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.

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

• 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

Double Blue Ocean Event 2026-2027? - update

Arctic sea ice

A Blue Ocean Event could be declared when Arctic sea ice reaches or crosses a threshold of 1 million km² in extent.

On June 14, 2026, the Arctic sea ice extent was 10.680 million km², a record low for the time of year, as illustrated by the image below, adapted from NSIDC. The Arctic sea ice extent has been very low in the year to date, despite the dominance of La Niña conditions. The Arctic sea ice extent will continue to fall rapidly as the 2026 El Niño is strengthening. Forecasts indicate that this El Niño will be the strongest on record.

As illustrated by the image below, Arctic sea ice extent was 10.63 million km² on June 13, 2026 (black), lowest on record for the time of year and a deviation from 1981-2010 of -3.12σ. Highlighted in blue is the sea ice extent in 2012 (record low year) and highlighted in purple is the extent in 2016, when there was a strong El Niño.

Another measure is Arctic sea ice volume. The image below, adapted from the Danish Meteorological Institute, shows that the daily Arctic sea ice volume was at a record low for the time of year on June 18, 2026, as it has been for years. 

The April 2026 Arctic sea ice volume was about 18,500 km³ (as illustrated by the image on the right, from an earlier post), which is very close to the magenta bar which stands for strong melting (18,000 km³) after the annual maximum volume was reached. 

The image below, from an earlier post, shows Arctic sea ice volume through April 2026, with the strength of the melting between the annual maximum (blue circle) and the annual minimum (red circle) highlighted by colored bars, magenta for strong melting (18,000 km³) and green for little melting (15,000 km³). 

Last year, only about 15,000 km³ of sea ice melted away from the maximum in 2025 to the minimum in September 2025, and this relatively little melting can be attributed in part to La Niña conditions.

The April 2026 volume was about 18,500 km³, so if strong melting (18,000 km³) will take place over the next few months (dashed magenta line), as can be expected with a super El Niño coming up, a Blue Ocean Event will occur and virtually all Arctic sea ice volume will be gone in September 2026. 

In the above image, the difference between strong melting (magenta) and little melting (green) is 3000 km³. With strong melting taking place from April 2026, this may well cause a Blue Ocean Event to occur, with virtually all Arctic sea disappearing in September 2026.

The animation below, made with NASA images, shows the Arctic sea ice just north of the northern tip of Greenland, from June 3 through June 10, 2026. This is where some of the thickest Arctic sea ice is located. The animation illustrates that even the thickest sea ice can break up with the pieces getting moved by wind and ocean currents into the Atlantic Ocean where they will melt away.

The 2026 El Niño 

The upcoming 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.

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 update for June 16, 2026, for the Niño3.4 region (which is indicative for El Niño development). Forecasts exceed 4°C for parts of some forecast members and exceed 3.5°C for part of the forecast for the Coupled Forecast System version 2 (CFS.v2) ensemble mean (black dashed line).

The image below shows a sea surface temperature anomaly forecast update for June 16, 2026, for the Niño3 region, with forecasts exceeding 4°C for parts of some forecast members and approaching 4°C for part of the mean.

The combination image below shows sea surface temperature anomalies versus 1981-2010 in the Niño 1+2 region (located close to South America), where a rise of 4.4°C (from -1.6°C in the top image to +2.8°C in the bottom image) occurred within six months through June 17, 2026.

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.

The image below, adapted from NOAA, shows El Niño (red), La Niña (blue) and neutral episodes (grey). 

Temperature

The image below shows that on June 17, 2026, the sea surface temperature (SST) was the highest on record for this time of year in the Niño3.4 region (5°S–5°N, 120–170°W), an area in the Pacific Ocean that is indicative for development of El Niño. The inset shows sea surface temperature anomalies on June 17, 2026, with the Niño3.4 region highlighted.

The June 17, 2026, sea surface temperature in the Nino3.4 region was 29.37°C, a jump of 3.62°C in a span of about 5 months from the 25.75°C recorded on January 9, 2026. SST were higher only during the super El Niño in November 2015, as marked on the right of the image. 

