Arctic News: 2025

Monday, June 2, 2025

Arctic Blue Ocean Event 2025? (update June 2025)

High temperatures

The image below shows the temperature anomaly (versus 1951-19801) for May 2025. The large difference in anomalies on and around Antarctica is striking, highlighting the predicament of the West Antarctic Ice Sheet.

How large is the temperature rise now? In the image below, created with NASA data, the decade from 1903 through 1912 is used as a custom base, illustrating that temperature anomalies were 1.5°C or more above this base for the past two years, i.e. for each of the 24 consecutive months from June 2023 through May 2025. So, when using 1903-1912 as a reference, the temperature rise has clearly breached the 1.5°C threshold for the averaging period going back two years through May 2025. What is the best reference period or base against which the rise is to be measured? An earlier analysis suggests that the rise may be even higher when compared to a genuinely pre-industrial base. What averaging period is most appropriate in analyses that include the temperature rise to come? The issue is discussed below.

In the above image, the red line (two-year Lowess Smoothing trend) shows a steep rise that, when extended, points at 2°C above this base (1903-1911) getting crossed in late 2026, implying both goals of the Paris Agreement have been breached, i.e. to limit the temperature increase to 1.5°C above pre-industrial and to limit it to well below 2°C. What type of trend is most appropriate in analyses that include the temperature rise to come? Using a Lowess Smoothing trend and extending that trend linearly into the future may not be the most appropriate way to go.

The image below shows a polynomial trend, calculated over data from 24 months ago (June 2023) through May 2025, and extended 24 months into the future. It's a cubic trend indicating that the temperature rise may be 3°C in 2026 and 5°C in 2027.

[ A 3°C rise in 2026 and a 5°C rise in 2027? - click on images to enlarge ]

How bad could 3°C or 5°C be? The image below adds some perspective, it is from the 2019 post When Will We Die?

Would things look much better when calculating the temperature rise over a longer period?

When using only past data, the average anomaly for the period starting 12 months ago through May 2025 is 1.67°C, for the period starting 24 months ago through May 2025 it is 1.69°C. When using an averaging period starting 10 years ago through May 2025, the average rise is 1.41°C.

Going back further in time can reduce the average, but such an analysis would incorporate unacceptable bias toward past data at the expense of the rise to come. Indeed, the rise to come should not be ignored by selecting an averaging period that only uses past data. Instead, it makes sense to look at both past data and projections into the future and to also take into account potential acceleration of the rise due to compound impact of feedbacks and further mechanisms, as discussed further below.

The image below uses a 20-year averaging period centered around the end of May 2025. If the temperature rise followed a cubic trend based on data going back one decade, the rise averaged over the entire period would be 5.79°C, while the rise would cross 5°C in late 2031 and would cross 8°C at the end of 2034.

[ click on images to enlarge ]

What if an even longer averaging period was used? In the image below, the inset is added to confirm that the temperature rise vs 1903-1912 has been 1.5°C or higher for each of the past 24 months. The trend in the image covers a 30-year averaging period, centered around the end of May 2025. The trend confirms indications that the temperature rise would be high and cross 8°C in 2037 and 10°C in 2039.

[ click on images to enlarge ]

In other words, the longer the averaging period, the more the trend will be based on (and may be biased toward) data going further back in the past when temperatures were lower and feedbacks were weaker. As temperatures rise over time, however, feedbacks are likely to get stronger. Furthermore, tipping points may get crossed and Black Swan Events may occur. As an example, crossing the clouds tipping point at 1200 ppm CO₂ could - on its own - push temperatures up by an additional 8°C globally, which may occur well before 2028 (as discussed further below) and such tipping points should not be ignored. Indeed, much depends on the strength and combined impact of feedbacks and further mechanisms that could accelerate the temperature rise, so the more reason to discuss them in more detail.

There are many conditions contributing to even higher temperatures. Emissions and temperatures have recently been rising at a rate that is unprecedented in history. The temperature rise may accelerate further and there are many conditions, feedbacks and further mechanisms that point at further acceleration.

