Sunday, May 21, 2017

Arctic Warming - Update May 2017

The image below illustrates how much and how fast oceans are warming on the Northern Hemisphere.
Trend points at 1.5°C warmer NH oceans in 2025. Shaded area covers seasonal fluctuations and natural variability.
As ocean warming continues, prospects for the sea ice in the Arctic are grim.

Warmer water is melting the sea ice from below. The image on the right shows ever less sea ice volume in the Arctic, reflecting huge thinning of the sea ice over the years.

As the sea ice gets thinner, it becomes ever more prone to break up in pieces that will melt quicker (as more surface area becomes exposed to heat from the atmosphere and heat from the water).

[ images from: Arctic Sea Ice May 2017 ]
Moreover, with more open water, stronger waves and winds can develop, increasing the chances that sea ice will melt and get pushed out of the Arctic Ocean.

El Niño looks set to strike again this year and the Arctic looks set to be hit much stronger than the rest of the world, as illustrated by the image on the right. The images below show updated indications for El Niño 2017.

Above on the right is a NOAA animation showing a Kelvin Wave forming in the Equatorial Pacific. The image on the left is the most recent frame from this animation.

[ click on images to enlarge ]
Above image shows ECMWF (European Centre for Medium-Range Weather Forecasts) plumes with strong positive anomalies in all three El Niño regions (image on right shows location of regions).

In other words, temperatures in 2017 look set to be very high, which spells bad news for the Arctic where temperature anomalies are already several times higher than in the rest of the world.

As a reminder, take February 2016.
Globally, it was 1.65°C warmer then, compared to 1890-1910, as shown on the inset of the image on the right.

Anomalies in the Arctic were even higher. As the main image on the right shows, it was around 6°C warmer at latitudes north of 70°N.

Note that insufficient data were available to include latitudes north of 85°N in the analysis, as also indicated by the grey areas on the image.

To get  an idea of the situation north of latitude 80°N, have a look at the image on the right, by Nico Sun, showing freezing degree days anomaly over the years, compared to the 1958 - 2002 mean temperature.

Warming looks set to strike the Arctic even harder and high levels of greenhouse gases over the Arctic are contributing to this.

The Scripps image below illustrates this, showing that carbon dioxide levels at Mauna Loa are now well above 410 ppm.
The image on the right shows carbon dioxide levels on May 18, 2017. The color indicates that the highest levels were present over the Arctic.

Temperature anomalies in the Arctic have already been the highest in the world for years, as also illustrated by the NOAA image below on the right, showing temperature anomalies above 2.5°C over the Arctic Ocean over the  365-day period up to May 18, 2017.

[ click on images to enlarge ]
There is a huge danger that temperatures will accelerate very rapidly in the Arctic, as self-reinforcing feedbacks are starting to kick in with greater force.

This applies in particular to feedbacks associated with loss of snow and ice cover in the Arctic and to methane releases from clathrates contained in sediments at the seafloor of the Arctic Ocean.

The latter danger is also illustrated by the images below, showing the (lack of) sea ice in the ESAS and the Bering Strait. The image underneath shows the temperature anomaly of water.

[ click on images to enlarge ]
Above NASA satellite image below shows the (lack of) sea ice in the ESAS and in the Bering Strait. The image below shows temperature anomaly of the water. In the ESAS, the water was 2.8°C or 5.1°F warmer on May 19, 2017, compared to 1981-2011.

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

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