Arctic News

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

Tuesday, June 11, 2024

Arctic Sea Ice Alert

[ click on images to enlarge ]

Temperatures remain high, as illustrated by the above image, adapted from Copernicus.

Meanwhile, El Niño is no longer prevalent. Instead, La Niña conditions are expected to be dominant soon, as illustrated by the NOAA ENSO update on the right.

There are fears that self-amplifying feedbacks have taken over as the dominant drivers of the temperature rise, as discussed in earlier posts such as this one.

Temperatures are getting very high in the Northern Hemisphere.

The image on the right shows maximum temperatures on June 10, 2024, with very high temperatures showing up over a large area around the North Pole.

Temperatures can be expected to keep rising. The image underneath shows a forecast of maximum temperature on June 13, 2024, with very high temperatures showing up on land around the Arctic Ocean, above 20°C in Alaska, parts of Siberia and on an area in Greenland.

This year, temperatures are extremely high, and this is especially the case for temperatures in the Gulf of Mexico and in the North Atlantic.

Temperatures in the North Atlantic strongly affect Arctic sea ice.

As temperatures rise the Jet Stream gets more deforms, as discussed at the Jet Stream page.

Deformation of the Jet Stream enables heatwaves to extend over the Arctic, and to also result in strong wind over the North Atlantic, which can at times strongly accelerate the speed at which hot water is flowing toward the Arctic Ocean along the path of the Gulf Stream.

The image on the right shows markedly higher temperatures than at similar latitudes in the path of the Gulf Stream, indicating a flow of heat from the Gulf of Mexico in the direction of the Arctic Ocean.

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 shows sea surface temperatures as high as 32.1°C on June 15, 2024.

The image below shows high ocean heat content anomalies in the Gulf of Mexico, compared to the 2013-2023 mean, with anomalies recently reaching a new record high of above 20 KJ per cm².

North Atlantic sea surface temperature anomalies have risen strongly over the past few years, as illustrated by the image below that highlights anomalies from 1951-1980 for May 2022, May 2023 and May 2024.

As illustrated by the image below, the North Atlantic sea surface temperature anomaly has moved higher recently.

After an astonishing rise in 2023, sea surface temperature anomalies fell for six months in the Northern Hemisphere, but they are rising again, threatening to cause dramatic sea ice loss over the next few months and destabilize sediments at the seafloor, resulting in huge amounts of methane erupting and abruptly entering the atmosphere.

Sea surface temperatures were actually rising on June 18, 2024, even though we may already be in a La Niña by now. The image below, created with a ClimateReanalyzer.org screenshot (text box added), shows that the sea surface (60°S–60°N, 0–360°E) reached a temperature of 20.94°C (69.69°F) on June 18, 2024, a record high for the time of year.

Heatwaves over land can also cause the water of rivers to heat up, with a lot of heat running off into the Arctic Ocean.

The image on the right shows temperatures as high as 15.6°C in the Bering Strait on June 20, 2024.

As temperatures rise in the Northern Hemisphere, Arctic sea ice extent is falling, as illustrated by the image below. While this image shows that Arctic sea ice extent is not the lowest on record for the time of year, extent is only one way to measure the state of the sea ice. There are further ways to measure Arctic sea ice, such as area, concentration, volume and thickness.

NSIDC explains the difference between extent and area: A simplified way to think of extent versus area is to imagine a slice of Swiss cheese. Extent would be a measure of the edges of the slice of cheese and all of the space inside it. Area would be the measure of where there is cheese only, not including the holes. Therefore, if you compare extent and area in the same time period, extent is always bigger.

Another measure is concentration. The image on the right, from NSIDC, shows Arctic sea ice concentration on June 18, 2024.

Volume is another measure. The image below is adapted from the Danish Meteorological Institute and shows that Arctic sea ice volume is at a record low for the time of year, as it has been for most of the year.

Volume is calculated by multiplying thickness with concentration and with area, which implies that Arctic sea ice is very thin, as also indicated by the image below, adapted from the University of Bremen, which is combined with a NASA satellite image for comparison.

The Uni of Bremen image on the left shows sea ice thickness in cm on June 11, 2024, with the added square corresponding to area covered by the NASA satellite image on the right, which also shows a lot of open water (black), while the white color can indicate either ice or it can be clouds.

The image below measures thickness by using both the brightness temperature data from ESA’s Soil Moisture and Ocean Salinity (SMOS) satellite and NASA’s Soil Moisture Active Passive (SMAP) satellite.

