The 2026 El Niño

Double Blue Ocean 2026/2027?

The developing 2026 El Niño threatens to contribute to loss of virtually all Arctic sea ice in September 2026, which would in turn result in albedo loss, transfer of ocean heat to the atmosphere and additional emissions that could jointly increase the global temperature dramatically and could subsequently also cause virtually all Antarctic sea to disappear a few months later, as also discussed in an earlier post.

Forecasts indicate that the upcoming El Niño will reach historic heights within a few months time.

The above image, adapted from NOAA, shows a sea surface temperature anomaly versus 1991-2020 forecast dated June 30, 2026, for the Niño3.4 region (which is indicative for El Niño development). Forecasts exceed 4°C for parts of many members and also for part of the CFS.v2 (Coupled Forecast System version 2) ensemble mean (the black dashed line).

The image below shows a sea surface temperature anomaly forecast dated June 30, 2026, for the Niño3 region. Forecasts exceed 5°C for part of one forecast member and exceed 4°C for part of the mean.

The image below is adapted from Climate Reanalyzer and also features in an earlier post. The image shows sea surface temperature anomalies versus 1951-1980 in the Niño3.4 region over time. This region in the Pacific Ocean is indicative for the strength of El Niño. The image has a potential 2026 El Niño anomaly of 3.5°C added (red dashed line on the right).

According to NOAA, there is a 97% chance of El Niño in May-July 2026 and 98% chance of El Niño in January–March 2027. The image below, from NOAA, also shows strength probabilities. NOAA adds that there is a 63% chance that El Niño will be very strong in November 2026-January 2027.

Conclusion

The situation is dire and unacceptably dangerous, and the precautionary principle necessitates the danger to be acknowledged, while facilitating rapid, comprehensive and effective action to reduce the damage and to improve the outlook, where needed in combination with a Climate Emergency Declaration, as described in posts such as in this 2022 post and this 2025 post, and as discussed in the Climate Plan group.

Links

• NOAA - Seasonal climate forecast from CFSv2
https://www.cpc.ncep.noaa.gov/products/CFSv2/CFSv2_body.html

• NOAA - ENSO: Recent Evolution, Current Status and Predictions
https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/lanina/enso_evolution-status-fcsts-web.pdf

• NOAA - El Niño/Southern Oscillation (ENSO) Diagnostic Discussion - issued June 11, 2026
https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory/ensodisc.shtml

• NOAA - Official NOAA CPC ENSO Strength Probabilities
https://cpc.ncep.noaa.gov/products/analysis_monitoring/enso/roni/strengths

• Double Blue Ocean Event 2026-2027?
https://arctic-news.blogspot.com/2026/04/double-blue-ocean-event-2026-2027.html

• Transforming Society
https://arctic-news.blogspot.com/2022/10/transforming-society.html

• Climate Plan
https://arctic-news.blogspot.com/p/climateplan.html

• Climate Emergency Declaration
https://arctic-news.blogspot.com/p/climate-emergency-declaration.html

Water Vapor Worries

The Ozone Layer

[CC image, credit: nptel.ac.in ]

The Atmosphere can be divided into layers. The Troposphere is the layer that is closest to the surface. When rising up in the Atmosphere, the next layer up is the Stratosphere. The next layer up is the Mesosphere and the fourth layer from the bottom is the Thermosphere.

The temperature rises or falls in a different way in each of these layers, as illustrated by the red line in the image CC from archive.nptel.ac.in on the right and the scale on the bottom.

The ozone layer is located in the lower stratosphere at an altitude of 15 to 35 km or 9 to 22 miles above the Earth's surface, with the highest concentrations usually peaking around 25 km. This altitude corresponds with a pressure level of 100 to 10 mb or hPa.

The ozone layer absorbs 97% to 99% of the Sun's medium-frequency ultraviolet light (from about 200 nm to 315 nm wavelength), which otherwise could cause severe damage to life on Earth.

Water vapor rising over Antarctica

The image below shows a temperature anomaly forecast for July 3, 2026. At this time of year very little sunlight is reaching Antarctica, so the temperature over Antarctica can get very low. At the same time, global warming has increased sea surface temperatures and this also keeps air temperatures over water relatively warm. The difference in temperature strengthens wind patterns from the Southern Ocean to Antarctica, which can lead to atmospheric rivers moving toward Antarctica, carrying water vapor and heat from the Southern Ocean to Antarctica.

The red color on the above image indicates high temperature anomalies over Antarctica. The dark blue areas indicate where snow has fallen over the sea ice around Antarctica and over the interior of Antarctica. 

As temperatures rise, the water vapor in the air increases. The amount of water vapor that the air can hold rises by 7% for each 1°C temperature rise (Clausius-Clapeyron relation). While much of the water vapor will fall out of the air as precipitation, in the form of rain or snow, some of the water vapor will remain in the air. This extra water vapor increases temperatures, since water vapor is a strong greenhouse gas. The IPCC adds: Water vapor feedback acting alone approximately doubles the warming from what it would be for fixed water vapor. Furthermore, water vapor feedback acts to amplify other feedbacks in models, such as cloud feedback and ice albedo feedback. If cloud feedback is strongly positive, the water vapor feedback can lead to 3.5 times as much warming as would be the case if water vapor concentration were held fixed.

