Natural Cycles of Polar Sea Ice: The Arctic Iris Effect

The Arctic Iris Effect, Dansgaard-Oeschger Events, 

and Climate Model Shortcomings. 

Lesson from Climate Past - part 1.

Dansgaard Oeschger Events and the Arctic Iris Effect

During the last Ice Age, Greenland’s average temperatures dramatically rose on average every 1500 years by 10°C +/- 5°C in a just matter of one or two decades, and then more gradually cooled as illustrated in Figure 1 below (8 of the 25 D-O events are numbered in red on upper graph; from Ahn 2008). These extreme temperature fluctuations between cold “stadials” that lasted about a thousand years and warm “interstadials” lasting decades are dubbed Dansgaard-Oeschger events (D-O events). These rapid temperature fluctuations not only rivaled the 100,000‑year fluctuations between maximum glacial cold and warm interglacial temperatures but D‑O warm events coincided with expanding Eurasian forests (Sánchez Goñi 2008, Jimenez-Moreno 2009), northward shifts of subtropical currents along the California coast (Hendy 2000), and shifts in belts of precipitation in northern South America (Peterson 2001).

Dansgaard Oeschger Events

Just 25 years ago most climate researchers were hesitant to accept initial Greenland ice core evidence suggesting such abrupt D‑O warming events (Dansgaard 1985). But as other Greenland ice cores verified their reality, it was clear that the only mechanism realistically capable of producing such abrupt warming was the sudden removal of insulating sea ice that allowed ventilation of heat previously stored in the Arctic as Dansgaard (1985) had first proposed. Still that begged the question ‘what caused the sudden loss of insulating sea ice’?

Changes in CO2 concentration are unlikely to have had much impact on D‑O events (3^rd graph from the top in Figure 1). CO2 concentrations did fluctuate by about 20 ppm during a third of the D-O events (red numbers), but could contribute directly to no more than 0.4°C to only 30% of the largest warming events.  In contrast during 68% of the other D-O events (not numbered), abrupt warming occurred while CO2 was declining.  Thus rapid warming and cooling seems independent of any CO2 forcing.

Abrupt D‑O warming and cooling suggested to researchers (Broecker 1985) that the Atlantic Meridonal Overturning Circulation (AMOC) turned “on” and “off”. Based on the misleading belief in the existence of a simplistic “ocean conveyor belt” (Wunsch 2007), researchers incorrectly interpreted a lack of deep-water formation as evidence of a lack of warm water flowing into the Arctic. However based on increasing proxy evidence (Rasmussen 2004, Ezat 2014), it is now understood that the inflow of warm Atlantic Waters never “shut off” but continued to enter the Arctic and warmed the subsurface layers. As seen in Figure 2  (from Itkin 2015) the upper layer of fresh water and the halocline insulate the warm Atlantic water from the overlying ice.  Together the thick sea ice and polar mixed layer simply “turn off“ any heat flux from the ocean to the air, thus maintaining cold stadial air temperatures. Furthermore if the salty Atlantic Water cannot be cooled by the cold Arctic air, then North Atlantic Deep Water is shut off as well.

Basic Vertical Structure of Arctic Ocean

Although climate models have failed to simulate D‑O events, models were manipulated to shut off poleward heat transport by prescribing ad hoc floods of freshwater. As long as freshwater “hosing” was applied, the models prevented the cooling and sinking of North Atlantic waters, which shutoff the deep water formation and thus “ocean conveyor belt” resulting in contrived cooling.  That interpretation became the reigning paradigm and researchers began searching for evidence of a flood of freshwater, while nearly every model engaged in “hosing” experiments to explain abrupt climate change. But evidence of the required freshwater flooding has yet to be found and a growing wealth of proxy evidence suggested there was as much freshwater during stadials as there was during interstadials. Even the notion of freshwater floods from an armada of melting icebergs was not consistent with the timing of D‑O events (Barker 2015). Freshwater shutdown of the Atlantic Meridonal Overturning Circulation is most likely just a figment of the models’ configuration.

Other researchers suggested drivers of past and present rapid temperature change were likely to be very similar (Bond 2001, 2005), and recent findings are now supporting that notion. More recent explanatory hypotheses for D‑O events are gaining widespread critical acceptance and do not require any massive floods of freshwater nor a shutdown of the AMOC (Rasmussen 2004, Li 2010, Peterson 2013, Dokken 2013, Hewitt 2015). When sea ice prevents heat ventilation, the inflow of warm and dense Atlantic Waters continues to store heat in the subsurface layers. As heat accumulated, the warm Atlantic Waters became more buoyant, upwelled and melted the insulating ice cover. The loss of an insulating ice cover “turns on” the heat flux causing a dramatic rise in surface temperatures to begin the D‑O interstadial.  Although details of hypothesized D‑O mechanisms vary slightly, they all agree on the ability of growing and shrinking sea ice to affect the heating and cooling of the northern hemisphere. I refer to this sea ice control of heat ventilation the Arctic Iris Effect.

The signature of an Arctic Iris Effect is the opposing temperature trends in the ocean versus atmosphere: when ice is removed, warmer air temperatures coincide with cooler ocean temperatures. When ice returns cooler air temperatures coincide with a warmer ocean. The thicker the sea ice, as during the last Ice Age, the longer the period between ventilations such as the D‑O events. Thick sea ice is less sensitive to small changes in insolation and/or natural variations of inflowing Atlantic Waters. As discussed in Hewitt 2015 decreases in the freshwater layer that separates sea ice from the warm Atlantic Waters are also likely critical contributors to D‑O events. For example as the Laurentide Ice Sheet grew, sea levels fell shutting of the inflow of fresher Pacific water through the Bering Strait, coinciding with an increased frequency between D‑O events from 8 thousand to 1.5 thousand years.

Peterson 2013 suggested that in addition to thick multiyear sea ice, ice shelves were critical for maintaining the longer cold stadials by better resisting small oscillations of increased inflow of Atlantic Water. Likewise with the current reduction of Arctic ice shelves and reduced multiyear sea ice during our present interglacial, much smaller changes in insolation and/or Atlantic inflow could more easily initiate ventilation events. With smaller time spans between each ventilation event, less heat accumulates and warm spikes are more muted (1°C to 2°C) compared to 10°C +/- 5°C during the D‑O interstadials. Over the past 6000 years, decades of rapid ice loss resulted in 2°C to 6°C air temperatures warmer than today quickly followed by centuries of colder temperatures and more sea ice (Mudie 2005).

