Translate

Thursday, December 3, 2015

Is Antarctica’s Climate Change Natural or CO2 Driven? There Is Absolutely No Consensus


The record growth of Antarctic sea ice has long been a troubling contradiction for global warming theory. But those who embrace CO2 as the driver of climate change typically countered that global warming was still melting the continental glaciers and raising sea levels. However on October 29, 2015 a team of NASA researchers led by Jay Zwally published the paper “Mass gains of the Antarctic ice sheet exceed losses”. If the new NASA research proves correct - and there is good evidence to suggest it is - continental ice is increasing and lowering sea level. That would highlight another major failure for both CO2 driven models and models of sea level change. The reaction of Dr. Theodore Scambos, senior research scientist at the National Snow & Ice Data Center, was all too reminiscent of the “hide the decline” mentality evidenced by advocacy scientists in the climategate scandal. In an Al Jazeera interview Scambos asked, “Please don’t publicize this study.”  Others pushed back by simply listing any research that disagreed with Zwally, but rarely did they list the research supporting Zwally’s results. Nor did they delve into why there is no Antarctica consensus, as I will do here.

Some researchers did acknowledge the great climate uncertainties. Robin Bell, a research professor at Columbia University's Lamont-Doherty Earth Observatory admitted, "To me this points out that we still don't understand everything about how snow turns into ice and how the ice sheets are changing." Even more revealing were comments posted by Dr. Eric Steig at Michael Mann’s RealClimate website, comments that reveal a total lack of consensus and suggest greater support for natural climate change. Dr Steig has published extensively on Antarctica and has been a regular contributor to the RealClimate website. So he is not someone who can be dismissed as a “denier”.  Steig wrote,

I think the evidence that the current retreat of Antarctic glaciers is owing to anthropogenic global warming is weak. The literature is mixed on this, about 50% of experts agree with me on this.”

On the other side of the issue RealClimate’s Gavin Schmidt downplayed Zwally’s results as we would expect telling interviewers, "I would pin more weight to the GRACE data than to this latest paper." But it is not a matter of putting more weight on satellite data that measures gravity change (GRACE) or satellite data that measures changes in elevation (Zwally et al).  Both methods are victimized by faulty Glacial Isostatic Adjustment models (GIA). All measurements of increased ice elevation or gravity changes are adjusted according to the assumptions of their GIA model of choice. Most GIA models assume Antarctica has been rebounding upwards since deglaciation removed the weight of glacial ice. The degree of estimated rebound depends on the region and more importantly 1) uncertain estimates of the mantle’s viscosity below the bedrock and 2) assumptions about the glacial history of Antarctica.

It is not clear if Schmidt’s advocacy for the GRACE estimates was guided by his persistent protection of the global warming meme, or if his interviewers omitted any honest discussion of papers demonstrating the upward bias in most GIA estimates. Similarly other Zwally detractors pointed to papers such as Harig 2015 that claimed Antarctica was losing ice, but Harig 2015 used GIA models that were well known to over‑estimate glacial rebound.

To remove bias in GIA models, our best method requires comparing Global Positioning System data (GPS) that measures the current bedrock uplift with GIA modeled predictions. This requires placing GPS instruments on solid bedrock, which is relatively rare throughout most of ice covered Antarctica. However along the coast wherever GPS measurements have been possible, research revealed GIA models had biased the  uplift upwards by 4.9 to 5.0 mm/years relative to GPS observations. Zwally argues that current GIA models should be lowered by just 1.6 mm/ year and that small adjustment would bring the estimates based on GRACE data into agreement with Zwally’s elevation data.

There is more evidence to support Zwallys critique of GIA models. In recent years researchers have been lowering their estimates of mass gained during the last Ice Age and lost ice mass during the recent deglaciation. Previous models estimated Antarctica deglaciation contributed 24-37 meters of sea level rise, but  that contribution has now been reduced to just 6-14 meters. This meant early GIA models had grossly overestimated the weight of past glaciers and the subsequent rebound. By adjusting the de‑glaciation history, Whitehouse 2012 revised their GIA model so that the upward bias was reduced to 1.2 mm/year with error estimates of 2.3 mm/year. Less ice also meant previous models that budgeted sources of sea level rise were wrong. Zwally’s estimate that Antarctica has been gaining ice and thus reducing sea level has created more angst that current models of sea level rise are still in need of further adjustments.

