Showing posts with label extent. Show all posts
Showing posts with label extent. Show all posts

Friday, October 4, 2024

Double Blue Ocean Event 2025?

A double Blue Ocean Event could occur in 2025. Both Antarctic sea ice and Arctic sea ice could virtually disappear in 2025. A Blue Ocean Event (BOE) occurs when sea ice extent falls to 1 million km² or less, which could occur early 2025 for Antarctic sea ice and in Summer 2025 in the Northern Hemisphere for Arctic sea ice.

Arctic sea ice volume

In September 2024, Arctic sea ice reached a new record low volume, as illustrated by the image below, adapted from the Danish Meteorological Institute, with markers for September (red) and April (blue) corresponding with the year's minimum- and maximum volume.


Trends could be added pointing at Arctic sea ice approaching zero volume soon; even more worrying, tipping points could be crossed and speed up the temperature rise beyond a smooth curve. Feedbacks are typically seen as increasing the temperature gradually and smoothly, either in a linear or non-linear way. Feedbacks are mechanisms, but there are also mechanisms that act more abruptly.

Indeed, some mechanisms can have a more abrupt impact. Sea ice could shrink strongly and rapidly as a (tipping) point is reached where the latent heat buffer disappears abruptly and as further incoming ocean heat suddenly can no longer be consumed by melting of what once was thick sea ice that extended meters below the surface. Arctic sea ice typically reached its annual low about half September, but an abrupt decline of Arctic sea ice may well occur earlier than that. Sea ice may melt strongly, and large pieces of sea ice may additionally get pushed out of the Arctic Basin by strong winds. Large and rapid loss of Arctic sea ice may therefore well occur in July 2025 or even earlier, as the latent heat tipping point gets crossed and additional mechanisms further contribute to increase the temperature.

Antarctic Sea ice extent

Antarctic sea ice extent has passed its maximum for the year, and looks set for a steep decline, in line with seasonal changes.

On October 11, 2024, Antarctic sea ice was more than 1 million km² lower in extent than on October 11, 2022, and almost 3 million km² lower in extent than a decade ago, as illustrated by the image below.


Antarctic sea ice extent was 
16.757 million km² on October 11, 2024 
17.926 million km² on October 11, 2022 
19.412 million km² on October 11, 2014

This difference indicates that extent may fall below 1 million km² in February 2025. 

As illustrated by the image below, Antarctic sea ice extent was 1.976 million on February 25, 2022, so 1 million km² less extent than that would result in a Blue Ocean Event early next year. A Blue Ocean Event is deemed to occur when the sea ice extent falls to 1 million km² or less. 

Low Antarctic sea ice extent is a tipping point, as sea ice thickness by February 2025 can be expected to be minimal, resulting in no further ocean heat getting consumed by sea ice below the surface. So, there would be less sunlight getting reflected back into space for months and by February 2025 there would no longer be thicker sea ice that previously consumed incoming ocean heat, and both of these mechanisms are further increasing temperatures.

Note also that Antarctic sea ice extent looks set for a steep decline, the more so as the impact of less sunlight getting reflected will increase over the coming months as more sunlight reaches the Southern Hemisphere, in line with seasonal changes. Albedo changes hit Antarctic sea ice in particular, as it is located at higher latitudes than Arctic sea ice, which is located mostly around the North Pole.

As the image below illustrates, the Antarctic Sea ice extent minimum was well below 2 million km² in each of the past three years.

Minimum annual Antarctic sea ice extent was:
1.976 million km² on February 25, 2022
1.788 million km² on February 21, 2023
1.985 million km² on February 20, 2024

The image below highlights Antarctic sea ice extent in the months September and October, showing NSIDC data from 2010 through November 2, 2024.


As above image shows, Antarctic sea ice extent in September and October 2023 & 2024 was much lower than in previous years, a huge difference that occurred during a period when little or no sunlight was reaching Antarctic sea ice. 

So, what mechanisms caused this huge difference?

