Showing posts with label Blue Ocean Event. Show all posts
Showing posts with label Blue Ocean Event. Show all posts

Friday, February 2, 2024

Blue Ocean Event 2024?

How likely is an Arctic Blue Ocean Event (BOE) to occur in 2024 or even a Double BOE? The image below is alarming. 


The highest daily sea surface temperatures on record (going back to 1981) were reached in February 2024, even higher than the peaks in 2023. Even higher temperatures may be reached over soon, in March 2024 and April 2024.

As the above image shows, the highest temperatures for the year are typically reached in March. This was the case for the previous years on record, except for 2023 when the current El Niño started to emerge and when the highest peak for the year occurred in August. According to NOAA, the majority of models indicate that this El Niño will persist through March-May 2024. 

Antarctic sea ice extent typically reaches an annual minimum end February, while Arctic sea ice extent typically reaches an annual minimum in September, after a steep decline resulting from more sunlight reaching higher latitudes North and ocean heat reaching a second peak in August.   

Ominously, daily surface air temperatures in the Southern Hemisphere exceeded 17°C recently, something that never happened before in the record going back to 1981. Antarctic sea ice extent typically reaches an annual minimum end February. Loss of sea ice acts as a self-reinforcing feedback loop, accelerating the temperature rise. The daily surface air temperature in the Southern Hemisphere was 17.005°C on Feb 1, 2024, following a peak of 17.01°C on Jan 31, 2024.


Higher temperatures can cause sea ice to melt, even out of season

As illustrated by the image below, adapted from Pidwirny, sunlight does not reach the North Pole until the March Equinox. From that time on, insolation rises steeply. Around the June Solstice, more sunlight reaches the North Pole than anywhere else on Earth. In the image below, insolation is calculated taking into account the combined effects of angle of incidence and day length duration. 

The conclusion is that ocean heat is the main reason why melting of Arctic sea ice can occur early in the year. More specifically, the narrowing of the temperature difference between the Arctic and the Tropics can at times cause strong wind to be present along the path of the Gulf Stream. Rising ocean heat combined with strong wind can cause heat to move abruptly toward the Arctic Ocean, causing sea ice to fall in extent. 

Such an event is illustrated by the image below, adapted from NSIDC. The image shows a drop in sea ice extent at the end of January 2024 (blue), a time of year when Arctic sea ice is still expected to increase in extent and to keep increasing in extent for some time to come (grey). In this case, strong wind may have caused a huge amount of ocean heat that is present in the North Atlantic to move abruptly toward the Arctic Ocean, as discussed in an earlier post

For the time of year, Arctic sea ice extent is currently still extensive, compared to earlier years, which is a reflection of more water vapor in the atmosphere and more precipitation. While sea ice extent is relatively large, sea ice volume is among the lowest of all years on record for the time of year, as illustrated by the image below. 

This indicates that Arctic sea ice is very thin. Ominously, the image below indicates that there is a huge area near the North Pole with very thin sea ice. 


Furthermore, much of the thicker sea ice is located off the east coast of Greenland, which means that this sea ice is likely to melt away quickly as more sunlight starts reaching the Northern Hemisphere and temperatures rise in line with seasonal changes (see the insolation image further above).


The North Atlantic sea surface temperature was 20.4°C on February 15, 2024, i.e. 0.6°C higher than on February 15, 2023.

High North Atlantic sea surface temperatures spell bad news for the Arctic, as much ocean heat gets pushed toward the Arctic from the North Atlantic. 

North Atlantic sea surface temperatures are just starting to heat up from their annual minimum and can be expected to rise strongly, in line with seasonal changes. 

[ click on images to enlarge ]
Ominously, a peak temperature of 25.4°C was reached on Aug.31, 2023, much higher than the peak in any of the preceding years dating back to 1981.

During the six months between the September Equinox and the March Equinox (see image further above), no sunlight is reaching the North Pole. 