The image below, adapted from nullschool.net, shows sea surface temperature anomalies on June 17, 2026. The temperature of the sea surface was as much as 21°F or 11.7°C higher (Lake Michigan, at the green circle) than 1981-2011 on June 17, 2026.

On June 14, 2026, the world (60°S–60°N, 0–360°E) sea surface temperature (inset also shows anomalies on June 14, 2026) was 20.98°C, the highest temperature on record for this time of year, as illustrated by the image below, which also has marked the years 2023 and 2024, while the year 2025 is colored orange. 

Sea surface temperatures (SST) peak twice each year: in March/April (when it's Summer in the Southern Hemisphere) and in August (when it's Summer in the Northern Hemisphere). Despite La Niña conditions in early 2026, which suppressed temperatures, 2026 SST were close to the record high 2024 SST, when El Niño conditions were present. Meanwhile, 2026 SST have reached the highest temperatures on record for this time of year. 

The combination image below, adapted from nullschool.net, shows sea surface temperatures in the Arctic on June 11, 2026 (left) and on June 16, 2026 (right). The images show many areas with water temperatures high enough for no sea ice to be present. The green circle on the right marks an area where the sea surface temperature is -1.6°C. 

[ click on images to enlarge ]

The combination image below shows, on the left, temperatures above 0°C forecast over much of the Arctic Ocean including the North Pole for June 17, 2026, adapted from ClimateReanalyzer on the left, and on the right sea ice concentration on June 16, 2026, adapted from NSIDC. 

[ click on images to enlarge ]

On land in the Northern Hemisphere (where most people live), the average temperature departure from 1901-2000 will rise dramatically with strengthening of the 2026 El Niño, as illustrated by the NOAA plot below. 

Temperatures can be expected to rise dramatically in the course of 2026 for a number of reasons including acceleration of the temperature rise over the years (more than 1°C rise from 2013 as illustrated by the green trend in the above image) and rising strength of the 2026 El Niño.

The image below should act as a warning, illustrating the danger that the upcoming El Niño could trigger a rapid and steep rise in temperatures on land in the Northern Hemisphere in the course of 2026 that could cross the 3°C threshold.

[ from earlier post ]

The above image shows land-only data in the Northern Hemisphere through March 2026, with a polynomial trend added that points at 3°C crossed later in 2026. About 0.5°C of the rise can be attributed to El Niño, with further contributions from feedbacks and further forcers. Note that the 1901-2000 base is not pre-industrial, the outlook may be even more dire when using a genuinely pre-industrial base.

The image below, adapted from tropicaltidbits.com, shows a temperature forecast for January 2027, with high temperature anomalies showing up all over the Arctic Ocean and over areas where currently sea ice is present around Antarctica. This indicates that there will be dramatic loss of Antarctic sea ice.

The images below show forecasts for the monthly sea surface temperature anomaly (SSTA) from December 2026 through March 2027, further confirming indications that there will be dramatic Antarctic sea ice loss. 

SSTA December 2026

SSTA January 2027

SSTA February 2027

SSTA March 2027

Antarctica

The image below, from Berkeley Earth Temperature Report for 2024, illustrates the importance of Antarctic Sea ice loss in accelerating the temperature rise in 2020-2023 compared to 2010-2019.

[ image from earlier post ]

The red color on the above image shows an area with an extra radiative forcing of +2.1 W/m², which is primarily the result of loss of Antarctic sea ice. 

This additional radiative forcing of +2.1 W/m² is about as much as the change in radiative forcing caused by all carbon dioxide released by people from 1750 to 2019, according to IPCC AR6 figures (image right).  

Antarctic sea ice area was only 1.09 million km² on February 22, 2023, very close to the 1 million km² threshold when a Blue Ocean Event could be called, as illustrated by the image on the right, from an earlier post. 

Loss of Antaratic sea ice causes albedo loss, which can dramatically increase sea surface temperatures of the Southern Ocean. The image below is created with NOAA January 2001 through May 2026 NOAA data with a trend added to highlight the danger of accelerating sea surface temperature rise and Antarctic sea ice loss.

