extreme heat, floods and storms seen worldwide
- The likelihood that future La Niña and El Niño events will play out in an ever-warmer climate background
Meanwhile, NOAA (the U.S. National Oceanic and Atmospheric Administration) leads much of the operational science behind:
- ENSO monitoring and forecasts, including the La Niña advisory and 2026 outlookClimate Prediction Center+2iri.columbia.edu+2
- Hurricane prediction and tracking in the Atlantic, including real-time analysis of storms like MelissaThe Guardian+1
Together, agencies like NOAA and WMO provide the backbone of evidence that national governments, NGOs and communities need to prepare for the coming year.
What 2026 could look like — and what we can still change
No scientist can tell you exactly what weather you’ll experience in July 2026. But based on current ENSO forecasts and greenhouse gas trends, some broad expectations are reasonable:
- Higher baseline risk of extremes: even in a La Niña phase, global temperatures remain elevated, so heatwaves, intense rainfall and severe storms remain more likely than they were a few decades ago.AP News+2Le Monde.fr+2
- Regional “hotspots” of risk: island nations and coastal regions (like those hit by Melissa), arid regions heading into drought, and rapidly urbanising areas lacking resilient infrastructure.The Washington Post+2paho.org+2
- Ongoing health pressure: from heat, pollution, food and water insecurity, and trauma associated with repeated disasters.World Health Organization+2WHO+2
The good news? The same expert bodies raising the alarm also emphasise that strong climate action now has huge co-benefits:
- Cutting fossil fuel use improves air quality and reduces deaths from pollution.World Health Organization+1
- Investing in climate-resilient health systems saves lives during storms, floods and heatwaves, as WHO has stressed.World Health Organization+2World Health Organization+2
- Better early-warning systems and risk communication — a big focus for WMO and NCAS — dramatically reduce mortality from extreme weather.World Meteorological Organization+2NCAS+2
At community and individual levels, this translates into practical steps: disaster-ready infrastructure, robust building codes, heat-health action plans, flood-resilient planning, and prioritising the most vulnerable people in adaptation efforts.
This is a wake-up call, not a one-off
Hurricane Melissa is a stark expression of what happens when record-warm oceans, rising seas and a shifting ENSO pattern collide. It unfolded at the tail end of 2025 just as La Niña conditions were consolidating in the Pacific — an early taste of the climate we’ll be navigating in 2026. ENSO will continue to shape the broad rhythm of global climate, but human-driven warming is rewriting the scale of the impacts, tilting the odds toward more intense storms, more dangerous heat and more damaging floods.
Agencies such as NOAA, WMO, WHO and NCAS now paint a consistent picture: unless emissions fall rapidly and societies invest serious resources in adaptation, events like Melissa will increasingly define “normal” risk rather than stand out as historic anomalies. The choices we make now — in energy, planning, health, and international cooperation — will determine whether 2026 is remembered as another step into crisis, or as a year when we finally started to treat the climate emergency like the life-and-health issue it truly is.
To discover more, check out these links:
El Niño vs La Niña
The Guardian – Climate crisis means super-strength Hurricane Melissa is ‘dangerous new reality’
