Saturday 26 July 2014

Climate change news

Big Arctic Warm-Up Predicted For This Week: Melt to Speed Up, Or Sea Ice to Show Resiliency Due to Variability, Strength of Negative Feedbacks?



25 July, 2014

Rate of Sea ice volume decline for all months
(Rate of Arctic sea ice volume decline with trend lines for all months in the PIOMAS measure. Updated through June of 2014. Image source: Wipneus.)
What it really all comes down to is heat energy balance. Beneath a warming, moistening Arctic atmosphere, sea ice loses resiliency due to slow attrition of the ice surface, due to loss of albedo as ice melts, and due to slower rates of refreeze during winter. Atop a warming Arctic Ocean, sea ice loses bottom resiliency, tends to be thinner and more broken, and shows greater vulnerability to anything that churns the ocean surface to mix it with the warming deeper layers — storms, strong winds, powerful high pressure systems.

It is this powerful set of dynamics under human caused climate change that has dragged the Arctic sea ice into what has been called a ‘Death Spiral.’ A seemingly inexorable plunge to zero or near zero ice coverage far sooner than was previously anticipated.

But in the backdrop of what are obviously massive Arctic sea ice declines and a trend line, that if followed, leads to near zero ice coverage sometime between next year and 2030, lurk a few little details throwing a bit of chaos into an otherwise clear and, rather chilling, picture of Arctic sea ice decline.

The Fresh Water Negative Feedback

One of these details involves the greatly increasing flow of fresh water into the Arctic Ocean. For as the Arctic heats, it moistens and rainfall rates over Arctic rivers increase. This results in much greater volumes of fresh river water flushing into the Arctic Ocean and freshening its surface. Another source of new fresh water flow for the Arctic is an increasing rate of Greenland melt outflow. The volumes, that in recent years, ranged from 300 to 600 cubic kilometers, can, year-on-year, add 1-2% to the total fresh water coverage in the Arctic Basin and North Atlantic. These combined flows mean that fresh water accumulates more rapidly at the surface, resulting in an overall increase in fresh water volume.
Change in salinity
(Change in Arctic Ocean Salinity between the mid 1990s and mid 2000s. Image source: Benjamin Rabe, Alfred Wegener Institute via Science Daily.)
Since 1990, we have observed just such an accumulation. For a recent study in 2011 showed that since 1992, Arctic Ocean surface fresh water content had increased by 20%. A remarkable increase due to the changing conditions that included greatly increased river outflows into the Arctic Ocean as well as a ramping ice melt from Greenland and the Canadian Archipelago Islands.
Fresh water is less dense than salt water and will tend to float at the surface. The physical properties of fresh water are such that it acts as a heat insulator, deflecting warmer, saltier ocean water toward the bottom. As such, it interrupts the heat flow from deeper, warmer Arctic Ocean waters to the sea surface and into the atmosphere.

As an added benefit to the ice, fresher water freezes at higher temperatures. So as the Arctic Ocean freshens, it creates a bit of wiggle room for the sea ice, giving it about a 0.5 to 1 C boost so it can sometimes even form during conditions that were warmer than those seen in the past.

In this manner, an expanding fresh water zone acts as a kind of last refuge for sea ice in a warming world. A zone in which sea ice may even periodically stage comebacks in the backdrop of rampant human warming. We may be seeing such a comeback in the Antarctic sea ice, which has shown anomalous growth and even contributed to an expanding cool atmospheric zone in the Southern Ocean, despite ongoing global warming. The freshwater and iceberg feeds from the vast Antarctic ice sheets have grown powerful indeed due to warm water rising up to melt the ice sheets from below, letting loose an expanding surface zone of ice and fresh water. This process will necessarily strengthen as more and more human heating hits the deep ocean and the submerged bases of ice sheets. An effect that will dramatically and dangerously reverberate through the ocean layers, setting the stage for a horrible stratification.

