Arctic News: ocean

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Wednesday, July 3, 2024

Feedbacks

Water vapor feedback

There are numerous self-amplifying feedbacks that accelerate the temperature rise. One of them is the water vapor feedback. Just the temperature rise itself will cause more water vapor to be in the atmosphere.

[ from Moistening Atmosphere ]

The February 2024 temperature was 1.76°C above 1885-1915, which could be as much as 2.75°C above the pre-industrial temperature.

A 2.75°C rise corresponds with almost ⅕ more water vapor in the atmosphere, as the extinction page points out.

The increase in water vapor in the atmosphere is a self-amplifying feedback, since water vapor is a powerful greenhouse gas, accelerating the temperature rise, as illustrated by the image on the right.

As illustrated by the image below, created with NOAA data, surface precipitable water reached 26.741 kg/m² in June 2024.

As the above image also illustrates, surface precipitable water reached a record high of 27.139 kg/m² in July 2023, and was much higher for each of the first six months in 2024 than for the same months in 2023.

More emissions of greenhouse gases (from earlier post)

As temperatures rise, due to stronger emissions of carbon dioxide, methane and nitrous oxide, there will be a corresponding extra amount of water vapor in the atmosphere.

Studies such as by Hubau (2020) warn that the uptake of carbon into Earth’s intact tropical forests peaked in the 1990s. Thawing permafrost can cause huge emissions of carbon dioxide, methane and nitrous oxide. Studies now warn that the Arctic has also changed from sink to source.

A study by Del Vecchi et al. (2024) suggests that a gradual thawing of Arctic permafrost could release between 22 billion and 432 billion tons of carbon dioxide by 2100 if current greenhouse gas emissions are reined in — and as much as 550 billion tons if they are not.

An analysis by Ramage et al. (2024) concludes that Arctic terrestrial permafrost now emits more greenhouse gases than it stores, and the trend is likely to accelerate as temperatures keep rising in the Arctic. The highest carbon dioxide emissions over the 2000-2020 period came from inland rivers and wildfires. The non-permafrost wetlands exhaled the most methane, and dry tundra released the most nitrous oxide.

The prospect of further releases looks dire. The analysis gives estimates that the upper three meters of permafrost region soils store 1,000 Gt of soil organic carbon, while deeper deposits could store an additional amount of as much as 1,000 Gt C. The analysis concludes that the permafrost region is the largest terrestrial carbon and nitrogen pool on Earth.

Note that the joint CO₂e of emissions in this analysis only covers part of global emissions, e.g. the analysis excludes emissions from Arctic subsea permafrost and from oceans in general, from many mountain areas and from the Southern Hemisphere. The study also appears to have excluded emissions caused by anthropogenic disturbances such as clear-cutting, logging and fracking activities in the region, while calculations typically use a low global warming potential (GWP) for methane (100-year horizon).

Miesner et al. (2023) warn that an additional 2822 Gt of organic carbon is stored in subsea Arctic shelf permafrost and Huang et al. (2024) warn that the top two meters of soil globally holds about 2300 Gt of inorganic carbon, which has been left out of environmental models, and 23 Gt of this carbon may be released over the next 30 years.

The transition from sink to source of the region is an important feedback of the temperature rise that is not fully reflected in many climate models. According to the IPCC, 14–175 Gt CO₂e (in carbon dioxide and methane) gets released per 1°C of global warming, which is likely to underestimate the situation by downplaying many feedbacks. Despite the dire situation, the IPCC keeps promoting less effective policies such as support for biofuel and tighter fuel efficiency standards, as discussed in earlier posts such as this 2022 one.

Further feedbacks

The image below illustrates the mechanism of how multiple feedbacks accelerate the heating up of the atmosphere.