The 20^th century ventilation events produced only a 1°C to 2°C increase yet the signature of the Arctic Iris Effect is still observed.  In 2001, Dr. Vinje of the Norwegian Polar Institute reported on the opposing temperature effects as ice retreated in the Nordic Seas. Between 1850 and 1900 there was a rapid warming of 0.5°C ocean temperatures between 1850 and 1900 with very little change in atmospheric temperature. Then they reported, “The warming event during the first decades of this century is characterized by a significant decrease in the Nordic Seas’ April ice extent, an increase of ~3°C in the Arctic surface winter temperature, averaged over the circumpolar zone between 72.5° and 87.5°N, and an increase in the Spitsbergen mean winter temperature of as much ~9°C. During this warming event the temperature in the ocean was lower than normal.

An increasing preponderance of positive ice extent anomalies, with an optimum in the 1960s, is observed during the period 1949–66, concurrent with a cooling in the circumpolar zone of ~1°C, a fall in the Spitsbergen mean winter temperature of ~3°C, and an increase in the mean winter air pressure in the western Barents Sea of ~6 hPa. During this cooling event the temperature in the ocean was higher than normal.” [Emphasis Added]

Similarly the most recent Arctic warming again reveals the fingerprint of the Arctic Iris Effect. There was no atmospheric warming in Arctic when there was an insulating cover of multiyear sea ice. Measurements between 1950 and 1990 reported a cooling Arctic atmosphere prompting researchers to publish, “Absence Of Evidence For Greenhouse Warming Over The Arctic Ocean In The Past 40 Years”.  They concluded, “This discrepancy suggests that present climate models do not adequately incorporate the physical processes that affect the Polar Regions.”

Abruptly rapid Arctic warming began in the 1990s with an initial loss and thinning of Arctic sea ice when the Arctic Oscillation’s shifted wind directions and below‑freezing winds from Siberia pushed multiyear ice out of the Arctic. Rigor 2002 correctly pointed out, “One could ask, did the warming of SAT [Surface Air Temperatures] act to thin and decrease the area of sea ice, or did the thinner and less expansive area of sea ice allow more heat to flux from the ocean to warm the atmosphere?” They concluded, “Intuitively, one might have expected the warming trends in SAT to cause the thinning of sea ice, but the results presented in this study imply the inverse causality; that is, that the thinning ice has warmed SAT by increasing the heat flux from the ocean.” [Emphasis Added] That conclusion has been further supported by recent analyses of ocean heat content by Wunsch and Heimbach 2014, two of the world’s premiere ocean scientists from Harvard and MIT. They reported the deep oceans are cooling suggesting the oceans and atmosphere are still not in equilibrium and oceans are still ventilating heat from below 2000 meters that was stored long ago.  Also in their map illustrating changes in the upper 700 meters of the world’s oceans (their Figure shown below), we see the entire Arctic Ocean has cooled between 1993 and 2011, as would be expected from the Arctic Iris Effect. Keep in mind that the warm layer of Atlantic water on average occupies the depths between 100 and 900 meters.

Change in upper 700  meters Ocean Heat Content 1993 t0 2011

The Earth’s Energy Budget

The Earth’s energy budget depends on a balance between absorbed solar radiation and outgoing infrared radiation. While some atmospheric scientists have focused on a possible energy imbalance created by 2 watts/m² generated by rising CO2, widespread regions of the ocean absorb and ventilate over 200 watts/m² of heat each year. As illustrated in Figure 3 (from Liang 2015), the oceans absorb heat (blue shades, in watts/m2) along the equator and over the upwelling zones along the continents’ west coast. Intense tropical insolation and evaporation creates warm dense salty waters that sink below the surface storing heat at depth. Changes in insolation, tropical cloud cover, and ocean oscillations like El Nino affect how much heat the oceans absorb or ventilate. Excess heat absorbed in the tropics is transported poleward. To gain a proper perspective on the importance of heat transport from the tropics to the poles, currently Polar Regions average 30°C colder than the equator. If there was no heat transport, the poles would be 110°C colder than the tropics (Gill 1982, Lozier 2012).

On average, the greatest ventilation of ocean heat happens where heat transportation is most concentrated: along the east coast of Asia over the Kuroshio Current and along east coast of North America along the Gulf Stream. Additionally large amounts of heat are also ventilated over Arctic’s Nordic Seas region, a focal point of the Arctic Iris Effect. A comparison of the temperature changes at varying ice core locations from southeast to northwest Greenland, points to this North Atlantic region as the main source of heat ventilated during each D‑O event (Buizert 2014). Likewise modeling work (Li 2010) shows that reduced ice extent in this region exerts the greatest impact on Greenland temperatures and snow accumulation rates. And it is in this same region that Vinje 2001 reports the greatest reduction in ice cover coinciding with the rapid changes in Greenland’s instrumental data. While CO2 warming would predict the greatest rate of Greenland warming in the most recent decades, the Arctic Iris effect would predict a greater rate of warming in the 1920s because thick sea ice from the Little Ice Age would have caused a greater accumulation of heat. Indeed Chylek 2005 reported, “the rate of warming in 1920–1930 was about 50% higher than that in 1995–2005.”

 

Global Ocean Heat Flux (blue: heat enters ocean, red heat exits ocean) Liang 2015

Climate Model Shortcomings

In 2008 leading climate scientists at the University of East Anglia’s Climatic Research Unit published Attribution Of Polar Warming To Human Influence.  As seen in their graph below, their models completely failed to account for the 2°C Arctic warming event observed from 1920 to the 1940s, (illustrated by the black line labeled “Obs” for observed).  This was a warming event that climate scientists called “the most spectacular event of the century” (Bengtsson 2004). Their modeled results of natural climate change grossly underestimated the 40s peak warming by ~0.8° C, and simulated a flat temperature trend throughout the 20^th century as illustrated by the blue line labeled “NAT” for natural. More striking when the models added CO2 and sulfates, the modeled results (red line labeled all) cooled the observed warming event further. Despite their failure to model natural events they concluded, “We find that the observed changes in Arctic and Antarctic temperatures are not consistent with internal climate variability or natural climate drivers alone, and are directly attributable to human influence.”