Lack of sea ice in the Kara Sea and the Laptev Sea (at top of the above images) is worrying, since these are shallow seas that hold huge amounts of carbon in sediments at the seafloor. Heat can penetrate these sediments and destabilize hydrates, resulting in eruption of huge amounts of methane.

Loss of sea ice comes with numerous further feedbacks that accelerate the temperature rise, and just the temperature rise itself comes with feedbacks such as more water vapor in the atmosphere.

Surface precipitable water reached a record high of 27.139 kg/m² in July 2023, as illustrated by the image below, adapted from NOAA. 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.

Thawing permafrost can cause huge emissions of carbon dioxide, methane and nitrous oxide. Ominously, the image below shows high methane levels over Scandinavia, which could be the result of higher temperatures.

As illustrated by the image below, adapted from Climate Reanalyzer, the temperature anomaly in Scandinavia was high in May 2024.

Studies such as by Hubau (2020) warn that the uptake of carbon into Earth’s intact tropical forests peaked in the 1990s. Studies now warn that the Arctic has also changed from sink to source.

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.

Links

• Copernicus - Climate Pulse
https://pulse.climate.copernicus.eu

• NOAA - ENSO diagnostic discussion
https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory/ensodisc.shtml

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

• Climate Reanalyzer
https://climatereanalyzer.org

• Ocean Heat Content - by Brian McNoldy
https://bmcnoldy.earth.miami.edu/tropics/ohc

• NOAA - National Centers for Environmental Information - Climate at a Glance - Global Time Series
https://www.ncei.noaa.gov/access/monitoring/climate-at-a-glance/global/time-series/nhem/ocean/1/0/1850-2024

• Arctic Data archive System - National Institute of Polar Research - Japan

https://ads.nipr.ac.jp

• NOAA - Global Monitoring Laboratory - Carbon Cycle Gases, Mauna Loa, Hawaii, U.S.
https://gml.noaa.gov/dv/iadv/graph.php?code=MLO&program=ccgg&type=ts

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

• NSIDC - National Snow and Ice Data Center

https://nsidc.org

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

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

• NOAA - Physical Sciences Laboratory

https://psl.noaa.gov

• Copernicus

https://atmosphere.copernicus.eu

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

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

• Copernicus - Climate Pulse
https://pulse.climate.copernicus.eu

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

• Tropical forests’ carbon sink is already rapidly weakening (news release)
https://news-archive.exeter.ac.uk/featurednews/title_780594_en.html
Asynchronous carbon sink saturation in African and Amazonian tropical forests - by Wannes Hubau et al. (2020)
https://www.nature.com/articles/s41586-020-2035-0
Discussed at Facebook at:
https://www.facebook.com/groups/arcticnews/posts/10158152112254679

• Amplifying feedback loop between drought, soil desiccation cracking, and greenhouse gas emissions - by Farshid Vahedifard et al. (2024)
https://iopscience.iop.org/article/10.1088/1748-9326/ad2c23
Discussed on facebook at
https://www.facebook.com/groups/arcticnews/posts/10161298567849679

• Subsea permafrost organic carbon stocks are large and of dominantly low reactivity - by Frederieke Miesner et al. (2023)
https://www.nature.com/articles/s41598-023-36471-z

• Size, distribution, and vulnerability of the global soil inorganic carbon - by Yuanyuan Huang et al. (2024)

https://www.science.org/doi/10.1126/science.adi7918
Discussed at facebook at
https://www.facebook.com/groups/arcticnews/posts/10161354439024679

• Biodiversity loss reduces global terrestrial carbon storage - by Sarah Weiskopf et al. (2024) https://www.nature.com/articles/s41467-024-47872-7
Discussed at Facebook at:
https://www.facebook.com/groups/arcticnews/posts/10161454674974679

• Permafrost extent sets drainage density in the Arctic - by Joanmarie Del Vecchi et al (2024)
https://www.pnas.org/doi/epdf/10.1073/pnas.2307072120
Discussed at Facebook at:
https://www.facebook.com/groups/arcticnews/posts/10161248133064679

• IPPCC AR6 Workgroup 1 Frequently Asked Questions

Sunday, June 2, 2024

Have feedbacks taken over?

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 0.86°C on June 1, 2024.

What could be behind these persistently high temperatures? Many causes such as El Niño and sunspots have been discussed in earlier posts. How much do emissions contribute to these high temperatures?

Despite pledges by politicians to ensure that temperatures would not cross 1.5°C above pre-industrial, the growth rate of the concentration of carbon dioxide in the atmosphere appears to be accelerating, as illustrated by the image below, adapted from NOAA and showing concentration of carbon dioxide at Mauna Loa, Hawaii.