Feedback #1: albedo loss (loss of reflectivity) as sea ice melts due to rising temperatures and due to the ice getting covered by soot, dust, algae, meltpools and rainwater pools;

Feedback #14: loss of the latent heat buffer - as sea ice disappears, heat can no longer be consumed by the process of melting, and the heat will instead go into increasing the temperature;

Feedback #16: eruptions of seafloor methane - as more heat reaches the seafloor of the Arctic Ocean, sediments and hydrates contained in them destabilize, resulting in methane releases;

Feedback #25: extra water vapor feedback - rising temperatures will result in more water vapor in the atmosphere (7% more water vapor for every 1°C warming), further amplifying the temperature rise, since water vapor is a potent greenhouse gas;

Feedback #19: distortion of the Jet Stream as the temperature difference narrows between the Arctic and the Tropics, in turn causing further feedbacks to kick in stronger, such as hot air moving into the Arctic and cold air moving out, and more extreme weather events bringing heavier rain and more intense heatwaves, droughts and forest fires that cause black carbon to settle on the sea ice;

Feedback #28: freshwater lid on the North Atlantic - melting of sea ice and glaciers and thawing of the permafrost results in meltwater accumulating in the North Atlantic, where it forms a cold freshwater lid on top of the water; this lid grows further due to more rain falling on top of this lid. This results in less evaporation and transfer of heat from the North Atlantic to the atmosphere, and more ocean heat getting carried by the Gulf Stream underneath the sea surface into the Arctic Ocean.

There is interaction between feedbacks; the image's focus is on illustrating the mechanism, rather than the proportional contribution or the order of feedbacks over time. Sea ice decline comes with both loss of albedo and loss of the latent heat buffer, each of which will accelerate the temperature rise of the water of the Arctic Ocean, thus contributing to the threat that hydrates contained in sediments at the seafloor of the Arctic Ocean will be destabilized, which in turn threatens to cause eruption of huge amounts of methane.

A further danger lies in changes occurring to wind and ocean current patterns; the temperature rise will cause stronger wind, waves and storms, as well as deformation of the Jet Stream. In addition, the temperature rise causes loss of reflectivity of clouds and more ocean stratification, exacerbated by more freshwater accumulating at the surface of oceans, due to stronger ice melting, due to heavier runoff from land and rivers and due to changes in wind patterns and ocean currents and circulation. In the North Atlantic, there is the additional danger that formation of a freshwater lid will cause huge amounts of ocean heat to be pushed into the Arctic Ocean and enter the atmosphere as sea ice disappears.

Further developments

Furthermore, developments such as rising emissions from industry, transport, land use, forest fires and waste fires, ocean acidification and reductions in sulfur emissions can all contribute to further acceleration of the temperature rise.

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

• Moistening Atmosphere
https://arctic-news.blogspot.com/p/moistening-atmosphere.html

• Did the climate experience a Regime Change in 2023?

https://arctic-news.blogspot.com/2024/04/did-the-climate-experience-a-regime-change-in-2023.html

• Pre-industrial
https://arctic-news.blogspot.com/p/pre-industrial.html

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

• NOAA - Physical Sciences Laboratory
https://psl.noaa.gov

• Arctic Sea Ice Alert

https://arctic-news.blogspot.com/2024/06/arctic-sea-ice-alert.html

• Will there be Arctic sea ice left in September 2023?

https://arctic-news.blogspot.com/2023/05/will-there-be-arctic-sea-ice-left-in-september-2023.html

Monday, June 24, 2024

How hot will it get?

Temperatures as high as 125°F or 51.67°C are forecast to hit California on July 6, 2024, as illustrated by the image below, adapted from Climate Reanalyzer by the University of Maine.

On June 23, 2024, the temperature in the Northern Hemisphere was higher than it was last year at this time of year, as illustrated by the image below, created with University of Maine content. The image shows that a temperature of 21.5°C was reached in the Northern Hemisphere on June 23, 2024. The question is: Will temperatures over the next few months exceed the high temperatures reached last year?

El Niño is no longer prevalent and La Niña conditions are expected to be dominant soon, as illustrated by the NOAA ENSO update on the right, from an earlier post.

Nonetheless, there are fears that temperatures will remain high and continue to rise, as self-amplifying feedbacks have taken over as the dominant drivers of the temperature rise. This was discussed earlier, in recent posts such as this one and this one.

There are numerous feedbacks that can further accelerate the temperature rise. Higher temperatures come with more water vapor in the atmosphere, an important feedback since water vapor is also a potent greenhouse gas.