However their results only demonstrated that their models failed to account for natural climate change, the Arctic Iris Effect and ventilation of ocean heat during the 1930s and 40s. By all accounts the recent warming of the 1990s and 2000 was likewise a ventilation event that also cooled the upper layers of the Arctic Ocean. The failure to model ventilated heat events led to incorrectly attributing that warming to increasing concentrations of CO2.  That failed modeling further led to explanations that reduced albedo effect allowed greater absorption of summer insolation, warming the Arctic Ocean and amplifying temperatures. But observations show the ocean has cooled.  Like the 40s peak, it is likely 1990s/2000s ventilation similarly contributed a minimum of ~0.8° C to the recent rise in Arctic temperatures, and probably much more as the greater reduction in sea ice extent has allowed for much more ventilation.

Failed Climate Model and Warm Arctic Events

If climates models are correctly configured, they should be able to reproduce both D‑O events and the 1940s ventilation events. We don’t expect model perfection, but turning a massive warming event into a below average cool period is unacceptable.  When the modeling community simulates the Arctic Iris Effect more accurately, only then will their attribution of polar warming to human vs. natural factors be trustworthy! Until then all the natural factors - lower insolation with reduced Atlantic inflow, cooler oceans, negative North Atlantic Oscillation, and increasing multiyear ice – all suggest the current ventilation event will soon come to a close. But the return to cooler surface temperatures and more sea ice has always been much slower than the abrupt warming. When sea ice is reduced, the winds are suddenly able to mix the ocean’s fresher upper layer with the saltier lower Atlantic Waters disrupting the halocline. But once the halocline and upper layers of freshwater are restored, the cooling is rapid.  

In contrast, those who attribute Arctic warming to rising CO2 predict a continued sea ice death spiral. And those who also suggest global warming is slowing down the poleward flow of Atlantic Water, also argue CO2 warming will offset any cooling effects of that slowdown (Rhamstorf and Mann 2015). Within the next 2 decades, nature should demonstrate how well these competing models and competing interpretations extrapolate into the future. Good scientists always embrace 2 or more working hypotheses. But with the politicization of science, I sincerely doubt President Obama is travelling to the Arctic to advise the world to be good scientists!

When Warming is Cooling!

published in the Pacifica Tribune, December 30, 2019

What’s Natural?

When Warming is Cooling!

The media has been awash with doomsday headlines, trumpeting a human-caused “climate crisis” simply because the estimated average global temperature has risen about 1.7°F since the end of the cold Little Ice Age 150 years ago. However, the Arctic has been the greatest climate outlier and its much warmer temperatures, averaging 3.6°F higher than the 1951–1990 average, has shifted the global warming average upwards. 

Furthermore, increased ventilation of stored ocean heat has contributed to much of the Arctic’s recent high temperatures. Ventilating heat warms the air but cools the ocean, and climate history reveals ventilating heat has caused several bouts of extreme warming. Over the past 100 thousand years Greenland’s ice cores recorded 24 extreme warming episodes when air temperatures suddenly rose 14°F - 28°F in a few decades or less. More recently over 4000 years in the Canadian Arctic, decades of rapid ice loss accompanied air temperatures 3°F -10°F warmer than today, quickly followed by centuries of more sea ice and colder temperatures. Although the physics of those dramatic warming events are still in play today, the good news is: warming climates minimize such dramatic warm events.

The most extreme Arctic warming episodes were named “Dansgaard-Oeschger events” in honor of two scientists who discovered them. Although Greenland experienced the greatest warming, Dansgaard-Oeschger events affected climates globally. Ventilating warmth changed global atmospheric circulation, shifting European forests and altering California’s ocean currents. Counter-intuitively, each Dansgaard-Oeschger extreme warming event happened during the last Ice Age when the northern hemisphere was covered with great ice sheets and global temperatures were 5°F-14°F colder than pre-industrial times. 

The climate dynamics responsible for these dramatic warm events is easily demonstrated, and a simple experiment might ease the troubled minds of students plagued with “climate crisis” anxiety. Heat a large covered pot of water. Measure the air temperature above the pot’s lid. If you don’t have a thermometer, simply hold your hand above the lid. Then remove the lid and feel the escaping heat. In a similar fashion, Arctic sea ice (and a surface layer of fresher water) act like the pot’s lid. Remove the ice and the air dramatically warms. Conversely, extensive ice-cover will cool the air but warm the underlying ocean.

Ocean currents constantly transport tropical heat towards the poles, making Arctic climates far warmer than possible if only the sun and greenhouse gases controlled the Arctic’s climate. Warm dense “Atlantic water” constantly enters the Arctic Ocean. Some heat ventilates but some is stored at intermediate depths. Currently there is enough stored heat to melt sea ice many times over. The extensive sea ice of the last Ice Age insulated the Arctic Ocean causing heat to increasingly accumulate. Eventually that great store of heat melted sea ice from below, allowing heat to vent and greatly warm the atmosphere. 

The same dynamics triggering past Dansgaard-Oeschger events provide insight into today’s Arctic warming. During the 1970s and 80s, measurements over an ice covered Arctic recorded cooling air temperatures prompting researchers to publish, “Absence of Evidence For Greenhouse Warming Over the Arctic Ocean In the Past 40 Years.” Those cooling air temperatures did not reduce modern Arctic sea ice. But other factors did.

Arctic winds can trap ice in the Arctic causing ice to thicken. However when the winds shift, thick sea ice will be blown out and melt in warmer Atlantic waters. The resulting open water and thinner ice allows more Arctic subsurface heat to ventilate. In addition to wind-driven ice loss, satellites reveal the greatest area of open Arctic waters corresponds to the pathway where warm dense tropical waters, via a branch from the Gulf Stream, enter the Arctic and melt sea ice from below. It is now widely believed high inflows of warm Atlantic water helped to melt sea ice and trigger the Dansgaard-Oeschger warm events, just as oscillating warm inflows now melt Arctic sea ice today.

