Current Issues in Climate Science: Focus on the Poles Print E-mail
Written by Robert Ferguson   
Friday, 13 July 2007 10:28

 

> Let me give you just one fact. Al Gore says the Antarctic and Greenland ice sheets will melt and cause sea level to rise 20 feet, putting the present-day populations of Manhattan, Shanghai, Bangladesh and other coastal regions at risk. The official scientific consensus, represented by the UN Intergovernmental Panel on Climate Change, says that over the coming century the contribution of these two ice sheets to sea-level rise will be not 20 feet but 2 inches; that in each of the past four interglacial warm periods sea level rose to a height five metres above its present level, and did so without any influence from humankind; that sea level will do the same in the present interglacial period; but that it will not rise by 20 feet for several millennia. Indeed, the UN says the probability that our activities make any difference to sea level is little better than 50:50. So, on the scariest of all the "global warming" scares - sea-level rising and displacing hundreds of millions - Al Gore is exaggerating 120-fold, or almost 12,000 per cent. He does not represent the scientific mainstream consensus, but instead speaks for a small, fringe group of politically-motivated scientists. - Lord Christopher Monckton.

 

I. Introduction

In 2007, the heat has been turned up at the Poles. Not by climate change, but by climate alarmists: “Greenland is melting into the sea, Antarctica is soon to follow, sea level will rise by several meters this century. Polar bears will become extinct. Permafrost will melt. Methane will be released. Warming will accelerate.” So the litany goes.

But are things really so? Should school children fear a devastating rise in global sea levels? Will we soon mourn the passing of the polar bears? Will changes in the climate of the Polar Regions lead to ecological and biological devastation? The answer is resoundingly, No! Not according to current observations. Not according to our knowledge of the past. Not according to our best understanding of the future.

Polar bears, as a species, have survived through periods in the past lasting several thousands of years in which Arctic temperatures were significantly higher and Arctic sea ice was significantly less than conditions currently. Their existence today is the strongest testament to their ability to adapt to a changing climate.

The Intergovernmental Panel on Climate Change (IPCC) projects, in its just-released Fourth Assessment Report, a median sea level rise throughout the 21st century of just 14 inches. If the current inputs from Greenland and Antarctica simply reflect natural variability (there is evidence to support this possibility) and/or short-term accelerations, then future sea level rise may even be less.

This paper examines the evidence supporting a non-alarmist view of climate change science, with special emphasis on the polar regions, both the Arctic and the Antarctic. Evidence is presented suggesting that the near term impact of future climate change on the polar regions of the earth, and the rest of the Earth at large - although detectable - will be modest. While this evidence may not be the type that is splashed across the evening news, it is nevertheless a more realistic assessment of the of the Earth’s ever dynamic and variable climate.

II. Greenland Ice Sheets: Yesterday, Today, and Tomorrow

Greenland’s glaciers and ice fields respond to climate changes by advancing and retreating. During rapid warm-up in the early 20th century, Greenland’s glaciers recessed significantly from their extended locations at the end of the Little Ice Age. Currently, many of Greenland’s glaciers are no shorter than the limits established during the mid-20th century.

The existence of the Greenland ice cap is actually a geographical and climatological anomaly, as Greenland sits too far south to have as much snow and ice as it does (about 5% of the world’s ice, enough to raise sea level about 23 feet, lies atop Greenland). Compare the southern portions of Greenland, which lies beneath nearly a mile of ice, with say the European capital cities of Oslo, Stockholm, and Helsinki, which lie roughly along the same line of latitude.

The reason that Greenland currently has so much ice and snow is the altitude and geological formation of the central plateau. More than a mile thickness of ice sits atop all but the coastal portions of Greenland and this enormous mountain of ice serves to make its own climate. Due to its elevation, the surface of Greenland’s central ice cap is some 20 to 30ºF colder than it would be if there was no ice at all. And further, this mountain of ice perturbs the atmospheric circulation and spins up weather systems producing ample precipitation from the moisture supplied to it by the warm Gulf Stream waters. Together, the enhanced precipitation and increased elevation maintain Greenland’s ice cap—a remnant of the last ice age.

But this does not imply that Greenland’s ice cap and glaciers are immune to climate changes. Greenland ice sheets respond to temperature (and precipitation) changes, just like ice everywhere else. When the temperatures local to Greenland warm, the ice load on Greenland generally shrinks, and vice versa for periods of cooling. A complicating factor to the ice/temperature relationship is precipitation change. Warming temperatures also tend to lead to increased precipitation, which, over the inland of Greenland, usually means more snow (and thus ice accumulation and lower sea levels). On the other hand, more precipitation falling as rain along the continental margins enhances melting (and ice loss).