Surface precipitable water reached a record high of 27.139 kg/m² in July 2023, as illustrated by the image below, adapted from NOAA, from an earlier post. Worryingly, a value of 26.138 kg/m² was reached in May 2024, much higher than the 25.378 kg/m² in May 2023, which raises fears that surface precipitable water will reach an even higher peak in 2024 than was reached in 2023.

Rising temperatures speed up the decline of sea ice and permafrost, which can in turn result in huge emissions of carbon dioxide, methane and nitrous oxide.

The decline of permafrost results in more meltwater that speeds up the flow of rivers. The image on the right shows sea surface temperatures as high as 18.3°C in the Bering Strait on June 29, 2024.

Deformation of the Jet Stream is another important feedback and it particularly affects the Northern Hemisphere where the Arctic heats up more rapidly than the rest of the world, thus narrowing the temperature difference between the Tropics and the Arctic, which changes the shape of the Jet Stream.

The Jet Stream will meander more and can at times even form circular wind patterns in some areas, which can strongly amplify extreme weather events such as storms that come with flooding and heatwaves that come with forest fires on land.

On land, more extreme weather can cause strong rainfall, resulting in more water running off into the Arctic Ocean. As heatwaves cause the water of rivers to heat up, a lot more heat can enter the Arctic Ocean.

Heatwaves and increased lightning can also cause fires that result in emissions and cause black carbon to settle on ice, causing temperature rise due to albedo loss and speeding up the thawing of permafrost and melting of sea ice. The image below, adapted from Copernicus, shows biomass burning aerosols, i.e. a forecast for June 29, 2024.

Over oceans, the impact of deformation of the Jet Stream can be even larger, since wind tends to be stronger over oceans than over land. Near the ocean, the greater temperature difference between land and sea will result in stronger winds.

The image below shows sea surface temperatures in the Northern Hemisphere. Heavy melting occurs in the blue-colored areas. Where the sea ice has disappeared, red and yellow colors show up, indicating temperatures higher than they used to be at this time of year in the respective area. High anomalies result from the loss of the latent heat buffer that previously absorbed heat and from the albedo changes that result in more sunlight getting absorbed by the surface.

Furthermore, the image shows a deformed Jet Stream with many circular wind patterns (at 250 hPa) over the Arctic. Deformation of the Jet Stream contributes to these high temperatures, by enabling heatwaves to extend over the Arctic Ocean, increasing not only the intensity, but also the frequency, duration and areas covered by such events.

The above image shows sea surface temperatures as high as 8.2°C or 46.7°F (i.e. 4.5°C or 8.1°F higher than 1981-2011) in the Laptev Sea (at the green circle), illustrating how a deformed Jet Stream is moving hot air over the Arctic Ocean and is also heating up the water of the Lena River and accelerating the speed at which the water is flowing into the Arctic Ocean.

The image below shows sea surface temperatures as high as 15.4°C or 59.7°F (i.e. 14.9°C or 26.8°F higher than 1981-2011) in Hudson Bay (at the green circle), while a deformed Jet Stream is moving hot air from Siberia far over the Arctic Ocean.

[ click on images to enlarge ]

Deformation of the Jet Stream enables strong winds to develop over the North Atlantic, which can at times strongly accelerate the speed at which hot water is flowing toward the Arctic Ocean along path of the Gulf Stream.

A deformed Jet Stream can temporarily speed up this flow, causing huge amounts of ocean heat to get abruptly pushed into the Arctic Ocean in the path of the Gulf Stream.

The image on the right shows hot water getting pushed along the path of the Gulf Stream from the Gulf of Mexico toward the Arctic Ocean. The image shows sea surface temperatures as high as 32.3°C on June 22, 2024.

As Arctic temperatures keep rising, two tipping points threaten to get crossed as temperatures rise and Arctic sea ice disappears, i.e. the latent heat tipping point and the seafloor methane tipping point, as discussed in an earlier post.

The combination image below, adapted from the University of Bremen, indicates that most of the thicker sea ice has melted in the course of June 2024, and that the latent heat buffer may be gone soon.

