Showing posts with label thickness. Show all posts
Showing posts with label thickness. Show all posts

Monday, June 20, 2022

Arctic sea ice June 2022 - why the situation is so dangerous

Sea Ice Extent


Arctic sea ice extent has fallen strongly in June 2022. On June 22, 2022, Arctic sea ice extent was among the lowest on record for the time of year, as illustrated by the above image, adapted from the National Snow and Ice Data Center (NSIDC Chartic). 

The image below, from an animation by Zachary Labe, shows Arctic sea ice extent up to June 20, 2022, based on Vishop data. The yellow line is the year 2022. The white line shows extent for the year 2012, when it reached a record minimum in September. The blue line shows extent the year 2020, when the minimum in September was second lowest.
 

The image below, adapted from Vishop, shows that on June 23, 2022, global sea ice extent was at a record low for the time of year.


La Niña

[ adapted from NOAA - click on images to enlarge ]
The fact that sea ice is so low for the time of the year is the more striking as we are currently in the depths of a persistent La Niña, which suppresses the temperature rise.

El Niños typically occur every 3 to 5 years, according to NOAA and as also illustrated by the NOAA image below, so the upcoming El Niño can be expected to occur soon.

The NOAA image below indicates that going from the bottom of a La Niña to the peak of an El Niño could make a difference of more than half a degree Celsius (0.5°C or 0.9°F).


Furthermore, the rise in sunspots from May 2020 to July 2025 could make a difference of some 0.15°C (0.27°F). The next El Niño looks set to line up with a high peak in sunspots, in a cataclysmic alignment that could push up the temperature enough to cause dramatic sea ice loss in the Arctic, resulting in runaway temperature rise by 2026.

Multi-year Sea Ice

The NSIDC compilation below illustrates how much multi-year sea ice has already declined over the years. The top panel shows the age of Arctic sea ice for the March 12 to 18 period in (a) 1985 and (b) 2022. The oldest ice, greater than 4 years old, is in red. Plot (c) shows the timeseries from 1985 through 2022 of percent cover of the Arctic Ocean domain (inset, purple region) by different sea ice ages during the March 12 to 18 period.


Sea Ice Volume

On June 18, 2022, Arctic sea ice volume was among the lowest on record for the time of year, as illustrated by the image below, adapted from Polarportal.


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 Thickness

The Naval Research Laboratory one-month animation below shows Arctic sea ice thickness up to June 18, 2022, with 8 days of forecasts added.


The above animation shows a dramatic fall in sea ice thickness over a large area, while sea ice is disappearing altogether in some places. 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 University of Bremen combination image below shows the difference in sea ice thickness between June 1 and June 30, 2022. The image on the right shows a large areas where sea ice is less than 20 cm thick.


The NASA Worldview image below shows the situation on June 24, 2022. Plenty of water is showing up as close as 200 km to the North Pole.


Also view the NASA Worldview animation comparing sea ice at June 24 and 25, 2022 at facebook

Ocean Heat and decline of the Latent Heat Buffer


Ocean heat keeps rising; in 2021, despite La Niña conditions, ocean heat reached yet another record high, as illustrated by the above image, from an earlier post.

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.


Close to the coast of Siberia, where much of the sea ice has disappeared altogether, the decline is due for a large part to warm water from rivers flowing into the Arctic Ocean. 


Sea ice has also disappeared altogether in the Bering Strait, for a great part due to warm water from rivers in Alaska, especially the Yukon River, the Kuskokwim River and the Copper River, as illustrated by the above NOAA image, which shows sea surface temperatures as high as 15.6°C or 60.08°F.


On June 10, 2022, the sea surface temperature anomaly from 1981-2011 in the Bering Strait was as high as 15.5°C or 27.9°F (at green circle), illustrated by the above nullschool.net image. In 1981-2011, the Bering Strait was still largely frozen at this time of year.