Furthermore, Zwally referenced evidence from Siegert 2003 showing parts of east Antarctica had been gaining mass for the past 10,000 years (Figure 2 below). Counter‑intuitively during the last Glacial Maximum ice accumulation dropped to a minimum. In contrast during warmer interglacials greater incursions of moisture entered the interior of Antarctica and ice accumulation peaked. Because east Antarctic is so cold (South Pole’s average summer temperature is -28C), ice ablation is minimal, so it is more likely east Antarctica is still subsiding under that weight, not uplifting. Zwally’s inference that GIA models should decrease their estimates of bedrock uplift by just 1.6 mm/year again is well supported.

Zwally questioned if snow accumulation could continue to offset the ice lost from glacier thinning elsewhere. But recent evidence suggests it will. Zwally’s study did not extended past 2008 but he estimated that during the period studied, net accumulation had reduced sea level rise 0.23 mm/year ( a 6 to 10% reduction). More recent GRACE evidence has suggested even larger accumulation events since then. A 2012 study determined east Antarctica gained 350 Gigatons of snow between 2009 and 2011, enough to decrease sea level rise by 0.32 mm/year. A 2015 study using regional ice core data reveals no unusual temperature changes but an exceptional 30% increase in snow accumulation during the twentieth century, supporting Zwally’s analysis of mass gain in interior west Antarctica.

East Antarctic Ice Accumulation between glacial and interglacial periods



Similarly Greenland’s snowfall accumulation is at all time highs and recent GRACE results show that after several years of accelerated ice loss due to glacier thinning, the net loss from Greenland in 2013-2014 was insignificant. As discussed here, relative to the years of greater ice loss in Greenland, the rate of sea level rise should have dropped by an additional 1.3 mm/year in 2014. Combining Zwally’s calculations with recent evidence from Greenland, sea level models driven by global warming should reveal a decreasing rate of sea level rise. It appears that global warming fears have been misdirecting research concerned with coastal flooding. Research shows groundwater extraction is not only contributing significantly to recent sea level rise, but land is sinking at a faster rate due to that extraction. Regretfully President Obama has highlighted coastal flooding to further politicize climate change, but never mentions the more critical issue of ground water extraction that desperately needs attention.

Zwally’s analysis also noted that previous estimates of Antarctica’s ice mass assumed that increases in elevation were due to snowfall. But when ice accumulation is greater than ice discharge, drainage basins undergo dynamic thickening, and dynamic thickening can occur in response to accumulation events that happened thousands of years ago. Because the density of ice is about 3 times the density of snow, if researchers incorrectly assume increased elevations are only due to snowfall and not dynamic thickening, estimates of ice mass will be greatly underestimated. This points out the need to see climate change within a framework of thousands of years, not just the past few decades, and Zwally’s interpretation of dynamic thickening can be readily tested by additional ice cores.

In the face of Zwally’s analysis, defenders of the CO2 warming meme retreated to stressing uncontested observations of lost ice due to dynamic glacier thinning or uncritically accepting speculative models  catastrophic deglaciation. Although Zwally calculated the net “mass gains from snow accumulation exceeded losses from ice discharge by about 112 and 82 Gt/year respectively during the 1992-2001 and 2003-08 measurement periods”, he also reported that the rate of ice loss along the west Antarctic coast and the peninsula had increased from 64 GT/year to 135 GT/year during those same periods. Alarmists seize upon this short‑term acceleration to suggest rising CO2 will cause the rate of dynamic thinning to increase. But research shows dynamic thinning has been more cyclical, intermittent and episodic with no correlation with CO2 concentrations. For example a large 1987 calving event removed 100 years of ice accumulation from the Ross Ice Shelf in just one day, an amount second only to the loss of the Larsen Ice Shelf. Such episodic events can easily be misinterpreted as an “acceleration” of ice loss. However due to the heavier snow accumulation since that time, the ice shelf has expanded further northward exceeding it previous extent in just over a decade (Keys 1998). Antarctica undergoes rapid ice loss followed by periods of slower recuperation depending on regional rates of snow accumulation. So a much broader timescale of climate change must be embraced.

