Arctic News: Peter Carter

Showing posts with label Peter Carter. Show all posts

Sunday, February 1, 2026

Is SSP5-8.5 the worst-case scenario?

SSP5-8.5

SSP5-8.5 is one of a number of Shared Socioeconomic Pathways (SSP). It is a scenario in which radiative forcing would be 8.5 W/m⁻² in 2100. The image on the right shows the IPCC projection of the temperature rise in 2081–2100 relative to 1850–1900 corresponding with a SPP5-8.5 scenario (from IPCC AR6 WG11 SPM).

The image below, created by Peter Carter, Climate Emergency Institute, shows the WMO's averaged 2025 global temperature increase of 1.44°C on top of IPCC AR6 WG1 Figure 4.02 (a), illustrating that the WMO rise of 1.44°C for 2025 is spot on the SSP5-8.5 projection (in dark red).

SSP5-8.5 is often said to be a "worst-case" scenario, but as illustrated by the image below, current temperatures are on track or even exceeding SSP5-8.5 projections, given that the rise in 2024 was 1.55°C and 2025 resembled a La Niña year. So, has the IPCC been downplaying the danger? It sure makes one wonder whether SSP5-8.5 is the worst-case scenario. Indeed, Business As Usual (BAU) may turn out to be even worse, so let's have a closer look at what the outlook for some of the worst-case scenarios could be.

A further image by Peter Carter is added below.

How much could temperatures rise?

The image below, adapted from ClimateReanalyzer, shows the Coupled Model Intercomparison Project Phase 6 (CMIP6) for the SSP5-8.5 scenario pointing at a temperature rise of 1.661°C in February 2025, of 4.388°C in February 2083 and of 5.163°C in February 2100, when using a 1901-2000 base (temperatures will be higher when a genuinely pre-industrial base is used).

The map below shows the CMIP6 SSP5-8.5 rise versus 1881-1920 in February 2100. The map shows that the temperature rise in areas on land (where most people live) could be as much as 8°C higher in Feb 2100 in the SSP585 model.

The map warns that temperatures over large parts of the Arctic may be as much as 20°C higher than 1881-1920 in February 2100. This would suggest that by 2100 the snow and ice cover in the Arctic will have declined dramatically and that huge amounts of greenhouse gases will likely have been released from the seafloor of the Arctic Ocean and from thawing terrestrial permafrost, with huge albedo changes as well as loss of the latent heat buffer, further accelerating the temperature rise over the years. There are further contributors to a rapid and potentially huge temperature rise, so the SSP5-8.5 model may severely underestimate the temperature rise. Indeed, the SSP5-8.5 model may not be the worst-case scenario.

CMIP6 SSP5-8.5 can be used to project temperature rises beyond 2100, as illustrated by the image below, from an earlier post and from a 2016 paper by Brian O'Neill et al.

[ from earlier post, click on images to enlarge ]

In the above analysis, CO₂ emissions keep rising in CMIP6 SSP5-8.5 to about 35 GtC in 2100, to fall gradually after 2100 (a), while atmospheric CO₂ concentrations keep rising and remain at levels higher than 2000 ppm beyond 2250 (b), while radiative forcing (RF) rises to and remains at 12.5 W/m⁻² (c) and global mean temperature change rises to 8°C in 2300 (d).

Equilibrium climate sensitivity (ECS) can be used to convert RF into °C temperature change. ECS in IPCC AR6 is 3, i.e. lower than in CMIP models. A study led by James Hansen concludes the IPCC ECS is too low and suggests to use 1.2°C per W/m⁻², which in a 8.5 W/m⁻² scenario would correspond with a 10.2°C temperature anomaly in 2100. Hansen et al. add that equilibrium global warming for today’s GHG amount is 10°C, which is reduced to 8°C by today’s human-made aerosols.

A 2020 analysis by Jorgen Randers et al. (image above on the right) points out that, even if all greenhouse gas emissions by people could stop immediately and even if the temperature anomaly could fall to 0.5°C above pre-industrial, greenhouse gas levels would start rising again after 2150 and keep rising for centuries to come.