The NOAA image below illustrates how the Gulf Stream is pushing warm water toward the Arctic, with sea surface temperatures in the North Atlantic reaching as high as 32.1°C or 89.78°F on June 19, 2022. 


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.


The combination image below illustrates how much ocean heat is entering the Arctic Ocean from the Atlantic Ocean, heating up the sea ice from below.

The left panel shows the depth of the Arctic Ocean, with darker blue indicating greater depth.

In the right panel, the light blue, green and yellow colors indicate the thickest ice, located in the shallow waters off the coasts of North America and Greenland. The darker blue colors indicate where much of the sea ice has melted away, from below, as also illustrated by the one-month animation below showing sea ice thickness up to June 22, 2022, with an added 8 days of forecasts. The white color indicates where the sea ice has melted away entirely, e.g. in the Bering Strait and north of Siberia, mainly due to warm water from rivers entering the Arctic Ocean.


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 Atlantic 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.

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 ]

Conclusion

In conclusion, temperatures could rise strongly in the Arctic soon, due to sea ice loss in combination with an upcoming El Niño and 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.

• Blue Ocean Event 

• Polarportal

• Naval Research Laboratory

• University of Bremen

• NASA Worldview satellite

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

• nullschool
https://earth.nullschool.net

• Albedo, latent heat, insolation and more

• Latent Heat Buffer

• Feedbacks in the Arctic

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

• Climate Plan
https://arctic-news.blogspot.com/p/climateplan.html




Tuesday, July 6, 2021

Arctic sea ice disappearing fast


Above image, from the National Institute of Polar Research in Japan, shows Arctic sea ice extent at a record low for the time of year, on July 4, 2021, at 8.4 million km².


[ for earlier animations, see discussions ]
Subsequently, the NSIDC also indicated that Arctic sea ice was at record low extent for the time of year, on July 5, 2021, at 8.867 million km² (image above). 

Arctic sea ice is getting very thin rapidly, threatening the latent heat tipping point to get crossed soon. 
     
The U.S. Navy animation on the right shows Arctic sea ice thickness (in m) for the 30 days up to July 31, 2021, with eight days of forecasts included. 

The very thin Arctic sea ice featuring on the University of Bremen image further below on the right indicates that there is now virtually no buffer left to consume further incoming heat. 

Is the Buffer is gone?

[ disappearing sea ice north of Greenland ]
An often-used threshold for a Blue Ocean Event (BOE) is that a BOE occurs when sea ice extent falls below 1 million km². Similarly, a threshold for the latent heat tipping point of Arctic sea ice could be sea ice thickness.

Disappearance of the buffer constituted by subsurface sea ice could be measured by a threshold of most sea ice becoming less than 0.5 meter thin. By that measure, the buffer is now virtually gone, implying that virtually no further heat arriving from the Atlantic Ocean and the Pacific Ocean in the Arctic Ocean can be absorbed in the process of melting of the sea ice.

The NASA Worldview image on the right shows the sea ice on July 29, 2021, north of Greenland, where once the thickest sea ice was located. 

The combination image below show forecasts for July 16 run one day earlier for Arctic sea ice in 2014 (left) and 2021 (right). 



As sea ice gets thinner, ever less ocean heat gets consumed in the process of melting the subsurface ice, to the point where there is only a thin layer of ice left at the surface. While this thin layer of ice may remain at the surface for as long as air temperatures are still low enough, and this ice will still consume some heat at the bottom, at the same time it acts as a seal, preventing heat from the Arctic Ocean to enter the atmosphere.

Albedo loss, latent heat loss, storms and changes to the jet stream can add up to dramatically amplify the temperature rise of the water in the Arctic Ocean, which comes with the danger of destabilization of hydrates at its seafloor, resulting in eruption of huge amounts of methane from hydrates and opening up pathways for release of even further amounts of free gas from underneath these hydrates, as illustrated by the image below.