Research has determined these episodic calving events are most often driven by periodic upwelling of warm Circumpolar Deep Water (CDW) that melts glaciers from below (basal melting). The extremely cold Antarctic climate maintains a 200 to 300 meter  surface layer of near freezing Winter Water that insulates warmer CDW below. All grounding points below 300 meters have been susceptible to basal melting from upwelled CDW for millennia, and a pattern has emerged that glaciers with deeper grounding points incur greater basal melting. Thus the topography of the coastal shelves and depth of submerged glacier grounding points determines the impact of upwelled CDW and limits extreme basal melting to a relatively few locations as illustrated by the red and orange areas in the figure below (from Depoorter 2013)..


Glacial Thinning and Basal Melting Hot Spots


Reports of increased basal melting due to “warmer” water is often misinterpreted to mean CDW water had been warmed by rising CO2. But CDW is a tremendous reservoir of heat that only experiences temperature changes on long‑term scales of centuries and millennia. Upwelled CDW water can be cooled when modified by winter water, or remain warm when it directly accesses a glacier grounding point. Reading recent research carefully reveals no change in the temperature CDW source waters. It is periodic increases in the volume and velocity of intruding CDW that accelerates basal melt. Coastal shelves that allow the  greatest intrusions of relatively warm CDW experience that greatest basal melt such as Pine Island and Thwaites glaciers, which account for the overwhelming majority of Antarctica’s dynamic thinning. Antarctica’s glacial thinning is a very localized phenomenon, and not evidence of global warming.


In addition to conducive topography, intrusions of warm CDW are driven by periodic changes in  the winds which in turn are controlled primarily by the Amundsen Sea Low (ASL), a quasi-permanent low pressure system. The ASL shifts poleward and equatorward, as well as eastward and westward with the seasons. It also shifts in response to inter‑annual and decadal changes in sea surface temperatures in the tropical Pacific. The shifting center of the ASL causes varying wind intensities that also alternate direction between easterlies and westerlies. As illustrated below the direction of the wind over the shelf break determines the amount of CDW that reaches the glaciers grounding points along the peninsula and Amundsen Sea. Paleo‑climate research suggests the position of the ASL also shifts between glacials and interglacials, and drove warm CDW shoreward during interglacials and accelerated glacier retreat.

Modern cycles of CDW‑driven basal melting are likewise correlated with the position of the ASL and changes in the central Pacific temperatures..  Warming of the central Pacific is associated with an El Nino variation called Modoki EL Niño (see Tisdale for further discussion). And here again there is absolutely no consensus regards the effects of CO2 on the frequency or types of El Niño, but most researchers believe El Niño is an expression of the natural climate variability.  Steig 2012 points out that a cycle warming in the central Pacific, similar to recent years, had last occurred during the 1940s. That earlier warming was associated with a large calving event of the Pine Island Glacier that likely occurred in association with an EL Nino event. Accordingly a 2013 paper reports the  “climate in West Antarctica cannot be distinguished from decadal variability that originates in the tropics.”



Wind driven upwelling of warm Circumpolar Deep Water (CDW)



Zwally deemed it necessary to acknowledge climate change fears and suggested that if the rate of dynamic thinning continues, Antarctica could begin exhibiting a net loss of ice within the next 20 years, but only if there was no compensating snowfall. Yet curiouser and curiouser neither Zwally or the researchers highlighting accelerated thinning of Amundsen Sea glaciers ever mention recent research that measured a 53% decrease in basal melting and up to a 1C drop in melt water temperatures between 2010 and 2012. Melt water temperatures that were lower under the Pine Island Glacier than 1992 temperatures. The decrease in basal melt was attributed to stronger easterly winds that encouraged downwelling along the Amundsen shelf break, which lowered the top of the thermocline (where cold winter waters meets warm CDW) and reduced the volume of upwelled  warm CDW intruding onto the shelf.  Researchers concluded that “Continuation of a deep thermocline would reverse the current ice-shelf thinning.”