The image on the right uses content from a study by Christina Schädel et al, which concludes that permafrost fires and thaw will release 63 Gt C for each degree Celsius rise in temperature from a 389-691 Gt pool of permafrost carbon.

That 63 Gt C would translate into 231 Gt CO₂ if only CO₂ gets released. By comparison, the total annual human emissions are now about 55 Gt CO₂e and NOAA calculates that the atmosphere has changed from 1750 to 2024 by 539 CO₂e due to people's greenhouse gas emissions.

Importantly, some of the carbon will be released in the form of methane and CO₂e is much higher for releases in the form of methane than for carbon dioxide, especially when a high multiplier is used to calculate methane's CO₂e. Even worse, releases from submarine permafrost would come mostly in the form of methane.

The danger is even more menacing when looking at how fast temperatures are rising in the Arctic and when including more feedbacks, i.e. not only the impact of permafrost fires and permafrost thaw, but also the impact of destabilizing sediments at the seafloor of the Arctic Ocean resulting in eruptions of huge amounts of methane, on top of the impact of albedo loss and loss of the latent heat buffer of declining sea ice and permafrost.

How fast could temperatures rise?

Next to the size of the temperature change, the rate of change is also important. Large changes did take place in prehistoric times, but they typically did take a long time to evolve. The current temperature rise looks set to be huge and also looks set to be rising at accelerating speed, dwarfing anything seen in previous extinction events. The image below, from an earlier post, shows extinction rates and temperature changes for the five major extinction events (grey vertical lines).

The image and quote below also featured in an earlier post by Andrew Glikson.

“The paleoclimate record shouts to us that, far from being self-stabilizing, the Earth's climate
system is an ornery beast which overreacts even to small nudges” (Wally Broecker)

[ from an earlier post ]

The image below further illustrates that temperatures may currently be rising much faster than they ever did in history.

[ from earlier post ]

Contributors to a potentially huge temperature rise

[ see the Extinction page ]

The bar-chart on the right conceptually dates back to 2016, when analysis of contributions concluded they could add up to a potentially huge rise in temperature in the near future. The bar-chart includes an 8°C rise when CO₂e levels cross 1200 ppm (CO₂ emissions peak at 130Gt before 2100 and concentrations stay above 2000 ppm from 2350 in the O'Neil analysis, while methane and N₂O emissions keep rising beyond 2100 in RCP8.5).

The image below uses NASA Land-only temperature anomalies versus 1880-1920, illustrating that temperature could rise more rapidly than SSP5-8.5 suggests. The image illustrates that the 1.5°C threshold was crossed for temperatures on land since 2015, when politicians pledged (at the Paris Agreement) to take efforts to prevent a rise of more than 1.5°C from pre-industrial from occurring.

Note that this 1880-1920 base is not pre-industrial; temperature anomalies can be higher when using a genuinely pre-industrial base.

The image below has a polynomial trend added that points at 3°C getting crossed on land in early 2027.

As discussed, crossing 3°C on land is important, since most people live on land and there are indications that such a rise will cause many species (including humans) to go extinct.

Meanwhile, the 3-year running average for the mean rate of atmospheric CO₂ growth through January 2026 broke 8.00 ppm per 3 years, reaching a new record high growth rate of 8.06 ppm per 3 years, as illustrated by the Eliot Jacobson image below.

Below are 14 contributors to a potentially huge temperature rise:

1. High and rising greenhouse gas concentrations

2. Earth Energy Imbalance rapid and accelerating rise
3. Rapid and accelerating decline in Earth Albedo
- Sea ice decline
- Snow and ice cover on land decline
- The aerosol masking effect getting reduced
- Lower clouds reflectivity decline
4. Further feedback kicking in with accelerating ferocity
- Water vapor feedback
- Ocean stratification, acidification and hypoxia (dead zones)
- Polar amplification of the temperature rise