Since little or no sunlight reaches the area around Antarctica at this time of year, sea surface albedo changes (i.e. changes from sea ice to water) or albedo changes of clouds over the sea surface are unlikely to contribute much (yet) to this huge difference.

Changes in wind patterns and changes in oceans (temperature, currents, vertical mixing and stratification) can make a lot of difference and so can changes in emissivity, a feedback that is active throughout the entire year. Mechanisms that are contributing to the demise of the snow and ice cover (and thus are contributing to the temperature rise) are discussed point by point further below in this post.  

Global sea ice extent at record low for time of year

Rising global temperatures go hand in hand with lower global sea ice extent. On November 3, 2024, global sea ice extent was 23.15 million km², a record low for the time of year and well below the 2023 extent at this time of year. This record low global sea ice extent is in turn accelerating the rise in global temperatures. Global sea ice typically reaches its annual maximum extent around this time of year, as Arctic sea ice expands in extent. 

[ Click on images to enlarge ]

Antarctic Sea ice thickness and volume

The images by University of Bremen below show sea ice thickness on August 27, 2024 (left), September 29, 2024 (center) and October 28, 2024 (right). The fall in sea ice thickness also indicates that Antarctic sea ice volume is decreasing. 

[ Click on images to enlarge ]

Temperatures keep rising

Temperature anomalies were high in September 2024, while there have been ENSO-neutral conditions since May 2024 through September 2024. Parts of Antarctic sea ice were hit by very high anomalies, of over 10°C, while very little sunlight is yet reaching Antarctic sea ice in September. 


The Copernicus image below illustrates that for most of the year, temperatures in 2024 have been higher than in 2023. The temperature was 14.71°C on November 2, 2024, a record high for the time of year. 

The image below, based on ERA5 data from early 2023 through November 2, 2024, indicates that, overall, temperature anomalies have been rising even before El Niño started, a rise that has continued during El Niño, during ENSO-neutral conditions and into La Niña. 


Note that the above temperature anomalies are calculated from 1991-2020, which isn't pre-industrial. When using a pre-industrial base, the anomalies will be a lot higher.


The above image, created with NASA data through September 2024 while using a 1903-1924 custom base, illustrates that the monthly temperature anomaly has been more than 1.5°C above this base for each of the past consecutive 15 months. The red line shows the trend (2-year Lowess Smoothing) associated with the rapid recent rise.

Note again that the above temperature anomalies are not calculated from pe-industrial, in this case they are calculated from 1903-1924. When using a pre-industrial base, the anomalies will be higher.

Mechanisms accelerating the temperature rise

Emissions by people are driving up temperatures and, as temperatures rise, feedbacks can accelerate the rise. The image below illustrates the mechanism of how multiple feedbacks can jointly accelerate the temperature rise.


[ from earlier post ]

As illustrated by the image below, there are at least seven mechanisms that can accelerate the rise in surface temperatures, and thus in turn accelerating sea ice decline.


Each of these seven mechanisms are feedbacks that are also described at the feedback page and in earlier posts. These seven mechanisms are grouped together here since they all relate to changes in snow and ice cover, changes in oceans and changes in wind patterns, i.e. the orange part of the stacked bar chart at the conclusion of this article. In other words, as temperatures rise on the Southern Hemisphere, these seven mechanisms could contribute to dramatic sea ice loss around Antarctica over the next few months. The are described below in more detail:

1. latent heat buffer loss  ➭  less heat gets consumed by melting (feedback #14)

Sea ice constitutes a buffer that consumes ocean heat; the temperature of the water will not rise as long as there is ice, but once all ice has melted, further heat will raise the temperature of the water. 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.

[ Latent heat ]

2. sea ice changing into dark ocean  ➭  less sunlight is reflected (feedback #1)
Water covered by snow and ice can reflect as much as 90% of the sunlight back into space, absorbing only 10%. By contrast, water without snow and ice can absorb as much as 94% of sunlight, with as little as 6% reflected back into space.  
A study by Duspayev et al. (2024) finds that global sea ice has lost 13%–15% of its planetary cooling effect since the early/mid 1980s, and the implied global sea ice albedo feedback is 0.24–0.38 W m⁻² K⁻¹.