But today, we won’t talk about that. Today is for negative feedbacks due to fresh water flows from increasing polar precipitation and through ice sheet melt.
In the end, human warming dooms Arctic sea ice to an eventual final melt. But before that happens the increasing volume of fresh water from river flows and the potentially more powerful negative feedback coming from a growing ice and fresh water release from Greenland and the Canadian Archipelago will inevitably play their hands.

The Slower Than Terrible 2014 Melt Season

And so we arrive at the 2014 sea ice melt season for the Arctic. As with 2013, the melt got off to a relatively rapid start and then slowed through July as weather conditions grew less favorable for ice melt. Above freezing temperatures hit the ice above 80 degrees North about one week later than average, also providing some resiliency to the central ice — a condition that historically leads to higher end-season sea ice values in about 80 percent of the record.

The high pressure systems of early June gave way to weak storms and overall cloudy conditions. This shut down the cycle of strong melt, compaction, and transport of ice out of the Arctic that may have put 2014 on track for new records and another horrible slide down the Arctic sea ice death spiral. Instead, conditions set up for slower melt. Ice was retained and backed up through the Fram Strait, and the ice spread out, taking advantage of the thickened fresh water layer to slow its summer decline.

This is in marked contrast to the terrible 2007 and 2012 melt seasons which severely damaged the ice, making a total Arctic Basin ice melt all more likely in the near future. And it was also cutting against the 2010 to 2012 trend in which sea ice volume measures continued to plunge despite ambiguous numbers in sea ice area and extent (no new record lows) during 2010 and 2011. For this year, sea ice volume is now, merely, ‘only’ 4th lowest on record, according to the PIOMAS measure.

The fact that we are looking at a 4th lowest year as another bounce-back year is a clear indication of how terrible things became since 2010. And so far, this year’s melt has, like 2013, simply not been so terrible and terrifying. A wag back toward 2000s levels that is likely due to the inherent negative feedback of freshening surface water and to a swing in natural weather variability that, during any other year and in any other climate, would have pushed summer ice levels quite high indeed.

If the storms had been strong enough to draw a large enough pulse of warm water to the surface, the story might have been different. But, as it stands, this summer of weak Arctic weather hasn’t activated any major melt mechanism to push the ice into new record low territory. And so in many major monitors we are now above 2013 melt levels for this day.

Cryosphere Today shows sea ice area at 5.22 million square kilometers, above 2013 and just slightly above 2011 while ranging below 2008 for the date. Overall, the area measure is at 6th lowest on record for the date. Meanwhile, NSIDC shows sea ice extent at 7.74 million square kilometers or just above 2013 values for the same day but remaining below 2008 and 2009 by a substantial margin. Overall, also a sixth lowest value for the date:
Sea ice july 2014 v2
(NSIDC chart comparing sea ice melt years 2012 [dashed green line], 2008 [maroon line], the 1981 to 2010 average [solid line] and 2013 [pink line]. Image source NSIDC.)
So in the sea ice butcher board tally, with the negative feedback of fresh water floods and glacial melt moderately in play and with weather that is highly unfavorable for melt, we currently stand at 4th lowest in the volume record, 6th lowest in the extent record, and 6th lowest in the area record.
And now, things may just be about to get interesting…

Forecast Shows Arctic Heatwaves on the Way

GFS and ECMWF model runs show two warm ridges of high pressure developing over the Arctic this week. And the emergence of these warm and moist air flows into the Arctic may well have an impact by pushing the Arctic back toward melt-favorable conditions.

The first ridge is already expanding across the Canadian Archipelago. Yesterday it brought 80 degree temperatures to Victoria Island which still sits between wide channels clogged with sea ice. Smoke from wildfires is being entrained in this ridge and swept north and east over the remaining Archipelago sea ice and, today, the Greenland Ice Sheet.