The behavior of Greenland ice sheets to climate changes appears to be well-established in the scientific literature, dating back to the mid-1940s and even earlier—before climate changes potentially induced by anthropogenic activities were possibilities. Prominent climatologists of the time had clearly documented a series of glacial advances and retreats in Greenland since the end of the last ice age, some 12,000 years ago. The most readily detectable of which was the rapid and large-scale pullback associated with a warming climate after the end of the Little Ice Age in the mid-19th century. Earlier 20th century warming was well documented, as was the accompanying glacial retreat, sea ice melting, permafrost recession, and shifts in biology (including the northward expansion of the ranges of plants and animal species). It is interesting to note that back then the warm-up was termed a “climate improvement.”

Here is how the noted Arctic climatologist H. W. Ahlmann described his research in an article titled “Researches on Snow and Ice, 1918-1940” written more than 60 years ago in 1946 for the scientific journal The Geographical Journal:

Like the Fröya glacier, all the other glaciers in north-east Greenland have terminal moraines marking their maximum extension in post-glacial times. There is reason to presume that in Greenland, as in Norway and Iceland, this maximum extension occurred in the latter half of the eighteenth [1700s] and beginning of the nineteenth [1800s] centuries. In north-east Greenland, as elsewhere round the northernmost Atlantic, a post-glacial warm period occurred [the Climate Optimum, ~9,000 to 5,000 years ago], during which time the local glaciers disappeared completely or became much reduced in size. The outlet glaciers of the inland ice receded considerably, and the peripheral parts of the inland ice itself grew thinner. After this postglacial warm period, glaciation again increased and, after alternating advance and regression, culminated in the maximum extension of the eighteenth and nineteenth centuries [maximum extent of the Little Ice Age]. This was followed by a slow regression, which was interrupted by minor advances, but has increased rapidly during the last decades [1918-1940]. The present extensive regression is due to the recent climatic improvement.

Apart from the proofs of climatic improvement given by these investigations, the following facts may also be mentioned. The experiences of the Russian scientists along the North-East Passage are especially noteworthy. In 1930 the Leningrad Arctic Institute was established, and in 1933 became responsible for the scientific work of the Central Northern Sea Route Administration in Moscow. Throughout the 1939 war the Arctic Institute has maintained seventy-seven scientific stations in the Russian sector of the Arctic. The regular air surveys of the extent of the drift-ice, which are carried out during the summer months, have shown that between 1924 and 1942 the drift-ice was reduced by about 1 million square kilometres. The average thickness of the sea-ice in the Polar Sea has diminished from 365 centimetres at the time of the Nansen Fram expedition of 1893-95, to the 218 centimetres found by the ice-breaker Sedov, which in 1937-40 drifted along a route similar to that followed by the Fram. Two fossil-ice islands in the Laptev Sea have completely melted in recent years, leaving only submarine banks. And finally, the temperature has increased in the so-called Atlantic waters of the Polar Sea as well as in the Kara Sea…

On the basis of the known extension of the drift-ice it is possible to calculate the general distribution of atmospheric pressure. The direction of the ice-drift is parallel to the isobars, and the speed of the ice-drift is inversely proportional to the distances between the isobars. The Arctic fauna has followed the climatic change, and both fishes and fowl are now found much farther north than formerly. The southern limit of permanently frozen ground in Asia has moved many kilometres farther north, and the Spitsbergen period of navigation has lengthened considerably. From 1909 to 1912 it lasted ninety-five days, but in 1930-38 it had increased to one hundred and seventy-five days, and in 1939 to as many as two hundred and three days (from April 29 to November 17). This part of the Arctic may, without exaggeration, be said to have experienced a climatic revolution.

Again, the above passage was written in 1946, describing the events associated with a warming climate that had little if anything to do with human activities in that it occurred during a period prior to a significant atmospheric build-up of carbon dioxide from the combustion of fossil fuels. It demonstrates that rapid and significant climate swings can and do occur naturally and that elements of the earth’s natural systems react accordingly.

Thus, changes in both the cryosphere and the biosphere that have been associated with the current warming period (beginning in the early-1990s in Greenland) are neither extraordinary, unprecedented, nor unanticipated, despite often vocal claims, by scientists, environmentalists, politicians, and the media, to the contrary.

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Temperature history (and location) of various temperature stations established along the margin of Greenland, including the more than century-long histories from the stations of Godthab (Nuuk) and Ammassalik. Recent temperatures are only starting to approach those of the extended warm period from the 1920s through the 1940s (from Chylek et al., 2006).