3. less sea ice  ➭  less outward radiation (feedback #23)

A 2014 study finds significantly lower values of far-IR emissivity for ocean surfaces than for sea ice and snow, leading to a decrease in surface emission at far-IR wavelengths, reduced cooling to space, and warmer radiative surface temperatures.

4. ocean warming  ➭  less lower clouds  ➭  less sunlight reflected (feedback #25)

A 2021 study finds that warming oceans cause fewer bright clouds to reflect sunlight into space, admitting even more energy into Earth's climate system.

[ Earthshine annual albedo anomaly expressed as reflected flux in W/m². CERES data. ] 

The image below highlights the Pattern Effect of the Southern Ocean's committed warming (around -60°S) becoming more manifest over the years, as warming causes low-level clouds to disappear that reflect sunlight back. A 2021 study concludes this could make a difference of 0.7°C.

[ The Pattern Effect could account for a 0.7°C temperature rise. ]

5. ocean warming  ➭  stratification  ➭  less heat reaches deeper waters (feedback #29)

Higher sea surface temperatures come with greater stratification.

[ from earlier post ]

A recent study by Goreau et al. concludes:
Decreased vertical exchange in cold surface currents and in upwelling zones increases thermal stratification and slows down the Atlantic Meridional Overturning Circulation (AMOC), retains heat longer in the surface ocean, and reduces CO₂ exchange among the atmosphere, surface ocean, and the deep sea. The HotSpot maps from year to year suggest that upwelling systems can abruptly shut off, causing sudden sharp rises in regional air temperatures, and reducing air-ocean exchange of temperature and CO₂.

6. ocean currents and wind patterns change  ➭  less heat reaches deeper waters (feedback #19)

[ from earlier post ]
Oceans are still absorbing an estimated 91% of the excess heat energy trapped in the Earth's climate system due to human-caused global warming. If just a small part of that heat instead remains in the atmosphere, this could constitute a huge rise in the  temperature of the lower atmosphere.

Polar amplification of the temperature rise causes a relative slowing down of the speed at which heat flows from the Equator to the poles. This impacts ocean currents and wind patterns, resulting in slowing down of the Atlantic meridional overturning circulation (AMOC) and of ocean currents around Antarctica that carry heat to the deep ocean, as well as in deformation of the Jet Stream.

Another recent study warns about intensification of global warming due to the slowdown of the overturning circulation. The overturning circulation carries carbon dioxide and heat to the deep ocean, where it is stored and hidden from the atmosphere. As the ocean storage capacity is reduced, more carbon dioxide and heat are left in the atmosphere. This feedback accelerates global warming.

7. freshwater lid forms at ocean surface  ➭  more heat reaches Arctic Ocean (feedback #28)

Greater stratification, meltwater and rain can contribute to the formation of a freshwater lid that expands at the surface of the North Atlantic, enabling more ocean heat to travel underneath this lid from the North Atlantic into the Arctic Ocean, which can occur abruptly at times when a deformed Jet Stream causes storms that speed up ocean currents along this path.

8. Further mechanisms

8.1. El Niño and sunspots

Further mechanisms that could accelerate the temperature rise include a new El Niño in 2025, coinciding with a peak in sunspots that is higher than expected. The black dashed line in the image below, adapted from NOAA, indicates a transition to La Niña in October 2024, persisting through Jan-Mar 2025.


The image below shows the October 2024 IRI ENSO forecast. NOAA adds that the IRI plume predicts a weak and a short duration La Niña, as indicated by the Niño-3.4 index values less than -0.5°C.

[ IRI ENSO forecast from Oct 2024 ]

A new El Niño looks set to emerge soon and this may occur in the course of 2025, while Earth's Energy Imbalance is high (and rising), while feedbacks and other mechanisms add further heat and while sunspots reach a peak in this cycle (expected to occur in July 2025), all contributing to further accelerate the temperature rise.

[ click on images to enlarge ]

The above image, adapted from NOAA, illustrates that El Niño conditions were present from June 2023 through April 2024, and that ENSO-neutral conditions were present from May 2024 through September 2024.

