Showing posts with label volume. Show all posts
Showing posts with label volume. 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. 


Tuesday, April 30, 2024

Arctic sea ice under threat

The image below indicates that Arctic sea ice volume has meanwhile passed its annual maximum. Over the coming months, volume can be expected to decrease rapidly. The image also highlights that, over the past few months, Arctic sea ice volume has been the lowest on record for the time of year.


The image below illustrates the decline of Arctic sea ice volume over the years. The image also confirms that the annual maximum volume was recently reached and that it was the lowest maximum for the 24 years on record. 

Given that Arctic sea ice currently is still relatively extensive, this record low volume indicates that sea ice is indeed very thin, which must be caused by ocean heat melting sea ice from below, since little or no sunshine is yet reaching the Arctic at the moment and air temperatures are still far below freezing point, so where ocean heat may be melting sea ice away from below, a thin layer of ice will quickly be reestablished at the surface, keeping sea ice extent relatively large for now.

This situation looks set to dramatically change over the next few months, as air temperatures will rise and as more ocean heat will reach the Arctic Ocean. Moreover, as illustrated by the map below, much of the thicker sea ice is located off the east coast of Greenland. This sea ice and the purple-colored sea ice can be expected to melt away quickly with the upcoming rise in temperatures over the next few months.

Sea surface temperatures at record high

The image below, created with Climate Reanalyzer screenshots, shows that the sea surface temperature (SST 60°S - 60°N mean) was 21.2°C on April 24, 2024, reaching yet another record high.

[ image from earlier post ]

These record high sea surface temperatures are reached as long-term sea surface temperatures are falling and as El Niño is predicted to weaken, which is fueling fears that feedbacks are kicking in with accelerating ferocity.

The image below, adapted from NOAA, shows global ocean temperature anomalies from 1901-2000, with the green line (LOcally Estimated Scatterplot Smoothing) giving a warning that higher temperature anomalies could be coming up.

[ image from earlier post ]

The image below shows that the monthly Atlantic surface temperature anomaly in March 2024 was 1.422°C when compared to a 1901-2000 base.


The high anomalies over the past two months indicate how much heat has accumulated in the Atlantic, and these anomalies are even higher when using a pre-industrial base, as discussed earlier.

The images also highlight the potential for the slowing down of the Atlantic meridional overturning circulation (AMOC) to contribute to more heat accumulating at the surface of the Atlantic Ocean.

Arctic sea ice under threat

As temperatures rise, many feedbacks are kicking in with greater ferocity, including increased stratification of oceans, loss of sea ice, loss of reflectivity of clouds and increased freshwater due to stronger melting of sea ice and glacial ice, due to heavier runoff from land and rivers and due to changes in ocean circulation.

While this may look to cause less ocean heat to reach the Arctic Ocean for now, the result is that a huge amount of ocean heat is accumulating in the North Atlantic that threatens to abruptly move into the Arctic Ocean. The danger is that an influx of ocean heat can cause large amounts of methane to erupt from the seafloor of the Arctic Ocean.

An enormous amount of ocean heat has accumulated and is still further accumulating in the North Atlantic and much of this heat threatens to abruptly move into the Arctic Ocean. The danger is that, due to strong wind along the path of the Gulf Stream and extensions of this current into the Arctic Ocean, 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.

The danger is growing, due to a number of factors. Firstly, the amount of ocean heat in the North Atlantic is increasing. Secondly, Arctic sea ice volume is at record low, implying that there is little or no buffer left to consume ocean heat flowing from the Atlantic Ocean into the Arctic Ocean.

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 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. 

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

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

Strong hurricanes can significantly add to the danger. More hurricanes are forecast for the 2024 Atlantic hurricane season than during 1950-2020, as illustrated by the image below, from an earlier post.


Many of the dangers have been discussed in earlier posts, e.g. the danger that sea currents in the Arctic Ocean will change direction was discussed in this 2017 post.

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

• Climate Reanalyzer
https://climatereanalyzer.org

• NOAA - Ocean temperature anomalies
https://www.ncei.noaa.gov/access/monitoring/climate-at-a-glance/global/time-series/globe/ocean/1/0/2015-2024?filter=true&filterType=loess

• Atlantic ocean heat threatens to unleash methane eruptions
https://arctic-news.blogspot.com/2024/03/atlantic-ocean-heat-threatens-to-unleash-methane-eruptions.html

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

• North Atlantic heating up
https://arctic-news.blogspot.com/2024/04/north-atlantic-heating-up.html

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

• 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



Friday, June 30, 2023

Arctic sea ice under threat - update 5

The NASA Worldview satellite image below shows Arctic sea ice on June 29, 2023, with the North Pole on the left. 