A recent study led by Robert Massom describes how stronger wind can causes stronger waves that can break up and pulverise ice floes into small fragments and slush, and that can also cause ice floes to flood over, resulting in ponds of seawater that enable algae growth. Unlike melt ponds, seawater wave ponds occur year-round. These feedbacks all reduce albedo, further speeding up the melting of sea ice.  

   [ Saltier water, less sea ice - from earlier post ]

Until 2015, rising temperatures resulted in melting of ice and enhanced precipitation that freshened the surface of the Southern Ocean, exacerbated by increasing stratification that prevented mixing. The temperature rise over the years also caused winds to be stronger, at the time causing the sea ice to spread out wider.

The higher the water's salt content, the lower its melting point. Seawater typically has a salinity of about 3.5% (35 grams of salt per liter of water). Sea ice starts melting when the temperature rises to about -2°C (28.4°F). By contrast, freshwater remains frozen as long as the temperature remains below 0°C (32°F).

A recent study led by Theo Spira finds that, in 2015, anomalously strong winds enhanced mixing across the thin Winter Water layer, entraining warm and salty subsurface waters, which broke down upper-ocean stratification. Another recent study led by Earle Wilson find that in 2015, intensified wind-driven upwelling reversed the freshening trends, releasing years of accumulated ocean heat that contributed to unprecedented sea ice loss.

A recent study led by Da Nian warns that Antarctic regions (60°S − 90°S) may warm by around 6°C due to the collapse of the Atlantic meridional overturning circulation (AMOC).

A recent study led by Aditya Narayanan finds that East Antarctic sea ice loss was primarily subsurface driven via enhanced upward circumpolar deep water flux, whereas West Antarctic sea ice loss was also forced by longwave radiative flux anomalies. Findings suggest that persistent upwelling-favorable conditions under anthropogenic forcing may push the Southern Ocean into a prolonged low sea ice state.

[ image from: 10°C or 18°F warmer by 2021? ]

An earlier post discusses the finding of a study led by Alessandro Silvano that, around 2015, surface salinity in the Southern Ocean began rising sharply – just as sea ice extent started to crash.

The post also points at the danger that heat, previously stored in the deep ocean by sinking circumpolar waters, will instead remain at the surface and cause atmospheric temperatures to rise, as illustrated by the image on the right.

The post warns that higher temperatures come with feedbacks such as stronger wind and stronger evaporation, resulting in increased water vapor in the atmosphere.

The post further warns that, while much of the water vapor will return to the surface in the form of precipitation such as rain and snow, part of this precipitation will fall over Antarctica, with the net result of an increase in salinity of surface of the Southern Ocean, facilitating increased melting of Antarctic sea ice.

The image below, from a 2025 study led by Wei Wang, shows that, while Antarctic sea ice has decreased over the past few years, the Antarctic ice sheet has gained mass recently. 

Driven by extratropical cyclones, strong winds can transport heat and moisture from the warmer Southern Ocean deep into the interior of Antarctica, where the water vapor condenses to fuel heavy snowfall events, as warned about in studies such as a 2025 study led by Jonathan Wille and a 2026 study led by Kyohei Yamada and as illustrated by the combination image below showing a forecast for June 2, 2026, for Antartica of temperature anomalies (left) and wind speed (right).

Ominously, the image below shows a relative humidity (RH) of 100% at the location marked by the green circle at 70 hPa over Antarctica on June 18, 2026.

This 70 hPa is a pressure level corresponding with an altitude in the lower stratosphere. RH shows the capacity of the atmosphere to hold water vapor. Below 0°C and at 100% RH, water vapor starts turning into ice crystals that can fall down as snow. 

The image below, also adapted from nullschool.net, shows a relative humidity of 100% on June 18, 2026, at the surface at the location marked by the green circle.