8.2. Earth's Energy Imbalance and lack of political will to act

Earth's growing energy imbalance is perhaps the most obvious mechanism that increases the temperature. 


The image below, by Leon Simons, shows Earth's Energy Imbalance to April 2024 (12-month running mean) as the difference between absorbed and outgoing radiation. 


It's obvious that political action can and must improve Earth's Energy Imbalance, which can and must be achieved by reducing greenhouse gas emissions and further action, through transitions in energy use, agriculture, transport, etc. 

The IPCC has for many years weaved and twisted findings by scientists into a political narrative that downplays the temperature rise and refuses to point at the most effective measures to be taken to act on climate change, in an effort to create the illusion that there was a carbon budget to be divided among polluters as if pollution could continue for decades to come.

Lack of political will to act on the climate emergency is perhaps the most depressing mechanism accelerating the temperature rise. Moreover, where action is taken, blunt political instruments are all too often chosen that won't last long or turn out to be counter-productive. 

8.3. Aerosols

A further mechanism that could strongly accelerate the temperature rise is the falling away of the masking effect of aerosols currently emitted jointly with the greenhouse gases produced in the process of burning fossil fuel and biofuel. Blunt measures may be taken to reduce burning of fossil fuel and biofuel, which will reduce greenhouse gas emissions and also reduce emission of cooling aerosols, while such measures can at the same time encourage many to use more wood burners, thus also causing more warming aerosols to be emitted.

Sadly, few people are calling for more sophisticated measures, let alone for more effective measures such as local feebates. It is important to be open and clear as to what can and must be achieved and how, and why.  

Scientist warn that the combined impact of aerosols and nitrogen fertilizers has been underestimated; a recent study concludes that when ammonia, nitric acid and sulfuric acid are present together, they contribute strongly to the formation of cirrus clouds.

The IPCC image below shows how much temperatures are currently suppressed in the Arctic due to aerosols and thus also shows how much temperatures in the Arctic look set to rise as the aerosol masking effect falls away. 


8.4. Water vapor and the importance of the size of the temperature rise

The water vapor feedback is also getting stronger. The image below, created with NOAA data, shows surface precipitable water through September 2024. Note that values in 2024 are higher than in 2023. 

The image below, adapted from Climate Reanalyzer, shows the spread of the September 2024 anomaly in precipitable water, with less over the Amazon, but more over the Sahara, while more also shows up at higher northern latitudes, i.e. over the Barents Sea and the Canadian Arctic Archipelago. 


Since the water vapor feedback roughly follows the temperature rise (7% more water vapor for every 1°C warming), it's important to know the full rise from pre-industrial, as opposed to a rise calculated from a later base. If the temperature rise since pre-industrial is significantly larger, then the extra water wapor feedback will accordingly be larger. 

A lot of the extra water vapor gets into the atmosphere through evaporation from oceans, but a significant part also comes from land and water bodies on land. A lot of energy gets consumed in the process of evaporation from land and lakes and in the process of thawing of permafrost. Water that previously remained present in the ground, is increasingly moving up into the atmosphere. The water vapor feedback results in more moisture getting sucked up into the air as temperatures rise, a process that can be further accelerated by stronger wind as temperatures rise.

The image on the right shows shallow groundwater storage in most of South America for the week of October 7, 2024, as measured by the Gravity Recovery and Climate Experiment Follow-On (GRACE-FO) satellites (NASA image, discussed on facebook). 

The image illustrates the danger of the Land Evaporation Tipping Point getting 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. 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.

Similarly, the rise to come (over the next few years) could be significantly larger than expected, e.g. due to the above seven mechanisms relating to changes in snow & ice, winds and oceans, in which case the extra water vapor will accordingly be larger. 

The image below shows the global September 2024 sea surface temperature anomaly (versus 1951-1980, ERA5 data, adapted from Climate Reanalyzer). 


The image below shows that the September 2024 sea surface temperature anomaly (versus 1951-1980) was at a record high, in a tie with October 2023, in the area between latitudes 10°North and 40°North. 