Have feedbacks taken over as the dominant driver of the temperature rise? The image below shows NOAA March 2009 through May 2024 monthly CO₂ concentration at Mauna Loa (black) with a trend (magenta) added for a joint 30-year coverage. The trend shows how CO₂ could cross the clouds tipping point at 1200 ppm (parts per million) in 2038, which in itself would push up temperatures by a further 8°C.

What could cause such a steep rise? Many studies point at organic carbon and inorganic carbon releases from soils that could further raise both CO₂ concentrations and temperatures. A recent study by Weiskopf (2024) finds that biodiversity declines from climate and land use change could lead to a global loss of up to 103.14 GtC for a global sustainability scenario and up to 145.95 GtC for a fossil-fueled development scenario, indicating a self-reinforcing feedback loop where higher levels of climate change lead to greater biodiversity loss, in turn leading to greater carbon emissions.

The clouds tipping point is actually at 1200 ppm CO₂e (carbon dioxide equivalent), so it could be crossed even earlier when also taking into account more methane, nitrous oxide, etc. As discussed in an earlier post, the daily mean CO₂ on April 26, 2024, was 428.59 ppm, while peak daily average methane is approaching 2000 parts per billion (ppb) at Mauna Loa, Hawaii. A methane concentration of 2000 ppb corresponds, at a Global Warming Potential (GWP) of 200, with 400 ppm CO₂e. Together with the daily average CO₂ concentration of 428.63 ppm this adds up to a joint CO₂e of 828.63 ppm, i.e. only 371.37 ppm away from the clouds tipping point.

This 371.37 ppm CO₂e could be added almost immediately by a burst of seafloor methane less than the size of the methane that is currently in the atmosphere (about 5 Gt). There is plenty of potential for such an abrupt release, given the rising ocean heat and the vast amounts of methane present in vulnerable sediments at the seafloor of the Arctic Ocean, as discussed in earlier posts such as this one and at the threat page.

There are many further developments and feedbacks that should be taken into account. Furthermore, note that anomalies in the image at the top are calculated from a 1991-2000 base. The temperature rise and the resulting feedbacks are even larger when anomalies are calculated from a pre-industrial base.

[ from earlier post ]

[ from Moistening Atmosphere ]

The above image, created with NASA content, shows that the February 2024 temperature was 1.76°C above 1885-1915, which could be as much as 2.75°C above pre-industrial (bright yellow inset right).

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, further accelerating the temperature rise.

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 earlier post ]

Worryingly, data for the first four months of 2024 are way higher than they were in 2023 at the same time of year, which raises fears that surface precipitable water will reach an even higher peak in 2024 than was reached in 2023. The situation is depicted even more clearly on the image below, created with the same data.

As said, more water in the atmosphere further accelerates the temperature rise. Furthermore, high relative humidity also makes high temperatures more unbearable. The human body can cool itself by sweating, which has a physiological limit that was long described as a 35°C wet-bulb temperature, i.e. once the wet-bulb temperature reaches 35°C, one can no longer lose heat by perspiration, even in strong wind, but instead one will start gaining heat from the air beyond a wet-bulb temperature of 35°C.

A 2022 study (by Vecellio et al., 2022) finds that the actual limit is lower — about 31°C wet-bulb or 87°F at 100% relative humidity — even for young, healthy subjects. The temperature for older populations, who are more vulnerable to heat, is likely even lower. In practice the limit will typically be lower and depending on circumstances could be as low as a wet-bulb temperature of 25°C, as discussed in an earlier post.

Temperature in either °C or °F and the relative humidity for spots on Earth can be viewed at nullschool, and then the associated wet-bulb temperature can be calculated here.

North Atlantic

There are numerous tipping points and non-linear, self-amplifying feedbacks that can all contribute, interact and start to kick in with greater ferocity, amplifying and further accelerating the rise, as discussed at the feedbacks page.

What could push up temperatures dramatically is loss of Arctic sea ice, as discussed in earlier posts such as this one. Ominously, the North Atlantic sea surface temperature anomaly has risen strongly recently, as illustrated by the images below.

The maps below, adapted from Climate Reanalyzer, show sea surface temperatures (left) and sea surface temperature anomalies (right) on June 2, 2024.

North Atlantic sea surface temperatures keep rising, as illustrated by the image below that highlights temperature anomalies from 1951-1980 for May 2022, May 2023 and May 2024.