Other researchers have demonstrated warming in Antarctica that followed the last glacial maximum preceded any increase in atmospheric CO2. Both warming and CO2 appear to be driven by changes in the position and strength of the westerly winds and the upwelling of warm CDW. During the past 10,000 years research at Marguerite Bay on the peninsula reveals extensive glacial melt, limited sea ice which enhanced primary productivity that lasted for over 2000 years and was consistent with evidence of increased upwelling of warm CDW. The George VI Ice Shelf collapsed about 9000 years ago but reformed 7000 years ago and that shelf still persists today. Over the last 5000 years intermittent melting and reforming of sea ice in the Marguerite Bay is consistent with enhanced sensitivity to ENSO forcing and increased upwelling of CDW; a similar sensitivity to ENSO events has been documented over the most recent decades. History strongly suggests periods of accelerated glacial thinning are natural and quite common.

A more thorough and objective  review of the peer-reviewed literature reveals an abundance of evidence supporting claims of natural climate variability that easily matches, if not outweighs, the trumpeted papers asserting CO2 driven change. It is no wonder Dr. Steig admitted ““I think the evidence that the current retreat of Antarctic glaciers is owing to anthropogenic global warming is weak. The literature is mixed on this, about 50% of experts agree with me on this.”

It will be of great interest to see how the IPCC spins this state of affairs.


Thursday, November 26, 2015

Petition Congress to Investigate USGS Polar Bear Research Methods

 More Research Finds Polar Bears’ Condition Unaffected by Reduced Summer Sea Ice.




Sign Petition Here:     

Share this petition


Although the Inuit steadfastly claim it is “the time of the most polar bears”, the most recent IUCN polar bear assessment predicts a 30% drop in the global polar bear population by mid‑century by assuming a linear correlation between summer sea ice melt and polar bear survival. They suggest bears “require sea ice to hunt” and thus predict less sea ice will prevent access to their preferred prey. However polar bear ecology and observations contradict that simplistic assertion. As listed below the current alarming predictions are due to extremely biased models and critical sins of omission presented in USGS publications, which ultimately misguide conservation efforts and the public’s understanding of the effects of climate change. Please petition congress to promote more reliable polar bear population studies and sign the petition here:


1)   Greater than eighty percent of most polar bears’ annual stored fat is accumulated during the ringed seal pupping season that stretches from late March to the first week of May. Well‑documented observations (Stirling 2002, Harwood 2012, Chambellant 2012) report that cycles of heavy springtime sea ice have drastically reduced ringed seal reproduction. Heavy springtime ice is likely the greatest cause of polar bear nutritional deprivations, yet not one USGS model incorporates sea ice conditions during this critical time.

2)   In areas like the Chukchi Sea that have experienced some of the greatest reductions in summer sea ice, there has been no reduction in polar bear body condition and some improvement (Rode 2014), contradicting USGS models driven by the hypothesis that less summer sea ice leads to nutritional deprivation.

3)   All USGS models incorporate measures of minimal summer sea ice area in September despite the fact that ringed seals leave the ice in June, after pupping and molting, and swim in distant open waters. During this time less summer ice has little effect on the accessibility of seals.

4)   USGS models assume more open water is detrimental to polar bears. But all published ecological studies (i.e. Harwood 2012, Chambellant 2012) show that ringed seal body condition, and thus seal reproductive outputs, decline when sea ice is slow to clear in the spring. It is longer periods of sea ice that cause lower ringed seal body condition and reproductive fitness that ultimately reduces the polar bears’ prey availability.

5)   The IUCN’s assessment predicting a 30% decline in the global polar bear population is driven largely by the USGS’ models suggesting unique declining polar bear population in Southern Beaufort Sea’s. USGS models:

a.     -calculated unrealistic bear survivorship estimates (0.77 here) during 2005 and 2006 based on mark and recapture models, that were unrealistic compared to known survivorship calculations of radio-collared bears (0.969 here) and survivorship estimates in 2002 to 2004. Only by uncritically embracing unrealistically low survivorship, USGS models created a dramatic drop in estimated abundance.

b.     -blamed less summer ice and global warming for re‑capturing fewer bears, despite observations that heavy springtime sea ice had reduced seal ovulation rates to 30% in 2005 (Harwood 2012), the year models determined the lowest survivor rate for adult bears.

c.      -ignored the 70% reduction in seal pups in 2005 due to heavy springtime ice that forced polar bears to increasingly hunt outside the USGS’ study area and making marked bears unavailable for re‑capture. As discussed here and here, the lack of recaptures due to temporary emigration is easily mistaken as a bear’s death.  The USGS dismissed their own observations of increased transiency. And despite acknowledging an increased number of radio-collared bears outside the study area in 2005 and 2006, USGS modelers suggested that instead of searching elsewhere, bears just died, resulting in a dramatic population decline without the bodies to prove it.

d.     -never published calculations of biological survival for known radio‑collared bears (10% of their study). Biological survival calculations provide a constraint on the reliability of estimated apparent survival from mark and recapture models. Previous research demonstrated that modeled apparent survival dramatically underestimates true biological survival.