As illustrated by the image below, adapted from IRI, La Niña may develop during July-September 2024. A combination of feedbacks and their interaction, including the water vapor feedback, deformation of the Jet Stream and loss of albedo and loss of the latent heat buffer, may cause a continuation of high temperatures even during this La Niña. A new El Niño may develop in 2025 and be prevalent in 2026.

In other words, we may move into the next El Niño while the temperature rise keeps accelerating, while the masking effect of aerosols gets further reduced and while sunspots are moving toward a peak (in July 2025).

Links

• Climate Reanalyzer
https://climatereanalyzer.org

• Arctic Sea Ice Alert

https://arctic-news.blogspot.com/2024/06/arctic-sea-ice-alert.html

• Have feedbacks taken over?
https://arctic-news.blogspot.com/2024/06/have-feedbacks-taken-over.html

• Copernicus
https://atmosphere.copernicus.eu

• nullschool
https://earth.nullschool.net

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

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

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

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

• Albedo
https://arctic-news.blogspot.com/p/albedo.html

• Two Tipping Points
https://arctic-news.blogspot.com/2023/08/two-tipping-points.html

• The International Research Institute for Climate and Society, Columbia University Climate School
https://iri.columbia.edu/our-expertise/climate/forecasts/enso/current/?enso_tab=enso-sst_table

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

• Aerosols

https://arctic-news.blogspot.com/p/aerosols.html

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

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

• Transforming Society
https://arctic-news.blogspot.com/2022/10/transforming-society.html

• Climate Emergency Declaration
https://arctic-news.blogspot.com/p/climate-emergency-declaration.html

Monday, May 13, 2024

Temperature rise may soon accelerate even more

The April 2024 temperature was 1.32°C higher than 1951-1980, as illustrated by the above image, created with NASA content. Local anomalies are as high as 6.2°C.

The April 2024 temperature was 1.62°C higher than 1900-1930, as illustrated by the above image, created with NASA content. The red line highlights acceleration of the temperature rise (Lowess Smoothing).

The image below, created with NOAA content, uses a LOESS filter (green line) to highlight the recent acceleration in the temperature rise of the ocean. In this case, the temperature anomaly is calculated versus a 1901-2000 base.

[ click on images to enlarge ]

The temperature anomaly is even higher when calculated from a pre-industrial base. The image below, created with NASA content, shows that the February 2024 temperature was 1.76°C above 1885-1915, and potentially 2.75°C above pre-industrial (bright yellow inset right).

[ from earlier post ]

The image below, created with NASA content, shows Land+Ocean monthly mean global temperature anomalies versus a 1900-1923 custom base, further adjusted by 0.99°C to reflect ocean air temperatures, higher polar anomalies and a pre-industrial base.

[ from earlier post ]

The above image shows a magenta trend that points at the temperature crossing 3°C above pre-industrial later this year (2024). What could be behind such a steep rise?

Have Feedbacks taken over?

In April 2024, El Niño conditions were still dominant. Sea surface temperatures have been extremely high recently. The correlation between El Niño and temperature anomalies (from 1901-2000) is illustrated by the image below, created with NOAA content.

[ click on images to enlarge ]

As illustrated by the image below, created with NOAA content, El Niño conditions are no longer dominant. Instead, neutral conditions now prevail and La Niña conditions may develop as early as June-August 2024 (49% chance) or one month later, i.e. July-September (69% chance).

The extremely high recent temperatures and the trends depicted in the images further above raise the question as to what the underlying driver is, given that we're no longer in an El Niño. Indeed, the question is whether feedbacks have taken over as the main driver causing the temperature rise to further accelerate.

[ from Moistening Atmosphere ]

As mentioned above, the February 2024 temperature could be as much as 2.75°C higher than pre-industrial. The extinction page points out that a 2.75°C rise corresponds with almost ⅕ more water vapor in the atmosphere. This increase in water vapor in the atmosphere is a self-reinforcing feedback loop, since water vapor is a powerful greenhouse gas, further accelerating the temperature rise.

There is no single feedback that could cause the recent steep rise of temperatures and its acceleration, instead there are numerous non-linear, self-amplifying feedback loops that can all contribute, interact and start to kick in with greater ferocity, amplifying and further accelerating the rise.

