Major arctic warming event predicted for the coming week robertscribbler v gashi 2013


It’s been consistently, abnormally, warm in the Arctic for about as long as any of us can remember. But during recent years, the changes — caused by a massive and ongoing accumulation of heat-trapping gasses in the Earth’s atmosphere — appear to be speeding up.

This week, two major warm air invasions — one issuing from Siberia and another rising up through the Fram Strait and extending north of Greenland are expected to bring locally 10-20 C above normal temperatures and accelerate early season sea ice melt in an already reeling Arctic.

The farthest north region of our world has just come out of a winter during which sea ice extents consistently entered never before seen daily low ranges. With the advent of spring, sea ice measures have rebounded somewhat from winter record lows. However, according to Japan’s Polar Research Division, we are presently experiencing the second lowest daily sea ice extents since consistent measurements began. Meanwhile, Greenland during April saw an odd early bump in surface melt.

Much of the heating action this year has occurred over the Bering and Chukchi seas — which have never seen so much ice lost. Already sea ice is greatly reduced through these regions. Open water extends far into the Chukchi — onward and north of Barrow, Alaska. Still further into regions in which sea ice is typically rock-solid during this time of year, the Beaufort is experiencing its own late April break-up. But the areas that are expected to see the greatest warming over the coming days run closer to Siberia and the Atlantic.

Today, a wedge of above-freezing air is invading the Laptev Sea north of Central Siberia. Strong southerly winds issuing from Central Asia are running north into the Arctic Ocean. They bring with them 10 to 20 C above average temperatures for this time of year — which is enough to push readings as high as 35 degrees F (2 C) over what during the 20th Century would have been a solid fringe of the polar ice cap.

(5-Day forecast maximum temperatures show considerable warm air invasions proceeding throughout the Arctic. In many cases, temperatures near the North Pole will be warmer than regions far to the south. An impact of the warming world ocean on the Arctic environment. Image source: Climate Reanalyzer.)

But the main warming event for the Arctic this week will occur in the region of the Fram Strait east of Greenland. A strong low pressure system near Iceland is expected to drive wave after wave of much warmer than normal air north into the Arctic. This warm air thrust will bring with it temperatures in some places that exceed 20 C above average. Overall, Arctic Ocean basin temperatures are expected to average more than 2.3 C warmer than normal for the entire first week of May. Such high temperature departures are particularly notable for this time of year — as Arctic thermal variance tends to moderate during spring and summer.

The system will push above freezing temperatures deep into the Arctic — generating a repeat of the strange flip-flop that has become so common recently where temperatures near the North Pole are much warmer than readings further south. Warmer than freezing temperatures will also over-ride coastal portions of northeastern Greenland in yet another odd aspect of the event.

Warm storm effects including gale force winds and waves of 8-12 feet will provide added effect to above freezing temperatures in impacting the sea ice throughout the Fram Strait and northeast Greenland region. Increased insolation due to sunlight spreading over the region will also add to the overall potential for melt.

Stefan at Real Climate explained it – it was new to me too! “ It sounds paradoxical when one thinks of the shock-freeze scenario of the Hollywood film The Day After Tomorrow: a study by Duchez et al. (2016) shows that cold in the North Atlantic correlates with summer heat in Europe. This is due to the fact that the heat transport in the Atlantic has not yet decreased strongly enough to cause cooling also over the adjacent land areas – but the cold of the sea surface is sufficient to influence the air pressure distribution. It does that in such a way that an influx of warm air from the south into Europe is encouraged. In summer 2015, the subpolar Atlantic was colder than ever since records began in the 19th century – associated with a heat wave in Europe. Haarsma et al (2015) argue on the basis of model calculations that the weakening of the AMOC will be the main cause of changes in the summer circulation of the atmosphere over Europe in the future. Jackson et al (2015) found that the slowdown could lead to increased storm activity in Central Europe. And a number of studies suggest that if the AMOC weakens, sea levels on the US coast will rise more sharply (e.g. Yin et al. 2009). The impacts are currently being further researched, but a further AMOC slowdown cannot be considered good news. Yet, although the oscillations seen in Fig. 2 suggest the AMOC may well swing up again for a while, a long-term further weakening is what we have to expect if we let global warming continue for much longer.” The whole article is superb as you would expect from such a gifted science communicator.

Only during certain months and at certain times. Will refer to the anomaly maps above again to give broader perspective. Though recent cold snaps for the U.S. East have been intense and likely influenced by the cool pool during winter, what we’ve seen is overall warmer than normal conditions so far relative to the middle 20th Century.

For the decade of 2001 to 2010 during Jan-March, both the Eastern U.S. and Europe were relatively warmer compared to the rest of the world. And even though the warming trend, overall continued for the Eastern U.S. during the 2012-2018 timeframe, it slowed relative to the Globe. In parts of Europe, eastern Canada, and the North Atlantic, the seasonal warming trend has halted or reversed. Add in a few strong cold snaps due to the cool pool influence and that’s where you get this sense of ‘it’s cooler in the East.’ Of course the perception is relative. If it’s much hotter in the west but in the East you get these big swings between hot and cold that we are seeing now, then people tend to think the east is cooling even though that hasn’t happened in the longer term trend yet. It has happened for parts of Europe, the N. Atlantic, and parts of Canada, however.

The largest U.S.-British Antarctic mission in seven decades officially launched at an event in Cambridge on Monday, as the two countries pooled dollars and scientific resources for missions to West Antarctica’s Thwaites glacier — a Florida-size ice body that, scientists fear, could flood the world’s coastlines in our lifetimes.

“For global sea-level change in the next century, this Thwaites glacier is almost the entire story,” said David Holland, a geoscientist at New York University, who will pair with British Antarctic Survey researcher Keith Nicholls to lead one of the six scientific field missions.

Thwaites is a key part of the reason that recent computer modeling studies have predicted that the Antarctic could double the previously projected rate of sea-level rise during this century. But it is located in an extremely remote area, and the critical region that will determine how fast the glacier retreats — the “grounding line” where ocean, ice and bedrock meet at 2,600-foot depths — remains little studied.