Nonetheless, temperature anomalies in the Arctic are already extremely high, due to ocean heat that has entered the Arctic Ocean from the North Atlantic, as illustrated by the two maps on the right and the two maps on the right further below.

Northern Hemisphere Sea Surface Temperature Anomalies were as much as 12.6°C or 22.7°F higher than 1981-2011 on February 15, 2024, locarion marked by the green circle on the image below.


Feedbacks 

Slowing down of AMOC and cooling due to heavier melting of Greenland's ice is causing less ocean heat to reach the Arctic Ocean, while a huge amount of ocean heat is accumulating in the North Atlantic, as it did in 2023. A large part of this heat in the North Atlantic can also be present underneath the sea surface.

These developments occur at the same time as ocean stratification increases (as temperatures rise, see above images), as more freshwater enters the ocean (as a result of more meltwater and of runoff from land and from rivers), and as more evaporation takes place and more rain falls further down the path of the Gulf Stream, all of which can contribute to formation and growth of a cold, freshwater lid at the surface of the North Atlantic.

cold freshwater lid on North Atlantic ]

Furthermore, storms can get stronger as temperatures rise and as changes take place to the Jet Stream. Strong wind can temporarily speed up currents that carry huge amounts of ocean heat with them toward the Arctic Ocean, as discussed in earlier posts such as this one. Much of the ocean heat in the North Atlantic can therefore be pushed abruptly underneath this freshwater lid and flow into the Arctic Ocean. The image below shows that the Jet Stream reached speeds as high as 455 km/h or 283 mph north of Washington on February 18, 2024 03:00 UTC, with Instantaneous Wind Power Density as high as 387.5 kW/m².


The image below shows wind speed at 250 hPa on a background of sea surface temperature anomalies versus 1981-2011. 


The danger is that, due to strong wind along the path of the Gulf Stream, huge amounts of ocean heat will abruptly get pushed into the Arctic Ocean, with the influx of ocean heat causing destabilization of hydrates contained in sediments at the seafloor of the Arctic Ocean, resulting in eruptions of huge amounts of methane.

Changes to the Jet Stream and ocean heat accumulating in the North Atlantic Ocean are both consequences of the overall temperature rise. A distorted Jet Stream can cause an abrupt influx of ocean heat into the Arctic Ocean.

Such additional ocean heat, combined with a steep rise in insolation hitting the Arctic in April and May, may suffice to cause a Blue Ocean Event (BOE) to occur in 2024.

[ click on images to enlarge ]
The far North has the highest temperature anomalies, they can as high as 7.04°C, as the image on the right shows.

A BOE occurs when virtually all sea ice disappears and less than 1 million km² of sea ice remains. As the sea ice disappears, the surface color changes from white (sea ice) to blue (ocean) resulting in far more sunlight getting absorbed by the Arctic Ocean, instead of getting reflected back into space as was previously the case.

Albedo change constitutes a huge self-reinforcing feedback loop, i.e. the more sea ice disappears, the more sunlight gets absorbed by the Arctic Ocean, further accelerating sea ice melting. 

[ Albedo change, from the Albedo page ]

Next to the albedo loss, there is loss of the latent heat buffer constituted by the sea ice. Latent heat is energy associated with a phase change, such as the energy consumed when solid ice turns into water (i.e. melts). During a phase change, the temperature remains constant. Sea ice acts as a buffer that absorbs heat, while keeping the temperature at about zero degrees Celsius. As long as there is sea ice in the water, this sea ice will keep absorbing heat, so the temperature doesn't rise at the sea surface.

The amount of energy absorbed by melting ice is as much as it takes to heat up an equivalent mass of water from zero to 80°C. 

Without the buffer constituted by thicker sea ice, an influx of ocean heat could destabilize hydrates contained in sediments at the seafloor of the Arctic Ocean, resulting in eruptions of huge amounts of methane.

