Will there be Arctic sea ice left in September 2023?

The above image is from a recent analysis by Karina von Schuckmann et al. and shows that the Earth is heating up, as outgoing radiation is suppressed. More and more extra heat is kept captive on Earth and gets stored mainly in oceans (89%), with smaller proportions getting stored on land (6-5%), in the cryosphere (4%) and in the atmosphere (1-2%). The image also shows another change: 1% more heat gets stored in the atmosphere while 1% less gets stored on land for the period going back to 1971, compared to the period going back to 2006.

What could cause that change? Most heat on land is stored in the ground (90 %), with inland water bodies accounting for 0.7 % and permafrost thawing accounting for 9 %. This raises fears that water that was previously present in the ground, is increasingly moving into the atmosphere, as a warming atmosphere holds more water vapor (7% more water vapor for every 1°C warming).

An atmosphere that sucks up more water vapor increases the atmospheric vapor pressure deficit (VPD). A 2019 study warns that increased VPD reduces global vegetation growth: “VPD greatly limits land evapotranspiration in many biomes by altering the behavior of plant stomata. Increased VPD may trigger stomatal closure to avoid excess water loss due to the high evaporative demand of the air. In addition, reduced soil water supply coupled with high evaporative demand causes xylem conduits and the rhizosphere to cavitate (become air-filled), stopping the flow of water, desiccating plant tissues, and leading to plant death. Previous studies reported that increased VPD explained 82% of the warm season drought stress in the southwestern United States, which correlated to changes of forest productivity and mortality. In addition, enhanced VPD limits tree growth even before soil moisture begins to be limiting.”  

More water vapor in the atmosphere further amplifies the temperature rise, since water vapor is a potent greenhouse gas and it also constitutes a tipping point, the Land Evaporation Tipping Point, that gets crossed when water will no longer be available locally for further evapotranspiration from the soil and vegetation, with the rise in land surface temperatures accelerating accordingly. 

Loss of ice constitutes several further tipping points. About a quarter of the 4% heat consumed by the cryosphere goes into melting glaciers. Disappearance of glaciers could be coined the Glaciers Tipping Point, since from that point heat can no longer go into melting the glacier and will instead go elsewhere. 

Similarly, about a quarter of the 4% heat consumed by the cryosphere goes into melting Arctic sea ice. Loss of Arctic sea ice also constitute a  tipping point, since incoming heat will from that point on instead go into the Arctic. 

So, will there be Arctic sea ice left in September 2023?  Current conditions make that the outlook is grim. 

[ click on images to enlarge ]

The image on the right, adapted from NOAA, shows ocean heat moving toward the Arctic along the path of the Gulf Stream.

Vast amounts of ocean heat are moving toward the Arctic, especially in the North Atlantic, threatening to cause rapid and massive melting of Arctic sea ice and thawing of permafrost. 

As discussed in a recent post, the world sea surface temperature (between 60°South and 60°North) has been at 21°C or higher for as many as 38 days. Such temperatures are unprecedented in the NOAA record that goes back to 1981. 

The images above and below show the situation up to May 8, 2023. 

Arctic sea ice is still extensive, but sea ice concentration is already getting lower in many places, as illustrated by he image on the right. 

As illustrated by the satellite image below, adapted from NASA Worldview, the sea ice has many cracks and there is open water in the Beaufort Sea. 

Conditions are dire, i.e. greenhouse gas levels are high, an El Niño is on the way and sea surface temperatures are high, all contributing to the threat of Arctic sea ice loss.

On top of that, there are developments that could make things even worse. Loss of Arctic sea kice comes with loss of the latent heat buffer and loss of albedo that threaten to trigger subsequent eruptions of methane from the seafloor of the Arctic Ocean, as has been described many times before, such as in this post, in this post and in this post.

Consequently, a huge temperature rise threatens to unfold soon.

An earlier post discussed the Terrestrial Biosphere Temperature Tipping Point, coined in a recent study finding that at higher temperatures, respiration rates continue to rise in contrast to sharply declining rates of photosynthesis, which under business-as-usual emissions would nearly halve the land sink strength by as early as 2040.

A 2021 study on oceans finds that, with increased stratification, heat from climate warming less effectively penetrates into the deep ocean, which contributes to further surface warming, while it also reduces the capability of the ocean to store carbon, exacerbating global surface warming. An earlier analysis warns about growth of a layer of fresh water at the surface of the North Atlantic resulting in more ocean heat reaching the Arctic Ocean and the atmosphere over the Arctic, while a 2023 study finds that growth of a layer of fresh water decreases its alkalinity and thus its ability to take up CO₂, a feedback referred to as the Ocean Surface Tipping Point.