 
And while the situation in 2021 is dire, the outlook for the years beyond 2021 is that things look set to get progressively worse. 

Outlook is getting worse

This situation in 2021 is the more remarkable given that we're in a La Niña period, as illustrated by the NOAA image on the right showing a forecast issued July 5, 2021, that indicates that La Niña is expected to reach a new low by the end of 2021. 

El Niño events, according to NASA, occur roughly every two to seven years. As temperatures keep rising, ever more frequent strong El Niño events are likely to occur. NOAA anticipates the current La Niña to continue for a while, so it's likely that a strong El Niño will occur somewhere from 2023 to 2025.

Sunspots are on the rise. We were at a low point in the sunspot cycle late 2019/early 2020. As the image on the right shows, the number of sunspots is rising and can be expected to rise further as we head toward 2026, and temperatures can be expected to rise accordingly. 

According to James Hansen et al., the variation of solar irradiance from solar minimum to solar maximum is of the order of 0.25 W/m⁻².

Temperatures are currently also suppressed by sulfate cooling, and their impact is falling away as we progress with the necessary transition away from fossil fuel and biofuel, toward the use of more wind turbines and solar panels instead. Aerosols typically fall out of the atmosphere within a few weeks, so as the transition progresses, this will cause temperatures to rise over the next few years.

So, the outlook is grim. The right thing to do now is to help avoid the worst things from happening, through immediate, comprehensive and effective action as described in the Climate Plan.


Links

• National Institute of Polar Research (NIPR) in Japan
https://ads.nipr.ac.jp/vishop

• The National Snow and Ice Data Center (NSIDC) at the University of Colorado Boulder
https://nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph

• NOAA ENSO Evolution
https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/lanina/enso_evolution-status-fcsts-web.pdf

Thursday, June 3, 2021

Greenhouse gas levels keep rising at accelerating rates

At the Paris Agreement in 2015, politicians pledged to limit the global temperature rise from pre-industrial levels to 1.5°C and promised to stop rises in greenhouse gas emissions as soon as possible and to make rapid reductions in accordance with best available science, to achieve a balance between people's emissions by sources and removals by sinks of greenhouse gases in the second half of this century. 

Yet, greenhouse gas levels keep rising and the rise appears to be accelerating. 

Carbon Dioxide

The annual mean global growth rate of carbon dioxide (CO₂) has been increasing over the years (see above image). The February 2021 global CO₂ level was 2.96 ppm higher than the February 2020 global CO₂ level (image left).
The March 2021 global CO₂ level was 2.89 ppm higher than the March 2020 global CO₂ level (image left), again much higher than the average annual growth rate over the past decade. No discernible signal in the data was caused by restrictions associated with the COVID-19 pandemic.

More recent values are available for Mauna Loa, Hawaii. As the image on the right shows, the monthly average CO₂ level at Mauna Loa was 419.13 ppm for May 2021, while the weekly average was as high as 420.01 ppm (for the week ending at May 1, 2021). 

On April 8, 2021, CO₂ levels at Mauna Loa, Hawaii, reached a level of 421.36 ppm, while several hourly averages recorded in early April were approaching 422 ppm (see earlier post).

According to NOAA, the atmospheric burden of CO₂ is now comparable to where it was during the Pliocene Climatic Optimum, between 4.1 and 4.5 million years ago, when CO₂ was close to, or above 400 ppm. During that time, the average temperature was about 4°C (7°F) higher than in pre-industrial times, and sea level was about 24 m (78 feet) higher than today.

Methane
 
The 2020 global annual methane (CH₄) growth rate of 15.85 ppb was the highest on record. The global CH₄ level in January 2021 was 1893.4 ppb, 20 ppb higher than the January 2020 level. 