[ click on images to enlarge ]
The above image illustrates these tipping points and Northern Hemisphere Ocean Temperature anomalies vs 1901-2000, created with NOAA data. Trends and tipping point estimates are added. The magenta trend is based on Jan.1880-Jan.2024 data and warns that the Seafloor Methane Tipping Point may be crossed in 2025. The red trend is based on Jan.2010-Jan.2024 data and better reflects variables such as El Niño, and it warns that the Seafloor Methane Tipping Point may be crossed in 2024. 


The above image, adapted from tropicaltidbits.com, shows a forecast for November 2024 of the 2-meter temperature anomaly in degrees Celsius, based on 1984-2009 model climatology. The anomalies are forecast to be very high for the Arctic Ocean.

Many additional feedbacks are active, such as changes to the Jet Stream and slowing down of AMOC, and they could speed up the crossing of such tipping points, as also discussed at the feedbacks page. The danger is that a cascade of events will unfold like a domino effect, leading to extinction of most species, including humans, as the image below warns. 

[ from earlier post - click on images to enlarge ]

Greenhouse gases rising

Meanwhile, concentrations of greenhouse gases keeps rising, as illustrated by the image below. 

The average daily carbon dioxide (CO₂) at Mauna Loa, Hawaii, was 426.21 ppm (parts per million) on February 4, 2024. The weekly average was 425.83 ppm. 

Critical is the rate of change, in particular the rapid rise in temperatures and greenhouse gas concentrations. To find higher CO₂ concentrations, one has to go back millions of years. 


A recent study concludes that: 
- A doubling of CO₂ is predicted to warm the planet a whopping 5°C to 8°C.
- The last time atmospheric CO₂ consistently reached today’s human-driven levels of 420 ppm was 14 million years ago.
- The hottest period was about 50 million years ago, when temperatures were as much as 12°C higher than today.

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

• Blue Ocean Event
https://arctic-news.blogspot.com/p/blue-ocean-event.html

• Climate Reanalyzer - Daily Sea Surface Temperature, World (60°S-60°N)
https://climatereanalyzer.org/clim/sst_daily

• Pidwirny, M. "Earth-Sun Relationships and Insolation". Fundamentals of Physical Geography, 2nd Edition (2006)
http://www.physicalgeography.net/fundamentals/6i.html

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

• NSIDC - Arctic sea ice extent
https://nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph

• Polar Portal - Sea Ice Thickness and Volume
http://polarportal.dk/en/sea-ice-and-icebergs/sea-ice-thickness-and-volume

• University of Bremen - Arctic sea ice

• Scripps Institution of Oceanography at UC San Diego.

• Toward a Cenozoic history of atmospheric CO₂ - by The Cenozoic CO₂ Proxy Integration Project (CenCO₂PIP) Consortium






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


Saturday, July 23, 2022

Arctic sea ice July 2022

Blue Ocean Event

[ from Blue Ocean Event ]
A Blue Ocean Event occurs when virtually all sea ice disappears and the surface color changes from white (sea ice) to blue (ocean). According to many, a Blue Ocean Event starts once Arctic sea ice extent falls below 1 million km².

The image on the right shows a trend pointing at zero Arctic sea ice volume by September 2027.

Note that the volume data in the image are averages for the month September ⁠— the minimum for each year is even lower. Furthermore, since zero volume implies zero extent, this indicates that a Blue Ocean Event (extent below 1 million km²) could happen well before 2027.

Sea ice extent

The image below, adapted from NSIDC, shows the extent of Arctic sea ice on July 26, 2022. 
[ click on images to enlarge ]

The extent of Arctic sea ice was among the lowest on record for the time of year on July 26, 2022. Furthermore, Antarctic sea ice extent is currently at a record low for the time of year, as illustrated by the image below, adapted from Vishop and showing the situation up to July 27, 2022. 


As a result, global extent of sea ice is close to record low for the time of year, as illustrated by the image below, adapted from Vishop and showing the situation up to July 27, 2022. 


Both Vishop and NSIDC use 15% concentration as the threshold for including an area in calculations of sea ice extent. This makes it important to look at the concentration of the sea ice. 