Additional Supporting Evidence for Petitioning a USGS investigation

Whether or not reduced Arctic sea ice is the result of natural variability or rising CO2, reduced sea ice benefits the Arctic ecosystem. As discussed in Why Less Summer Ice Increases Polar Bear Populations, evidence and theory unequivocally demonstrates that less ice allows more sunshine for plankton to photosynthesize, causing marine productivity to increase 30% this decade (i.e. Arrigo 2015). Increased marine productivity then reverberates throughout the entire Arctic food chain benefitting cod that are fed on by seals that are fed on by bears. Furthermore all observations have determined that thinner sea ice benefits ringed seals, the polar bears main prey item. Contrary to alarming assertions, less sea ice has generated a more robust food chain!


In a recently published United States Geological Survey (USGS) article, Rode et al (2015) Increased Land Use by Chukchi Sea Polar Bears in Relation to Changing Sea Ice Conditions, researchers tracked radio-collared bears in the Chukchi Sea region and analyzed how much time bears spent on land versus sea ice for the months of August to October. Then they compared that behavior between the 1986–1995 period to 2008–2013. As should be expected with less sea ice, bears naturally spent more time on land. However despite theoretical assertions that less sea ice causes polar bears to suffer “nutritional deprivation”, these researchers observed that a 


lack of a change in the body condition and reproduction of Chukchi Sea polar bears during the time period of this study suggest that Chukchi Sea polar bears either come onshore with sufficient body fat or they are finding sufficient food resources on land (marine or terrestrial) to offset increased durations on land.” 

This confirmed an earlier study during that same time period concluding, “body condition was maintained or improved when sea ice declined”. 

In 2007 the 2nd greatest decrease in Arctic sea ice was observed in the waters surrounding Wrangel Island in the Chukchi Sea. That summer researchers likewise observed greater numbers of polar bears on the island. However again contradicting the “less‑ice‑means‑starving‑bears” theory, there were no signs of increased nutritional stress. Quite the opposite! Researchers determined that only less than 5% of the Wrangel Island bears were skinny or very skinny and that compared very favorably to their previous designations of the 7 to 15% skinny bears observed in years with heavier ice. Furthermore researchers determined that not only did 29% of all bears look “normal”, the remaining 66% were fat or very fat.  Those polar bear experts wrote, 


“Under certain circumstances, such as were observed on Wrangel Island in 2007, resources available in coastal ecosystems may be so abundant that polar bears are able to feed on them more successfully than while hunting on the sea ice.

Wrangel Island equally illustrates Rode (2015)’s alternative explanation for finding healthy polar bears on land: bears can find sufficient food resources on land to supplement their diet after ringed seals leave the ice.” In the essay Has David Attenborough Become A Propaganda Mouthpiece Promoting Climate Fear?  I provided links to published accounts from past centuries and earlier BBC videos demonstrating that polar bears throughout the Chukchi Sea commonly hunt walrus on land; a fact that Attenborough distorted into a cinematic illusion misrepresenting a natural behavior as a function of catastrophic climate change. There is a long list of observations of bears on land actively hunting walruses, reindeer and fish, foraging on berries or scavenging whale carcasses. Although there has been a hypothetical debate on whether or not such supplemental diets could provide the appropriate calories to maintain polar bears’ body condition, based on observations, most bears are doing just fine during years with reduced sea ice.




So why is it suggested that less sea ice reduces polar bears access to food? The short answer is the politics of the “climate wars”. For centuries walruses and polar bears have been observed on land despite much heavier Arctic sea ice during the Little Ice Age. However in the past decade there is a widespread attempt in the media to characterize observations of walruses and bears on land as a “perversion” caused by less sea ice from rising CO2. Skinny injured bears absurdly become media icons of climate change. Yet there is a multitude of peer-reviewed evidence (i.e. McKay 2008,  Fisher 2006) that bears and walruses are well adapted to thrive in the extensive periods of reduced Arctic sea ice that were much less than today and persisted throughout the last 10,000 years of the Holocene.