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

• NSIDC - National Snow and Ice Data Center - Sea Ice Today
https://nsidc.org/sea-ice-today/sea-ice-tools/charctic-interactive-sea-ice-graph

• Climate Reanalyzer
https://climatereanalyzer.org

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

• Tropicaltidbits.com
https://www.tropicaltidbits.com

• NASA - Worldview
https://worldview.earthdata.nasa.gov

• NOAA - Climate at a Glance - Time Series

https://www.ncei.noaa.gov/access/monitoring/climate-at-a-glance/global/time-series/shem/ocean/tavg/1/0/1850-2026

• 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

• The influence of ocean waves on Antarctic sea-ice albedo and seasonal melting, and potential coupled physical and biological feedbacks - by Robert Massom et al. 
https://tc.copernicus.org/articles/20/3271/2026

also discussed on facebook at: 

https://www.facebook.com/groups/arcticnews/posts/10164358963719679

• nullschool.net - relative humidity

https://earth.nullschool.net

also discussed on facebook at: 
https://www.facebook.com/groups/arcticnews/posts/10164364227369679

• Spatiotemporal mass change rate analysis from 2002 to 2023 over the Antarctic Ice Sheet and four glacier basins in Wilkes-Queen Mary Land - by Wei Wang et al. (2025)

https://link.springer.com/article/10.1007/s11430-024-1517-1
News release at: 
https://www.eurekalert.org/news-releases/1080537

• Atmospheric rivers in Antarctica - by Jonathan Wille et al. (2025)

https://www.nature.com/articles/s43017-024-00638-7

• Interannual Variations of Precipitation Events at Dome Fuji Station, Antarctica - by Kyohei Yamada et al. (2026) 
https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2025JD045296

also discussed on facebook at: 

https://www.facebook.com/groups/arcticnews/posts/10164385286809679

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

• Ocean heat threatens sea ice
https://arctic-news.blogspot.com/2026/05/ocean-heat-threatens-sea-ice.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

Carbon dioxide highest in millions of years - update 2

SSP5-8.5 scenario

The above image shows IPCC projections for CO₂ concentration and temperature change for the SSP5-8.5 scenario. The IPCC translates concentrations of greenhouse gases into radiative forcing (see image below), which can in turn be converted into temperature change (see image above) by using a climate sensitivity multiplier.

In the SSP5-8.5 scenario, radiative forcing is by definition projected to increase to 8.5 W/m² by 2100. When using an (older) climate sensitivity multiplier of 0.75, this could result in a temperature rise of more than 6°C by 2100. Recent research such as by James Hansen et al. suggests that a higher climate sensitivity multiplier should be used, which could result in a temperature rise of more than 10°C by 2100 in the SSP5-8.5 scenario. 

The IPCC has a history of trying to downplay the strength of global warming and refuses to accept that its projections have been too low. Lo and behold, some scientist have now come forward to accommodate the IPCC by suggesting to drop SSP5-8.5 altogether, arguing it had become "implausible, based on trends in the costs of renewables, the emergence of climate policy and recent emission trends".

Let's take a look into those arguments. While the cost of renewables and sales of coal have fallen, the emergence of climate policy depends on political opinion. The temperature rise is accelerating and feedbacks are threatening to kick in with greater ferocity. The rise in the Earth Energy Imbalance and in ocean heat is outpacing SPSS5-8.5, as discussed in an earlier post. Furthermore, the aerosol masking effect is decreasing. Additionally, IPCC models subtract assumed carbon dioxide removal (CDR), despite doubts regarding the way the IPCC seeks CDR to take place, as discussed in this post and in this video posted on facebook.

Therefore, it is vital to include SSP5-8.5 as a reference, in order to inform and warn about a potentially huge temperature rise, the more so since mainstream media fail to do so and policymakers typically look only a few years ahead. Indeed, not including warnings could be a recipe for bad climate policy, halting or even reversing the necessary climate action.

Feedbacks

[ click on image to enlarge ]

There are numerous feedbacks that can dramatically accelerate the temperature rise, such as albedo changes and changes to wind tracks and ocean currents causing oceans to take up less heat, resulting in more heat in the atmosphere.

The image on the right shows cold sea surface temperatures over the North Atlantic. Such low sea surface temperatures don't mean that global warming is slowing down, instead they are part of feedbacks that constitute huge dangers, as written on the image and further discussed in this post on facebook.

The danger is that a strong storm will cause a huge amount of warm, salty water to travel underneath the surface of the Atlantic Ocean into the shallow parts of the Arctic Ocean, pushing up temperatures and salinity levels at the seafloor and destabilizing methane hydrates, in turn resulting in eruptions of methane from these hydrates and from free gas underneath the hydrates, as discussed at this post and at this page.