Sea ice concentration

The image below, adapted from University of Bremen, shows Arctic sea ice concentration on July 22, 2022, with concentration in many areas close to the North Pole down to 0%. 


The image below, adapted from NSIDC, shows Arctic sea ice concentration on July 26, 2022, with very low concentration of sea ice visible close to the North Pole. 


Sea ice thickness

The Naval Research Laboratory one-month animation below shows Arctic sea ice thickness up to July 25, 2022, with 8 days of forecasts added. 


The combination image below shows the fall in Arctic sea ice thickness from June 8 through August 6, 2022.

[ click on images to enlarge ]
The above combination image shows that most sea ice on June 8 (left) was forecast to be over 2 meters thick, that most sea ice on July 8 (center) was forecast to be over 1 meter thick, and that most sea was forecast to be under 1 meter thick on August 6, 2022 (right).

While the fall in extent over this period wasn't as dramatic, due to the suppression of air temperatures by the current La Niña, note that the green and yellow colors where the sea ice on June 8 was more than 2.5 meters thick, north of Greenland and north of the Canadian Arctic Archipelago, have virtually disappeared in the August 6 forecast.

The above maps show a dramatic fall in sea ice thickness over a large area. This fall in thickness is mostly due to warm water from the Atlantic Ocean that is melting the sea ice hanging underneath the surface. This is where the sea ice constitutes the latent heat buffer, consuming incoming heat in the process of melting.

The above Naval Research Laboratory maps may be conservative. The NASA Worldview and University of Bremen images below indicate that Arctic sea ice may be even thinner than that, especially north of the North Pole. 

The NASA Worldview combination image below shows the sea ice north of the North Pole on July 22, 2022 (left), and on July 23, 2022 (right), indicating that at many places there is no sea ice left at all. Note that the view in many places is obscured due to clouds. 


The University of Bremen combination image below shows the difference in sea ice thickness between June 1, 2022, June 30, 2022, and July 22, 2022. The images at the center and on the right show large areas where sea ice is less than 20 cm thick, indicating that the latent heat buffer had already disappeared in June 2022,  as also discussed further below. 

[ click on images to enlarge ]
The NASA Worldview combination image below shows the sea ice north of Greenland on July 19, 2022 (top), and on July 22, 2022 (bottom), indicating that even at places where the sea ice once was the thickest, it can melt away rapidly. The mechanism behind this is that, as thick ice breaks off and fragments, it additionally gets heated up from the sides, and this further accelerates the melting as the sea ice breaks up further, into ever smaller pieces.


The image below was created with a screenshot of a July 26, 2022, NASA Worldview satellite image, with the Earth at Night layer activated and brightness and contrast enhanced, which enables a closer look to be taken through the clouds. The image shows very little sea ice near the North Pole. 


The image below, a screenshot of a July 26, 2022, NASA Worldview satellite image, further shows that there is little sea ice close to the North Pole. 


Conditions behind the danger

One reason why sea ice has fallen so much in thickness so close to the North Pole is that around the time of the June Solstice (June 22, 2022) the North Pole receives more insolation than anywhere else on Earth.

Around this time of year, the sunlight has less distance to travel through the thinner atmosphere over the Arctic, so less sunlight gets absorbed or scattered before reaching the surface. In addition, the high angle of the Sun produces long days and sunlight is concentrated over a smaller area. Above the Arctic Circle, the Sun does not set at this time of year, so solar radiation continues all day and night.


How much sunlight does reach the surface further depends on weather conditions such as clouds and how much heat gets pushed by the wind toward the North Pole. As temperatures have risen over the years, the Jet Stream has become more deformed, increasing the chance that heatwaves over land extend over the Arctic Ocean. Deformation of the Jet Stream can also lead to increasingly strong winds speeding up ocean currents that can abruptly push huge amounts of ocean heat into the Arctic ocean, as further discussed below. For more background, also see the feedbacks page. 