Earth's Energy Imbalance has more than doubled in recent decades, and reached 1.8 W/m⁻² in 2023, twice the "best" estimate from the IPCC, after having more than doubled within just two decades, as illustrated by the image below, from Mauritsen, 2025).

Below is a video in which Paul Beckwith discusses the study led by Mauritsen. Paul's video has the title: 57 scientists (@46 institutions) co-author 4-page paper ignoring almost all James Hansen's EEI work. James Hansen attributes 1.05 W/m² of the albedo loss to the clouds feedback, 0.15 W/m² to the snow/ice feedback and 0.5 W/m² to changes in shipping regulations (aerosol forcing). James Hansen blames the IPCC for failing to warn about the impact of many feedbacks and further mechanisms that are causing albedo loss. Indeed, the IPCC keeps downplaying the dangers in many ways, such as by ignoring a potentially much higher historic temperature rise and rise to come. Paul Beckwith highlights that the 57 authors of the study are merely calling for a "robust and reliable capability to observe the energy imbalance", without calling for more effective climate action that includes an overhaul of the IPCC narrative.

Concentrations and emissions of greenhouse gases are high and rising. The image below shows recent carbon dioxide (CO₂) concentrations at Mauna Loa, Hawaii.

The image below shows monthly CO₂ at Mauna Loa, Hawaii.

Black Swan Event 1. Crossing the clouds tipping point

The image below shows the same monthly data, this time from May 2022 through May 2025, with a trend added that warns about 1200 parts per million (ppm) getting crossed in 2028.

Crossing the clouds tipping point at 1200 ppm CO₂ could - on its own - push temperatures up by 8°C globally, in addition to the temperature rise caused by the extra CO₂ to reach the tipping point. Moreover, the clouds tipping point is actually at 1200 ppm CO₂e (carbon dioxide equivalent), so when taking into account the impact of growth of other gases, strengthening feedbacks and further mechanisms, this tipping point could be crossed much earlier than in 2028, potentially as early as in 2026.

Crossing the clouds tipping point early could be regarded as a Black Swan Event. Black Swan Events are events that are unforeseen in climate models. Such events can suddenly and unexpectedly increase temperatures. While there have been many warnings about such events, they are typically ignored or minimized in climate models. In fact, many warnings about acceleration of the temperature rise are ignored in climate models. Ten black swan events are identified in this post. Since black swan events are inherently unforeseen in climate models, there is little or no discussion about them and there may be many more of them on the way than the ten that are mentioned here.

The situation is also dire regarding other conditions, i.e. concentrations and emissions other than CO₂ are also higher for further gases and aerosols (also fueled by fires and war), while sea ice is low, the Jet Stream is distorted, AMOC is slowing down and sunspots are high.

On top of this, there are numerous self-amplifying feedbacks that can dramatically accelerate the temperature rise and mechanisms are in progress that increase temperatures, such as reductions of aerosols that are currently masking the temperature rise. Not only are many of the feedbacks self-amplifying, strengthening feedbacks and changing conditions can also amplify each other, e.g. a freshwater lid can form at the surface of the North Atlantic and a distorted Jet Stream can combine with hurricanes to cause more ocean heat to get pushed toward the Arctic Ocean underneath this lid, and subsequently speed up sea ice loss and cause eruptions of methane from the seafloor of the Arctic Ocean.

[ formation of a freshwater lid at the surface of the North Atlantic ]

There are further tipping points, in addition to the above-mentioned clouds tipping point. Tipping points include loss of Arctic sea ice and loss of the latent heat buffer as Arctic sea ice disappears; crossing such tipping points can abruptly and strongly increase temperatures and thus trigger crossing of further tipping points.

Black Swan Event 2. Early El Niño

Models do not predict the next El Niño to appear soon, as illustrated by the image below. Instead, NOAA expects La Niña to return in the Northern Hemisphere fall and winter 2025-26.