Such feedbacks do include more water vapor, as said, as well as stronger wind, waves and storms, more ocean stratification, faster loss of sea ice, faster loss of reflectivity of clouds and more freshwater accumulating at the surface of oceans, due to stronger ice melting, due to heavier runoff from land and rivers and due to changes in wind patterns and ocean currents and circulation.

Furthermore, developments such as rising emissions from industry, transport, land use, forest fires and waste fires, ocean acidification and reductions in sulfur emissions over the past few years all contribute to further acceleration of the temperature rise.

Two tipping points threaten to get crossed

For about one year now, global temperature anomalies have been extremely high, as illustrated by the image below, created with a screenshot from Copernicus, showing an anomaly from 1991-2020 of 0.84°C on May 31, 2024.

The image below, adapted from Copernicus, shows sea surface temperature anomalies from 1991-2020 on May 31, 2024.

The temperature rise is hitting the Arctic harder than elsewhere, as illustrated by the images at the top and below, created with NASA content.

Contributing to these high temperatures in the Arctic are high temperatures of the North Atlantic Ocean, which are now rising rapidly, in line with seasonal changes, as illustrated by the image below, created with Climate Reanalyzer content.

The above image shows that the North Atlantic sea surface temperature was 22.4°C on May 31, 2024, higher than the temperature in 2023 for this time of year. 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, due to prevailing winds and ocean circulation.

North Atlantic sea surface temperatures are now rising strongly, in line with seasonal changes. Ominously, a peak of 25.4°C was reached in August 2023. The question is how high the North Atlantic temperature will be in 2024 at that time of year.

The image below shows North Atlantic sea surface temperature anomalies versus 1982-2011. Data shown are from September 1, 1981, through May 31, 2024.

As discussed, one reason for the high temperatures of the North Atlantic is that sulfur emissions have been reduced over the years. Furthermore, there are many feedbacks. Importantly, there is potential for the slowing down of the Atlantic meridional overturning circulation (AMOC) to contribute to more heat accumulating at the surface of the North Atlantic Ocean, as also illustrated by the image below.

[ click on images to enlarge ]

The above image highlights mechanisms with the potential to contribute to further heating up of the Arctic Ocean resulting in more methane erupting from the seafloor of the Arctic Oceans, including storms and changes to the Jet Stream, as discussed before. e.g. in this post.

One tipping point that threatens to get crossed is loss of Arctic sea ice. Loss of Arctic sea ice comes with albedo change, which 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, while less sunlight gets reflected back into space.

[ 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, in this case the energy consumed as solid ice turns into liquid 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.

As long as air temperatures over the Arctic are below freezing, sea ice can persist at the surface, maintaining sea ice extent, which may give the false impression that sea ice was healthy, whereas in fact sea ice has steadily been declining in thickness.

Arctic sea ice volume is at its lowest on record for the time of year, as illustrated by the image below, created with Danish Meteorological Institute content, and as also discussed in earlier posts such as this one.

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. Loss of sea ice thickness implies loss of the latent heat buffer and constitutes a tipping point, i.e. once crossed, the Arctic Ocean will heat up at accelerating pace.

The above map, created with Danish Meteorological Institute content, shows that much of the thicker sea ice is located away from the North Pole, such as off the east coast of Greenland. 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.

Seafloor methane constitutes a second tipping point. When methane escapes from hydrates that get destabilized by rising temperatures, the methane will expand to 160 times its previous volume and enter the atmosphere with force. Without the buffer constituted by thicker sea ice, an influx of ocean heat could cause large-scale destabilization of hydrates contained in sediments at the seafloor of the Arctic Ocean, resulting in eruptions of huge amounts of methane.

[ from earlier post ]

[ image from the Extinction page ]

On the above image, estimates for these two tipping points are added to Northern Hemisphere Ocean Temperature anomalies vs 1901-2000, created with NOAA data. Furthermore, two trends are added. The magenta trend is based on January 1880-January 2024 data and warns that the Seafloor Methane Tipping Point may be crossed in 2025. The red trend, which is based on January 2010-January 2024 data and better reflects variables such as El Niño, warns that the Seafloor Methane Tipping Point may be crossed in 2024.

