All posts tagged Arctic Sea Ice Extent

A Season of Record Melt — Sea Ice Extent In Uncharted Territory For 94 Days

From March 25th through June 26th, sea ice extent measures, as provided by Japan’s Arctic data system were in record low ranges. In other words, for about a quarter of a year, and according to this monitor, the Arctic Ocean and its surrounding estuaries have witnessed the lowest ice coverage ever measured for any similar period since record keeping began in the 1979.

(An amazingly long period of record low sea ice extents in JAXA’s sea ice monitor.)

This new period of extreme sea ice record lows comes during a time of continuous decadal sea ice losses. Average sea ice coverage for each successive ten year period since the 1980s during the March through June period has fallen by about 400,000 to 500,000 square kilometers. For 2016, the new record lows widened this gap to more than 2 million square kilometers — or a surface area of sea ice coverage lost roughly equivalent the size of Greenland.

Over recent days, the JAXA measure has edged slightly over the record low 2010 line for the period, ending a season-long escapade into record low ranges.

Winter/Spring Heat The Driver of New Record Lows This Year

Overall, these losses were driven by an extraordinary warming of the Arctic that has extended and intensified over these time periods. A warming that has itself been forced upon the Arctic by human greenhouse gas emissions which are, for the largest part, the result of fossil fuel burning. This year, the Arctic experienced new record warmth during a Winter that included odd periods when North Pole temperatures rose briefly above freezing.

Alaska, a microcosm of this building Arctic heat, experienced its second warmest winter on record — which was then immediately followed by its warmest spring ever recorded. Across the state, it was warmer than normal pretty much everywhere and mostly all the time.

According to this 25 Alaska city composite index (provided by Climatologist Brian Brettschnieder above) every day but two through June 30 of this year saw above normal temperatures in the related regions. Yet another pretty clear indication that there’s nothing normal about Arctic or near Arctic temperatures these days.

Closer to the 2012 Line But Still in Record Low Range

All this extreme Arctic heat during Winter and Spring was probably the major contributor to new record low sea ice extents continuing for more than three months running. However, storms over the Arctic Ocean have since moderated temperatures into closer to normal ranges for June even as these weather systems’ circulatory patterns have tended to spread the ice out. As a result, rapid rates of melt slowed somewhat into June and the extent monitor has crossed the 2010 line, coming closer to the 2012 line in the JAXA measure, while flipping back and forth over the 2012 line in other major measures (NSIDC).

(Arctic storm churns through the East Siberian and Laptev seas of the Arctic Ocean on July 1 of 2016. Sea ice measures are currently near new record lows, but a steep rate of decline will be required to challenge or break with 2012. Image source: LANCE MODIS.)

The upshot is that the sea ice state during early July doesn’t look quite as bad as it did during late May and early June. Chances for a blue ocean event in which Arctic sea ice volume exceeds an 80 percent loss since the late 1970s, in which sea ice extent falls below 1.5 million square kilometers, or sea ice area falls below 1 million square kilometers seems less likely by end Summer at this time. Such an event would now likely require some rather severe Summer weather episodes including strong highs over the Central Arctic and/or very strong late summer lows pushing heavy swells into the Central Arctic Basin. That’s not to say we shouldn’t be on the lookout for strong negative sea ice departures over the next few months — which are certainly still possible. And given the current trend, 2016 remains in a position to hit near or below 2012 records by end Summer.

Links/Attribution/Statements:

Sea Ice Hit Record Lows Every Single Day in May

Hat tip to The Arctic Sea Ice Blog

Climatologist Brian Brettschnieder

LANCE MODIS

JAXA

NSIDC (please support public, non special interest based science by re-funding critical NSIDC satellite monitoring of the Arctic)

Alaska Experiences Warmest Spring on Record

Warm Arctic Storm to Push Temperatures Above Freezing at North Pole in Winter

NASA GISS

Hat tip to DT Lange

Hat tip to Cate

Hat tip to Colorado Bob

Hat tip to DaveW

(Disclaimer — The views and analysis expressed in this blog are my own. The related analysis is an exploration of current trends and possible future climate states informed by my own best assessment of the science. In no way is this analysis meant to be misconstrued as an absolute authoritative final word on sea ice states. For example, we cannot say with absolute certainty that any one of the following — new record lows, blue ocean events, or a failure to hit new record lows — will happen. As such, the analysis should instead be viewed as a middle-certainty forecast informed by current trends. Further scientific opinion and informed discussion on the issue is welcome.)