- Jet Stream distortion and more extreme weather events
- Sea currents such as AMOC and SMOC slowing down
- Decline in the capacity of oceans and land to take up CO₂ and heat
5. Thinning of sea ice resulting in loss of the ability to consume incoming ocean heat
6. More fuel getting burned worldwide
7. Worldwide rise in agricultural emissions
8. Depletion of soil moisture and water from lakes, rivers and aquifers
9. Deforestation, loss of soil carbon and associated emissions

- Forest fires increase

- Trees becoming more vulnerable to droughts, fires, pests and diseases

- More trees cut and burned to create pasture, for construction and energy use

- Increase in ozone due to storms and lightning
10. Loss of wildlife and biodiversity
11. Pollution of water and soil

- Oil spills on sea, infrastructure collapse on land

- Pesticides, agricultural chemicals, etc.

- Plastic and PFAS contamination

- Flooding and fires in urban areas (waste, toxic substances from warehouses, etc.)

- Pollution from military activities
12. Politicians hardly take environmental and climate action
13. Many media focus on selling consumables instead of on climate action
14. Meanwhile, a new El Niño may emerge in the course of 2026

While each of these points is alarming in itself, they can also amplify each other and together they can cause a dramatic and rapid temperature rise, as discussed in a recent post and as illustrated and supported by the rapidly rising polynomial trend in the image below, which is based on many years of historic data and which adds further weight to important warnings.

[ Image from earlier post, also discussed on facebook ]

When could humans go extinct?

As the likeliness of a huge and accelerating temperature rise, the severity of its impact, and the ubiquity and the imminence with which it will strike all become more apparent and manifest—the more sobering it is to realize that a mere 3°C rise will likely suffice to cause human extinction.

A 2018 study (by Strona & Bradshaw) indicates that most life on Earth will disappear with a 5°C rise. What does this mean for humans?

Terrestrial vertebrates are more in danger than many other species, since they depend on numerous other species for food. Humans are terrestrial vertebrates and humans are also large warm-blooded mammals with high metabolic rates, thus requiring more habitat. It also takes a long time for humans to reach maturity. Additionally, humans have become addicted to processed food, fossil fuels, plastic, etc. Furthermore, humans require large amounts of fresh water, including for sweating when temperatures rise. A 3°C rise may therefore suffice to cause humans to disappear, as illustrated by the image below.

[ from earlier post ]

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

• Climate Emergency Institute
https://www.climateemergencyinstitute.com
image discussed on facebook at:
https://www.facebook.com/groups/arcticnews/posts/10163795386309679

https://www.facebook.com/groups/arcticnews/posts/10163807449809679

• WMO confirms 2025 was one of warmest years on record
https://wmo.int/news/media-centre/wmo-confirms-2025-was-one-of-warmest-years-record

• WMO confirms 2024 as warmest year on record at about 1.55°C above pre-industrial level
https://wmo.int/news/media-centre/wmo-confirms-2024-warmest-year-record-about-155degc-above-pre-industrial-level

• IPCC AR6 WG1 Figure 4.2 (a)
https://www.ipcc.ch/report/ar6/wg1/figures/chapter-4/figure-4-2

• Understanding Shared Socio-economic Pathways (SSPs)

https://climatedata.ca/resource/understanding-shared-socio-economic-pathways-ssps

• CMIP6 and Shared Socio-economic Pathways overview

https://climate-scenarios.canada.ca/?page=cmip6-overview-notes

• Climate Reanalyzer
https://climatereanalyzer.org

• The Scenario Model Intercomparison Project (ScenarioMIP) for CMIP6 - by Brian O'Neill et al. (2016)
https://gmd.copernicus.org/articles/9/3461/2016

• Is CMIP6 SSP585 the worst-case scenario? (2024 post)

https://arctic-news.blogspot.com/2024/05/is-cmip6-ssp585-the-worst-case-scenario.html

• Greenhouse gas rising

https://arctic-news.blogspot.com/2026/01/greenhouse-gas-rising.html

• Permafrost and wildfire carbon emissions indicate need for additional action to keep Paris Agreement temperature goals within reach - by Christina Schädel et al.

https://www.nature.com/articles/s43247-026-03189-5

discussed on Facebook at:
https://www.facebook.com/groups/arcticnews/posts/10163804667894679

• The climate change runaway chain reaction-like process - by Andrew Glikson
Amplifying feedbacks leading to accelerated planetary temperatures

https://arctic-news.blogspot.com/2021/06/the-climate-change-runaway-chain-reaction-like-process.html

Sunday, September 14, 2025

El Nino 2026, extinction?

