Sea ice loss

Global sea ice area was 13.00 million km² on February 9, 2025, a deviation (1981-2000 base) of -5.75 σ and the lowest area on record, as illustrated by the image below, adapted from seaice.visuals.earth.

What is the difference between sea ice area and extent? Extent is the total region with at least 15% sea ice cover. Extent can include holes or cracks in the sea ice and melt ponds on top of the ice, all having a darker color than ice. Sea ice area is the total region covered by ice alone. 

Therefore, sea ice area is a critical measure in regard to albedo. Loss of sea ice area is a self-reinforcing feedback that causes the temperature to rise, resulting in further melting of sea ice, thus accelerating the temperature rise. 

A Blue Ocean Event is often defined as crossing a tipping point that is crossed when sea ice falls below 1 million km² in extent. Doesn't it make more sense to look at sea ice area, rather than at sea ice extent?

Loss of albedo as a result of loss in sea ice is only one out of many feedbacks that come with rising temperatures, as described at the Threat. 

Antarctic sea ice

There are many mechanisms that are driving up, if not accelerating the temperature rise and loss of sea ice.  

As illustrated by the image below, Antarctic sea ice area was 1.05 million km² on February 22, 2023, and was 1.39 million km² on February 9, 2025. Will there be a Double Blue Ocean Event 2025? 

Sea ice thickness is another important measure. The image below shows Antarctic sea ice thickness on four different dates, including February 4, 2025, from the University of Bremen.

The image below shows Antarctic sea ice thickness on February 7, 2025.

For a comparison of Antarctic sea ice thickness at earlier dates, also have a look at this earlier post. 

Arctic sea ice

As illustrated by the image below, there are at least seven mechanisms that can accelerate the rise in surface temperatures, and thus in turn accelerating sea ice decline and further accelerating the temperature rise.

[ from the earlier post Double Blue Ocean Event 2025? and discussed here ]

The image below shows Arctic sea ice extent up to February 8, 2025. During the first few months of the year, Arctic sea ice extent is growing, but this recently stopped and extent was at a record low for the time of year on February 8, 2025, despite La Niña conditions. The red line and red marker shows 2025 sea ice. Dots mark sea ice extent on February 8 for the respective year. 

As said, extent is only one way the sea ice can be measured; another way is to measure sea ice area. Furthermore, warmer water flowing into the Arctic Ocean causes Arctic sea ice to lose thickness and thus volume, diminishing its capacity to act as a buffer that consumes ocean heat entering the Arctic Ocean from the North Atlantic. This means that - as sea ice thickness decreases - a lot of incoming ocean heat can no longer be consumed by melting the sea ice from below, and the heat will therefore contribute to higher temperatures of the water of the Arctic Ocean.

[ from earlier post ]

[ Arctic sea ice volume, click to enlarge ]

The image on the right shows Arctic sea ice volume up to February 10, 2025. Arctic sea ice volume in 2024 and 2025 has been much lower than in previous years. 

More incoming heat therefore threatens to reach the seafloor of the Arctic Ocean and destabilize methane hydrates contained in sediments at the seafloor, resulting in eruptions of huge amounts of methane, as illustrated by the above image.

Following the influx of ocean heat from the North Atlantic into the Arctic Ocean, methane peaks above 2400 ppb were recorded by three different satellites, as illustrated by the image below, i.e.
2413 ppb at 399.1 mb by the N20 satellite on February 2, 2025 (left), 

2469 ppb at 399.1 mb by the N21 satellite on February 2, 2025 (center), and 

2446 ppb at 487.2 mb by the Metop-C satellite on February 3, 2025 (right). 

[ Methane peaks above 2400 ppb on Feb 2 & 3, 2025, click to enlarge ]

Arctic temperature rise

The image below shows that the Arctic temperature, i.e. at latitudes higher than 80°N, on February 6, 2025, was much higher than the mean temperature for the period 1959-2002. 

As said before, rising temperatures come with many feedbacks, such as albedo loss and loss of the latent heat buffer. Feedbacks can contribute strongly to further acceleration of the temperature rise. Another feedback is more water vapor ending up in the atmosphere, as illustrated by the image below.

[ from earlier post ]

The above image shows the average daily precipitable water anomaly on February 2, 2025. More water vapor is another self-reinforcing feedback, since water vapor is a potent greenhouse gas that further accelerates the temperature rise.

A new El Niño may emerge in the course of 2025, while Arctic sea ice extent, area thickness and volume are all at record low, while numerous self-reinforcing feedbacks are kicking in with accelerating ferocity and while further mechanisms are accelerating the temperature rise, such as high sunspots and reductions in cooling aerosols, which could lead to a huge temperature rise and an Arctic Blue Ocean Event in 2025, threatening huge amounts of methane to erupt from the seafloor — yet another feedback that comes with rising temperatures.

Ominously, very high temperature anomalies are forecast over the Arctic Ocean for November 2025. 

[ Very high temperature anomalies forecast over Arctic Ocean, click to enlarge ]

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

• Kevin Pluck - seaice.visuals.earth
https://seaice.visuals.earth

• NSIDC - What is the difference between sea ice area and extent?

https://nsidc.org/learn/ask-scientist/what-difference-between-sea-ice-area-and-extent

• Albedo, latent heat, insolation and more
https://arctic-news.blogspot.com/p/albedo.html

• Feedbacks
https://arctic-news.blogspot.com/p/feedbacks.html

• Heat flux forecast to enter Arctic early February 2025

https://arctic-news.blogspot.com/2025/01/heat-flux-forecast-to-enter-arctic-early-february-2025.html

• Danish Meteorological Institute - daily temperature Arctic
https://ocean.dmi.dk/arctic/meant80n.uk.php

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

• Arctic and Antarctic Data Archive System (ADS) of the National Institute of Polar Research of Japan
https://ads.nipr.ac.jp

• Climate Reanalyzer
https://climatereanalyzer.org

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

• Tropical Tidbits
https://www.tropicaltidbits.com

• 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

Further Confirmation Of Arctic Sea Ice Dramatic Fall

Since early April, 2016, there have been problems with the sensor on the F-17 satellite that provided the data for many Arctic sea ice images. On April 12, NSIDC issued a notice that it had suspended the provision of sea ice updates. On May 6, NSIDC announced that it had completed the shift to another satellite. The red dotted line in the image below shows data from the F-18 satellite from April 1 to May 15, 2016.

The JAXA site also provides sea ice extent images, obtaining data from a Japanese satellite. They show that Arctic sea ice extent on May 15, 2016 was 11,262,361 square km, 1.11 million square km less than it was on May 15, 2012.

The Cryosphere Today is still using data from the F17 satellite, showing some weird spikes. Albert Kallio has taken a recent image and removed faulty spikes, resulting in the image below showing sea ice area up to May 3, 2016.

[ yellow line is 2016, red line is 2015 ]

Importantly, above image confirms that Arctic sea ice in 2016 has indeed been very low, if not at its lowest for the time of the year. Especially since April 2016, sea ice has fallen far below anything we've seen in earlier years. Below, Albert elaborates on comparing data.

by Albert Kallio‎ REPAIRED USA (F-17) SATELLITE DATA SHOWS RECORD SMALL SEA ICE AREA IN MAY 2016 AGREEING JAPANESE (JAXA) DATA A corrected Special Sensor Microwave Imager and Sounder (SSMIS) data set on the Defense Meteorological Satellite Program (DMSP) F-17 satellite that provides passive microwave brightness temperatures (and derived Arctic and Antarctic sea ice products) has been corrected here for the system instrumentation error. This agrees with the Japanese JAXA curve, and has been accomplished by removal of the uncharacteristic upward 'ice growth' spikes by linear intrapolation of the corrupt data points. This reinforces the JAXA data that shows the Northern Hemisphere sea ice area is seasonally at new record low which has continued in May 2016. Smoothened F-17 curve agrees with the Japanese JAXA satellite curve. The reconciliation of the two has been accomplished by removal of the uncharacteristic upward spikes by linear intrapolation of the corrupt days' data points which incorrectly showed immense sea ice area growth in the middle of spring melt season. This reinforces the JAXA data that shows the sea ice area is seasonally at record lows. Therefore, media who are citing recent F-17 satellite sea ice area figures are intentionally distorting the facts with their claims of the Northern Hemisphere having a record sea ice area for this time of season - whereas in reality - the exact opposite has been happening.

Arctic sea ice is in a bad shape and looks set to deteriorate even further, for a number of reasons.

The year 2016 is an El Niño year, as illustrated by the 51.1°C (124.1 °F) forecast for May 22, 2016, over the Indus Valley in Pakistan (see image right).

Insolation during the months June and July is higher in the Arctic than anywhere else on Earth. Greenhouse gases are at record high levels: CO2 was 408.2 ppm on May 12, 2016, and methane levels are high and rising, especially over the Arctic.

Ocean heat is also very high and rising. The image below shows that oceans on the Northern Hemisphere were 0.93°C (or 1.7°F) warmer in the most recent 12-months period (May 2015 through April 2016) than the 20th century average.

The situation is further illustrated by the image below, using the NOAA data with a trendline added that points at a rise of 3°C (5.4°F) before the year 2040.

Chances are that Arctic sea ice will be largely gone by September 2016. As the ice declines, ever more sunlight gets absorbed by the Arctic Ocean. This is one out of numerous feedbacks that are hitting the Arctic. The danger is that, as these feedbacks start to kick in more, heat will reach the seafloor of the Arctic Ocean and trigger methane to be released in huge quantities from the Arctic Ocean seabed.

Recently, an abrupt methane release from the Arctic Ocean seafloor did enter the atmosphere over the East Siberian Sea, showing up with levels as high as 2578 ppb (at 586 mb on May 15, 2016, pm, see image below). Such abrupt releases are indications that methane hydrates are destabilizing and are warnings that climate catastrophe is waiting to happen.

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

Record Arctic Warming

On April 3rd, 2016, Arctic sea ice extent was at a record low for the time of the year, reports the National Snow and Ice Data Center (NSIDC).

The image below, created with an image from the JAXA site, gives an update on sea ice extent.

Besides sea ice extent, sea ice area is important. For more on what constitutes "ice-covered" and what is sea ice extent (versus sea ice area), see this NSIDC FAQ page.

Another measure is sea ice area. On April 2nd, 2016, Northern Hemisphere sea ice area was at a record low for the time of the year, reports the Cryosphere Today.

In 2015, there still was more sea ice area than there is now when it was half a month later (15 days) into the year. In 2012, there still was more sea ice when it was 25 days later in the year. In other words, sea ice area decline is almost one month ahead compared with the situation in 2012.

NSIDC scientist Andrew Slater has created the chart below of freezing degree days in 2016 compared to other years at Latitude 80°N. See Andrew's website and this page for more on this.

The Arctic has warmed more than elsewhere on Earth. Surface temperatures over the past 365 days were more than 2.5°C or 4.5°F higher than they were in 1981-2010.

The image below compares sea ice thickness on April 3rd for the years 2012, 2015 and 2016 (respectively the left, center and right panel).

Sea ice thickness has fallen dramatically over the years, as illustrated by the image on the right, from NSIDC, showing Arctic sea ice age for the week from March 4 to 10, from 1985 to 2016.

The high temperatures that have hit the Arctic Ocean over the past 365 days make that the outlook for the sea ice in the Arctic this year is not good.

As illustrated by the image on the right, the current El Niño is still going strong, with temperatures above 100°F recorded in three continents.

The year 2016 is already shaping up as the warmest year on record by far.

Temperatures look set to soar over the coming months, over the Northern Hemisphere at large and over the Arctic in particular.

The image below shows that over a 90-day period from January 13, 2016, to April 11, 2016, most of the Arctic Ocean was more than 6°C (10.8°F) warmer than 1981-2011.

The DMI image below shows recent melting in Greenland up to April 11, 2016. Maps in the left panel show areas where melting has taken place on April 10 and April 11, 2016. The chart in the right panel shows 2016 melting (blue line), against the 1990-2013 average (the vertical axis reflects the percentage of the total area of the ice where the melting occurred).

As a recent study confirms, ice sheets can contain huge amounts of methane in the form of hydrates and free gas. Much methane can escape due to melting and fracturing during wild weather swings.

Rapid melting on Greenland looks set to continue. The forecast for April 12, 2016 (0000 UTC), on the right shows temperature anomalies at the top end of the scale (20°C or 36°F) over most of Greenland and Baffin Bay, while the Arctic as a whole is hit by a temperature anomaly of over 5°C (over 9°F), compared to 1979-2000.

Furthermore, ocean temperatures are currently very high. These high temperatures, together with the poor condition of the sea ice, make that chances are that the sea ice will be largely gone by September 2016.

[ click on images to enlarge them ]

The image on the bottom right shows sea surface temperature anomalies above Latitude 60°N on April 4, 2016.

The image below shows that, on April 7, 2016, sea surface in the Barents Sea was as warm as 10.1°C or 50.2°F, an anomaly of 9.4°C or 16.9°F from 1981-2011 (at the location marked by the top right green circle), while there were anomalies as high as 11.3°C or 20.3°F off the coast of North America (green circle bottom left).

The white line shows the approximate path of the cold exit current, while the red line shows the approximate path of the warm entry current.

The high temperatures in the Barents Sea give an indication of the ocean heat traveling toward the Arctic Ocean, while the high temperature anomalies off the east coast of North America give an indication of the heat that is building up there. Much of this heat will make its way to the Arctic Ocean over the coming months

April 11, 2016: SST anomalies as high as 11.6°C or 20.8°F

In the Pacific, sea surface temperature anomalies from 1981-2011 were as high as 11.6°C or 20.8°F near Japan on April 11, 2016 (see image right), giving a further indication of the huge amount of additional heat that there now is in oceans on the Northern Hemisphere. The prospect is that temperatures will rise over the next few months to levels even higher than they were last year (see earlier post on temperatures in June 2015).

Sea ice acts as a buffer, absorbing heat and keeping the temperature of the water at freezing point. Without such a buffer, further heat will instead make that the temperature of the water will rise rapidly. Furthermore, less sea ice means that less sunlight gets reflected back into space and more sunlight instead gets absorbed by the Arctic Ocean.

These are just some of the many feedbacks that accelerate warming in the Arctic. Warm water reaching the seafloor of the Arctic Ocean can penetrate sediments that can contain huge amounts of methane in the form of hydrates and free gas, triggering abrupt release of methane in gigantic quantities, escalating into runaway warming, and subsequent destruction and extinction at massive scale.

On a 10-year timescale, the current global release of methane from all anthropogenic sources already exceeds all anthropogenic carbon dioxide emissions as agents of global warming; that is, methane emissions are more important than carbon dioxide emissions for driving the current rate of global warming.

Above image shows that growth in methane levels has been accelerating recently; a trendline points at a doubling of methane levels by the year 2040. Unlike carbon dioxide, methane's GWP does rise as more of it is released. Methane's lifetime can be extended to decades, in particular due to depletion of hydroxyl in the atmosphere.

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

Albert Kallio comments: 
More could have been added from the last National Snow and Ice Data Center (NSIDC) Arctic sea ice report for March, the general outlook for massive sea ice loss because the near-all-time record low marine snow and ice cover is coinciding with near-all-time record low terrestrial snow cover. NSIDC forecast that due to dark surfaces being so high, this easily leads to loss of sea ice. In fact, 2016 situation is even worse that it was previous record loss 2012 when snow cover was much larger. Same in 2007 when the sea ice area was slighly smaller, there was much larger terrestrial snow cover. Furthermore, neither 2007 nor 2012 occurred during strong El Nino like 1998. El Nino 2015-2016 is the strongest ever, also accompanied by the very warm Indian Ocean, Atlantic Ocean, and Southern Ocean around Antarctica. At times Antarctic sea water temperatures were also high leading to second smallest Austral summer sea ice at one point. Sea ice area also around Antarctica has been smaller than average most of time, despite increased melt water and reduced salinity - due to high temperatures. All these additional factors should be added into your conclusions without forgetting to mention that the added heat in the earth system is ripping the Polar Vortex apart as the jet streams have started to blend into other irregular atmospheric wind patters. Note also the increased flow of sea ice through the Fram Strait due to lowered spatial viscosity of sea ice that also results from larger wave action, vertical mixing of ocean by wind, thinner sea ice breaking easier apart and collapsing into pack ice, as well as being mostly seasonal ice (containing trace amounts of salts that make the chemical bounds in ice crystals weaker and fragile and melting easier), May be you can update and rejoice on NSIDC's March 2016 report noting all the points therein..

Arctic sea ice remains at a record low for time of year

For the time of year, Arctic sea ice remains at a record low since satellite records started in 1979, both for area and extent. The image below shows Arctic sea ice area up to February 12, 2016, when area was 12.49061 million square km.

The image below shows Arctic sea ice extent up to February 12, 2016, when extent was 14.186 million square km.

The reason for the record low sea ice is that there is more ocean heat than there used to be. The image below shows that on February 12, 2016, the Arctic Ocean sea surface temperature was as warm as 11.3°C (52.4°F) at a location near Svalbard marked by the green circle, a 10.4°C (18.7°F) anomaly.

The reason for this is that the water off the east coast of North America is much warmer than it used to be.

The Gulf Stream is pushing heat all the way into the Arctic Ocean.

The image below shows that on February 14, 2016, sea surface temperature anomalies (compared to 1981-2011) off the east coast of North America were was as high as 10.1°C or 18.1°F (at the location marked by the green circle).

While sea surface looks cooler (compared to 1981-2011) over a large part of the North Atlantic, an increasing amount of ocean heat appears to be traveling underneath the sea surface all the way into the Arctic Ocean, as discussed at this earlier post.

This spells bad news for the sea ice in 2016, since El Niño is still going strong. Temperatures in January 2016 over the Arctic Ocean were 7.3°C (13.1°F) higher than in 1951-1980, according to NASA data, as illustrated by the graph on the right.

See the Controversy page for discussion

A polynomial trend added to the January land temperature anomaly on the Northern Hemisphere since 1880 shows that a 10°C (18°F) rise could eventuate by the year 2044, as illustrated by the graph on the right. Over the Arctic Ocean, the rise can be expected to be even more dramatic.

As the NASA map below illustrates, the global January 2016 land-ocean temperature anomaly from 1951-1980 was 1.13°C (or over 2°F) and the heat did hit the Arctic Ocean stronger than elsewhere.

In January 2016, it was 1.92°C (3.46°F) warmer on land than in January 1890-1910. Before 1900, temperature had already risen by ~0.3°C (0.54°F), which makes it a joint 2.22°C (4°F) rise. On the Northern Hemisphere, the rise on land was the most profound, with over 10°C (18°F) warming occurring at the highest latitudes.

Meanwhile, methane levels as high as 2539 parts per billion (ppb) were recorded on February 13, 2016, as illustrated by the image below.

The danger is that, as the Arctic Ocean keeps warming, huge amounts of methane will erupt abruptly from its seafloor.

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

Update: Arctic sea ice extent keeps falling. Last year (2015), maximum sea ice extent was reached on February 25. Could it be that maximum extent for this year was already reached on February 9, 2016? The image below illustrates this question. discussed further at the Arctic News group.

discuss this further at the Arctic News group

Arctic sea ice extent keeps falling. Last year (2015), maximum sea ice extent was reached on February 25. Could it be...
Posted by Sam Carana on Monday, February 15, 2016

Arctic sea ice area at record low for time of year

Arctic sea ice area on January 28, 2016, was only 12.17902 million square km. At this time of year, sea ice area hasn't been as low as this for at least since satellite records started in 1979, as illustrated by the image below.

based on image from: arctic.atmos.uiuc.edu/cryosphere/arctic.sea.ice.interactive.html

Furthermore, on January 29, 2016, Arctic sea ice reached its second lowest extent since the satellite records began, as the image below shows.

based on image from: nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph

Why is sea ice at record low?

The sea ice is in a bad shape due to very high temperatures. A forecast for January 30, 2016, shows surface temperatures over the Arctic that are 2.7°C (4.86°F) warmer than they were in 1979-2000. The image below further illustrates this, showing temperature anomalies at the top end of the scale, i.e. 20°C (36°F) above 1979-2000, in many places in the Arctic.

At this time of year, there is very little sunshine in the Arctic. Therefore, these anomalies are caused by sea water that is warmer than it used to be. The image below shows that on January 24, 2016, sea surface temperature was 12.3°C (54.2°F) at a location near Svalbard marked by the green circle, a 10.4°C (18.7°F) anomaly.

Such anomalies are in turned caused by water that is much warmer than it used to be, and that is being carried by the Gulf Stream all the way into the Arctic Ocean.

Water much warmer off the North American coast

The water off the coast of North America is much warmer than it used to be due to emissions that extend from North America over the Atlantic Ocean due to the Coriolis effect. The image below, from an earlier post, shows carbon dioxide levels as high as 511 ppm over New York on November 5, 2015, and as high as 500 ppm over the water off the coast of coast of New Jersey on November 2, 2015.

from the post: 2015 warmest year on record

As discussed at an earlier post, also relevant are other emissions such as carbon monoxide that depletes hydroxyl, making it harder for methane to be oxidized. Below is an update on carbon monoxide levels.

These emissions heat up the Gulf Stream and make that ever warmer water is carried underneath the sea surface all the way into the Arctic Ocean, while little heat transfer occurs from ocean to atmosphere, due to the cold freshwater lid on the North Atlantic.

Arctic sea ice in uncharted territory

Update 1: For the time of the year, Arctic sea ice is now at a record low since satellite records started in 1979, both for area and extent. The image below shows Arctic sea ice area up to February 1, 2016, when area was 12.27298 million square km.

based on image from: arctic.atmos.uiuc.edu/cryosphere/arctic.sea.ice.interactive.html

The image below shows Arctic sea ice extent up to February 2, 2016, when extent was 13.932 million square km.

based on image from: nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph

Update 2: For the time of the year, Arctic sea ice remains at a record low since satellite records started in 1979, both for area and extent. The image below shows Arctic sea ice area up to February 4, 2016, when area was 12.30656 million square km.

[ click on image to enlarge ]

Comprehensive and effective action is needed

This situation spells bad news for what will happen later in 2016, also given the current El Niño. Less sea ice means that less sunlight is reflected back into space, resulting in more heat being absorbed by the Arctic Ocean.

As more heat reaches the bottom of the Arctic Ocean, the risk increases that heat will penetrate and destabilize sediments containing methane hydrates. Methane escaping from hydrates could strongly accelerate warming in the Arctic, causing further melting of the sea ice, in a spiral of warming that could escalate into runaway warming.

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


Related posts

- Why America should lead on climate
arctic-news.blogspot.com/2016/01/why-america-should-lead-on-climate.html

- Sea surface warmest on record
arctic-news.blogspot.com/2015/10/september-2015-sea-surface-warmest-on-record.html

- Climate Plan
arctic-news.blogspot.com/p/plan.html

- 2015 warmest year on record
arctic-news.blogspot.com/2015/12/2015-warmest-year-on-record.html

Arctic sea ice area on January 28, 2016, was only 12.17902 million square km. At this time of year, sea ice area hasn't...
Posted by Sam Carana on Sunday, January 31, 2016