Nevertheless, the next El Niño may emerge earlier, and it may be a strong El Niño. Over the past few months, there's been a zigzag pattern of rises and falls in sea surface temperatures in Niño 3.4, an area in the Pacific (inset) that is critical to the development of El Niño, as illustrated by the image below.

Black Swan Event 3. Low sea ice

One feedback of high temperatures and high concentrations of greenhouse gases is loss of sea ice. Polar amplification of the temperature rise is hitting the Arctic hard, and is also causing dramatic loss of Antarctic sea ice. Global sea ice area has been very low over the past few years, as illustrated by the image below, something that wasn't anticipated in climate models. Low global sea ice comes with dramatic loss of albedo, i.e. a lot of sunlight was in previous years reflected back into space and it is now instead getting absorbed by the sea surface. On June 2, 2025, global sea ice area was 17.52 million km², lowest on record for the day.

Arctic sea ice extent is currently lowest on record for the day, as illustrated by the image below. On June 16, 2025, Arctic sea ice extent was 10.653 million km², lowest on record for the day.

Low sea ice can also be regarded as a Black Swan Event, the more so since there currently is no El Niño present, but instead ENSO-neutral conditions dominate. Importantly, low sea ice does increase ocean heat, as discussed next.

Black Swan Event 4. Loss of lower clouds

Low global sea ice area comes with albedo loss and this causes more heat to be absorbed by oceans. Higher sea surface temperatures result in loss of lower clouds, further reducing albedo and thus accelerating the temperature rise.

This extraordinary loss of albedo may result in a Blue Ocean Event in the course of 2025, as discussed next.

Black Swan Event 5. Blue Ocean Event

On June 2, 2025, Arctic sea ice area was 2nd lowest on record for that day, only slightly higher than 2016. Significantly, 2016 was a strong El Niño year. On June 2, 2025, Arctic sea ice area was 0.44 million km² lower than on June 2, 2012. If the sea ice area will be 1.34 million km² less than 2012 on September 12 this year, there will be a Blue Ocean Event.

[ from earlier post ]

Black Swan Event 6. Loss of latent heat buffer

Volume and thickness are two further measures to assess the health of Arctic sea ice, and they are critical in regard to the latent heat buffer, which decreases as sea ice, permafrost and glaciers disappear.

Latent heat is energy associated with a phase change, such as the energy consumed when ice turns into water. During a phase change, the temperature remains constant. As long as there is ice, additional heat will be absorbed by the process of ice turning into water, so the temperature doesn't rise at the surface.

[ from Albedo, latent heat, insolation and more ]

[ Arctic sea ice volume, click to enlarge ]

The amount of energy absorbed by melting ice is as much as it takes to heat an equivalent mass of water from zero to 80°C. The energy required to melt a volume of ice can raise the temperature of the same volume of rock by as much as 150ºC.

Warmer water flowing into the Arctic Ocean causes Arctic sea ice to lose thickness and thus volume, diminishing its capacity to act as a buffer that consumes ocean heat entering the Arctic Ocean from the North Atlantic.

This means that - as sea ice thickness decreases - a lot of incoming ocean heat can no longer be consumed by melting the sea ice from below, and the heat will therefore contribute to higher temperatures of the water of the Arctic Ocean.

[ Arctic sea ice volume, click to enlarge ]

Similarly, there is a point beyond which thawing of permafrost on land and melting of glaciers can no longer consume heat, and all further heat will instead warm up the surface.

The image on the right shows that Arctic sea ice volume has been at a record daily low for more than a year, reflecting severe loss of the latent heat buffer.

Loss of the latent heat buffer constitutes a tipping point. Beyond a certain point, further ocean heat arriving in the Arctic Ocean from the Atlantic Ocean and the Pacific Ocean will no longer be able to be consumed by melting sea ice from below.