251 Comments

by robertscribbler on July 1, 2016 • Permalink

Posted in Climate Change

Tagged A Season of Record Losses, arctic sea ice, Arctic Sea Ice Area, Arctic Sea Ice Extent, environment, extreme weather, global warming, Hothouse, Human Hothouse, Record Arctic Temperatures, record lows, science, weather

Posted by robertscribbler on July 1, 2016

https://robertscribbler.wordpress.com/2016/07/01/a-season-of-record-melt-sea-ice-extent-in-uncharted-territory-for-94-days-and-counting/

Warm Storms Rage Through Barents as Arctic Sea Ice Enters 13th Day of Record Low Extent

On March 4, amidst a building polar heat amplification and a strong, thousands mile long, south to north wind and storm flow across the North Atlantic and into the Arctic, sea ice extent coverage for the northern polar region plunged to new record lows.

(26 foot wave heights [left frame] and 50-60 mph sustained southerly winds [right frame] in conjunction with warm storm near the ice edge at Svalbard on March 15, 2015. Storms of this kind have been raging up through the Barents delivering powerful, warm southerly winds and immense swells to the ice edge region for at least the past half month. This strong melt pressure and warm air delivery has contributed to record low sea ice extent totals continuing for the past 13 days running. Image source: Earth Nullschool. Data source: GFS.)

Human-forced heat continued to build throughout the Arctic as warm and intensely windy storms churned northward through the Barents, bringing with them powerful swells ranging from 15 to, at times, 40 feet in height. As these great swells ground away at the ice edge, temperatures hit daily anomalies greater than 4 C above the 1979-2000 average on Sunday, March 8 for the entire Arctic region. The next day, sea ice extent, according to NSIDC, plummeted to 14,273,000 square kilometers. A value 303,000 square kilometers, or an area about the size of Arizona, smaller than the previous record low value for the date set in 2006.

Ever since March 4, the Arctic has remained in new record low territory — a period that has now lasted 13 days. Though anomalous warmth has faded somewhat — dropping today to a range of 2.65 degrees Celsius above the 1979-2000 average — sea ice has only bounced back slightly. On March 15, the NSIDC extent measure had inched up to 14,333,000 square kilometers, still about 235,000 square kilometers below the previous record low for the date.

(Arctic sea ice extent as measured by NSIDC drops below previous record low values on March 4 of 2015 [bottom dark blue line] and has remained at record low levels ever since. For reference, previous record low years for March dates include 2006 [pink line], 2007 [light blue line], and 2011 [orange line]. The top dark blue line [1979] indicates how much sea ice extent has been lost during March over the past 36 years. Image source: NSIDC.)

Over the next week, however, these new record lows are more likely to continue to fade as warm Arctic surface temperature anomalies drop to around 1-2 C above average, the Arctic Oscillation shifts toward neutral or slightly negative, and the warm storm track through the Barents is interrupted by cold winds pushing south toward Scandinavia from the pole. Although mid-week warming forecast for Alaska and Baffin Bay may retard any potential rebound somewhat.

For the past two years, Arctic sea ice has experienced a bit of a rebound during the March through early April time-frame. This has appeared to coincide with a restrengthening of the polar Jet Stream as mid latitudes have warmed which, in turn, has weakened meridional patterns transporting heat into the Arctic during winter time. Low angle sunlight entering the Arctic at this time of year has also not yet gained enough momentum to significantly push the ice to melt. So we still have about a 2-3 week window for potential bounce-back before sunlight builds and begins to apply its steady heat forcing to the greatly diminished ice.

(Arctic Oscillation [AO] index forecast shows dip toward slightly negative or neutral AO status by end week after a rather extreme high in early March, with a return to mildly positive AO values by end month. Positive AO enhances edge melt of sea ice by encouraging storm formation at the ice edge and warm air invasions over the central ice. Image source: NOAA/CPC.)

That said, the ice is quite frail now, even with potential volume rebounds to mid 2000s levels. So even the slight addition of solar insolation may be enough to keep ice coverage values depressed in the neutral or moderately positive Arctic Oscillation regime that is predicted through the end of March. Extent measures maintaining near record lows along the 2006, 2007 and 2011 tracks, or just below, would establish a very low launching pad for a melt season that, lately, has tended to include precipitous declines in ice during the summer months.

The ongoing record low extent status, despite a return to weather patterns that are more favorable for rebound or maintenance, therefore, should be closely monitored.

Links: