Arctic sea ice volume
In September 2024, Arctic sea ice reached a new record low volume, as illustrated by the image below, adapted from the Danish Meteorological Institute, with markers for September (red) and April (blue) corresponding with the year's minimum- and maximum volume.
Indeed, some mechanisms can have a more abrupt impact. Sea ice could shrink strongly and rapidly as a (tipping) point is reached where the latent heat buffer disappears abruptly and as further incoming ocean heat suddenly can no longer be consumed by melting of what once was thick sea ice that extended meters below the surface. Arctic sea ice typically reached its annual low about half September, but an abrupt decline of Arctic sea ice may well occur earlier than that. Sea ice may melt strongly, and large pieces of sea ice may additionally get pushed out of the Arctic Basin by strong winds. Large and rapid loss of Arctic sea ice may therefore well occur in July 2025 or even earlier, as the latent heat tipping point gets crossed and additional mechanisms further contribute to increase the temperature.
On October 11, 2024, Antarctic sea ice was more than 1 million km² lower in extent than on October 11, 2022, and almost 3 million km² lower in extent than a decade ago, as illustrated by the image below.
This difference indicates that extent may fall below 1 million km² in February 2025.
On October 17, 2024, global sea ice extent was 22.03 million km², a record low for the time of year. Global sea ice extent is now several million km² lower than it was decades ago, i.e. more than 2.5 million km² lower than the 2010's average extent and more than 5 million km² lower than the 1980's average extent.
[ click on images to enlarge ] |
Antarctic Sea ice thickness and volume
There are indications that Antarctic sea ice volume is already decreasing. The images by University of Bremen below show sea ice thickness on August 27, 2024 (left), September 29, 2024 (center) and October 5, 2024 (right).
Temperatures keep rising
Mechanisms accelerating the temperature rise
As illustrated by the image below, there are at least seven mechanisms that are accelerating the surface temperatures rise, and therefore are accelerating sea ice decline.
[ Earthshine annual albedo anomaly expressed as reflected flux in W/m². CERES data. ] |
[ The Pattern Effect could account for a 0.7°C temperature rise. ] |
Higher sea surface temperatures come with greater stratification.
[ from earlier post ] |
[ from earlier post ] |
Polar amplification of the temperature rise causes a relative slowing down of the speed at which heat flows from the Equator to the poles. This impacts ocean currents and wind patterns, resulting in slowing down of the Atlantic meridional overturning circulation (AMOC) and of ocean currents around Antarctica that carry heat to the deep ocean, as well as in deformation of the Jet Stream.
The IPCC image below shows how much temperatures are currently suppressed in the Arctic due to aerosols and thus also shows how much temperatures in the Arctic look set to rise as the aerosol masking effect falls away.
[ from earlier post - click on images to enlarge ] |
[ for more background, also view the Extinction page ] |
A huge temperature rise could occur soon, as the impact of these mechanisms keeps growing, as the latent heat tipping point gets crossed in a Double Blue Ocean Event and the seafloor methane tipping point subsequently gets crossed.
As temperatures keep rising in the Arctic, changes to the Jet Stream look set to intensify, resulting in loss of terrestrial albedo in the Arctic that could equal the albedo loss resulting from sea ice decline.
Further feedbacks include permafrost degradation, both terrestrial and on the seafloor of the Arctic Ocean, which looks set to cause huge releases of greenhouse gases (particularly CO₂, CH₄ and N₂O).
This would in turn also cause more water vapor to enter the atmosphere, further speeding up the temperature rise.
The 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.
• Arctic Data archive System - National Institute of Polar Research - Japan
https://ads.nipr.ac.jp/vishop
https://ocean.dmi.dk/arctic/icethickness/thk.uk.php
• University of Bremen - Arctic sea ice
https://seaice.uni-bremen.de/start
• NSIDC - Interactive sea ice chart
https://nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph
https://www.facebook.com/groups/arcticnews/posts/10161543138459679
• NOAA - Climate Prediction Center - ENSO: Recent Evolution, Current Status and Predictions
https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/lanina/enso_evolution-status-fcsts-web.pdf
• NOAA - Physical Sciences Laboratory
https://psl.noaa.gov
https://arctic-news.blogspot.com/p/feedbacks.html
• Jet Stream
https://arctic-news.blogspot.com/p/jet-stream.html
• Freshwater lid on the North Atlantic
https://arctic-news.blogspot.com/p/cold-freshwater-lid-on-north-atlantic.html
• Latent Heat
https://arctic-news.blogspot.com/p/latent-heat.html
• Sunspots
https://arctic-news.blogspot.com/p/sunspots.html
• Indicators of Global Climate Change 2023: annual update of key indicators of the state of the climate system and human influence - by Piers Forster et al.
• Pre-industrial
https://arctic-news.blogspot.com/p/pre-industrial.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