While the smoke aerosol from fires blocks some of the incoming solar short wave radiation, it absorbs and re-radiates it as long-wave radiation. Many studies have shown this albedo-reducing darkening of the cloud layer by black and brown carbon aerosols has a net positive warming effect. In addition, the soot falls over both land and sea ice where it reduces reflectivity medium to long-term (Dark Snow).
Smoke streaming over Canadian Archipelago and Northwestern Greenland
(Smoke associated with record wildfires in the Northwest Territory streaming over the Canadian Archipelago, Northern Baffin Bay, and Northwestern Greenland beneath a dome of record heat. Image source: LANCE-MODIS.)
The ridge is expected to expand east over the next few days until it finally settles in as a moderate-strength high pressure system over Greenland. There it is predicted to juxtapose a set of low pressure systems that will slowly slide south and east over Svalbard. The conjoined counterclockwise cyclonic wind pattern of the lows and the clockwise anti-cyclone of the high over Greenland in the models runs over the Fram Strait. And so, for at least 4-5 days, the models predict a situation where sea ice transport out of the Arctic may be enhanced.

Meanwhile, on the other side of the Arctic, a series of high pressure systems are predicted to back up over the Pacific Ocean section of Irkutsk and Northeast Siberia. This ridge is expected to dominate coastal Siberia along the Laptev and East Siberian Seas. Temperatures along the coast are expected to reach 15-20 C above average, while temperatures over the waters are expected to rise to melt enhancing levels of 1 to 5 C.

Ahead of the ridge runs a warm frontal boundary that is heavily laden with moisture and storms. So a liquid and mixed precipitation band is likely to form over the East Siberian and Beaufort Sea ice as the ridge advances.


The ridge is projected to drive surface winds running from the south over the East Siberian Sea, across the polar region, and into the Greenland and Barents Seas. This cross-polar flow of warm, moist air will also enhance the potential for ice transport.
Melt Pattern
(Pattern more favorable for sea ice melt and transport emerging over the next seven days. This Climate Reanalyzer snapshot is at the 120 hour mark. Note Arctic positive temperature anomalies at +1.18 C. Will the pattern override potential negative feedbacks such as high fresh water content in the Arctic and unfavorable weather likely produced by the late emergence of temperatures above 0 C in the 80 North Latitude zone? Image source: University of Maine.)
Overall, it is a weather pattern that shows promise to increase melt, especially in the regions of the Canadian Archipelago and the East Siberia Sea, and to speed ice mobility and transport. Persistent lows near the central Arctic for the first half of this period and shifting toward Svalbard during the latter half will continue to disperse sea ice which may lend one potential ice resiliency feature to a pattern that is, otherwise, favorable for ice loss.

Negative Feedbacks and Weather Unfavorable For Melt

If the melt pattern described above comes to impact the ice and push greater rates of sea ice loss over the coming days and weeks, it’s likely that end season 2014 will end up with sea ice measures below those of 2013, but above the previous record lows seen during past years. This would likely put 2014 well within the range of the post 2007 era at 3rd to 5th lowest on record for most monitors. Not a new record year, but still well within the grips of the death spiral.
If, however, the weather predicted does not emerge or the sea ice retains resiliency through it, then 2014 stands a chance of pushing above final levels seen in 2013. In such an event, end season area and extent measures may challenge levels last seen during 2005 while sea ice volume maintains between 4th and 5th lowest.

If this happens, we may need to start asking this question:

Are negative feedbacks, in the form of greatly increased freshwater flows from rivers and glaciers, starting to pull the Arctic sea ice out of a high angle nose dive and are they beginning to soften the rate of decline? Or is this just a year when weather again wagged the dog as natural variability played a trump card for the summer of 2014 but further drives for new records will follow come 2015, 2016, or 2017?

In any case, near-term sea ice forecasts remain somewhat murky, as they should given the high instability of the current situation.

Links:


Song of Flood and Fire Refrain: Epic Canadian Floods Wreck 5.5 Million Acres of Cropland

Robertscribbler,
24 July, 2014

For the Northwest Territory of Canada, the story this summer has been one of record-setting wildfires. Fires casting away smoke plumes the size of thunderstorms, fires that burn regions of tundra the size of small states. Fires that just burn and burn and burn for weeks on end.

But to the south and east in Saskatchewan and Manitoba, the story is drastically different. For over the past month, unprecedented flooding in this region has wrecked untold damage to Canada’s farmlands.

Canada floods
(Powerful storms over Manitoba and Saskatchewan on July 23rd, 2014. Image source:LANCE-MODIS)
This situation is the result of an odd and wreckage-inducing tangle in the Jet Stream. For hot air has been funneling up over the Northwest Territory for the better part of two months now, pushing temperatures in this Arctic region into an unprecedented range topping the 70s, 80s, and even 90s on some days. This high amplitude ridge in the Jet Stream has been reinforced and locked in place, a result some scientists attribute to the loss of Arctic sea ice during recent years, setting up a hot weather pattern favorable to wildfires.

As the massive Arctic wildfires ignited and burned, they cast off giant streams of smoke, burdening the down-wind atmosphere with aerosol particles — an abundance of condensation nuclei for cloud formation. These smoke streams fell into a trough flowing down over Manitoba and Saskatchewan. The deep trough, often extending far into the Central US formed a kind of trap for storms and, like the fixed ridge over the Northwest Territory, it has remained in place for months on end.
Given this mangled positioning of atmospheric heat and moisture flows, it was only a matter of time before massive rainstorms erupted in the wake of the large-scale Canadian fires. And the result was an unprecedented flooding. The offspring of an unprecedentedly powerful and persistent atmospheric pattern set off by human warming.
Major Floods Wreck Canadian Crops
For some local farmers, the past couple of days have seen 48 hour rain totals in excess of 10 inches. A 100 year rain event at a scale few farmers in the region have ever seen. And the recent floods are just the latest in a series of heavy rainfalls that have been ongoing ever since early July. Flood follows flood follows flood. A progression that has left most farms swimming in inches to feet of water and mud.
In total, farmland encompassing 3 million acres in Saskatchewan and 2.5 million acres in Manitoba are now under water and are unlikely to produce any crops this year. As a result, wheat plantings are expected to decline by 9.8 percent from last year, canola is expected to decline by 5.8 percent from the June forecast, and oat is expected to decline by 6 percent, according to estimates from Bloomberg.
July flooding in these regions has so far resulted in over 1 billion dollars in damages to farmers. As much as half of these losses may not be covered as insurers are still reeling from severe moisture damages during 2011, just two years ago. As a result of the ongoing parade of storm casualties, insurers have also raised deductibles, leaving farmers more vulnerable to the odd and powerful new weather coming down the pipe.
The Part Played By Climate Change and a Mangled Jet Stream
We often hear of the expanding droughts of human-caused climate change wrecking croplands. But the upshot of expanding drought in one region is record downpours in another. And downpours, if they are intense enough, can have a negative impact on crops as well.
The cause of this is as simple as warming’s enhanced ability to evaporate water. For it is estimated by climate scientists that each degree C in temperature increase amplifies the global hydrological cycle by 7-8 percent. That means that current warming of about 0.8 C since the 1880s has resulted in about a 6% increase in both evaporation and precipitation. At the level of weather, this translates into more intense droughts under dry, hot weather, and more intense rainfall events under wetter, cooler weather.

High Amplitude Rossy Wave Over North America July 2014
(High amplitude Jet Stream wave pattern fueling wildfires in the Northwest Territory and record floods in Manitoba and Saskatchewan. Note the extreme northward projection of the Jet over the Northwest Territory and the strong, deep, trough back-flowing from Hudson Bay into Manitoba, Saskatchewan and the northern tier of the Central US. Image source: University of Maine.)
One mechanism that has tended to amplify drought and rain events during recent years has been a weakening and intensifying waviness of the Northern Hemisphere Jet Stream. This weakening has been attributed by some scientists to a large-scale recession of Arctic snow cover and sea ice. For since 2007, not one day has seen an average sea ice extent and the range has typically fallen into a zone between 20-50 percent below levels seen during the 1970s and 1980s. New major record low years in 2007 and 2012 have also fueled speculation that sea ice may completely melt away during one summer between now and 2030, 2025, or even 2020 — 50-100 years ahead of model predictions.

As the sea ice serves as a haven for cold air masses, its loss is bound to impact the resiliency of these systems and since a solid pool of cold air to the north is a major driver of Northern Hemisphere upper air currents, the weakening of this cold pool has had dramatic impacts on climates
Dipole hot-cold pattern associated with mangled jet stream
(Extreme dipole hot/cold pattern associated with Jet Stream mangled by climate change. Image is for July 14, a match to the above Jet Stream shot. Note the extreme heat in the ridge and the much cooler air in the trough. This is exactly the kind of pattern we would associate with sea ice retreat and Jet Stream weakening. Image source: University of Maine)
For this year, the ridge over Canada’s Northwest territory was a direct upshot in a northward retreat of the Jet Stream over Canada and, at times, into the Arctic Ocean. This set the stage for severe wildfires in the zone of warmth underneath this ridge pattern. To the east, a powerful downsloping trough pulled cooler air into Saskatchewan and Manitoba as well as over the Central and Eastern US. This set the pattern up for cooler than average conditions as well as for strong rainstorms.
The crop-shattering events of July were a direct result of this climate change induced ‘Song of Flood and Fire.’ A pattern we’ve seen repeat again and again over the past few years and one that may well intensify as both time and human-caused warming advance.
Links:
Hat-tip to Colorado Bob.


Is This the Compost Bomb’s Smoking Gun? Second Mysterious Hole Found in Yamal Russia
24 July, 2014

Yamal, Russia — a stretch of tundra flats and peat bogs stretching as far as the eye can see before terminating into the chill waters of the Kara. A rather stark and desolate place, one that was mostly unknown until a massive and strange hole appeared in the earth there last week. Since that time, the strange hole has been the butt of every kind of wild speculation and controversy.
Yamal Siberia
(MODIS satellite shot of Yamal Siberia — the peninsula located in center frame and recent site of mysterious holes that may have been caused by the catastrophic destabilization of thawing methane gas embedded in the permafrost. Image source: LANCE-MODIS.)
The hole itself was an alien feature. “We haven’t seen anything like this before,” would be an entirely accurate statement. All about the hole was a large pile of debris — overturned earth, huge chunks of soil piled up in a signature very familiar to the ejecta of a meteor impact crater.
Approaching the hole edge, we came to a gradual slope that proceeded downward for about 40 feet at about a 35 degree incline. Along the surface of this incline, both the unfrozen soil cap and the frozen permafrost were visible.
But it wasn’t until we hit the bottom edge of this incline that we encountered the strangest feature of all — a sheer cliff, rounded in a shape like the smooth bore of a gun, and plunging straight down through icy permafrost for about another hundred and twenty feet before revealing a basement cavern slowly filling with melt.
It’s a combination of features that appears to be one half impact crater and one half sink hole.
Russia Siberia Crater
(The freakish combination of features including apparent ejecta piled around a crater with a sheer tunnel coring 220 feet down. Image source: The Siberian Times)
The Compost Bomb