The danger increases as greenhouse gases keep rising, so let's have a look at recent concentrations.  

Carbon dioxide (CO₂)

The image below, from an earlier post, shows the CO₂ concentration over 31 days at Mauna Loa, Hawaii. The hand points at a daily CO₂ concentration of 433.95 parts per million (ppm) recorded on May 1, 2026.

The image below, dated June 1, 2026, shows carbon dioxide concentration over the past few years at Mauna Loa, Hawaii. Note the high surface flask measurements recorded recently.

The image below shows daily carbon dioxide at Utqiaġvik, formerly know as Barrow, Alaska, June 1, 2026.

Nitrous oxide (N₂O)

The image below shows nitrous oxide concentration at Mauna Loa, Hawaii, June 1, 2026.

The image below shows monthly nitrous oxide at Utqiaġvik, formerly know as Barrow, Alaska, June 1, 2026.

Nitrous oxide has a lifetime of 109 years and a Global Warming Potential (GWP) of 273 for a horizon of 20 years and also a GWP of 273 over 100 years, according to IPCC AR6. Nitrous oxide is both a potent greenhouse gas and a compound that depletes ozone in the ozone layer. 

The image below shows the globally averaged marine surface mean nitrous oxide concentration through 2025 with a trend added to show the potential for a huge rise by 2047.

Methane (CH₄)

The image below shows monthly methane at Mauna Loa, Hawaii, June 1, 2026.

[ from earlier post, discussed on facebook ]

Greenhouse gas concentrations are rising and carbon dioxide and nitrous oxide are rising fast, while methane is rising even faster (see image on the right) and more methane threatens to erupt from the seafloor, as discussed in earlier posts such as this one and this one.

There are many feedbacks that further contribute to the temperature rise (such as albedo loss and more heat moving remaining in the atmosphere instead of being absorbed by oceans, ice and land, as discussed below). Altogether, this could result in a temperature rise of more than 20°C within one year, as discussed in an earlier post.

Sulfur hexafluoride (SF₆)

The image below shows a worrying recent rise in concentrations of sulfur hexafluoride (SF₆), which has a global warming potential (GWP) over 100 years of 24,300 and, because it has a lifetime of 1000 years, its GWP over 500 years is even higher, i.e. 29,000 (IPCC AR6).

Regarding SF₆, one does not have to bother to check historical levels, since the vast majority of SF₆ in the atmosphere is produced by people, it's a synthetic, industrial gas that leaked from its use mainly as an insulator in high-voltage and medium-voltage power systems and lines that can carry power over long distances. Clearly, too little is done politically to reduce SF₆ emissions, even though there are safe, viable alternatives available to using SF₆ in the power industry. Furthermore, rooftop solar systems can - where needed - be part of microgrids, which can reduce the need for transmission lines, poles and towers, so microgrids can also reduce fire hazards. Fire can also destroy warehouses where SF₆ is stored in tanks.

For high concentrations of surfur hexafluoride recorded at other locations, also see this post and comments at facebook.

The image below shows global annual mean SF₆ through 2025, with a trend added to show the potential for a huge rise by 2037.

This is an update of an earlier post that also discusses the Earth Energy Imbalance and the threat of a rapid rise in methane in more detail.  

Carbon monoxide (CO)

The image below, dated June 5, 2026, shows carbon monoxide (CO) concentration over the past few years at Mauna Loa, Hawaii, with some high recent readings showing up. 

The image below shows a Copernicus forecast of carbon monoxide for June 5, 2026.

[ image from earlier post ]

CO acts as the largest single sink for hydroxyl (OH). Elevated CO concentrations can therefore cause OH depletion that results in increases in the atmospheric lifespan of methane. More methane in turn also results in more ozone and stratospheric water vapor.

The IPCC AR5 image on the right depicts the global warming potential (GWP) and carbon dioxide equivalent (CO₂e) of methane (brown bars) and carbon monoxide (grey bars). 

The image below shows the effective radiative forcing of methane, ozone and stratospheric water vapor. 