Part of the precipitation will fall over Antarctica in the form of snow, thickening the snow cover there, without returning to the surface of the Southern Ocean. The net result is that the salinity of the Southern Ocean surface increases, facilitating increased melting of Antarctic sea ice, further speeding up the temperature rise, as also discussed in earlier posts such as this one.

The threat is further illustrated by the image below, which shows a forecast of precipitable water standardized anomalies on June 30, 2026. 

Damage to the Ozone Layer

Furthermore, part of the extra water vapor can rise up and moisten the atmosphere up to and above the ozone layer. The combination image below shows relative humidity on June 30, 2026 at 01:00 UTC, with relative humidity reaching up to 100% at surface level (left), up to 100% at 70 mb or hPa (center), and up to 23% at 10 mb or hPa (right).

[ from earlier post ]

Increases in stratospheric water vapor are bad news, as they not only speed up global warming but also lead to loss of stratospheric ozone, as Drew Shindell pointed out back in 2001.

It has long been known that deterioration of the ozone shield increases ultraviolet-B irradiation, in turn causing skin cancer.

Research (box right) suggests that, millions of years ago, it could also have led to loss of fertility and consequent extinction in plants and animals.

Water vapor reaching stratospheric altitudes causes ozone depletion, as James Anderson describes in a 2017 paper and discusses in the short 2016 video below.

[ from earlier post ]

Conclusion

The image below shows annual maximum daily precipitation change with a temperature versus 1850-1900 rise of 1.5°C, 2°C, and 4°C, from the IPCC AR6. 

The situation looks set to deteriorate further. More water vapor causes more warming, since water vapor is a potent greenhouse gas. As more snow falls over Antarctica, the sea surface of the Southern Ocean increases in salinity, which speeds up melting of sea ice. The extra water vapor and increased melting of sea ice can both strongly accelerate the temperature rise, while water vapor that reaches the stratosphere also causes damage to the ozone layer.

The situation is dire and unacceptably dangerous, and the precautionary principle necessitates the danger to be acknowledged, while facilitating rapid, comprehensive and effective action to reduce the damage and to improve the outlook, where needed in combination with a Climate Emergency Declaration, as described in posts such as in this 2022 post and this 2025 post, and as discussed in the Climate Plan group.

Links

• Moistening Atmosphere
https://arctic-news.blogspot.com/p/moistening-atmosphere.html

• Care for the Ozone Layer
https://arctic-news.blogspot.com/2019/01/care-for-the-ozone-layer.html

• Double Blue Ocean Event 2026-2027? - update 

https://arctic-news.blogspot.com/2026/06/double-blue-ocean-event-2026-2027-update.html

• Transforming Society
https://arctic-news.blogspot.com/2022/10/transforming-society.html

• Climate Plan
https://arctic-news.blogspot.com/p/climateplan.html

• Climate Emergency Declaration
https://arctic-news.blogspot.com/p/climate-emergency-declaration.html

Clouds Tipping Point - update 1

A 5 Gt burst of seafloor methane would nearly double the methane in the atmosphere and could instantly raise CO₂e level to well above 1200 ppm, thus triggering the cloud feedback. 

The image below is an update of an earlier analysis that refers to data dating back a few years. Meanwhile, concentrations of greenhouse gases have kept rising and radiative forcing estimates for 2025 have been released. 

The above image looks into a scenario in which methane concentrations nearly double, due to 5 Gt of methane getting released, instantly increasing CO₂e levels to above 1200 ppm and thus triggering the cloud feedback, as described in the image and as illustrated by the bar on the right in the above image.

Importantly, the clouds tipping point could also be crossed with far less methane getting released. As illustrated by the bar on the left in the above image, levels of further pollutants could increase rapidly while feedbacks strengthen and while sulfate cooling ends abruptly, causing the clouds tipping point to get crossed and resulting in a potential rise of 18.44°C (from pre-industrial) by the end of 2026, as also discussed at the extinction page.

Climate Emergency Declaration

The situation is dire and unacceptably dangerous, and the precautionary principle necessitates rapid, comprehensive and effective action to reduce the damage and to improve the outlook, where needed in combination with a Climate Emergency Declaration, as described in posts such as in this 2022 post and this 2025 post, and as discussed in the Climate Plan group.

Links 

• Clouds Tipping Point 

https://arctic-news.blogspot.com/2026/03/clouds-tipping-point.html

• Carbon dioxide highest in millions of years - update 2

https://arctic-news.blogspot.com/2026/06/carbon-dioxide-highest-in-millions-of-years-update-2.html

• Indicators of Global Climate Change 2025: annual update of key indicators of the state of the climate system and human influence - by Piers Forster et al. (2026)
https://essd.copernicus.org/preprints/essd-2026-287/essd-2026-287.pdf

• Transforming Society
https://arctic-news.blogspot.com/2022/10/transforming-society.html

• Climate Plan
https://arctic-news.blogspot.com/p/climateplan.html

• Climate Emergency Declaration
https://arctic-news.blogspot.com/p/climate-emergency-declaration.html

Extreme heat danger

Forecast of Wet Bulb Globe Temperature of 35°C or 96°F in south of Texas, U.S.