El Niño-Southern Oscillation (ENSO) is a climate pattern that fluctuates from El Niño to La Niña conditions and back. El Niño raises temperatures, whereas La Niña suppresses temperatures. This year, there have been neutral to La Niña conditions, as illustrated by the image below, which also shows that over the past few months, there has been a zigzag pattern of rises and falls around the mean sea surface temperature in Niño 3.4, an area in the Pacific (inset) that is critical to the development of El Niño.

[ click on images to enlarge ]

On September 13, 2025, the temperature reached an anomaly in this area of -0.54°C versus 1991-2020, indicating that La Niña conditions are likely to dominate late 2025/early 2026. The inset on the above image shows the Niño 3.4 area and sea surface temperature anomalies versus 1991-2020 on that day.

The image on the right, adapted from NOAA, shows the ENSO outlook (CFSv2 ensemble mean, black dashed line) favoring La Niña late 2025/early 2026.

[ image from earlier post ]

The image on the right, adapted from ECMWF, shows an ENSO forecast for developments in Niño3.4 through August 2026, indicating that the next El Niño may emerge early 2026 and grow in strength in the course of 2026.

Rising temperature in absence of El Niño

Critical is the temperature on land, which is after all where people live. The image below shows that in 2025, monthly temperature anomalies (from 1880-1920) on land have fallen from a high of +2.93°C in January 2025 to +1.45°C in July 2025, in line with the temperature suppression that comes with a move into La Niña.

The anomaly was +2.93°C in January 2025, very close to +3°C. Note that when using a genuinely pre-industrial base, anomalies can be much higher than depicted in the above image. While anomalies have come down somewhat, the anomaly rose again to +1.82°C in August 2025, which could indicate that acceleration of the temperature rise is overwhelming the temperature suppression that comes with a move into La Niña.

The sea surface temperature anomaly keeps rising, in particular from the latitudes of 30° and higher north, as illustrated by the image below.

Adding to fears that the temperature rise is accelerating despite the absence of El Niño is the most recent rise of the global temperature anomaly. As illustrated by the image below, the global temperature anomaly versus 1991-2020 has risen strongly recently, from +0.21°C on July 4, 2025, to +0.83°C on September 20, 2025.

A +3°C temperature rise constitutes an important threshold, since humans will likely go extinct with such a rise, as illustrated by the image below.

[ from the post When will humans go extinct? ]

[ from: When Will We Die? ]

Recent research led by David Fastivich finds that, historically, vegetation responded at timescales from hundreds to tens of thousands of years, but not at timescales shorter than about 150 years. It takes centuries for tree populations to adapt - far too slow to keep pace with today’s rapidly warming world.

Note that healthy vegetation relies not only on temperature, but also on the presence of good soil, microbes, rain, soil nutrients, pollinators, habitat, groundwater and an absence of toxic waste, pests and diseases.

A 2018 study by Strona & Bradshaw indicates that most life on Earth will disappear with a 5°C rise (see box on the right). Humans, who depend on a lot of other species, will likely go extinct with a 3°C rise, as discussed in the earlier post When Will We Die?

The map below shows the size of the population rather than the size of the territory, decreasing the size of Canada, Mongolia, Australia, and Russia, and highlighting how many people are vulnerable to heat stress.

[ cartogram from Ourworldindata.org - click to enlarge ]

In the video below, Herb Simmens discussed the situation with Peter Carter and Paul Beckwith.

Climate Emergency Declaration

The temperature rise is accelerating and the rise could accelerate even more due to decreases in buffers (as described in earlier posts such as this one), due to strengthening feedbacks, especially during an El Niño, and due to further reduction of the aerosol masking effect, which are all developments that could rapidly speed up existing feedbacks and trigger new feedbacks.