The image at the top shows a trend indicating that CH₄ could reach a level of 4000 ppb in 2026, which at a 1-year GWP of 200 translates into 800 ppm CO₂e, so just adding this to the current CO₂ level would cause the Clouds Tipping Point at 1200 CO₂e to be crossed, which in itself could raise global temperatures by 8°C, as described in an earlier post

Nitrous Oxide

The 2020 global annual nitrous oxide (N₂O) growth rate of 1.33 ppb was the highest on record. The global N₂O level in January 2021 was 333.9 ppb, 1.4 ppb higher than the January 2020 level. 

Greenhouse gas levels are accelerating, despite promises by politicians to make dramatic cuts in emissions. As it turns out, politicians have not taken the action they promised they would take. 

Of course, when also adding nitrous oxide, the Clouds Tipping Point can get crossed even earlier.

Elements contributing to temperature rise

Next to rising greenhouse gas levels, there are further elements that can contribute to a huge temperature rise soon. 


As illustrated by above image by Nico Sun, the accumulation of energy going into melting the sea ice is at record high for the time of year. 



As illustrated by above combination image, the thickness of the sea ice is now substantially less than it used to be. The image compares June 1, 2021 (left), with June 1, 2015 (right). 

The animation on the right shows that sea ice is getting rapidly thinner, indicating that the buffer constituted by the sea ice underneath the surface is almost gone, meaning that further heat entering the Arctic Ocean will strongly heat up the water.

As described in an earlier post, this can destabilizate methane hydrates in sediments at the seafloor of the Arctic Ocean, resulting in eruption of methane from these hydrates and from methane that is located in the form of free gas underneath such hydrates. 

Such methane eruptions will first of all heat up the Arctic, resulting in loss of Arctic sea ice's ability to reflect sunlight back into space (albedo feedback), in disappearing glaciers and in rapidly thawing terrestrial permafrost (and the associated release of greenhouse gases).

The Snowball Effect


Temperatures are rising and they are rising at accelerating pace, especially in the Arctic. A strong El Niño and a distortion in the jet stream could cause the latent heat and methane hydrates tipping points to be crossed soon, causing many feedbacks to kick in with ever greater ferocity, and pushing up the global temperature beyond 3°C, 4°C and 5°C above pre-industrial, like a snowball that keeps growing in size while picking up ever more snow, as it is racing down a very steep slope.

Crossing of tipping points and further events and developments can combine with feedbacks into a snowball effect of rapidly rising temperatures.

Feedbacks include changes to the Jet Stream that result in ever more extreme weather events such as storms and forest fires. Such events can cause huge emissions of greenhouse gases. 

Temperatures can also be expected to rise over the next few years as sulfate cooling decreases. Aerosols can further cause additional warming if more black carbon and brown carbon gets emitted due to more wood getting burned and more forest fires taking place. Black carbon and brown carbon have a net warming effect and can settle on snow and ice and speed up their decline.

Therefore, the 8°C rise as a result of crossing the Clouds Tipping Point would come on top of the warming due to other elements, and the total rise could be as high as 18°C or 32.4°F from preindustrial, as ilustrated by the image on the right, from an earlier post.

Very high sea surface temperature anomalies

Meanwhile, sea surface temperatures on the Northern Hemisphere keep rising. The image below shows that sea surface temperature anomalies off the North American east coast (at the green circle) were as high as as 13.7°C (24.7°F) on June 3, 2021.


More heat is flowing from the tropics along the North American east coast toward the Arctic Ocean, carried by the Gulf Stream, as illustrated by the image on the right. 

In conclusion, there could be a huge temperature rise by 2026. 

At a 3°C rise, humans will likely go extinct, making it from some perspectives futile to speculate about what will happen beyond 2026. 

Even so, the right thing to do is to help avoid the worst things from happening, through comprehensive and effective action as described in the Climate Plan.