Earth energy imbalance

As temperatures rise, the outgoing longwave radiation has not risen as fast as the absorbed incoming solar radiation, due to weakening of the Planck feedback as geographical patterns of warming are shifting and due to high (and rising) concentrations of greenhouse gases and loss of albedo, resulting in an increasingly larger amount of extra energy stored on Earth. The image below, from an earlier post, depicts Earth energy imbalance (in orange), i.e. the extra energy that is left after subtracting outgoing longwave radiation (in red) from incoming solar radiation (in black).

Where does the extra energy go? According to the IPCC AR6 WG1, 91% of the extra energy is taken up by oceans, 5% by land, 3% by ice melting and 1% remains in the atmosphere. Oceans, land and melting ice thus act as a buffer that did take up the vast majority (99%) of the extra energy, based on IPCC data. The image below, by Leon Simons, shows how, over time, absorbed solar radiation (black line) has increased more rapidly than outgoing longwave radiation (red line). The orange-colored area in between the lines depicts Earth's Energy Imbalance, or the extra energy that remains on Earth. 

[ image by Leon Simons, discussed on facebook ]

Not only is the extra energy increasing, as depicted by the above images, but the proportions of where the extra energy is going is additionally changing, resulting in an increasingly higher temperature rise of the lower atmosphere, as described below.

- Oceans
The ocean's capacity to act as an energy buffer is increasingly compromised by stratification, changes to ocean currents, changes in salinity, ocean oxygen depletion, acidification and more, as discussed in earlier posts such as this one. This is a big issue, since oceans take up 91% of the extra heat caused by greenhouse gases, so if there is even a 1% reduction in the heat taken up by oceans, the heat remaining in the atmosphere may double.

- Ice
Furthermore, the capacity for ice to act as a buffer by consuming energy in the process of melting is increasingly compromised by sea ice decline, by retreat of glaciers, and by darkening of ice due to dust, algae, black carbon and more. Arctic sea ice is facing a Blue Ocean Event with sea ice decline threatening to both dramatically lower albedo and reduce the ability for ocean heat to be consumed in the process of melting. Mountain glaciers are also in decline and permafrost is approaching the point where thawing of permafrost will speed up rapidly, as discussed in earlier posts such as this one.

- Land
The capacity for land to take up heat also faces a tipping point: The Land Evaporation Tipping Point can get crossed locally when water is no longer available locally for further evapotranspiration, i.e. from all processes by which water moves from the land surface to the atmosphere via evaporation and transpiration, including transpiration from vegetation, evaporation from the soil surface, from the capillary fringe of the groundwater table, and from water bodies on land. Once this tipping point gets crossed, the land and atmosphere will heat up strongly, due to the extra heat, i.e. heat that was previously consumed by evaporation and thawing, as described at this page.

- Atmosphere
As said, while the extra energy is increasing, as depicted by the above images, the capacity of oceans, land and ice to take up more energy is decreasing. Consequently, an increasingly large amount of extra heat threatens to accumulate in the lower atmosphere, especially in the Northern Hemisphere over land and in the Arctic, where temperatures are rising faster than anywhere in the world.

- Wetlands and freshwaters 
The image below is adapted from a recent study led by Zhen Zhang and shows projections in which the tropics (30° S–30° N) contribute approximately 68% of the net increase in estimated wetlands methane emissions, while temperate regions (30° N–60° N) and the Arctic (>60° N) are expected to contribute 21% and 8%.

Approximately half of all methane (CH₄) emissions come from freshwaters, where they are regulated by the microbial ‘CH₄ filter’ whose efficiency describes the fraction of CH₄ produced that is subsequently oxidized back to CO₂ (methanotrophy) before emission. CH₄ production becomes more efficient with warming, linked to increased abundance of methanogens and underpinned by community shifts. In contrast, while CH₄ oxidation activity increases, its process-level efficiency does not, and methanotrophs shift towards less efficient taxa. Consequently, the system-level CH₄ filter efficiency remains fixed, and CH₄ emissions increase. If this fixed CH₄ filter efficiency under warming is common to freshwaters worldwide (wetlands, lakes and rivers), then an upward trajectory for CH₄ emissions through future climate change appears inevitable. From a recent study led by Sarah Harpenslager. 

