Arctic sea ice set for steep decline

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The February 2024 temperature (at 2 meter) was much higher than in 1951-1980, especially in the Arctic, as the above image shows.

The above image is adapted from NASA and shows an average February 2024 temperature anomaly of 1.44°C above 1951-1980, with anomalies showing up as high as 11°C. 

The above image is created with NASA 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. 

Two trends are added, the blue trend is based on all data (Jan.1880-Feb.2024) and the magenta trend is based on a shorter period (Jan.2010-Feb.2024), to better reflect variables such as El Niño and non-linear feedbacks as discussed in the page Feedbacks in the Arctic and in this recent post

Ocean temperature

Sea surface temperatures (60°S-60°N, 0-360°E) reached a new record high of 21.22°C on March 10, 2024, in the Climate Reanalyzer daily records that go back to 1981. 

Sea surface temperatures may get even higher later this year. What could make the sea surface temperature go up even higher?

[ click on images to enlarge ]
The highest daily sea surface temperatures for the year are typically reached in March. 
This was the case for the previous years on record going back to 1981, except for the year 2023 when the current El Niño started to emerge, resulting in the highest peak for the year occurring in August 2023.
There is a 100% probability that El Niño will be present during the 3 months from February 2024 to April 2024, according to NOAA predictions updated February 26, 2024.

The image below shows the Northern Hemisphere Sea Surface Temperature Anomaly, January 2000-February 2024 NOAA data (degrees Celsius).

After an astonishing rise in 2023, sea surface temperatures have come down only a little bit in Winter on the Northern Hemisphere, raising the potential for a huge rise in ocean heat later in 2024 that threatens to destabilize sediments at the seafloor of the Arctic Ocean and cause huge amounts of methane to erupt and abruptly enter the atmosphere.
[ click on images to enlarge ]
Ocean heat content keeps rising at a rate of change that is non-linear, as illustrated by the image below, by Zack Labe.
North Atlantic
The animation below, from Nahel Belgherze, illustrates how much hotter the North Atlantic has been over the past 365 days, while a big rise in temperature can be expected over the next few months, due to the change in season.
In February 2024, the temperature (at 2 meter) over the North Atlantic was 1.927°C higher than 1951-1980, as illustrated by the image below. 
The map below shows the North Atlantic sea surface temperature anomaly versus 1951-1980 in February 2024. 
Arctic surface air temperature

The surface air temperature in the Arctic (66.5-90°N, 0-360°E) was 5.2°C above 1979-2000 on March 3, 2024, the highest anomaly on record for the time of year, as illustrated by the image below. 

[ click on images to enlarge ]

Arctic sea ice

As the atmosphere and the oceans keep heating up, Arctic sea ice keeps declining. As illustrated by the image below, Arctic sea ice extent was 14.746 million km² on March 6, 2024. 
As the above image shows, there are a few years with lower sea ice extent during this time of year than in 2024, which could be due to more water vapor in the air causing more precipitation in the Arctic. At this time of year, Arctic sea ice has typically reached its maximum annual extent and goes into steep descend until half September. With the change in seasons, more sunlight will be reaching the Northern Hemisphere and Arctic sea ice looks set for a steep decline over the next few months. 

As illustrated by the above image, Arctic sea ice volume is already at a record low for the time of year, at a time when little or no sunlight is yet reaching the Arctic. Given that Arctic sea ice currently is not at a record low extent for the time of year, this indicates that the sea ice is very thin, due to ocean heat causing sea ice to melt from below. 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, as also discussed in earlier posts such as this one

Emissions and concentrations of greenhouse gases keep rising
Meanwhile, emissions keep rising. The image below, adapted from IEA, shows the increase in energy-related carbon dioxide emissions, 1900-2023. 
February 2024 CO₂ was about 425 ppm (background image below). February 2023 CO₂ was 420.3 ppm (inset right). The highest annual rise on record is about 3 ppm, reached in 1998 and in 2015/2016 (inset left). 

The threat
The threat of a huge, abrupt temperature rise has been described many times before, e.g. on the Threat page that describes many elements contributing to the threat, both cumulatively and interactively, with some of the content dating back as far as 2007. Another page with more background is the Extinction page.
Further illustrating the threat is the image below, adapted from Climate Reanalyzer and using a CMIP6 SSP585 model. The image shows what the temperature anomaly (at 2 meter and compared to 1851-1900) could be by 2100. Such a temperature rise may unfold much earlier when including numerous feedbacks kicking in strongly.
What can strongly contribute to such a rise is that, without the buffer constituted by thicker sea ice, an influx of ocean heat threatens to destabilize hydrates contained in sediments at the seafloor of the Arctic Ocean, resulting in eruptions of huge amounts of methane.
[ The buffer is gone – Latent Heat Tipping Point crossed ]
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 – daily sea surface temperature (60°S-60°N, 0-360°E)

https://climatereanalyzer.org/clim/sst_daily

• NASA – Temperature Analysis
https://data.giss.nasa.gov/gistemp

• NOAA – ENSO: Recent Evolution, Current Status and Predictions (February 26, 2024 update)
https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/lanina/enso_evolution-status-fcsts-web.pdf

• Ocean heat content – image by Zack Labe
• North Atlantic daily sea surface temperature – animation by Nahel Belgherze
https://twitter.com/WxNB_/status/1765065264109101393

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

• International Energy Agency (IEA) – CO2 Emissions in 2023 report

• Keeling Curve, Scripps Institution of Oceanography, UC San Diego – CO₂ at Mauna Loa, Hawaii 

• NOOA – Monthly Averages CO₂ at Mauna Loa, Hawaii 
• NOAA – annual increase of CO₂ at Mauna Loa, Hawaii 
https://gml.noaa.gov/ccgg/trends/gr.html
• Feedbacks in the Arctic
• The Threat