A new monitoring system established off the coast of southern Florida in 2002, reports warm water increasingly flowed towards the Arctic until 2008, but since then warm inflows have been decreasing. So, we will now witness a natural experiment that tests competing climate hypotheses. If the increasing inflows of warm water caused most of the Arctic’s recent sea ice loss, then reduced flows should allow sea ice to recover within another decade. In contrast, the competing hypothesis is warming from increasing CO₂ concentrations will cause an ice-free Arctic Ocean. Early predictions of an ice-free Arctic have already failed. But many still predict an ice-free Arctic by 2030 or 2050. Of greater interest, if sea ice does recover, will the reduction of Arctic heat ventilating to the atmosphere, also reduce global temperatures and avert the ballyhooed “climate crisis”?

Jim Steele is director emeritus of the Sierra Nevada Field Campus, SFSU and authored Landscapes and Cycles: An Environmentalist’s Journey to Climate Skepticism. 

Contact: naturalclimatechange@earthlink.net

Pt 2: How Sea Ice Controls Arctic Heat Ventilation and Arctic Air Temperatures

Watch youtube video Pt 2: How Sea Ice Controls Arctic Heat Ventilation and Arctic Air Temperatures

https://youtu.be/bm8UcrOQoso

Below is the transcription of the video

Welcome 

Today, I'm looking at part two,  how sea ice controls the ventilation of heat from the Arctic ocean and the Arctic's air temperatures. 

Now there are three major factors affecting sea ice extent and thus Arctic temperatures. The first, as detailed in part one, the volume of inflowing warm Atlantic water into the Arctic has correlated with sea ice extent for decades and millennia. The warm inflow circulates inside the Arctic for 25 to 30 years and peer reviewed studies such as Polyakov (2017) have determined there is currently enough heat flowing into the Arctic to completely melt all the sea ice.

However, the heat of the inflowing Atlantic water has no effect on air temperature, if sea ice insulates that warmth from the atmosphere. Furthermore, the layers of fresher water, such as the inflowing Pacific water float above the warm Atlantic water, and also insulate the ice and the atmosphere from warmer subsurface temperatures.

The warm inflows create a warm subsurface Atlantic water between about 150 and 900 meters.

Due to the effects of saltiness, the melting point of Arctic water is a negative 1.8 degrees centigrade or 28.8 Fahrenheit. But peer reviewed study such as Shu (2019) has determined the warm water entering Arctic via the Fram Strait is much higher, about three degrees centigrade or 37.4 Fahrenheit, easily melting sea ice.

As the Atlantic water circulates around the Arctic heat ventilates from the open water and the thinner ice, and warms the air while it is cooling to about 0.4 degrees centigrade; still warm enough to have melt sea ice. However, regions with thick multi-year sea ice will insulate Atlantic water heat from radiating back to the atmosphere. Now the 3 degrees of inflowing heat through the Fram Strait thins the sea ice along its Eurasian coast pathway. But as the heat ventilates into the atmosphere, the inflowing water cools to 0.4 degrees centigrade. So sea ice in the Central and Western Arctic tends to be thicker than in the Eastern Arctic. 

But before that 3 degrees centigrade Atlantic water reaches the Fram strait,  water entering the Arctic circle (designated by this red line) is much warmer and has been keeping most of the Greenland, Norwegian and Barents eSeas free of winter ice. Now, the effects of thicker sea icce explains the results of a peer reviewed paper published in 1993 in the esteemed scientific journal Nature. Researchers measuring air temperatures over Western and central Arctic ice, found no warming over a period of 40 years and even a slight cooling.

So they reported no evidence of any greenhouse warming.

The effect of sea ice on Arctic temperature is more dramatically exhibited by the  Dansgaard-Oeschger events.                                                                                    

Between our current warm interglacial and the previous warm inter-glacial, there is the cold 100,000+ year glacial period. A closer look at that glacial period reveals over 20 rapid warming Dansgaard-Oeschger events, during which air temperature rose by an incredible 5 to 15 degrees centigrade or 9 to 27 Fahrenheit in just a few decades.

And despite a heavily glaciated Northern hemisphere, temperatures were almost as warm as the final warm event that led to the present warm into glacial.

Now there are several hypotheses, all of which may be in play explaining why se ice suddenly released ocean heat to produce those warm Dansgaard-Oeschger events. Some hypothesize that these warm events were caused by an increase in warm water inflows. 

Other suggests because thicker ice was preventing heat from ventilating as their temperatures cooled, sub surface temperatures increased to the point it melted the ice. 

And also as the glaciers grew covering the land from Chicago to Boston, with ice a half a mile thick,  sea level fell creating the Bering Strait land bridge that allowed humans to migrate from Asia to north America, but it also lowered sea level and blocked the inflow of fresher Pacific water.

And without the insulating layer of Pacific water, the warm Atlantic water had a greater direct contact with sea ice, which was then melted more readily.

In our present interglacial, sea ice grows each winter and then it melts each summer.

But typically only the thin first year sea ice represented by the purple color is lost, allowing heat to ventilate. The following winter, summer's open water is covered again by the new ice.  

Thick multi-year sea ice only grows where slabs of ice pile on top of one another, especially where ice slabs are pushed against the Northern Greenland coast or the Canadian Islands as represented by non purple colors. That is where the thickest four-year-old and older ice is maintained. And the bulk of that multi-year ice large is largely unaffected between winter and summer temperatures. However, the amount of thick ice can be greatly altered by the winds of the natural Arctic oscillation, which varies on timescales from weeks to decades to millennia

Peer reviewed science by Ignatius Rigor determined that in 1989, the positive phase of the Arctic oscillation became more dominant and removed thick multi-year ice from the Arctic allowing more heat to ventilate from the subsurface causing the recent rapid Arctic warming.

Now previously in the 1970s and eighties, when the negative phase dominated winds, trapped sea ice inside the Beaufort Gyre, seen in the lower yellow curve, increasing the amount of colliding and overlapping ice.