The image below shows that the September 2024 total column precipitable water anomaly (versus 1951-1980, ERA5 data) was at a record high in the area between latitudes 10°North and 40°North. 


8.5. Tipping points

Loss of Arctic sea ice and loss of Permafrost in Siberia and North America can be regarded both as feedbacks and as tipping points. Loss of Antarctic sea ice and loss of the snow and ice cover on land elsewhere (on Greenland, on Antarctica and on mountaintops such as the Tibetan Plateau) can also be regarded as tipping points. 

What makes them tipping points is that, once the snow and ice cover has disappeared and the ice in the soil has melted, further heat can no longer be consumed in the process of melting or thawing, resulting in a sudden local temperature rise that spreads to neighboring areas. 

As temperatures keep rising, this could cause a second Blue Ocean Event to occur in 2025, i.e. in the Arctic. Subsequently, as the oceans keep heating up, the seafloor methane tipping point could be crossed. 

The image below lists 14 events. Note that the 14 mechanisms below are from an earlier post and many mechanisms differ from the above 8 mechanisms. Note also that the order may differ and that, instead of one domino tipping over the next one sequentially, many events may occur simultaneously and reinforce each other in the speed at which they unfold and the temperature rise that results. There could be interaction and amplification between mechanisms, resulting in a huge abrupt acceleration of the temperature rise that leads to extinction of most species, including humans, as the image below warns, from an earlier post. Finally, note that there could be Black Swan Events that have not yet been identified. 

[ from earlier post - click on images to enlarge ]

Seven important tipping points are:
- The Latent Heat Tipping Point (feedback #14, as discussed above)
- The Seafloor Methane Tipping Point (feedback #16)
- The Clouds Tipping Point (also clouds feedback #30)
- The Terrestrial Biosphere Temperature Tipping Point
- The Ocean Surface Tipping Point (also discussed at facebook)
- The Land Evaporation Tipping Point (discussed above, also discussed at facebook)
- The Aquatic Deoxygenation Tipping Point (also discussed at facebook)

[ for more background, also view the Extinction page ]
A huge temperature rise could occur soon

A huge temperature rise could occur soon, as the impact of these mechanisms keeps growing, as the latent heat tipping point gets crossed in a Double Blue Ocean Event and the seafloor methane tipping point subsequently gets crossed. 

As temperatures keep rising in the Arctic, changes to the Jet Stream look set to intensify, resulting in loss of terrestrial albedo in the Arctic that could equal the albedo loss resulting from sea ice decline.

Further feedbacks include permafrost degradation, both terrestrial and on the seafloor of the Arctic Ocean, which looks set to cause huge releases of greenhouse gases (particularly CO₂, CH₄ and N₂O).

This would in turn also cause more water vapor to enter the atmosphere, further speeding up the temperature rise. 

The danger of a huge temperature rise is very large in the Arctic, where vast amounts of methane are held in sediments at the seafloor and in permafrost on land, and where there is very little hydroxyl in the air to break down the methane.

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

• Arctic Data archive System - National Institute of Polar Research - Japan
https://ads.nipr.ac.jp/vishop

• Danish Meteorological Institute - Arctic sea ice volume and thickness
https://ocean.dmi.dk/arctic/icethickness/thk.uk.php

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

• NSIDC - Interactive sea ice chart
https://nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph

• Climate Reanalyzer

• Copernicus

• Earth's Sea Ice Radiative Effect From 1980 to 2023 - by Duspayev et al. (2024) 
• 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 - Physical Sciences Laboratory
https://psl.noaa.gov

• NASA 
https://data.giss.nasa.gov

• Indicators of Global Climate Change 2023: annual update of key indicators of the state of the climate system and human influence - by Piers Forster et al. 
https://essd.copernicus.org/articles/16/2625/2024

• 2023 Record marine heat waves: coral reef bleaching HotSpot maps reveal global sea surface temperature extremes, coral mortality, and ocean circulation changes - by Thomas Goreau et al. 
https://academic.oup.com/oocc/article/4/1/kgae005/7666987

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

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

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

• Latent Heat
https://arctic-news.blogspot.com/p/latent-heat.html

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

• Indicators of Global Climate Change 2023: annual update of key indicators of the state of the climate system and human influence - by Piers Forster et al. 


