Warm waters entering the Arctic

Gulf Stream brings ever warmer water into Arctic Ocean

Arctic News,

11 June, 2015

The image below shows sea surface temperature anomalies in the Arctic as at June 9, 2015.

The image below shows the Arctic from a 180° rotated angle, while also showing the high sea surface temperature anomalies that are so prominent in the North Pacific (note also that the scale of sea surface temperature anomalies differs).



One may wonder why sea surface temperature anomalies below zero are visible in the North Atlantic, given that ocean heat is rising rapidly. As the IPCC said in AR5, more than 60% of the net energy increase in the climate system is stored in the upper ocean (0–700 m) during the relatively well-sampled 40-year period from 1971 to 2010, and about 30% is stored in the ocean below 700 m.

The image below further pictures the situation as at June 9, 2015, with large blue and purple areas showing in the North Atlantic where meltwater from the Arctic has spread over the years.



Indeed, the accumulation of meltwater over the past few years has created a huge area with relatively cold water that tends to float at the surface, rather than sink, as the meltwater's salt content is very low.

In other words, the ocean underneath the meltwater at the sea surface is much warmer than the temperatures shown on above images. This can be illustrated by the situation near Svalbard. The image below shows the depth of Barents Sea, which is relatively shallow around Svalbard,

As the image shows, cold meltwater with low salt content floats around Svalbard where the water is most shallow. A 'polar front' separates cold and warm water, following the borders of the area where the seafloor is high. Warm, salty water is carried by the Gulf Stream from the (much deeper) Atlantic Ocean into the Arctic Ocean. This warm water collides with cold water east of Svalbard where the seafloor rises steeply, making this warm water come to the surface. 

Warm water from the Atlantic also comes to the surface west of Svalbard, where warm and cold water are similarly separated by the height of the seafloor. 

The image below shows that on June 8, 2015, sea surface temperatures as high as 11.4°C (52.52°F) were recorded to the south-east of Svalbard (a 9.8°C or 17.64°F anomaly), while sea surface temperatures as high as 7.4°C (45.32°F) were recorded to the west of Svalbard (a 3.5°C or 6.3°F anomaly). 

Sea surface temperatures (top) and sea surface temperature anomalies (bottom) on June 8, 2015.

These spots where warm water comes to the surface give an indication of how high temperatures of the water are below the surface. As more than 90% of the extra heat caused by people's emissions continues to go into oceans, ever warmer water will be carried by the Gulf Stream into the Arctic Ocean, with the danger that this will warm up sediments under the Arctic Ocean seafloor, triggering huge methane eruptions with gigantic warming potential.

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