Compounding dangers in Arctic

Peatlands store approximately 30% of the global total soil carbon, with 80% of this carbon contained in Arctic peatlands. An emerging concern caused by accelerated climate change and permafrost thaw is the rapid increase in Arctic peatland fires, which have already expanded to the Siberian Arctic Ocean coast, Greenland, and Alaskan tundra peatlands. These fires occur along with record-breaking boreal forest fires raging in Canada. Peat fires may smolder for weeks and months, releasing massive amounts of, potentially ancient, carbon, which may transform them from a major carbon sink into a net carbon source into the atmosphere.

In addition to globally significant greenhouse gas emissions, peatland fires release abundant particulate matter. Smoldering peat fires may emit six times more aerosol mass per unit carbon combusted compared to flaming (grassland and forest) fires. Wildfires are a major source of Black Carbon (BC), which is the strongest light-absorbing particulate with a large positive global radiative effect. Simultaneously, wildfires release abundant Organic Carbon (OC), which can have a cooling effect either directly by scattering solar radiation or indirectly by modulating cloud properties. However, increasing evidence of substantial light-absorbing OC, i.e., Brown Carbon (BrC), being emitted in wildfires, suggests that the atmospheric net effect of biomass burning plumes is warming, as specifically shown for boreal and Indonesian peat combustion, while the properties and atmospheric lifetime of BrC vary depending on, for instance, combustion characteristics, biomass type, and moisture content. Moreover, BC and BrC decrease surface albedo when deposited on snow and ice, further accelerating Arctic climate change. Consequently, increasing high-latitude peatland fires are of great concern in the vicinity of snow- and ice-covered surfaces.

The above text and comparison images are adapted from a 2026 analysis led by Meri Ruppel.

[ image from earlier post, click to enlarge ]

Ominously, a peak methane level of 2628 parts per million (ppb) was recorded at 695.1 mb by the NOAA 20 satellite on May 18, 2026 PM, as illustrated by the above image, while the image below shows a peak level of 2579 ppb recorded by the NOAA 21 satellite on May 13, 2026 PM, at 840 mb, which is even closer to sea level, indicating that large releases of methane may have taken place from the seafloor of the ocean.

[ image from earlier post, click to enlarge ]

For more on the danger of rising methane concentrations, see the Clouds Tipping Point post. 

Could the Northern Hemisphere land-only temperature rise exceed 3°C soon?

The upcoming El Niño could trigger a rapid and steep rise in temperature on land in the Northern Hemisphere, as illustrated by the combination image below that uses land-only data in the top panel and Northern Hemisphere data in the bottom panel.

[ image from earlier post, discussed on facebook here ]

Conclusion

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

• NOAA - Global Monitoring Laboratory - data viewer
https://gml.noaa.gov/dv/iadv

• NOAA - Global Monitoring Laboratory - Carbon Cycle Greenhouse Gases - Mauna Loa, Hawaii
https://gml.noaa.gov/ccgg/trends/mlo.html

• NOAA - Office of Satellite and Products Operations - NOAA-20 and NOAA-21 satellites
https://www.ospo.noaa.gov/products/atmosphere/soundings/heap/nucaps/new/nucaps_products.html

• IPCC AR6, Workgroup 1, Chapter 4, Future Global Climate: Scenario-based Projections and Near-term Information
https://www.ipcc.ch/report/ar6/wg1/downloads/report/IPCC_AR6_WGI_Chapter04.pdf

• IPCC AR6, Workgroup 1, Chapter 7, Supplementary material - SF6 GWP and lifetime
https://www.ipcc.ch/report/ar6/wg1/downloads/report/IPCC_AR6_WGI_Chapter07_SM.pdf

• Copernicus - carbon monoxide forecasts 
https://atmosphere.copernicus.eu/charts/packages/cams/products/carbon-monoxide-forecasts

• 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

• A fixed methane filter maximizes freshwater emissions under warming - by Sarah Harpenslager et al. https://www.nature.com/articles/s41558-026-02649-2
as discussed on facebook at: 
https://www.facebook.com/groups/arcticnews/permalink/10164343110889679

• 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