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

• 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

• ECMWF - El Niño forecast
https://charts.ecmwf.int/products/seasonal_system5_nino_annual_plumes

• NASA - surface temperature analysis - gistemp
https://data.giss.nasa.gov/gistemp

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

• Population cartogram
https://ourworldindata.org/world-population-cartogram

discussed on Facebook at:
https://www.facebook.com/groups/arcticnews/permalink/10163232140864679

• 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

Saturday, May 3, 2025

Arctic sea ice May 2025

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

The above combination image shows Arctic sea ice thickness on March 13, 2025 (left), April 28, 2025 (center) and May 13, 2025 (right). The image on the right shows more open water off the coast of Siberia.

[ Arctic sea ice concentration ]

The above image is a screenshot of part of a NASA Worldview satellite image for May 1, 2025. The image similarly shows open water off the coast of Siberia. The red dots indicate fires.

The image on the right, adapted from NSIDC, shows Arctic sea ice concentration on May 13, 2025.

Arctic sea ice is under threat as numerous conditions are becoming increasingly dire, as discussed in earlier posts such as this one.

For some of these conditions, further updates are added below (carbon dioxide, temperature, variables and Arctic sea ice).

Carbon dioxide

A daily carbon dioxide (CO₂) concentration of 431.25 parts per million (ppm) was recorded on May 10, 2025, at Mauna Loa, Hawaii, the highest daily average on record.

CO₂ concentrations haven't been below 430 ppm for 14 days in a row at Mauna Loa, Hawaii, as illustrated by the above image, which shows CO₂ for the last 31 days through May 10, 2025. The image below gives another view of daily concentrations.

One has to go back millions of years in time to find CO₂ concentrations this high, while the impact of high CO₂ concentrations back in history was lower due to lower solar output and the rate of change was also much slower, as also discussed in an earlier post.

The image below illustrates that the weekly mean CO₂ concentration at Mauna Loa, Hawaii, was 430.60 ppm in the week beginning on April 27, 2025, i.e. 4.02 ppm higher than the weekly value from one year ago (green inset).

Weekly CO₂ for the week starting May 4, 2025, was 430.86 ppm at Mauna Loa, Hawaii, compared to 426.92 ppm one year ago, a difference of 3.94 ppm, as illustrated by the image below.

The annual global average surface concentration of carbon dioxide (CO₂) for 2024 was 422.79 parts per million (ppm). CO₂ concentrations grew by 3.75 ppm during 2024, the highest growth rate on record, as discussed in an earlier post.

Temperature

The global surface air temperature was 15.72°C on 9 May 2025, the highest temperature on record for this day, as illustrated by the image below.

The global surface air temperature was 15.75°C on 10 May 2025, again the highest temperature on record for this day. The image below shows ERA5 daily temperature anomalies from end 2022 through May 10, 2025, with two trends added, a black linear trend and a red cubic (non-linear) trend that reflects stronger feedbacks and that follows ENSO (El Niño/La Niña) conditions more closely. This red trend warns about further acceleration of the temperature rise.

The shading added in the above image reflects the presence of El Niño conditions that push up temperatures (pink shading), La Niña conditions that suppress temperatures (blue shading), or neutral conditions (gray shading). The trends warn about feedbacks and further mechanisms pushing up temperatures over the next few years.

The above image shows two bases to compare the anomalies with, 1991-2000 (left axis) and 1901-1930 (right axis). Neither of these two bases is pre-industrial, anomalies will be higher when using a genuinely pre-industrial base.

The image below shows NASA monthly data through April 2025 compared to a custom 1903-1924. This 1903-1924 base is not pre-industrial either, anomalies will be higher when using a genuinely pre-industrial base. The monthly temperature anomaly has now been more than 1.5°C higher than this 1903-1924 base for 22 consecutive months (July 2023 through April 2025, marked with red text). Anomalies are rising rapidly, the red line (2-year Lowess Smoothing trend) points at 2°C higher than 1903-1924 getting crossed in the course of 2027.