Along the Eurasian coast, the cold Siberian winds guided the Transpolar Drift (TPD) the upper yellow curve, which primarily carried just thin first-year ice out of the Arctic through the Fram straight to melt in the Atlantic 

The 1989 switch to the positive phase caused a Transpolar Drift to dive deep into the center of the Arctic. Following the path of the red curve seen here and then drove increasing amounts of thick multi-year sea ice out of the Arctic into the Atlantic, through the Fram Strait.

Ocean and atmospheric circulation are clearly the critical climate dynamics, controlling sea ice, heat ventilation, and Arctic warming. But those dynamics are the elephants in the room, rarely addressed by a mainstream media bent on pushing clickbait, driven by climate crisis headlines.

So to summarize 

Presently warm Atlantic inflows mediate sea ice extent and maintain the warm subsurface Atlantic water layer. 

The release of heat from the surface is largely mediated by sea ice thickness. The varying winds driven by the Arctic oscillation can either trap and grow thick ice or remove thick ice 

Combined, those two dynamics have reduced sea ice extent in recent decades, allowing more subsurface heat to ventilate. The ventilating heat cools the ocean while warming the Arctic air.  Higher temperatures caused by a cooling ocean should NEVER be added to a global average temperature that's intended to measure increasing stored heat. 

And although it's true, more ventilation made available more heat available to be recycled via the greenhouse effect, that dynamic is relatively insignificant. Rising CO2 attribution is the media's way of having the tail wag the elephant.

Ocean and atmospheric circulation are by far the most significant drivers of sea ice changes and Arctic warming.

I emphasize again,  ocean and atmospheric circulation are the most significant drivers of the so-called Arctic amplification. 

Up next In part three, I'll examine how the sun affects the amount of warm tropical waters flowing into the Arctic. 

And until then embrace Thomas Huxley's advice "That skepticism is the highest of duties and blind faith, the one unpardonable sin."

 And if you appreciate the science clearly presented here, science rarely presented by mainstream media.

Then please give it a, like, give it a share or copy the URL of the video and email it to friends, subscribe to my channel or read my book, landscapes and cycles and environmentalist journey to climate skepticism.

 Thank you.

Cycles of Rapid Climate Warming

Published in the Pacifca Tribune May 28, 2019

What’s Natural

Cycles of Rapid Climate Warming

The globally averaged temperature rose 1.5°F from 1880 to today. Various narratives suggest the rise since 1950 was driven by increasing concentrations of CO2. The rising temperature before 1950 was considered natural. Since 1990, Arctic temperatures rose 2 to 3 times faster than the global average. So, are rapidly rising Arctic temperatures evidence of an impending climate crisis? 

Astute students of climate history recall rapid Arctic warming has happened often and naturally. During the last Ice Age when CO₂ concentrations were just half of today’s, 25 abrupt warming eventshappened. Arctic temperatures rose 9°F, and sometimes as much as 14°F in just 40 years. These rapid warming episodes are now called Dansgaard–Oeschgerevents (D-O events) in honor of the researchers who first detected them in Greenland’s ice cores. These D-O episodes affected global climate, changed ocean currents along California’s coast and altered the range of European forests.

What caused such abrupt warming? Basic physics dismisses changes in greenhouse gases or solar insolation because neither radiative effect induces such rapid warming. The most reasonable explanation suggests episodes of ventilating heat, that had accumulated in the Arctic Ocean, rapidly warmed the air. 

The notion of stored heat in a freezing Arctic Ocean seems unfathomable to many laypeople. But it is scientifically well documented.Tropical Atlantic waters experience intense heating and evaporation. This results in warm salty water that is relatively dense. The Gulf Stream and its branching currents then transport that warm water northward. Because the water is salty and dense it sinks below colder and fresher surface waters as it approaches the Arctic Ocean. As a result, there is a layer of warm Atlantic water stored at depths between 300 and 2,700 feet below the Arctic Ocean’s surface.Arctic researchers report, “the total quantity of heat is substantial, enough to melt the Arctic sea ice cover several times over.”

Warm Atlantic Water in the Arctic Ocean

Sea ice and a layer of cold fresh water normally inhibit subsurface heat from ventilating to the atmosphere. But as the incoming heat increases and accumulates, the warm Atlantic Waters can eventually melt the overlying ice cover. Other times, changes in the direction of Arctic winds will blow sea ice out into the Atlantic, as it did in the late 1990s. Either way, without insulating ice, a burst of heat ventilates from the ocean and warms the atmosphere. 

Recently, anthropologists studying past Arctic cultures found the pre-Dorsett culture periodically abandoned then recolonized the Arctic coast as changes in sea ice affected temperatures. When sea ice covered coastal waters for 2 months longer than today, temperatures became 3-7°F cooler. Arctic people then abandoned the coast and moved south. A few hundred years later they re-colonized the coast when periods of open water, lasting 4 months longer than today, allowed heat to ventilate and raise temperatures 10°F warmer than today.  Such changes alternated over several hundred years. And that raises the question, is the Arctic still experiencing similar cyclical warming?

Over the past several hundred years, melting Arctic sea ice corresponds with observed periods of increased intrusions of warm Atlantic waters. The dramatic Arctic warming during the 1920s and 1930s corresponded with increased intrusions of warm water accompanied by Atlantic fish species normally found further south. As the 1922 newspaper clipping reveals (see above), the warming of the Arctic was so dramatic it raised concerns the frigid Arctic would soon be converted to a warmer “temperate zone”. 

Arctic 1922

When warm water inflows began retreating around 1950 so did the Atlantic fish. Sea ice then increased.  Such cycles have been recorded infishery data for hundreds of years. The most recent cycle of melting Arctic sea ice likewise coincided with intruding warm Atlantic waters with patterns of invading fish very similar to the 1920s-1930s warming episode.

So, we are now in the midst of an instructive natural experiment. If the loss of Arctic sea ice and warmer temperatures are due to rising CO₂concentrations, we should soon see a total loss of Arctic sea ice as predicted by some climate scientists. In contrast, if natural oscillations are controlling intrusions of warm Atlantic waters, Arctic sea ice will soon rebound. Indeed, a recent shift in ocean oscillations is now decreasing warm water intrusions. Temperatures should fall as less heat ventilates into the atmosphere. Based on earlier 20^thcentury patterns when lost sea ice rebounded in the 1960s and 70s, Arctic sea ice should begin rebounding by the year 2030. But then again, warmer temperatures did last for 300 years during cycles a few thousand years ago. Either way, natural climate cycles predict Arctic temperatures will not experience further accelerated warming. We will soon see which theory is most accurate within the coming decade.

Jim Steele is retired director of the Sierra Nevada Field Campus, SFSU

and authored Landscapes and Cycles: An Environmentalist’s Journey to Climate Skepticism

Contact: naturalclimatechange@earthlink.net

Listing the Bearded Seal as Threatened: A Disturbing Victory for Untestable Hypotheses and Flawed Models

Bearded Seal on typical small ice floe

I’m a longtime supporter of the Endangered Species Act (ESA). When properly abided by, it seeks to prevent extinctions and requires humanity to seek a win-win scenario where both humans and all the other species can thrive. Unfortunately, some organizations like the Center for Biological Diversity have weaponized the ESA in order to manipulate the debate on energy policy and climate change by petitioning the courts to designate perfectly robust species as endangered or threatened from future climate change. Such abuse has understandably caused a growing backlash that ultimately threatens the ESA’s original mission. The listing of the polar bear is a case in point. Despite Center for Biological Diversity assertions that “Arctic sea ice melt is a disaster for the polar bears”, research shows polar bear populations have continued to thrive and increase.

The Center for Biological Diversity also petitioned to list thriving populations of Bearded Seals as threatened or endangered by melting sea ice. In response to their petition, the National Marine Fisheries Service (NMFS) assembled a Bearded Seal Biological Review Team (BRT). The BRT’s report can be read here. Oddly, despite promoting a threatened designation, the BRT reports Bearded Seals have existed for over 1-2 million years, surviving far greater bouts of climate change as the earth bounced between several ice ages and warmer interglacials.

On average, every hundred thousand years for the past half million years, the earth has descended into an ice age. Ice accumulation on land lowered sea level by about 400 feet (120 meters). The Arctic’s presently bountiful shallow seas were left high and dry and passage from the Pacific Ocean to the Arctic Ocean was completely blocked by the resultant Beringia land bridge. Any seals trapped in a frozen Arctic were likely extirpated. During the last ice age, seals also experienced far more rapid changes than they are experiencing now or that are predicted in the future. Despite the extreme cold of the last ice age, the BRT reported “more than 20 so‐called Dansgaard‐Oeschger oscillations have been documented … each with rapid warming to near inter‐glacial temperatures over just a few decades.” 

Melting ice during our recent interglacial, known as the Holocene, has been good for seals. Sea levels rose and flooded coastal areas to create what is now the seal’s prime shallow-water habitat. Our best scientific data has determined Arctic temperatures between 9,000 and 6,000 years ago were a few degrees warmer than today, eliminating remnant glaciers and minimizing Arctic sea ice. Sea levels peaked around 6000 years ago, allowing an increased flow of warm, nutrient-rich “Pacific Water” across the shallow Bering Strait into the western Arctic. Our best scientific evidence reveals periodic warm water inflows coincide with peak marine productivity.

Unaffected by a slight increase in CO2 concentrations, sea levels began to fall as glaciers began to expand over the past 5000 years, the Neoglacial. Glaciers reached their greatest extent during the Little Ice Age 150 years ago. During the Neoglacial, average Pacific Water inflows subsided, average sea ice has increased, and marine productivity decreased. During this cooling trend, there were several warm spikes, usually associated with life-enhancing inflows of both warm Pacific and Atlantic water. High inflows consistently correlate with reduced sea ice and greater marine productivity. If the hypothesized warming from greenhouse gases proves to be true and if it can prevent further descent into another ice age or another little Ice Age, it is more likely than not such a warming effect would benefit the entire Arctic food web that sustains “threatened” bearded seals.

The state of Alaska and the Alaskan Oil and Gas Association correctly challenged the “threatened” designation as an “arbitrary, capricious abuse of discretion, or otherwise not in accordance with law”. A district court agreed concluding that the listing indeed violated the Administrative Procedure Act. In that decision, the court reported it was troubling that the Beringia population of bearded seals was listed as threatened simply based on threats predicted by climate models that would not manifest until the end of the 21st century. However, that ruling was quickly appealed and now reversed, as the courts upheld the “threatened” designation.

The judge wrote the court was required to “defer to the agency’s [NMFS] interpretation of complex scientific data so long as the agency provides a reasonable explanation for adopting its approach.” The court also ruled that the ESA requirement for proving an imminent threat in the “foreseeable future” only required a scenario that it was “more likely than not” seals could be endangered.

The court ruling maintained that “as long as the agency states a rational connection between the facts found and the decision made [for listing] it must be upheld.”  Unfortunately judges who decide the validity of a Center for Biological Diversity claim, rarely have any background in biology or climate science. Those judges must rely on what lawyers assert are “the best available scientific data”. But lawyers and advocacy scientists only present the “best available scientific data” that supports their arguments, and ignore equally valid scientific data that contradict their claims. Unfortunately all the known facts were not presented. So even though 2 million years of climate history illustrated bearded seals are highly resilient, the court was swayed by a limited selection of models and untestable predictions. So, as Paul Harvey would say, here’s the rest of the story.

Defining Sea Ice as Critical Habitat

Although the Biological Review Team acknowledged “there is ample evidence that bearded seals have

adapted successfully many times to both large and rapid ecological changes” they argued “history is not, on its own, an assurance that bearded seals can adapt to the changes projected for the foreseeable future.” To make the case bearded seals were threatened, the BRT argued sea ice is a critical habitat required for birthing, nursing, molting and for resting while over prime foraging habitat. Because global climate models predict critical sea ice habitat will disappear as CO2 concentrations rise, they argue the seals are ultimately endangered. However ample evidence suggests sea ice is not a survival requirement.

When Bearded Seals do haul out onto sea ice, they prefer tiny floes of thin first-year ice. Climate change, whether natural or anthropogenic, will not eliminate that first-year ice. As the BRT reported, “sea ice will always persist from late fall through mid‐summer due to cold and dark winter conditions.”  Much of the Bearded Seal’s habitat encompasses seasonal ice zones where first-year sea ice is renewed every winter but melts completely every summer. The Bering Sea, Barents Sea, Baffin Bay, the Sea of Okhotsk, and Hudson Bay are all seasonal ice zones. Renewed winter ice reaches its maximum in late March about the time of the solar equinox. Simultaneously whelping (giving birth) begins in March and peaks in April followed by 2 to 3 weeks of nursing, a time with plenty of ice. The loss of thick multi-year ice over the deep Arctic basin in September has no effect on bearded seals survival.