The combination image below shows Arctic sea ice thickness on April 28, 2025 (left), May 13, 2025 (center) and June 13, 2025 (right).

[ Arctic sea ice thickness, click on images to enlarge ]

The image below shows Arctic sea ice thickness on June 15, 2025.

Black Swan Event 7. Seafloor methane eruptions

Further incoming heat therefore threatens to instead reach the seafloor of the Arctic Ocean and destabilize methane hydrates contained in sediments at the seafloor, resulting in abrupt eruptions of huge amounts of methane, in turn threatening increased loss of permafrost, resulting in additional emissions, as illustrated by the above image and the image below.

[ The Buffer is gone, from earlier post, click to enlarge ]

The danger is especially large in the East Siberian Arctic Shelf (ESAS), which contains huge amounts of methane and which is hit strongly by the temperature rise, as described in earlier posts such as this one.

Methane in the atmosphere could be doubled in March 2026 if a trend unfolds as depicted in the image below. A rapid rise is highlighted in the inset and reflected in the trend, which is based on January 2023-October 2024 methane data, as issued in February 2025.

[ Double the methane in March 2026? Image from earlier post, click on images to enlarge ]

A rise like the one depicted in the trend could eventuate as rising ocean heat destabilizes methane hydrates contained in sediments at the seafloor of the Arctic Ocean. The temperature rise in the Arctic would accelerate since the methane would initially have a huge impact over the Arctic and cause depletion of hydroxyl, of which there is very little in the atmosphere over the Arctic in the first place. Such a rise in methane would also dramatically increase concentrations of ozone in the troposphere and concentrations of water vapor in the stratosphere.

The image below with high levels of methane recorded at Utqiagvik (Barrow), Alaska, should act as a warning.

Black Swan Event 8. Water vapor

The IPCC has failed to warn about the size of the temperature rise. Higher temperatures imply stronger feedbacks, such as stronger evaporation resulting in both a lot more water vapor and a lot more heat getting transferred from the surface to the atmosphere. Much of this will return to the surface with precipitation such as rain and snow, but 7% more water vapor will end up in the atmosphere for every degree Celsius rise in temperature. Moreover, water vapor is a potent greenhouse gas that will increase temperatures and it is a self-amplifying feedback that can strongly contribute to further acceleration of the temperature rise.

[ from April 2024 post, click on images to enlarge ]

As illustrated by the above image, the temperature rise from pre-industrial to February 2024 could be as large as 2.75°C, which corresponds with almost ⅕ more water vapor in the atmosphere.

Water that previously remained present in the ground, is increasingly moving up into the atmosphere, since a warming atmosphere holds more water vapor and thus sucks up increasingly more water. The water vapor feedback results in more moisture getting sucked up into the air as temperatures rise, a process that is further accelerated by stronger wind as temperatures rise.

More transpiration from vegetation and more evaporation from rivers, lakes and the soil contributes to stronger drought and makes vegetation more vulnerable to pests & diseases and also makes both vegetation and the soil more prone to get burned. After fires, the soils turns black (reflecting less sunlight back into space) and is more vulnerable to erosion and to further droughts and fires, having lost the vegetation that previously held the soil together.

Trees keep the soil together with their roots and also keep the soil cool. Because of the lower temperatures, the soil will also retain more moisture. Trees cool the surface by shading it, by transpiration and by releasing volatile organic compounds into the air that contribute to the formation of clouds that reflect more sunlight back into space and that cause more rainfall. If rainwater can run deep down into the soil along the roots of trees, it helps replenish the groundwater.

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. Additionally, more water vapor in the atmosphere accelerates the temperature rise, since water vapor is a potent greenhouse gas and this also contributes to speeding up the temperature rise of the atmosphere.
(discussed on facebook here, here and here).

Compound effect of several ignored Black Swan Events

Black Swan Events may be unexpected and they are typically excluded from models that seek to downplay the dangers, but that doesn't mean that Black Swan Events should be ignored. Using non-linear trends may show unexpected things, but sometimes they can turn out - in hindsight - to be pretty accurate, as illustrated by the combination image below.