• NOAA: Trends in Greenhouse gases
https://gml.noaa.gov/ccgg/trends

• NOAA: Carbon dioxide peaks near 420 parts per million at Mauna Loa observatory

• Overshoot or Omnicide?
• Cryosphere Computing - by Nico Sun
https://cryospherecomputing.tk

• Arctic Ocean invaded by hot, salty water

• Most Important Message Ever
https://arctic-news.blogspot.com/2019/07/most-important-message-ever.html






Monday, July 27, 2020

Arctic sea ice could disappear completely within two months' time

Arctic sea ice fell by 3.239 million km² in extent in 25 days (i.e. from July 1 to 25, 2020). Melting will likely continue for another two months. If it continues on its current trajectory, the remaining 6.333 million km² of Arctic sea ice could disappear completely within two months' time.


The fall in extent over the next two months' time may not remain as as steep as it was in July, yet the sea ice still could disappear completely. One reason for this is that, over the years, sea ice thickness has been declining even faster than extent. The rapid decline in sea ice thickness is illustrated by the sequence of images below.


The image on the right further illustrates that sea ice is getting very thin, which threatens the latent heat tipping point to get crossed. 

Sea currents and the Coriolis force will make that the influx of warm, salty water into the Arctic Ocean will continue. With no buffer of sea ice left underneath the surface of the sea ice to absorb incoming ocean heat, more heat will accumulate in the Arctic Ocean, threatening that the methane hydrates tipping point will get crossed.

The navy.mil animation below was run on August 3, 2020, and shows sea ice thickness over 30 days (last 8 frames are forecasts for August 4 - August 11, 2020). 


Here's another indication that the buffer is disappearing fast. North of Greenland and of the Canadian Arctic Archipelago, less than 700 km from the North Pole, the sea ice is disappearing, precisely where the thickest sea ice used to be located. 


High greenhouse gas levels are causing high temperatures over the Arctic and high ocean temperatures. 


On July 25, 2020, sea surface temperatures in the Arctic Ocean were as high as 20.8°C or 69.4°F (at the green circle on above image).


At that same location, on July 22, 2020, sea surface temperatures in the Arctic Ocean were as much as 17°C or 30.5°F higher than the daily average during the years 1981-2011. 

This location is where the Pechora River flows into the Barents Sea (the green circle pointed at by the white arrow on above image).

Distortion of the jet stream is causing more extreme weather, resulting in the recent lengthy heatwave over Siberia that has heated up the water of rivers flowing into the Arctic Ocean.

A cyclone was visible over the Arctic Ocean on July 28, 2020, as illustrated by the image on the right. 

Underneath on the right is a forecast for August 7, 2020, showing rain over the North Pole. 

In summary, Arctic sea ice may disappear completely over the next two months, and there are at least six reasons why this could occur:
• Low Arctic sea ice extent;
• Low Arctic sea ice thickness;
• High ocean temperature;
• High greenhouse gas levels;
• High temperatures over the Arctic;
• Distorted jet stream causing extreme weather such as storms that can break up the sea ice. 
As the image below shows, sea surface temperatures in the Arctic Ocean on August 1, 2020, were as much as 11.5°C or 20.7°F higher than 1981-2011 (at green circle, off the coast of Siberia, opposite Greenland). 


Ominously, the MetOp-1 satellite recorded peak methane levels of 2933 ppb, at 469 mb, on the afternoon of July 30, 2020.

The situation is dire and calls for immediate, comprehensive and effective action, as described in the Climate Plan.


Links

• NSIDC Arctic sea ice
http://nsidc.org/arcticseaicenews

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

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

• Arctic Hit By Ten Tipping Points
https://arctic-news.blogspot.com/2020/04/arctic-hit-by-ten-tipping-points.html

• Fast Path to Extinction
https://arctic-news.blogspot.com/2020/06/fast-path-to-extinction.html

• 2020 Siberian Heatwave continues
https://arctic-news.blogspot.com/2020/06/2020-siberian-heatwave-continues.html

• Climate Plan
https://arctic-news.blogspot.com/p/climateplan.html