[ more than 1.5°C above base for 22 consecutive months, trend points at 2°C above 1903-1924 crossed in 2027 ]

The picture can change when using a different base that anomalies are compared with. To illustrate this, the image below uses the decade from 1904 through 1913 as a custom base, resulting in higher anomalies and a trend 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 ]

An earlier analysis of pre-industrial suggests that using 1750 as a base could add as much as 0.3°C to the historic rise, while using a 3480 BC base could add as much as 0.79°C to the historic rise.

Those who seek to sabotage climate action typically call for use of a base that minimizes the historic temperature rise. A higher historic rise can imply 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 more due to stronger feedbacks such as more water vapor in the atmosphere and disappearance of lower clouds, so that would constitute a stronger call for climate action.

The Arctic is hit hardest by the temperature rise, as illustrated by the image below, which shows temperature anomalies compared to 1951-1981 for the period from November 2024 through April 2025.

The image below illustrates that the global temperature was at a record high for the time of year for five days in a row, i.e. from April 24, 2025, through April 28, 2025.

Variables

Some variables have a short-term impact on the temperature rise, including volcanoes, sudden stratospheric warming, sunspots and El Niño/La Niña variations. There have been no volcano eruptions and no sudden stratospheric warming events recently that could have provided significant cooling. Sunspots are at a high point in this cycle, which pushes up temperatures. Regarding ENSO (El Niño-Southern Oscillation), current conditions are ENSO-neutral, highlighting the significance of the high current temperatures, while a new El Niño may emerge soon. The image below shows NOAA's ENSO outlook dated May 11, 2025.

The image below shows temperatures through May 9, 2025, in Niño 3.4, an area in the Pacific (inset) that is critical to the development of El Niño.

[ temperature in Niño 3.4 area ]

Mechanisms such as self-amplifying feedbacks and crossing of tipping points, and further developments such as loss of the aerosol masking effect, can jointly contribute to further accelerate the temperature rise, resulting in a rise from pre-industrial of more than 10°C, while in the process also causing the clouds tipping point to get crossed and that can push the temperature rise up by a further 8°C, as discussed in earlier posts such as this one.

Arctic sea ice volume and area

Loss in sea ice can dramatically push up temperatures, as discussed in earlier posts such as this one. High ocean temperatures are causing Arctic sea ice volume to be very low compared to earlier years. The image below shows Arctic sea ice volume over the years in red for April, the month when Arctic sea ice typically reaches its maximum volume for the respective year.

The image below shows Arctic sea ice volume from 2000, with markers indicating volume in September (red) and in April (blue), corresponding to the year's minimum- and maximum volume.

The image below shows Arctic sea ice volume through May 14, 2025.

The image below illustrates that Arctic sea ice disappears not only as it melts away from below, due to heating up of the water of the Arctic Ocean. Arctic sea ice can also disappear as it gets broken up by ocean currents and moves out of the Arctic Ocean. The image shows how, on May 6, 2025, the sea ice gets broken up just north of the northern tip of Greenland, due to ocean currents that will also move the pieces to the south, alongside the edges of Greenland, toward the North Atlantic.

[ click on images to enlarge ]

On May 13, 2025, Arctic sea ice area was second lowest on record for that day, as illustrated by the image below.

The comparison with the year 2012 is important, since Arctic sea ice area reached its lowest minimum in 2012. Arctic sea ice area was only 2.24 million km² on September 12, 2012, i.e. 1.24 million km² above a Blue Ocean Event. While on May 13, 2025, Arctic sea ice area was only 0.8 million km² lower than on May 8, 2012, the difference between anomalies typically gets narrower in May. Therefore, if the difference between 2025 and 2012 will widen again, a Blue Ocean Event may occur in September 2025, as discussed in an earlier post.

Methane

Loss of Arctic sea ice can also trigger a very dangerous feedback: eruptions of methane from the seafloor of the Arctic Ocean. Methane in the atmosphere is already very high and large additional methane releases threaten to cause hydroxyl depletion, in turn extending the lifetime of all methane currently in the atmosphere.