Monday, December 5, 2022

Arctic Ocean overheating

Arctic sea ice extent was 10.31 million km² on December 4, 2022. At this time of year, extent was smaller only in two years, i.e. in 2016 and 2020, both strong El Niño years. With the next El Niño, Arctic sea ice extent looks set to reach record lows. 


The NOAA image on the right indicates that, while we're still in the depths of a persistent La Niña, the next El Niño looks set to strike soon.

The image below shows high sea surface temperature anomalies near the Bering Strait on December 2, 2022, with a "hot blob" in the North Pacific Ocean where sea surface temperature anomalies are reaching as high as 7°C or 12.6°F from 1981-2011. The Jet Stream is stretched out vertically from pole to pole, enabling hot air to enter the Arctic from the Pacific Ocean and from the Atlantic Ocean.


The image below shows a forecast for December 5, 2022, of 2m temperature anomalies versus 1979-2000, with anomalies over parts of the Arctic Ocean near the top end of the scale.


On December 6, 2022, the Arctic was 6.63°C or 11.93°F warmer compared to 1979-2000, as illustrated by the image below. 


The image below shows the daily average Arctic air temperature (2m) from 1979 up to December 6, 2022.


Given that we're still in the depth of a persistent La Niña, these currently very high air temperature anomalies indicate that ocean temperatures are very high and that ocean heat is heating up the air over the Arctic. 

Additionally, ocean heat is melting the sea ice from below. 

Accordingly, Arctic sea ice has barely increased in thickness over the past 30 days, as illustrated by the navy.mil animation on the right.

This leaves only a very short time for Arctic sea ice to grow back in thickness before the melting season starts again, which means that there will be little or no latent heat buffer to consume heat when the melting season starts. 

Furthermore, rising temperatures and changes to the Jet Stream contribute to formation of a freshwater lid at the sea surface at higher latitudes, resulting in further heating up of the Arctic Ocean. 

As a result, more heat threatens to penetrate sediments at the seafloor of the Arctic Ocean that contain vast amounts of methane in hydrates and free gas, and result in abrupt release of huge amounts of methane, dramatically pushing up temperatures globally. 

[ The Buffer has gone, feedback #14 on the Feedbacks page ]

The situation is dire and the right thing to do now is to help avoid or delay the worst from happening, through action as described in the Climate Plan.


Links

• Vishop sea ice extent
https://ads.nipr.ac.jp/vishop/#/extent

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

• nullschool.net
https://earth.nullschool.net

• Climate Reanalyzer
https://climatereanalyzer.org

• Naval Research Laboratory - HYCOM Consortium for Data-Assimilative Ocean Modeling
https://www7320.nrlssc.navy.mil/GLBhycomcice1-12/arctic.html

• Albedo, latent heat, insolation and more

• Cold freshwater lid on North Atlantic

Thursday, September 8, 2022

Blue Ocean Event 2022?

The image on the right shows a NASA Worldview satellite image of a blue Beaufort Sea (with Barrow, Alaska, at the top left, on September 7, 2022). 

The image shows that there is a lot of open water between the coast of Alaska and the sea ice.

Such a satellite image provides a visual way to determine how much sea ice is present. It can be hard to determine where there is open water and where the sea ice starts; the sea ice is often covered by clouds; furthermore, even when there are no clouds, the question remains what is to be regarded as sea ice and what is to be regarded as water. 

Another way to measure how much sea ice is there is to look at sea ice concentration. Sea ice concentration in the Central Arctic region has been very low for some time. 

The image on the right, from an earlier post, shows that on August 12, 2022, sea ice concentration in a large area close to the North Pole was as low as 0%. 

In the two images below, Nico Sun calculates the impact of albedo loss based on NSIDC sea ice concentration data. The images illustrate why sea ice loss in the Central Arctic region is so important.

The image below shows that further albedo loss in the Barents Sea, which is virtually icefree at the moment, doesn't make much difference now. 



The image below shows that, by contrast, more albedo loss in the Central Arctic region makes much more difference, even in September. 


Arctic sea ice has become extremely thin, so the latent heat buffer loss is also very strong. This loss of the latent heat buffer can continue to result in higher temperatures of the water for a long time, even long after insolation has passed its annual peak on the Northern Hemisphere, thus causing the combined accumulative impact to continue to be high.

Another way to measure how much sea ice is present is to look at the extent of the sea ice. According to many, a Blue Ocean Event starts once the Arctic sea ice falls below 1 million km² in extent.

Arctic sea ice extent was 4.912 million km² on September 6, 2022, which is larger than the extent in many previous years around this time of year (see NSIDC image below). However, the sea ice has become very thin, resulting in many areas where only small pieces of ice are present. 


NSIDC regard a cell to have sea ice if it has at least 15% sea ice, but when regarding a cell to have sea ice if it has at least 50% ice and if that's the case for ⅕ of the cells where there is (some) ice, then we're already in a Blue Ocean Event right now.

So let's have another look at how much of the above 4.912 million km² can be regarded as sea ice, by using the NSIDC map with sea ice concentration as a guide. 

The roughly-sketched outline drawn over the NASA map below indicates that there may only have been some 991 thousand km² of concentrated sea ice left on September 6, 2022 (inset shows NSIDC sea ice concentration for the day). 


As said, it's a rough sketch, so some cells with a higher concentration of sea ice may have been left out. Having said that, we're currently in the depth of a persistent La Niña and the associated lower air temperatures contribute to a relatively larger sea ice extent than would otherwise be the case. 

In conclusion, depending on what is counted as sea ice, we could already be experiencing a Blue Ocean Event right now. 

Further events and developments

A Blue Ocean Event constitutes the crossing of a huge tipping point and, as a strong El Niño looks set to emerge, this could trigger the unfolding of further events and developments leading to extinction of most species (including humans), as: 
  1. a strong El Niño triggers: 
  2. further decline of the Arctic sea ice, with loss of the latent heat buffer, combined with
  3. associated loss of sea ice albedo and
  4. destabilization of seafloor methane hydrates, causing eruption of vast amounts of methane that further speed up Arctic warming and cause
  5. rapid thawing of terrestrial permafrost, resulting in even more emissions,
  6. while the Jet Stream gets even more deformed, resulting in more extreme weather events
  7. causing forest fires, at first in Siberia and Canada and
  8. eventually also in the peat fields and tropical rain forests of the Amazon, in Africa and South-east Asia, resulting in
  9. decline of snow and ice on mountains, at first causing huge flooding, followed by 
  10. drought, heatwaves and urban collapse,
  11. collapse of the Greenland and West-Antarctic ice sheets,
  12. falling away of aerosol masking as civilization grinds to a halt, 
  13. further heating due to gases and particulates from wood and waste burning and biomass decomposition, and 
  14. further heating due to additional gases (including water vapor), cirrus clouds, albedo changes and heat rising up from oceans. 


Importantly, depicted above is only one scenario out of many. Things may eventuate in different order and occur simultaneously, i.e. instead of one domino tipping over the next one sequentially, many events may occur simultaneously and reinforce each other. Further events and developments could be added to the list, such as ocean stratification and stronger storms that can push large amounts of warm salty water into the Arctic Ocean.


Here is another example of such a scenario. Recent studies indicate that human-caused climate change will soon increase El Niño frequency and intensity. Accordingly, the upcoming El Niño may well be strong. As illustrated with above image, we're currently in the depth of a persistent La Niña, which suppresses the temperature rise, whereas the opposite occurs during El Niño, which amplifies the temperature rise, and this especially affects the Arctic, which is already heating up much faster than the rest of the world. Also, the upcoming El Niño may very well coincide with a peak in sunspots in 2025, further pushing up temperatures.

The image below shows that the rise in sea surface temperatures on the Northern Hemisphere has been suppressed during the ongoing La Niña, but as we move into the next El Niño, the seafloor methane tipping point could be crossed even earlier than the current trend indicates, say by 2025. 


One reason for this is that the narrowing temperature difference between the Arctic and the Tropics will further deform the Jet Stream and in turn cause more extreme weather, leading to more loss of sea ice and thus of its capacity to reflect sunlight and act as a buffer against incoming ocean heat.

A huge amount of heat has built up in the North Atlantic off the coast of North America, as illustrated by the image on the right.

Furthermore, the temperature of the water may well be substantially higher some 50 meter below the sea surface than at the sea surface. 

As discussed in an earlier post, rising temperatures result in stronger winds along the path of the Gulf Stream that can make huge amounts of warm, salty water travel from the Atlantic Ocean toward the Arctic and reach shallow parts of the Arctic Ocean such as the East Siberian Arctic Shelf (ESAS), where most of the sea is less than 50 m deep. The danger is illustrated by the Argo float compilation below.



Very high methane levels

The image below, from an earlier post, shows annual global mean methane with a trend added that points at a methane rise that could in 2028 represent a forcing of 780 ppm CO₂e (with a 1-year GWP of 200). 

In other words, the clouds tipping point at 1200 ppm CO₂e could be crossed in 2028 due to the forcing of methane and CO₂ alone, assuming that CO₂ concentration in 2028 will exceed 420 ppm. Moreover, this could happen even earlier, since there are further forcers, while further events and developments could additionally push up the temperature further, as discussed above. Furthermore, the NOAA data used in the above image are for marine surface measurements. More methane tends to accumulate at higher altitudes, as illustrated by the compilation image below. 


NOAA's globally averaged marine surface mean for April 2022 was 1909.9 ppb. The above image shows that, on September 4, 2022 am, the MetOp satellite recorded a mean methane concentration of 1904 ppb at 586 mb, which is close to sea level. At 293 mb, however, the MetOp satellite recorded a mean of 1977 ppb, while at 218 mb it recorded a peak of 2805 ppb. 

Such high methane levels could be caused by destabilization of methane hydrates at the seafloor of the Arctic Ocean, with large amounts of methane erupting (increasing 160 x in volume) and rising up at accelerating speed through the water column (since methane is lighter than water), concentrated in the form of plumes, which makes that less methane gets broken down in the water by microbes and in the air by hydroxyl, of which there is very little in the Arctic in the first place. Such a methane eruption entering the atmosphere in the form of a plume can be hard to detect as long as it still doesn't cover enough of the 12 km in diameter footprint to give a pixel the color associated with high methane levels. 


The above Copernicus image shows a forecast  for September 9, 2022 18 UTC, of methane at 500 hPa. 

In the video below, from this page, Guy McPherson addresses the question: Has the “Methane Bomb” Been Triggered?


Conclusion

The situation is dire and the right thing to do now is to help avoid or delay the worst from happening, through action as described in the Climate Plan


Links

• NSIDC - Frequently asked questions

• NASA Worldview

• NSIDC - sea ice concentration

• Nico Sun - CryosphereComputing

• NSIDC - sea ice extent

• More Frequent El Niño Events Predicted by 2040
Cutting-edge models predict that El Niño frequency will increase within 2 decades because of climate change, regardless of emissions mitigation efforts.

• Emergence of climate change in the tropical Pacific - by Yun Ying et al. 
https://www.nature.com/articles/s41558-022-01301-z

• Climate Reanalyzer

• Argo Float

• Monitoring of atmospheric composition using the thermal infrared IASI/MetOp sounder - by C. Clerbaux et al. 

• NOAA - MetOp satellite methane data 

• Copernicus methane forecasts

• Clouds feedback and tipping point

• NOAA - global methane

• NOAA - Sea surface temperature anomalies on the Northern Hemisphere 

• NOAA - Monthly Temperature Anomalies Versus El Niño

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

• WMO predicts first “triple-dip” La Niña of the century