Nearly every alarmist publication that asserts less sea ice causes polar bears to suffer from nutritional stress references as “proof” a 1999 paper by Ian Stirling showing body condition of bears in the western Hudson Bay declined from the 1980s to 1997. However, as seen in the graph below, since 1997 western Hudson Bay polar bears’ body condition has been improving surpassing levels observed in the1980s despite, or because of, years of reduced sea ice. The unpublished improvements of polar bear body condition during the 2000s corresponds well with published reports that since the heavy ice years of the early 1990s reduced ringed seal body condition and reproduction, ringed seal pups tripled during subsequent lighter ice years of the 2000s.  However Nicholas Lunn of Environment Canada, has yet to publish that data, while Lunn and other PBSG researchers continue to reference only older zombie pre‑1997 data in assessments as recently as 2014. Publication bias that fails to report positive changes has been a disturbing phenomenon observed elsewhere by authors making catastrophic climate assertions (here and here). Dr. Susan Crockford has also highlighted Lunn’s penchant for deceptive reporting here as he attempts to downplay a recent survey that reports increasing bear populations in the Hudson Bay area.




The recent assessment submitted to the International Union for the Conservation of Nature argued a “reduction in mean global population size greater than 30%” by mid‑century. In contrast all polar bear populations have increased after imposing hunting regulation in the late 60s and 70s. Despite a decadal trend of declining sea ice only 3 of 19 populations are now reported to be declining and uniquely only the Southern Beaufort Sea population is attributed to climate change. The Baffin Bay population has declined due to increased hunting by Greenlanders, and declines in the Kane Basin are attributed to low seal populations due to thick multiyear ice. Of the 7 sub‑populations for which there was comparative data presented in the IUCN’s report, four sub‑populations (Foxe Basin, Gulf of Boothia, Davis Strait, Northern Beaufort) have shown increasing populations. Two subpopulations (Western and Southern Hudson Bay) have shown no significant population change (Stapelton 2014).

Only the Southern Beaufort Sea population suggests a dramatic loss of polar bears, yet before the heavy springtime ice in 2005 there was little sign of reduced body condition. A 2007 USGS study reported that between 1982 and 2006, 95% of the bears in the Beaufort Sea region, exhibited body conditions that were stable or improving. Adult female bears that represented about 34% of all captures exhibited improved body condition. All other categories of bears showed no trend in body condition except for sub-adult males that comprised a mere 5% of the individuals examined. Stable and/or improving body condition again is evidence that the lack of summer sea ice has no detrimental effect on the body condition of polar bears. Nonetheless a co-author of that 2007 study, USGS’ Eric Regehr, used the same data to proclaim in a 2010 paper, “evidence suggests that polar bears in the southern Beaufort Sea are under increasing nutritional stress. From 1982 to 2006, body size and body condition for most sex and age classes were positively correlated with the availability of sea ice habitat, and exhibited a statistically significant decline during this period.” 







It is well documented that the Arctic undergoes periodic events producing heavy springtime sea ice that reduces local ringed seal populations in various locations. Ian Stirling co-authored a paper reporting, “heavy ice reduces the availability of low consolidated ridges and refrozen leads with accompanying snowdrifts typically used by ringed seals for birth and haul-out lairs.” He observed in 2005 and 2006, “Hunting success of polar bears (Ursus maritimus) seeking seals was low despite extensive searching for prey.” The most recent paper by USGS researchers Bromaghin 2014 (and discussed here) acknowledges the decline in seal reproduction, yet they never acknowledge that it was a result of a cyclic increase in thick spring ice. As spring ice conditions have now returned to normal, seal ovulation rates also returned to normal, approaching 100%, and the Southern Beaufort bear population is now increasing.  Yet because the USGS researchers continue to assert population declines are due to less summer ice and CO2 climate change, they conclude, 

For reasons that are not clear, survival of adults and cubs began to improve in 2007.”  

But the reasons are not unknown! The USGS simply refuses to acknowledge global warming and lost summer sea ice has not produced any catastrophic change for polar in the recent past. And the prediction of a 30% decline is a myth that they choose to perpetuate.

Sign Petition Here: