Originally published on

by at Arctic News

Blue Ocean Event

[ from Blue Ocean Event ]

A Blue Ocean Event occurs when virtually all sea ice disappears and the surface color changes from white (sea ice) to blue (ocean). According to many, a Blue Ocean Event starts once Arctic sea ice extent falls below 1 million km².

The image on the right shows a trend pointing at zero Arctic sea ice volume by September 2027.

Note that the volume data in the image are averages for the month September ⁠— the minimum for each year is even lower. Furthermore, since zero volume implies zero extent, this indicates that a Blue Ocean Event (extent below 1 million km²) could happen well before 2027.

Sea ice concentration
Another measure than sea ice extent or  volume is sea ice concentration. The image below, adapted from University of Bremen, shows sea ice concentration on July 22, 2022, with concentration in many areas close to the North Pole down to 0%. 

Sea ice thickness and NASA Worldview satellite images

The NASA Worldview satellite images below give a good idea of how much sea ice is still present in the Arctic, or how little, especially north of the North Pole. 

The Naval Research Laboratory one-month animation below shows Arctic sea ice thickness up to July 16, 2022, with 8 days of forecasts added. 

The above animation shows a dramatic fall in sea ice thickness over a large area. This fall in thickness is mostly due to warm water from the Atlantic Ocean that is melting the sea ice hanging underneath the surface. This is where the sea ice constitutes the latent heat buffer, consuming incoming heat in the process of melting.

The University of Bremen combination image below shows the difference in sea ice thickness between June 1, 2022, June 30, 2022, and July 22, 2022. The images at the center and on the right show large areas where sea ice is less than 20 cm thick, indicating that the latent heat buffer had already disappeared in June 2022,  as also discussed further below. 


The NASA Worldview combination image below shows the sea ice north of Greenland on July 19, 2022 (top), and on July 22, 2022, illustrating that even at places where the sea ice was the thickest, it can disappear rapidly.

As thick ice breaks off and fragments, it gets heat up more from the sides, accelerating the melting. 

Ocean heat
Of the extra heat from Earth’s energy imbalance, about 93% ends up in the ocean as increasing ocean heat content (see image below), 3% goes into melting ice, 4% goes into raising temperatures of land and melting permafrost, and less than 1% remains in the atmosphere, as discussed in an earlier post.

[ from earlier post ]
Sea ice has disappeared in the Bering Strait, in part due to warm water from rivers in Alaska, as illustrated by the NOAA image below, which shows sea surface temperatures as high as 18.6°C or 65.48°F.

On July 19, 2022, the sea surface temperature anomaly from 1981-2011 in the Arctic Ocean was as high as 14.0°C or 25.2°F (at green circle), as illustrated by the screenshot below of a nullschool.net image (with text added). In 1981-2011, the sea surface temperature at this spot (green circle) at this time of year in the Kara Sea was around freezing point.

The above image also shows a distorted Jet Stream (at 250 hPa) moving over the Arctic ocean, instead of circumventing the Arctic and thus keeping heat out of the Arctic and keeping cold inside the Arctic, as it used to be.  
The above NOAA image illustrates how the Gulf Stream is pushing warm water toward the Arctic, with sea surface temperatures in the North Atlantic reaching as high as 32.2°C or 89.96°F on July 20, 2022.
Latent heat

Latent heat is heat that is (less and less) going into melting the sea ice. The reason this heat is called latent (hidden) heat, is that it doesn’t raise the temperature of the water, but instead gets consumed in the process of melting the ice. Latent heat is energy associated with a phase change, such as the energy consumed when solid ice turns into water (i.e. melting). 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.

Once most of the sea ice that was hanging underneath the surface is gone, further heat will still keep moving underneath the sea ice from the Atlantic Ocean and – to a lesser extent – from the Atlantic Ocean into the Arctic Ocean. Without the latent heat buffer, this heat must go elsewhere, i.e. it will typically raise the temperature of the water. The atmosphere will also warm up faster. More evaporation will occur once the sea ice is gone, further warming up the atmosphere.
A 2019 analysis concludes that the latent heat tipping point gets crossed when the sea surface temperature anomaly on the Northern Hemisphere gets higher than 1°C above 20th century’s temperature and when there is little or no thick sea ice left. As the image below indicates, the temperature anomaly of 1°C above the 20th century average looks set to be crossed in the course of the year 2021.

As the Latent Heat Tipping Point gets crossed, there may still be a thin layer of ice at the surface, at least as long as air temperatures are low enough to keep it frozen and as long as strong winds haven’t pushed the sea ice out of the Arctic Ocean. This thin layer of ice will still consume some ocean heat below the surface, but at the same time it acts as a seal, preventing heat from the Arctic Ocean to enter the atmosphere. Even if a lot of sea ice remains, the situation is dangerous, if not even more dangerous. The continuing La Niña could cause a lot of thin sea ice to remain at the surface of the Arctic Ocean this year. The more sea ice remains, the less ocean heat can be transferred from the Arctic Ocean to the atmosphere over the Arctic Ocean, which means that more heat remains in the Arctic Ocean.

One huge danger is that, as the buffer disappears that until now has consumed huge amounts of ocean heat, more heat will reach methane hydrates at the seafloor of the Arctic Ocean, causing them to get destabilized and resulting in releases of methane from these hydrates and from free gas underneath that was previously sealed by the hydrates.

As the latent heat buffer of the sea ice underneath the surface disappears, more of this heat could then reach sediments at the seafloor of the Arctic Ocean, threatening eruptions to occur of seafloor methane (from hydrates and from free gas underneath the hydrates). The methane could similarly push up temperatures dramatically over the Arctic, and globally over the next few years.

[ feedback #14: Latent Heat ]

The above 2014 image, from the feedbacks page, shows three of the numerous feedbacks that are accelerating warming in the Arctic. Feedback #1 is the albedo feedback. Feedback #14 refers to the loss of the Latent Heat Buffer and warming of the Arctic Ocean. Feedback #2 refers to methane releases.

Heatwaves look set to continue on the Northern Hemisphere, extending heat over the Arctic Ocean and thus affecting Arctic sea ice from above, while warm water from rivers will cause more melting at the surface, and while rising ocean heat will continue to cause more melting of the ice underneath the surface. If this continues, we can expect a new record low for sea ice in September 2022 and the joint loss of the latent heat buffer and the loss of albedo could push up temperatures dramatically over the Arctic, while the additional methane could similarly push up temperatures dramatically over the Arctic, and globally over the next few years.

[ The Buffer has gone, feedback #14 on the Feedbacks page ]

Conclusion

In conclusion, temperatures could rise strongly in the Arctic soon, due to sea ice loss in combination with an upcoming El Niño and a peak in sunspots, with the potential to drive humans extinct as early as in 2025, while temperatures would continue to skyrocket in 2026, making it in many respects rather futile to speculate about what will happen beyond 2026. At the same time, the right thing to do now is to help avoid the worst things from happening, through comprehensive and effective action as described in the Climate Plan.

Links

• Blue Ocean Event
https://arctic-news.blogspot.com/p/blue-ocean-event.html

• Naval Research Laboratory
https://www7320.nrlssc.navy.mil/GLBhycomcice1-12/arctic.html

• University of Bremen
https://seaice.uni-bremen.de/databrowser

• NASA Worldview satellite
https://worldview.earthdata.nasa.gov

• NOAA – sea surface temperature

• Human Extinction by 2025?