Data for the annual increase in methane have been updated by NOAA. in 2024, there was a higher increase than in 2023, the 2024 increase was almost 10 parts per billion (ppb).

The image below shows the annual methane increase data (red circles), with two trends added. A quadratic trend (blue) is based on all available data (1894 through 2024), while a quintic trend (pink) is based on 2017 through 2024 data. The pink trend warns about a huge increase in methane, which could eventuate due to eruptions of seafloor methane.

Below are warnings from earlier posts.

[ from earlier post, also note the recent discussion on monthly methane ]

[ from earlier post ]

Also noteworthy is this analysis by Andrew Glikson and work by Peter Wadhams et al.

In the video below, methane emissions are discussed by Peter Wadhams, Paul Beckwith, Peter Carter and Herb Simmens

Methane concentrations in the atmosphere have been around 1960 parts per billion (ppb) recently at Mauna Loa, Hawaii, as illustrated by the image below.

Methane is more potent as a greenhouse gas than carbon dioxide. Methane also has indirect effects, such as ground-level ozone and stratospheric water vapor, while methane partly turns into carbon dioxide. Importantly, the warming potential of a pulse of methane will decrease over time, given methane's relatively short lifetime.

Accordingly, there are different ways to calculate methane's carbon dioxide equivalent (CO₂e). Also important is whether a specific concentration of methane is used (in ppb) or the weight is used of a pulse of methane. In each of these cases, different multipliers can be used to calculate methane's CO₂e.

When using a multiplier of 200, a methane concentration of 1960 ppb would translate into 392 ppm of CO₂e. As mentioned above, a daily CO₂ concentration of 431.25 ppm was recorded at Mauna Loa, Hawaii, on May 10, 2025. So, when adding up these two, the joint CO₂e would be 823.25 ppm CO₂e, i.e. just 376.75 ppm short of the clouds tipping point (at 1200 ppm). This joint total doesn't yet include contributions of nitrous oxide and other drivers, so the situation is even more dire. Moreover, concentrations of greenhouse gases are increasing and they may increase even more dramatically soon.

So, what multiplier is best used when calculating methane's CO₂e? The IPCC already uses a slightly higher GWP for methane emissions from fossil fuel fugitive emission sources than for other methane emissions. So, the idea of using different multipliers in different scenarios is not new.

One multiplier could be used that does include cooling aerosols and another one that doesn't. Most carbon dioxide results from burning coal and oil, which comes not only with high CO₂ emissions, but also with co-emissions of cooling aerosols. On the other hand, there are little or no cooling aerosols co-emitted with methane emissions. Therefore, inclusion of cooling aerosols could result in a higher multiplier to be used when translating concentrations of methane into CO₂e, compared to carbon dioxide.

[ warming contributions, from earlier post, click on images to enlarge ]

[ warming responsibility by sector ]

To illustrate this point, the above image shows contributions to warming from 2010 to 2019, using IPCC AR6 data. If masking (cooling) would be included in the image by subtracting cooling by sulfates from CO₂, then the contribution of CO₂ would be proportionally lower, while the contribution of methane would be proportionally higher than what the image shows.

The image on the right is from a recent analysis by Gerard Wedderburn-Bisshop.

Given the dire outlook and given methane's higher potency as a greenhouse gas, it makes most sense to seek urgent and dramatic reductions in methane and such action should not be allowed to be sabotaged by those who propose a low multiplier when calculating methane's CO₂e.

IPCC

Meanwhile, the IPCC remains silent. No updates or special reports on topics such as acceleration of the temperature rise. Instead, the IPCC keeps persisting in downplaying the potential for such dangerous developments (in terms of the severity, probability, ubiquity and imminence of their impact), in efforts to hide the most effective climate action. The IPCC keeps pointing at less effective policies such as support for BECCS and biofuel, while continuing to make it look as if there was a carbon budget to divide among polluters, as if polluters could continue to pollute for decades to come.

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 also discussed at this group.