Arctic News: Arctic Ocean November 2019

On November 16, 2019, there was little sea ice between Greenland and Svalbard. For reference, the image below has been added, showing coastlines for the same area.

The image on the right shows that the average air temperature (2 m) on November 15, 2019, was 4°C higher over the Arctic than during 1979-2000.
Ocean heat is rising up from the Arctic Ocean, while a wavy jet stream enables cold air to leave the Arctic and descend over North America and Eurasia. On November 13, 2019, it was warmer in Alaska than in Alabama.

The image below shows temperatures north of 80°N. The red line on the image shows the 2019 daily mean temperature up to November 16, 2019. The temperature is now well above the 1958-2002 mean (green line). The image also shows the freezing point of fresh water (273.15K, 0°C or 32°F, blue line).

The freezing point for salt water is lower, at around -2°C, or 28.4°F, or 271.2°K. In other words, a rise in the salt content of the water alone can make ice melt, i.e. even when the temperature of the water doesn't rise.

The image below shows that Arctic sea ice volume has been at record low levels for the time of year for some time.

As the image below shows, Arctic sea ice extent in the Chukchi Sea is currently very low.

[ image by Zack Labe, uploaded November 13, 2019 ]

Oceans are absorbing more than 90% of global heating, as illustrated by the image below.

Arctic sea ice used to absorb 0.8% of global heating (in 1993 to 2003). Ocean heat keeps flowing into the Arctic Ocean, carried by ocean currents, as illustrated by the image below.

As peak heat arrives in the Arctic Ocean, it melts sea ice from below. In Summer 2019, a critical tipping point was crossed; ocean heat could no longer find further sea ice to melt, as the thick sea ice that hangs underneath the surface had disappeared. A thin layer of sea ice at the surface was all that remained, as air temperatures remained low enough to prevent it from melting from above.

This indicates that the buffer has gone that has until now been consuming ocean heat as part of the melting process. As long as there is sea ice in the water, this sea ice will keep absorbing heat as it melts, so the temperature will not 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.

The images above and below shows very high sea surface temperature anomalies on the Northern Hemisphere for October 2015 and October 2019. In both cases, anomalies of 1.09°C or 1.96°F above the 20th century average were recorded.

The October 2015 anomaly occurred under El Niño conditions, whereas the equally-high anomaly in October 2019 occurred under El Niño/La Niña-neutral conditions, while another El Niño is likely to come in 2020. In other words, the threat is that even more ocean heat is likely to arrive in the Arctic Ocean in 2020.

The danger is particularly high in October, as Arctic sea ice starts growing in extent at the end of September, thus sealing off the water, meaning that less ocean heat will be able to escape to the atmosphere. This increases the danger that hot water will reach sediments at the Arctic Ocean seafloor and trigger massive methane eruptions.

Concentrations of carbon dioxide (CO₂, 407.8 ppm), methane (CH₄, 1869 ppb) and nitrous oxide (N₂O, 331.1 ppb) in 2018 surged by higher amounts than during the past decade, the WMO said in a recent news release and as illustrated by the image on the right, which shows that CH₄, CO₂ and N₂O levels in the atmosphere in 2018 were, respectively, 259%, 147% and 123% of their pre-industrial (before 1750) levels.

“There is no sign of a slowdown, let alone a decline, in greenhouse gases concentration in the atmosphere despite all the commitments under the Paris Agreement on Climate Change,” said WMO Secretary-General Petteri Taalas.

“It is worth recalling that the last time the Earth experienced a comparable concentration of CO2 was 3-5 million years ago. Back then, the temperature was 2-3°C warmer, sea level was 10-20 meters higher than now,” said Mr Taalas.

Global methane levels are very high. Mean global methane levels were as high as 1914 parts per billion on September 3, 2019, as discussed in a recent post. Peak methane levels as high as 2961 parts per billion were recorded by the MetOp-2 satellite on October 24, 2019, in the afternoon at 469 mb.

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

In the video below, Paul Beckwith discusses Arctic sea ice.

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Sunday, November 17, 2019

Arctic Ocean November 2019