The animation below shows that, while clouds can obscure a closer look, sea ice is clearly very thin with the thickest ice breaking up near the top of Greenland, some 750 km from the North Pole. 


The Uni of Bremen image below shows Arctic sea ice thickness on June 28, 2023.


The danger is that, as El Niño strengthens, there will be massive loss of Arctic sea ice over the coming months, with water in the Arctic Ocean heating up strongly due to loss of the latent heat buffer and loss of albedo, while huge amounts of ocean heat keep entering the Arctic Ocean from the Atlantic Ocean and the Pacific Ocean.

The image below shows that the North Atlantic sea surface temperature was 23.5°C on June 28, 2023 (on the black line), 0.9°C higher than the 22.6°C on June 28, 2022 (on the orange line). A record high of 24.9°C was reached on Sept. 4, 2022, even while La Niña was suppressing the temperature. This time, there's an El Niño. 


The image below, adapted from NOAA, shows ocean heat moving toward the Arctic along the path of the Gulf Stream on June 25, 2023, while sea surface temperatures on the map are as high as 32.6°C.


In addition, the Jet Stream is strongly deformed, and this threatens to strengthen heatwaves extending over the Arctic Ocean and causing hot water from rivers to enter the Arctic Ocean, and to strengthen storms accelerating the flow of ocean heat into the Arctic Ocean, while fires and storms contribute to darkening of the sea ice, further speeding up its demise.

The danger is that, as El Niño strengthens and as ocean heat keeps entering the Arctic Ocean from the Atlantic Ocean and the Pacific Ocean, a huge amount of heat will abruptly be pushed into the Arctic Ocean.

This danger is illustrated by the image on the right, from an earlier post, showing the Jet Stream pushing wind at a speed of 126 km/h (78 mph) up through Fram Strait (at the green circle) into the Arctic Ocean on June 21, 2023.

This situation threatens to cause massive loss of Arctic sea ice over the coming months, with water in the Arctic Ocean heating up strongly due to loss of the latent heat buffer and loss of albedo.

This in turn threatens to trigger methane eruptions from the seafloor of the Arctic Ocean, a threat that has been described many times before, such as here, here and here.

[ Latent heat loss, feedback #14 on the Feedbacks page ]
[ see the Extinction page ]
Loss of Arctic sea ice albedo, loss of the latent heat buffer and eruption of seafloor methane all constitute tipping points that threaten to abruptly accelerate the temperature rise in the Arctic, further speeding up loss of permafrost in Siberia and North America and thus threatening to trigger further releases of greenhouse gases.

In addition, there are further events and developments that could unfold and make things even worse.

The upcoming temperature rise on land on the Northern Hemisphere could be of such a severity that much traffic, transport and industrial activity will grind to a halt, resulting in a reduction in cooling aerosols that are now masking the full wrath of global heating. Without these cooling aerosols, the temperature is projected to rise strongly, while there could be an additional temperature rise due to an increase in warming aerosols and gases as a result of more biomass and waste burning and forest fires. Furthermore, as traffic slows down, there will be less nitrogen oxide emissions, which could result in less hydroxyl to curtail methane.

The bar on the right depicts the threat, as discussed at the Extinction page.

In conclusion, the situation is dire and calls for support for a Climate Emergency Declaration.


Links

• Arctic sea ice under threat

• Arctic sea ice under threat - update 1

• Arctic sea ice under threat - update 2

• Arctic sea ice under threat - update 3
https://arctic-news.blogspot.com/2023/06/arctic-sea-ice-under-threat-update-3.html

• Arctic sea ice under threat - update 4
https://arctic-news.blogspot.com/2023/06/arctic-sea-ice-under-threat-update-4.html

• Climate Reanalyzer - Daily sea surface temperatures
https://climatereanalyzer.org/clim/sst_daily

• NOAA - The National Centers for Environment Prediction Climate Forecast System Version 2  

• NOAA - Climate Prediction Center - ENSO Diagnostic Discussions
https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory/ensodisc.shtml

• NOAA - sea surface temperature
https://www.ospo.noaa.gov/Products/ocean/sst/contour/index.html

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

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