Ocean heat

On July 19, 2022, the sea surface was as warm as 1.8°C or 35.2°F north of Greenland, as the nullschool.net image below shows. 


The above image also shows how cold water (blue) flows down to the east of Greenland, while warm water (green) flows off the west coast of Norway toward to Arctic Ocean, diving under the sea ice north of Svalbard and reaching areas north of Greenland where sea surface temperatures rise above freezing point. 

Of the extra heat from Earth's energy imbalance, about 93% ends up in the ocean as increasing ocean heat content (see image below), 3% goes into melting ice, 4% goes into raising temperatures of land and melting permafrost, and less than 1% remains in the atmosphere, as discussed in an earlier post.

[ from earlier post ]

Sea ice has disappeared in the Bering Strait, in part due to warm water from rivers in Alaska, as illustrated by the NOAA image below, which shows sea surface temperatures as high as 18.6°C or 65.48°F.


On July 19, 2022, the sea surface temperature anomaly from 1981-2011 in the Arctic Ocean was as high as 14.0°C or 25.2°F (at green circle), as illustrated by the screenshot below of a nullschool.net image (with text added). In 1981-2011, the sea surface temperature at this spot (at the green circle in the Kara Sea) at this time of year was around freezing point.


The above image also shows a distorted Jet Stream (at 250 hPa) moving over the Arctic ocean, instead of circumventing the Arctic and thus keeping heat out of the Arctic and keeping cold inside the Arctic, as it used to be.  


The above NOAA image illustrates how the Gulf Stream is pushing warm water toward the Arctic, with sea surface temperatures in the North Atlantic reaching as high as 32.6°C or 90.68°F on July 23, 2022.

Latent heat

Latent heat is heat that is (less and less) going into melting the sea ice. The reason this heat is called latent (hidden) heat, is that it doesn't raise the temperature of the water, but instead gets consumed in the process of melting the ice. Latent heat is energy associated with a phase change, such as the energy consumed when solid ice turns into water (i.e. melting). During a phase change, the temperature remains constant. Sea ice acts as a buffer that absorbs heat, while keeping the temperature at zero degrees Celsius. As long as there is sea ice in the water, this sea ice will keep absorbing heat, so the temperature doesn't rise at the sea surface. 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.


Once most of the sea ice that was hanging underneath the surface is gone, further heat will still keep moving underneath the sea ice from the Atlantic Ocean and - to a lesser extent - from the Pacific Ocean into the Arctic Ocean. Without the latent heat buffer, this heat must go elsewhere, i.e. it will typically raise the temperature of the water. The atmosphere will also warm up faster. More evaporation will occur once the sea ice is gone, further warming up the atmosphere.

A 2019 analysis concludes that the latent heat tipping point gets crossed when the sea surface temperature anomaly on the Northern Hemisphere gets higher than 1°C above 20th century's temperature and when there is little or no thick sea ice left. As the image below indicates, the temperature anomaly of 1°C above the 20th century average looks set to be crossed in the course of the year 2021.
As the Latent Heat Tipping Point gets crossed, there may still be a thin layer of ice at the surface, at least as long as air temperatures are low enough to keep it frozen and as long as strong winds haven't pushed the sea ice out of the Arctic Ocean. This thin layer of ice will still consume some ocean heat below the surface, but at the same time it acts as a seal, preventing heat from the Arctic Ocean to enter the atmosphere. Even if a lot of sea ice remains, the situation is dangerous, if not even more dangerous. The continuing La Niña could cause a lot of thin sea ice to remain at the surface of the Arctic Ocean this year. The more sea ice remains, the less ocean heat can be transferred from the Arctic Ocean to the atmosphere over the Arctic Ocean, which means that more heat remains in the Arctic Ocean.

One huge danger is that, as the buffer disappears that until now has consumed huge amounts of ocean heat, more heat will reach methane hydrates at the seafloor of the Arctic Ocean, causing them to get destabilized and resulting in releases of methane from these hydrates and from free gas underneath that was previously sealed by the hydrates.

As the latent heat buffer of the sea ice underneath the surface disappears, more of this heat could then reach sediments at the seafloor of the Arctic Ocean, threatening eruptions to occur of seafloor methane (from hydrates and from free gas underneath the hydrates). The methane could similarly push up temperatures dramatically over the Arctic, and globally over the next few years.

[ feedback #14: Latent Heat ]

The above 2014 image, from the feedbacks page, shows three of the numerous feedbacks that are accelerating warming in the Arctic. Feedback #1 is the albedo feedback. Feedback #14 refers to the loss of the Latent Heat Buffer and warming of the Arctic Ocean. Feedback #2 refers to methane releases.

Heatwaves look set to continue on the Northern Hemisphere, extending heat over the Arctic Ocean and thus affecting Arctic sea ice from above, while warm water from rivers will cause more melting at the surface, and while rising ocean heat will continue to cause more melting of the ice underneath the surface. If this continues, we can expect a new record low for sea ice in September 2022 and the joint loss of the latent heat buffer and the loss of albedo could push up temperatures dramatically over the Arctic, while the additional methane could similarly push up temperatures dramatically over the Arctic, and globally over the next few years.

[ The Buffer has gone, feedback #14 on the Feedbacks page ]
As discussed at the albedo page and the feedbacks page, albedo change, loss of the latent heat buffer and changes to the Jet Stream are important feedbacks. 


The above image, adapted from an ECMWF.int forecast for July 29, 2022, 12 UTC, run at that time, shows virtually no snow and ice cover over land except Greenland. The image also shows the difference such cover or the lack thereof makes in albedo. 

[ click on images to enlarge ]
The above image, adapted from NOAA Coral Bleaching Heat Stress Monitoring, shows expected coral bleaching heat stress for August to November 2022. The image on the right shows that coral bleaching alert level 2 was reached in the Barents Sea (green circle) on July 29, 2022, while a distorted Jet Stream is pushing warm, salty water from the Atlantic Ocean into the Arctic Ocean. 

2022 study of the Blob, a warm water area in the North Pacific that began in late 2013, concludes that the unusually warm waters were transported northward from further south. The researchers found that abnormally warm temperatures extended 1,000 meters (3,280 feet) below the surface.


The above image shows the Blob on July 24, 2022, with sea surface temperature anomalies as high as 10.5°C or 18.8°F on July 24, 2022. The North Pacific Current is visible, extending eastward from the coast of Japan.

Arctic-news has long (e.g. in this 2017 post) warned that changes to the Jet Stream can strengthen storms that can in turn cause a large amount of warm, salty water to abruptly move north and enter the Arctic Ocean from the Atlantic Ocean and trigger destabilization of methane hydrates at the seafloor of the Arctic Ocean, resulting in eruption of huge amounts of methane that could drive humans into extinction in a matter of years. 


Conclusion

In conclusion, temperatures could rise strongly in the Arctic soon, due to sea ice loss in combination with feedbacks and an upcoming El Niño coinciding with a peak in sunspots, with the potential to drive humans extinct as early as in 2025, while temperatures would continue to skyrocket in 2026, making it in many respects rather futile to speculate about what will happen beyond 2026. At the same time, the right thing to do now is to help avoid the worst things from happening, through comprehensive and effective action as described in the Climate Plan.


Links

• Blue Ocean Event
https://arctic-news.blogspot.com/p/blue-ocean-event.html

• National Snow and Ice Data Center (NSIDC)
https://nsidc.org

• Visualization Service of Horizontal scale Observations at Polar region (Vishop) 
https://ads.nipr.ac.jp/vishop/#/extent

• Naval Research Laboratory
https://www7320.nrlssc.navy.mil/GLBhycomcice1-12/arctic.html

• University of Bremen
https://seaice.uni-bremen.de/databrowser

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

• NOAA - sea surface temperature

• Human Extinction by 2025?