Heavy sea ice is a bigger threat to bearded seals, so they avoid regions where sea ice cover is more than 90%. Heavy sea ice acts as a barrier that prevents access to their feeding grounds. Each winter bearded seals in the Pacific sector migrate southward as winter ice prevents access to their favored feeding grounds. As sea ice recedes with increasing spring and summer insolation, feeding grounds once again become available. Bearded seals are in competition with other benthic (sea floor) feeders, walrus and gray whales, who likewise migrate into the Arctic as the ice melts. Due to the advantage of accessing the sea floor as soon as dwindling sea ice permits, bearded seals are frequently associated with 70 to 90% sea ice concentrations. Although resting on floating ice above their feeding grounds imparts a small energetic benefit, it is not a life-saving requirement.

For example, although the sample size has been very small, studies of radio-collared seals in the Bering and Chukchi Seas observed those seals rarely hauled out at all, on land or sea ice, even when occupying ice covered areas. The BRT concluded that “at least in the Bering and Chukchi Seas, bearded seals may not require the presence sea ice for a significant part of the year”.

The BRT then manufactured an untested sea-ice threshold based solely on circumstantial evidence to assert whelping and nursing required sea ice concentrations over 25%. As the BRT stated, “Research suggests that, during the time of whelping and nursing, bearded seals prefer areas where the percent concentration of sea ice is >25%. Lacking a more direct measure of the relationship between bearded seal vital rates and ice coverage, the BRT assumed that this preference relationship reflects the species requirements for sea‐ice coverage.” Based Solely on that assumption wherever climate models projected ice falling below 25% concentration, they deemed it “inadequate for whelping and nursing.” [all emphasis mine]

But breeding seals’ ice association is not a matter of preference or a requirement!  To maximize the time spent over accessible foraging grounds, pups are born in the spring when winter sea ice begins its retreat. As the BRT reported, bearded seals prefer foraging in open ice cover where the sea floor is less tan 100 meters deep. Thus, to whelp in April and still remain for over shallow feeding grounds, seals are coincidentally surrounded by extensive winter sea ice. Figure 1 below illustrates the Pacific sector’s potential foraging grounds. White regions mark shallow areas, typically 50 to 100 meters depth. Because bearded seals cannot forage in deep waters (illustrated by the dark blue color), they cannot breed in ice free waters located south of the shallow Bering Sea.

The illustration’s colored lines represent the “ice front” position each month. In March, sea ice concentrations less than 15% are found to the south of the light green line. By peak whelping time in April, heavy sea ice concentrations (turquoise line) largely remain as in March. Thus, during the optimal season for whelping, 99% of their foraging habitat is covered by ice concentrations greater than 15% and as high as 100%. Seals do not prefer to breed in this heavy ice! They are forced to if they want access to required shallow feeding grounds. Consistent with this analysis, the BRT reports during the spring in the eastern and northern Bering Sea, the Chukchi Sea, and the Laptev Sea, where much of the first-year sea ice is heavily compacted, breeding bearded seals are not found in any significant numbers.

 

Figure 1. Monthly location of west Arctic ice front

On the other hand, bearded seals are definitely adapted to survive in ice free waters. Mating always happens in the water. Native Arctic hunters observe seals giving birth in the water. Furthermore, bearded seal pups are well adapted to enter the water immediately after birth. Harp Seals for example require weeks of development on the ice. To thermo-regulate harp seal pups are born with a white fur called the lanugo. The lanugo provides excellent protection from cold air, which is why baby Harp seals were heavily hunted for the fur trade. But the lanugo provides little insulation when wet. So after a few weeks, Harp seals molt their lanugo and gain a protective layer of fat so they can enter the sea. In contrast, most Bearded Seal pups amazingly molt their lanugo within the uterus. They are also born with a thicker layer of blubber and begin foraging in the sea right after birth. So, birthing on an ice floe is more likely a convenience, but not a requirement.

Although it has not yet been reported, newborn pups are probably capable of nursing underwater as well. Based on the amount of time spent in the water right after birth this seems likely. Marine mammals such as whales and manatees must nurse underwater. And although California Sea lion pups primarily nurse on land, they too have been observed nursing underwater.

In habitat where sea ice either melts completely or recedes beyond the limits of shallow-water feeding grounds, bearded seals simply come ashore. Observations of seals on dry land have been documented for the White and Laptev Seas, the Bering, Chukchi and Beaufort Seas, for Svalbard, the Hudson Bay and the Okhotsk Sea. The Okhotsk and Kamchatka populations thrive in the most southerly part of the seal’s range where ice melts completely each summer. There, bearded seals form numerous shore rookeries comprised of tens to hundreds of individuals, during a time that overlaps with molting.

Finally, their preferred small ice floes do not offer protection from the seals’ 2 major predators. Polar bears are well adapted for surreptitiously swimming up to floating ice and snatching an unwary seal. Killer Whales readily grab a seal from floating ice or tip that ice over, dumping the seal into the water where it is no match for the Orca. Thus, many lines of evidence suggest it is “more likely than not” that observations of bearded seals resting on sea ice platforms is only evidence of a convenience, not a survival requirement.

Small ice floes do not protect bearded seals from their predators

The IPCC Models

The Biological Review Team included one climate scientist, James Overland and he predicts the Arctic will be ice free within the next decade or two. (By “ice free” he means September ice will be reduced to about 1 million square kilometers.). Although there is a general consensus among models that rising CO2 will drive warming and continued ice melt into the future, IPCC models failed to predict the current level of rapid sea ice reduction. Because IPCC models projected currently observed sea-ice reduction would not occur until 2070, Overland believes IPCC models were simply too conservative. However other evidence suggests the models are flawed because they did not accurately incorporate natural variability. Nonetheless, Overland used a select group of 6 IPCC models to convince the courts rising CO2 concentrations threatened to destroy and modify the seals’ sea ice habitat.