Crossing of the latent heat tipping point and the seafloor methane tipping point results in ever more heat reaching and accumulating in the Arctic ocean, destabilizing methane hydrates contained in sediments at the seafloor of the Arctic Ocean, as discussed in many earlier posts such as this one.

Self-amplifying feedbacks and developments as discussed above, as well as crossing of these two tipping points, could all contribute to cause a temperature rise of over 10°C, in the process causing the clouds tipping point to get crossed that can push up the temperature rise by a further 8°C.

Altogether, the temperature rise may exceed 18°C from pre-industrial by as early as 2026, as illustrated by the image on the right, from the extinction page.

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 the Climate Emergency group.

Links

• NASA - datasets and images
https://data.giss.nasa.gov

• Climate Reanalyzer
https://climatereanalyzer.org

• Copernicus
https://pulse.climate.copernicus.eu

• NOAA - National Centers for Environment Information
https://www.ncei.noaa.gov

• NOAA - Climate Prediction Center / National Centers for Environmental Prediction
https://www.cpc.ncep.noaa.gov

• Pre-industrial
https://arctic-news.blogspot.com/p/pre-industrial.html

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

• Moistening Atmosphere

https://arctic-news.blogspot.com/p/moistening-atmosphere.html

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

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

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

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

• Arctic Ocean Feedbacks
https://arctic-news.blogspot.com/2017/01/arctic-ocean-feedbacks.html

• Arctic sea ice set for steep decline
https://arctic-news.blogspot.com/2024/03/arctic-sea-ice-set-for-steep-decline.html

• Did the climate experience a Regime Change in 2023?

https://arctic-news.blogspot.com/2024/04/did-the-climate-experience-a-regime-change-in-2023.html

• Arctic sea ice under threat

https://arctic-news.blogspot.com/2024/04/arctic-sea-ice-under-threat.html

• Blue Ocean Event 2024?

https://arctic-news.blogspot.com/2024/02/blue-ocean-event-2024.html

• 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

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, April 12, 2024

North Atlantic heating up

Sea surface temperature 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.

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.

The image below, adapted from Copernicus, shows March 2024 sea surface temperature anomalies from 1991-2020. High anomalies show up, especially around the Equator which can be expected given that the amount of sunlight there is highest at this time of year.

Carbon dioxide at Mauna Loa reaches new record high

The daily average carbon dioxide at Mauna Loa, Hawaii, was 428.42 ppm on April 24, 2024. To find carbon dioxide levels this high, one needs to go back millions of years.

The above image shows hourly (red) and daily (yellow) carbon dioxide averages at Mauna Loa for the last 31 days.

This carbon dioxide level of 428.42 ppm reached on April 24, 2024, is 4.45 ppm higher than the level on April 24, 2023, as the above image shows.

North Atlantic heating up

The North Atlantic Ocean is now heating up rapidly, as more sunlight is starting to reach the Northern Hemisphere. The image below, adapted from Climate Reanalyzer, shows sea surface temperatures up to April 23, 2024. The image shows that 2024 temperatures have been significantly higher than 2023 temperatures for the same dates. The annual maximum temperature in 2023 was reached on August 31. Temperatures can be expected to rise dramatically over the next few months, in line with the change in seasons.

Much will depend on the strength of the current El Niño over the next few months and El Niño is predicted to weaken, but as said there are fears that feedbacks are kicking in with accelerating ferocity. The image below, adapted from NOAA, shows monthly temperature anomalies versus 1901-2000 through March 2024, colored by El Niño/La Niña conditions.

NOAA warns that there is a bit of a delay in the effects of any given ENSO phase. So, the first part of this year will still be influenced by El Niño, which is in part why NOAA predicts a 55% chance that 2024 will be hotter than 2023.

Further factors (other than El Niño) may continue to accelerate the temperature rise, as discussed in earlier posts such as this one. One 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, as discussed in earlier posts such as this one.

Arctic sea ice getting very thin

The image below indicates that Arctic sea ice volume has recently been the lowest on record for the time of year.

Given that Arctic sea ice currently is still relatively extensive, this 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.

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.