Key to the second theory is that thawing permafrost contains vast stores of volatile methane at various depths. The methane is either trapped in pockets encased in ice and soil or locked in a water lattice structure forming what is called methane hydrate. Both forms are unstable, though they are often buried beneath tens to hundreds of meters of permafrost. Researchers have remained unsure how rapidly this methane would release and its rate of release is key to how fast the world will warm this century in response to human-caused greenhouse gas heat forcing.
Over 1,400 gigatons of carbon are sequestered in the permafrost. Much of this immense store is biological material buried over the 2 million year span of below-freezing conditions dominating much of the Arctic region of our planet. During this time, gradual glacial advance and retreat froze and refroze the earth in layers entombing a vast load of the stuff. Now, human warming is beginning to unlock it.
Permafrost spans much of the Arctic, under-girding Siberia, far Northern Europe, the northern tiers of Canada, and most of Alaska. It also rests beneath a flooded zone called the East Siberian Arctic Shelf. Initial reports and research from these regions indicate an ongoing release of millions of tons of methane and CO2 annually. Bubbling seabed stores from the shallow East Siberian Arctic Shelf have caused some to speculate that releases of 1 billion tons to 50 billion tons of methane could be possible during the coming years and decades.
Tundra map NASA
(Is a sleeping dragon awakening in the Arctic? Map of wide expanse of permafrost containing 1,400 gigatons of carbon. Image provided by NASA’s CARVE methane research experiment which is now under the aegis of ABOVE.
Peter Wadhams, in an article for Nature last year, attempted to bracket the potential impacts of such large releases. In the article, Wadhams estimated that a 50 gigaton emission from the Arctic methane store over the next two decades would increase global temperatures by about 0.6 C above the current rate of warming and force temperatures through the 2 C barrier by 2035 (ironically, Michael Mann comes to the same conclusion without implicit inclusion of a powerful methane release). The costs in human lives and economic damage from such a release would be immense and it would risk further outbursts from the large and vulnerable carbon store.

And though the potential for such very large releases remain highly controversial among scientists, the massive pile of thawing permafrost carbon is an ominously large and unstable store facing off against an initial human warming that is more than six times faster than at any time during the geological past.
In the shadow of this emerging and hard to gauge threat, a term emerged to encapsulate the vast warming potential stored in permafrost, should it release and hit the atmosphere. The term — compost bomb — alludes to the risk involved in pushing the two-million-year-old Northern Hemisphere permafrost stores into rapid thaw.
Mystery Hole — A Smoking Gun?
With the spontaneous emergence of a strange hole that Russian scientists are linking to destabilized gas pockets within the permafrost due to thaw, it became possible that, yet one more, explosive mechanism for release had presented itself. And now, today, a second and similar hole has been discovered:
According to the Moscow Times:
Global warming, causing an alarming melt in the ice under the soil, released gas causing an effect like the popping of a Champagne cork,” the news report said, citing an expert at the Subarctic Scientific Research Center.
The first hole is estimated to be about 50 meters wide and 70 meters deep, with water from melting permafrost cascading down its sides into the icy deposit below.
The second hole is “exactly” like the first one, but “much smaller,” local lawmaker Mikhail Lapsui told the Interfax-Ural news agency. “Inside the crater itself, snow can be seen. (emphasis added)”
And so, in the course of just one week, we have two very strange holes that Russian scientists are linking to destabilizing gas pockets beneath the thawing tundra. Smoking barrel of the compost bomb? Or as a commenter here called Colorado Bob puts it:
We’re going to see the tundra breaking out in these things like zits on a teenager.
Let’s hope these are mere sink-holes from collapsing ice pockets in the permafrost. Let’s hope there’s another explanation for what appears to be ejecta piled around these holes. Let’s hope that these ‘zits’ showing up in the Yamal permafrost remain local to the area. And let’s hope we don’t start seeing similar explosive outbursts from tundra in other regions, or worse, along the seabed of the East Siberian Arctic Shelf.
Lastly, let’s hope that any outbursts remain small in size and do not lift very large sections of land or submerged sea bed.
In any case, these initial reports are not promising and it appears we may both have a compost bomb smoking gun and a potential mechanism for rapid destabilization and explosive release of gas pockets deeply embedded in the frozen tundra all wrapped into one. Not very reassuring to say the least.
Links:
Hat tip to todaysguestis
Hat tip to Colorado Bob

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