Arctic News: path

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Sunday, June 14, 2020

Fast Path to Extinction

[ click on images enlarge ]

May 2020 was the hottest May on record, the third monthly record in the year to date, even though there was no El Niño in 2020 (yet). An El Niño event later in 2020, combined with further warming elements, such as loss of the aerosol masking effect due to COVID-19 lockdowns, could trigger a huge temperature rise, as the red trend illustrates. The year 2020 looks set or close to become the hottest on record, as illustrated by the blue trend that points at a continuing rise reaching 3°C by 2026, i.e. likely driving humans into extinction.

The May 2020 ocean temperature anomaly on the Northern Hemisphere was 0.94°C or 1.67°F higher than the 20th century average, the highest May anomaly on record.

The latent heat tipping point threatens to be crossed as ocean temperature anomalies on the Northern Hemisphere reach 1°C above the 20th century average, in turn threatening the methane hydrates tipping point to get crossed, i.e. as ocean temperature anomalies on the Northern Hemisphere become higher than 1.35°C above the 20th century average.

Arctic sea ice is getting very thin and, at this time of year, it is melting rapidly from below, due to the rising temperature of the Arctic Ocean. The sea ice underneath the surface of the Arctic Ocean is disappearing rapidly, due to the influx of warm and salty water from the Atlantic Ocean and the Pacific Ocean.

Sea surface temperature anomalies from the 20th century on the Northern Hemisphere in °C.
Yellow circles are anomalies for the month May, red circles are anomalies for other months.

An earlier analysis indicates that the latent heat tipping point threatens to get crossed as ocean temperature anomalies on the Northern Hemisphere reach 1°C above the 20th century average. As above image indicates, the tipping point was briefly crossed before, but this year it looks set to get crossed irreversibly.

At that point, there will be little or no Arctic sea ice left underneath the sea surface all year long, so the sea ice has lost most of its capacity to act as a buffer to consume further heat arriving from the Atlantic Ocean and the Pacific Ocean.

Arctic sea ice volume has been at record low for almost all of 2020 to date, while 2019 volume was at a record low from October, making that volume has been at record low for almost 8 months straight.

Crossing the latent heat tipping point means that huge amounts of incoming heat will get absorbed by the Arctic Ocean, instead of getting consumed by the melting of sea ice, as was previously the case.

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.

There is ever less sea ice left underneath the surface to absorb ocean heat, and the amount of energy that used to be absorbed by melting ice is as much as it takes to heat an equivalent mass of water from zero to 80°C.

Meanwhile, global heating continues and more than 90% of global heating is going into oceans.

As discussed in an earlier post, the loss of subsurface sea ice is only one of ten tipping points hitting the Arctic. As the temperature of the oceans keeps rising, more heat will reach sediments at the seafloor of the Arctic Ocean that contain vast amounts of methane, as discussed in this page and this post. The danger is that this heat will destabilize the ice and the hydrates, resulting in huge releases of methane. The methane hydrates tipping point threatens to get crossed as ocean temperature anomalies on the Northern Hemisphere become higher than 1.35°C above the 20th century average, which threatens to occur early next year.