[ screenshot from earlier post, click to enlarge ]

Several Black Swan Events can also combine with catastrophic results, as described below.

Black Swan Event 9. Abrupt collapse of the West-Antarctic ice sheet

A recent study warns that collapse of the West Antarctic Ice Sheet (WAIS) could contribute over 4 m sea-level rise with little (0.25 °C) or even no ocean warming above present, even without additional carbon emissions. The study concludes that we are likely already at (or almost at) an overshoot scenario and adds that, once on the lower branch, WAIS recovery by tipping back to the upper branch occurs only once the ocean temperature cools between −1.25 and −1.5 °C below present.

In the video below, Paul Beckwith discusses the study.

The very low Antarctic Sea Ice over the past few years was not anticipated by models, neither was the steep rise in sea surface temperatures. Continued loss of Antarctic sea ice could dramatically increase sea surface temperatures where the sea ice disappears. A further rise of global sea surface temperatures could make things worse. The joint impact could cause abrupt collapse of the West Antarctic Ice Sheet.

Black Swan Event 10. Fires and lightning

Emissions can increase strongly, abruptly and rapidly for many reasons, such as due to more burning of fossil fuel, forests, wood and other biofuel, and more vegetation starting to die due to droughts, heatwaves, pests and diseases, and decompose or burn due to fires. Peatlands, tar sands, rainforests and soil can all start to burn as temperatures keep rising. As temperatures rise rapidly, permafrost can release huge amounts of emissions, including carbon dioxide, methane and nitrous oxide.

The above image shows annual number of fires and area burned in Canada and is adapted from the Canadian National Fire Database, which adds that while lightning causes about 50% of all fires, it accounts for about 85% of the annual area burned. A 2022 study finds that increases in lightning ignition efficiency, together with a projected doubling of lightning strikes, result in a 39%–65% increase in lightning-caused fire occurrence per 1°C warming.

The combination of higher temperatures, stronger wind, higher vulnerability of forests and more lightning will cause more fires and more emissions of carbon dioxide, black carbon, brown carbon, methane, carbon monoxide and tropospheric ozone. At 3-8 miles height, during the summer months, lightning activity increases NOx by as much as 90% and tropospheric ozone by more than 30%. Tropospheric ozone has a direct warming impact as a greenhouse gas, while carbon monoxide can indirectly cause warming by extending the lifetime of methane.

The worst wildfires can send smoke high enough to affect the ozone layer in the stratosphere. Damage to the ozone layer and climate change are forming a dangerous feedback loop.

Scientists are shocked to see sea ice disappear

In the video below, Guy McPherson reflects on news that scientists are shocked to see sea ice disappear.

Climate Emergency Declaration

The situation is dire and the precautionary principle calls for rapid, comprehensive and effective action to reduce the damage and to improve the situation, as described in this 2022 post, where needed in combination with a Climate Emergency Declaration, as discussed at this group.

Links

• NASA - GISS Surface Temperature Analysis

https://data.giss.nasa.gov/gistemp

• Paris Agreement
https://unfccc.int/sites/default/files/english_paris_agreement.pdf

• When Will We Die?
https://arctic-news.blogspot.com/2019/06/when-will-we-die.html

• Earth's Energy Imbalance More Than Doubled in Recent Decades - by Thorsten Mauritsen et al. (2025)
https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2024AV001636

discussed on Facebook at:

https://www.facebook.com/groups/arcticnews/posts/10162759302779679/?comment_id=10162759968059679&reply_comment_id=10162767166574679

• NOAA - Monthly Average Mauna Loa CO2
https://gml.noaa.gov/ccgg/trends/mlo.html

• NOAA - Daily, Monthly and Weekly Average CO2

https://gml.noaa.gov/ccgg/trends/graph.html

• NOAA - Global Monitoring Laboratory

https://gml.noaa.gov/dv/iadv

• Clouds Tipping Point
https://arctic-news.blogspot.com/p/clouds-feedback.html

• Arctic Blue Ocean Event 2025?