A temperature of 39°C or 102°F is forecast for a location in the south of Texas, U.S., for June 18, 2026 20 UTC. With a relative humidity of 51%, this translates into a 'feels like' temperature of 52°C or 125°F and a Wet Bulb Globe Temperature of 35°C or 96°F.

Furthermore, as illustrated by the image below, a temperature of 41°C or 105°F is forecast for another location in the south of Texas, U.S., for June 18, 2026 20 UTC. With a relative humidity of 44%, this translates into a 'feels like' temperature of 52°C or 126°F and a Wet Bulb Globe Temperature of 35°C or 96°F.

According to NOAA, the Wet Bulb Globe Temperature (WBGT) is an indicator of heat related stress on the human body at work (or play) in direct sunlight. It takes into account multiple atmospheric variables, including: temperature, humidity, wind speed, sun angle, and cloud cover.

By contrast, the wet bulb temperature measures the lowest temperature to which an object can cool down through the evaporation of water, primarily accounting for heat and humidity in the shade.

Wet-bulb temperature (from earlier post)

The human body can cool itself by sweating and the stronger the wind, the more one can cool off by sweating. As temperatures and humidity levels keep rising, a threshold can be reached where the wind factor no longer matters, in the sense that wind can no longer provide cooling. This physiological limit was long described as a 35°C wet-bulb temperature. i.e. once the wet-bulb temperature reaches 35°C, one can no longer lose heat by perspiration, even in strong wind, but instead the human body will start gaining heat from the air beyond a wet-bulb temperature of 35°C.

Accordingly, a 35°C wet-bulb temperature (equivalent to 95°F at 100% humidity or 115°F at 50% humidity) was long seen as the theoretical limit, the maximum a human could endure. Many assumed that reaching such a limit would require a large increase in temperature, but a 2020 study (led by Raymond) warns that this limit could be regularly exceeded with a temperature rise of less than 2.5°C (compared to pre-industrial).

Furthermore, a 2022 study (led by Vecellio) finds that the actual limit is lower — about 31°C wet-bulb or 87°F at 100% humidity — even for young, healthy subjects. The temperature for older populations, who are more vulnerable to heat, is likely even lower. In practice the limit will typically be lower and depending on circumstances could be as low as a wet-bulb temperature of 25°C.

Forecast of extreme heat danger in Washington and Baltimore region 

Below is a forecast for July 2, 2026, of extreme heat danger in the Washington and Baltimore region, where a wet bulb globe temperature of 35°C is forecast for a location in Annapolis, 31 miles South-Southeast of Baltimore, Maryland.

The image illustrates that the wet bulb temperature threshold can increasingly be reached or even crossed in a large part of the United States. 

Compound impact of high temperatures, extreme weather events, lightning and ozone

The image below shows sea surface temperature anomalies of 9.3°C/16.8°F reached on June 27, 2026, at the mouth of the Northern Dvina River in Russia and of 8.2°C/14.8°F south of France in the Mediterranean Sea.

High sea surface temperatures go hand in hand with strong evaporation from the sea surface and high levels of water vapor in the air, which in turn can result in strong thunderstorms, storm damage and flooding.

Furthermore, ground-level ozone peaks during warm, sunny summer afternoons, as NOx from motor vehicles and industry reacts with sunlight and heat to form ozone. Lightning can contribute significantly to ozone. At the surface level, lightning can contribute to more than 40% of ozone during intense thunderstorms. Ozone in the troposphere is a short-lived yet potent greenhouse gas and ground-level ozone also constitutes a health hazard for vegetation, wildlife, livestock and people, also making forests more vulnerable to fires that can be ignited by lightning, as discussed on facebook in a recent comment.

The compound impact of high temperatures, extreme weather events, lightning and ozone was also discussed in this earlier post.

Conclusion

The situation is dire and unacceptably dangerous, and the precautionary principle necessitates the danger to be acknowledged, while facilitating rapid, comprehensive and effective action to reduce the damage and to improve the outlook, where needed in combination with a Climate Emergency Declaration, as described in posts such as in this 2022 post and this 2025 post, and as discussed in the Climate Plan group.

Links

• NOAA (National Oceanic and Atmospheric Administration) - National Weather Service
https://digital.weather.gov

• Heat Stress in the US (2025)

https://arctic-news.blogspot.com/2025/07/heat-stress-in-the-us.html

• Arctic Blue Ocean Event 2025? (update June 2025)

https://arctic-news.blogspot.com/2025/06/arctic-blue-ocean-event-2025-update-June-2025.html

• Transforming Society
https://arctic-news.blogspot.com/2022/10/transforming-society.html

• Climate Plan
https://arctic-news.blogspot.com/p/climateplan.html

• Climate Emergency Declaration
https://arctic-news.blogspot.com/p/climate-emergency-declaration.html