For the BRT analysis, Overland culled the most flawed IPCC models. His chosen models had to simulate the seasonal changes in ice cover to demonstrate an accurate sensitivity to changes in solar insolation. In addition, chosen models had to simulate (hindcast), within 20% accuracy, September sea ice extent observed from 1980 to 1999. The number of IPCC models fitting this selection criteria was reduced to six. However, the time span to accurately test the models’ reliability was far too short. IPCC models attempting to replicate 20^th century Arctic air temperatures have failed to reproduce the rapid warming from 1920 to 1940. Furthermore, those 6 models failed to accurately simulate observed sea ice extent for individual Arctic basins.

Of Overland’s 6 best models, all 6 only simulated past sea ice correctly in the Chukchi and Siberian seas. Four models correctly simulated sea ice in the eastern Bering seas.  Only one model could simulate recent sea ice in the western Bering and Barents sea. None of the models satisfactorily simulated sea ice in the Sea of Okhotsk, Hudson Bay and Baffin Bay, the Canadian Archipelago, or Greenland, Kara and Laptev Seas. As the BRT correctly cautioned, “loss of summer sea ice in the Arctic cannot be extrapolated to the seasonal ice zones which are behaving differently than the Arctic. For example, the Bering Sea has had 4 years of colder than normal winter and spring conditions from 2007‐2010, with near record sea‐ice extents, rivaling the sea ice maximum in the mid‐1970s, despite record retreats during summer in the Arctic.”

 

From Gillett 2008: IPCC models fail to simulate natural Arctic warming 1920-1940

As seen in the graph above from Gillett 2008, IPCC model simulations based solely on known natural factors (the blue line labeled NAT), erroneously reported no change in 20^th century Arctic temperatures. Observations revealed (the black line labeled OBS) temperatures had naturally oscillated. Actual temperatures compared to model results were as much as 0.6 C degrees higher in the 1930s and 40s but then lower after the 1960s. More disconcerting, when models added the effects of CO2 and aerosols to natural factors (the red line labeled ALL), discrepancies between models and 1940s observations worsened. A modeling study by Johannessen 2004 failed similarly. In contrast to flawed CO2-driven models, it is well-documented that warming from 1920-1940 as well as the current sea ice loss is more parsimoniously attributed to changes in atmospheric and ocean circulations that pump warm southerly air and water into the Arctic. Although judges believed they were presented with the “best scientific models”, those best scientific predictions had failed to simulate past natural climate change.

The BRT did not inform the courts of research that shows a small Arctic cooling trend for the period 1901 to 1997, a trend contrary to the CO2 global warming hypothesis. A similar cooling trend was reported in the 1993 paper, “Absence of Evidence for Greenhouse Warming over the Arctic Ocean in the Past 40 years”. Nor did the BRT discuss research detailing how the loss of sea ice in the 1990s was not caused by warmer air, but by a shift in the Arctic Oscillation resulting in below-freezing winds that pushed thick insulating ice out into the Atlantic.

Furthermore, it’s not obvious that the BRT advised the judges that our best scientific data has observed that past and recent reductions of sea ice have coincided with intrusions of relatively warm Atlantic and Pacific waters. Fishery data shows warming in the 1930s coincided with the arrival of fish normally found further south. Recent analyses show similar northward fish migrations are associated with intruding warm Atlantic waters, driven by natural shifts in the North Atlantic Oscillations and Atlantic Multidecadal Oscillation. In the Atlantic sector, the greatest loss of Arctic ice occurs in the Barents Sea and associated with the pathways of intruding warm water.

Intruding dense salty warm water also generates a reservoir of Arctic heat stored between 100 and 900 meters depth. That heat reservoir can melt all Arctic sea ice several times over. Indeed, the most recent scientific research reveals that warm reservoir has been rising closer to the surface and thinning sea ice. Researchers called this dynamic the atlantification of the Arctic Ocean.

In 2007, the greatest reduction of sea ice happened in the Chukchi Sea. Research by Rebecca Woodgate using mooring and satellite data, documented that the volume and heat content of intruding warm water. She reported Pacific water passing through the Bering Strait into the Chukchi had doubled since 2001. The inflowing Pacific Waters spread across half the Arctic Ocean with a heat equivalent equal to, and up to twice as great, as possible heat estimated from CO2 back-radiation. The amount of heat carried by those intruding waters was comparable to the solar heating of the entre Chukchi Sea.

The resulting enhanced loss of summer and winter sea ice resulted in feedbacks, associated with Arctic Amplification, which has raised Arctic air temperatures at a rate twice the global average. Less insulating ice allows the heat reservoir to more easily ventilate, cooling the ocean but warming the air. Furthermore, researchers show the loss of sea ice reconnects the oceans with the winds causing a stirring effect that brings warmer water to the surface. Less ice lowers the ocean’s albedo allowing more solar heat to be absorbed. Finally, the re-formation of lost ice, releases more latent heat. All those warming effects caused by increased inflows, have been myopically attributed to rising CO2.

Less ice benefits the food web. As outlined by Grebmeir 2015, the productivity in the Chukchi Sea (and likely the entire Arctic ocean) depends on the inflows of nutrient rich waters. The same intrusions of warm water through the Bering Strait that reduces sea ice, also bring vital nutrients that increases productivity, as well as bringing warmth that enhances faster growth. Our best scientific evidence suggests that if the Arctic becomes ice free by mid-21^st century, more open water will enhance photosynthesis so that marine productivity will increase by 67%. Thus, it is “more likely than not” that the dynamics that are now reducing Arctic sea ice are also increasing the food supply, not just for bearded seals but for the whole food web. Because bearded seals currently consume a huge variety of fish and invertebrates, it is highly likely bearded seals will easily adapt to any foreseeable changes in the food web.

When the “rest of the story” is told, it seems highly unlikely bearded seals will be endangered by reduced sea ice or warming temperatures. It is the Endangered Species Act itself that is endangered because the Center for Biological Diversity and their ilk abuse the ESA to promote climate fear. Instead what should rightfully evoke our greatest concern is how climate change alarmism is eroding objective science, allowing untestable hypotheses and flawed models to become codified in our legal system.