https://arctic-news.blogspot.com/2025/03/arctic-blue-ocean-event-2025.html

• Sunspots
https://arctic-news.blogspot.com/p/sunspots.html

• Kevin Pluck - seaice.visuals.earth
https://seaice.visuals.earth

• Climate Reanalyzer
https://climatereanalyzer.org

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

• NOAA - Climate Prediction Center - El Niño/Southern Oscillation (ENSO) Diagnostic Discussion
https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory/ensodisc.shtml

• Pre-industrial
https://arctic-news.blogspot.com/p/pre-industrial.html

• University of Bremen - sea ice
https://seaice.uni-bremen.de/start

• Feedbacks in the Arctic
https://arctic-news.blogspot.com/p/feedbacks.html

• NOAA - Office of Satellite And Product Operations - Sea Surface Temperatures
https://www.ospo.noaa.gov/products/ocean/sst/contour/index.html

• Jet Stream
https://arctic-news.blogspot.com/p/jet-stream.html

• Cold freshwater lid on North Atlantic
https://arctic-news.blogspot.com/p/cold-freshwater-lid-on-north-atlantic.html

• Arctic Blue Ocean Event 2025?
https://arctic-news.blogspot.com/2025/03/arctic-blue-ocean-event-2025.html

• Accelerating Temperature Rise

https://arctic-news.blogspot.com/2025/03/accelerating-temperature-rise.html

• The threat

https://arctic-news.blogspot.com/p/threat.html

• Feedbacks (including the Water Vapor Feedback)
https://arctic-news.blogspot.com/2024/07/feedbacks.html

• Extinction
https://arctic-news.blogspot.com/p/extinction.html

• Antarctic Ice Sheet tipping in the last 800,000 years warns of future ice loss - by David Chandler et al.

https://www.nature.com/articles/s43247-025-02366-2

• Future increases in lightning ignition efficiency and wildfire occurrence expected from drier fuels in boreal forest ecosystems of western North America - by Thomas Hessilt et al. (2022)

https://iopscience.iop.org/article/10.1088/1748-9326/ac6311
discussed on Facebook at
https://www.facebook.com/groups/arcticnews/posts/10159942902794679

• 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

Thursday, May 22, 2025

Paris Agreement thresholds crossed (update May 2025)

High temperatures persist

In the image below, created with NASA data, the decade from 1904 through 1913 is used as a custom base, illustrating that the temperature anomaly has been more than 1.5°C above this base for each of the past consecutive 22 months (July 2023 through April 2025), and even longer when compared to a pre-industrial base. The red line shows a trend (two-year Lowess Smoothing) that is pointing at 2°C above this base (1904-1913) getting crossed in the course of 2026.

[ trend points at 2°C above 1904-1913 getting crossed in 2026 ]

The temperature rise on land looks even more threatening, as illustrated by the image below.

The above image shows land only monthly temperature anomalies from 1880-1920, with the red line (2-year Lowess Smoothing trend) showing an acceleration in April 2022. If extended, the red line points at crossing 3°C in the course of 2026. Humans are likely to go extinct with a 3°C rise, as discussed in earlier posts such as this one.

An earlier analysis mentions that, when using 1750 as a base, this could add 0.3°C to the historic rise. The analysis adds that when using an even earlier base, even more could be added to the historic temperature rise.

Those who seek to delay or sabotage climate action typically call for use of a late base, in efforts to minimize the historic temperature rise. Using an earlier base can mean that temperatures are already higher than the thresholds that politicians at the adoption of the Paris Agreement pledged wouldn't be crossed, and it can also imply that the temperature rise is accelerating faster and further, due to stronger feedbacks such as more water vapor in the atmosphere and disappearance of lower clouds, all of which would constitute a stronger call for climate action.

The image below illustrates that air temperatures in the Northern Hemisphere have been very high over the past few months, at times reaching record high temperatures for the time of year, e.g. the temperature in the Northern Hemisphere was 10.08°C on May 14, 2025, the highest temperature on record for that day.

[ from earlier post, click on images to enlarge ]

These record high temperatures are the more significant as they were reached under ENSO-neutral conditions. On May 24, 2025, the sea surface temperature was 27.51°C, 0.35°C below 1991-2020, in Niño 3.4, an area in the Pacific (inset) that is critical to the development of El Niño, as illustrated by the image below. The Niño 3.4 anomaly is now lower than it has been for each day in March 2025, when La Niña conditions dominated.

The ENSO outlook below is dated May 8, 2025. It shows that ENSO-neutral conditions are likely to persist for the remainder of 2025, edging on La Niña conditions.

The ENSO outlook is dated May 18, 2025.

As said, to see such high temperatures under ENSO-neutral conditions is significant, it indicates that feedbacks are stronger than many models have anticipated, which implies that feedbacks will continue to grow stronger, given the rapid temperature rise over the past few years (black trend). A new El Niño may develop soon, potentially in April 2026, as the red trend in the image below warns about. The result could be a huge rise in temperature over the course of 2026 (red trend).

As said, different bases can be used, e.g. in the above images anomalies are calculated versus bases such as 1904-1913, 1880-1920, 1991-2020 and 1901-2000. None of them is pre-industrial. So, what would the temperature anomaly look like when a genuinely pre-industrial base was used?

The image below, from an earlier post, uses NASA monthly data through March 2023. Data are first adjusted from NASA's default 1951-1980 base to an earlier 30-year base, i.e. a 1886-1915 base, and then further adjusted by 0.99°C to reflect ocean air temperatures, higher polar anomalies and a pre-industral base.

The image below is an update, the same adjustments are made to data through April 2025.

How the 0.99°C adjustment in the above images is calculated is shown in the bright yellow inset of the image below.

[ from April 2024 post, click on images to enlarge ]

The images show that, when adjusting the data and using a genuinely pre-industrial base, the temperature rise may have already crossed both the 1.5°C and the 2°C thresholds that politicians at the 2015 Paris Agreement pledged shouldn't and wouldn't be crossed.

IPCC keeps downplaying the danger

The IPCC keeps downplaying the danger in many ways. One way the IPCC does this is by selecting a base that minimizes the temperature rise and then to keep making the claim that we're still well below the 1.5°C threshold. The above image, from an April 2024 post, shows that the February 2024 temperature was 1.76°C above 1885-1915, and potentially 2.75°C above pre-industrial (bright yellow inset right). The red line (a six-months Lowess smoothing trend) highlights the steep rise that had already taken place by then. Minimizing the temperature rise will also minimize feedbacks that come with the temperature rise, such as a rise in water vapor and loss of lower clouds, which are self-amplifying feedbacks that further accelerate the temperature rise. In other words, by minimizing the historic temperature rise, the IPCC also seeks to minimize the rise to come.

[ from a 2014 post, click on images to enlarge ]

An additional way used by the IPCC to downplay the danger is to suggest there was a "carbon budget", as if there was an amount of carbon to be divided among polluters that could continue to be consumed for decades to come.

The image on the right, from a 2014 post, points at the fallacy and deceit that comes with a carbon budget, carbon credits, offsets and net-zero emission targets that would, according to the IPCC, accomplish and maintain a "balance" between sources and sinks.

Instead, comprehensive and effective action is needed on multiple lines of action, simultaneously yet separately.

Indeed, action is needed to reduce concentrations of carbon both in oceans and in the atmosphere, while on land, the soil carbon content needs to increase, which can best be achieved by methods such as pyrolysis of biowaste and adding the resulting biochar to the soil, to reduce emissions, reduce fire hazards, sequester carbon, support the presence of moisture & nutrients in the soil and thus support the health & growth of vegetation, as discussed at the Climate Plan group and the biochar group.

The IPCC has failed on at least three points:
1. failed to warn about the historic temperature rise and associated larger feedbacks

2. failed to warn about mechanisms that could cause further acceleration of temperature rise soon

3. failed to point at the best ways to combat climate change.

Higher temperatures come with feedbacks, as illustrated by the image below, from an earlier post.

[ the temperature in the atmosphere can keep rising, even in the absence of further emissions ]

The above image illustrates how feedbacks and crossing of tipping points can cause the temperature of the atmosphere to keep rising, even in the absence of further emissions, due to shrinking heat sinks (e.g. sea ice thickness loss and oceans taking up less heat).

The IPCC failed to warn about Antarctic sea ice decline, and - importantly - the amplifying impact of Antarctic sea ice decline on the global temperature rise. This was addressed in an earlier post as follows:
Sea ice loss results in less sunlight getting reflected back into space and instead getting absorbed by the ocean and the impact of Antarctic sea ice loss is even stronger than Arctic sea ice loss, as Antarctic sea ice is located closer to the Equator, as pointed out by Paul Beckwith in a video in an earlier post. A warmer Southern Ocean also comes with fewer bright clouds, further reducing albedo, as discussed here and here. For decades, there still were many lower clouds over the Southern Ocean, reflecting much sunlight back into space, but these lower clouds have been decreasing over time, further speeding up the amount of sunlight getting absorbed by the water of the Southern Ocean, and this 'pattern effect' could make a huge difference globally, as this study points out. Emissivity is a further factor; open oceans are less efficient than sea ice when it comes to emitting in the far-infrared region of the spectrum (feedback #23 on the feedbacks page).

A 2024 study led by Norman Loeb finds that large decreases in stratocumulus and middle clouds over the sub-tropics and decreases in low and middle clouds at mid-latitudes are the primary reasons for increasing absorbed solar radiation trends in the northern hemisphere.

Slowing down of the Atlantic meridional overturning circulation (AMOC) can cause more heat to accumulate at the ocean surface. Higher sea surface temperatures also come with greater stratification (image below, from earlier post).

Stratification and further changes in oceans and in wind patterns can cause a freshwater lid to form on top of the ocean surface, enabling more hot & salty water to flow underneath this lid (feedback #28), contributing to calving of glaciers and destabilization of sediments at the seafloor.

Increases in water vapor in the atmosphere, loss of sea ice and loss of lower clouds are three self-amplifying feedbacks, i.e. as temperatures rise, such feedbacks will push temperature up even further and due to their self-amplification, the temperature rise will accelerate.

Sea ice loss

One feedback of high temperatures and high concentrations of greenhouse gases is loss of sea ice. Polar amplification of the temperature rise is hitting the Arctic hard, and is also causing dramatic loss of Antarctic sea ice. Global sea ice area has been very low for the past few years, as illustrated by the image below. This has caused a lot of sunlight that was previously reflected back into space, to instead get absorbed by the sea surface. On May 24, 2025, global sea ice area was 17.75 million km², lowest on record for the day.

The image below, adapted from the Danish Metereological Institute, shows that Arctic sea ice volume on May 29, 2025, was at a record low for the time of year, as it has been for more than a year.

Sea ice is disappearing over large parts of the Arctic Ocean. The image below, adapted from the University of Bremen, shows sea ice concentration on May 29, 2025.

The screenshot below, from an earlier post, further illustrates the dangers that come with sea ice loss. Eruptions of methane from the seafloor of the Arctic Ocean is one of the most terrifying dangers.

As the image below illustrates, some of the thickest sea ice disappears from the Arctic Ocean as it gets broken up by sea currents and the pieces get moved out along the edges of Greenland. The image shows how, on May 27, 2025, the sea ice gets broken up just north of Greenland, due to ocean currents that will also move the pieces to the south, alongside the edges of Greenland, toward the North Atlantic.