Currently, in 2007, some glaciers along the periphery of Greenland are shrinking, but it has only been within the last couple of years that they have begun to approach, or in some cases, exceeded their recessed locations during the late-1940s and early 1950s (most Greenland glaciers advanced to a limited degree during the late-1950s through the early-1990s, during a period of cooling there).

On some glaciers, the recent recession as been dramatic, but despite the attention that these rapid changes garner in the media, they are the exception rather than the rule. For instance, the glacier that empties into the bay near Jakobshavn, on Greenland’s western coast, has been called the fastest moving glacier in the world. In recent years, it is reported to have speed up to nearly twice its previous speed and rapidly retreated. This glacier is the one that House Speaker Nancy Pelosi just visited (http://apnews.myway.com/article/20070528/D8PDMFK80.html), and it has scheduled visits by a string of global dignitaries who want to see the effects of “climate change” for themselves.

Interestingly, had Speaker Pelosi gone astray and stumbled upon the Store Glacier, a large outlet glacier lying just 100km to the north of Jakobshavn, she would have witnessed much of the same thing—a big glacier flowing off the central Greenland ice cap into a large bay, dramatically calving off large icebergs in the process. If fact, here is how a trip to Greenland’s Store glacier, via kayak, is described on a travelogue website (http://www.ushuaia.com/anglais_version/emission3/groenland/c1.htm):

On the western coast of Greenland is the Store glacier. Its source is in the very heart of the icecap and emerges in a funnel: the fjord of Uumannaq, in the bay of Disko. The icebergs and growlers pile up at the bottom of the fjord, floating slowly along with the current. Traveling through the bay in a kayak is chancy; it is necessary to push back the pieces of ice to make progress. In the midst of this distressed world, the various sculptures of striated ice, whose colors develop from dark blue to azure blue, make navigation seem surreal. Approaching the glacier, a big cracking noise is heard; it is the ice decompressing. During the Arctic summer, the Store glacier cracks and breaks apart. The sight is impressive, but it can also become dangerous: the more the icebergs melt, the greater the risk of falling pieces of ice.

This is precisely the scene that Pelosi and her entourage encountered at the end of Jakobshavn’s glacier. But there would be one major difference—the calving front of the Store glacier, instead of recessing some tens of kilometers like Jakobshavn glacier has done in recent years, has remained in virtually the same location for the past 35 or more years. Obviously, Store glacier would not well serve in the role of climate change icon, and thus receives little attention.

This same thing is true for scores of other glaciers along coastal Greenland. The full picture is that aside from a few headlining grabbing glacial recessions in recent years, a large number of Greenland’s glacier have not recessed beyond their positions established in the 1940s-1970s.

For example, there is a new and comprehensive study on the natural fluctuations of glacier activity around Disko Island, central West Greenland - not far away from Jakobshavn's glacier - that appeared to be missed by Speaker Pelosi and her science advisors. The University of Aarhus scientists, Jacob Yde and Tvis Knudesen, described the results of their study as follows:

This study assesses glacier fluctuations on Disko Island, central West Greenland, during the 20th century. 247 glaciers of which 75 are classified as surge-type glaciers are included, representing about 95% of the glacierized area. ... [G]laciers on Disko Island have undergone a sustained period of recession throughout the 20th century, although the MAAT [Mean Annual Air Temperature] and MSAT [Mean Summer Air Temperature] has shown no long-term trends between 1930 and 1990. ... In the 1900, many glaciers were under recession after the last advance period during the LIA (Steenstrup, 1901). Field observations in 1913 and comparison with the 1931-1933 map indicated that glacier recession continued during the first half of the 20th century (Jost, 1940). From the early descriptions of glacier terminus positions and calculated recession rates, it seems that glacier recession rates have been higher during the first half of the 20th century than during the second half. This supports the findings of Weidick (1968) that accelerated recession occurred between 1920 and 1940. During the period from 1953 to 1964 the majority of glacier termini remained stationary followed by a period (1964-1985) with more glaciers under recession. Towards the end of the 20th century (1985-2005) most glaciers showed little change in length, although many still receded.

And in some cases, even the fast recessing glaciers have slowed back down. Consider this BBC story from December 2005, reporting on two rapidly retreating glaciers along Greenland’s central eastern coast (http://news.bbc.co.uk/2/hi/science/nature/4508964.stm):

Greenland glacier races to ocean

Kangerdlugssuaq Glacier on the east coast of Greenland has been clocked using GPS equipment and satellites to be flowing at a rate of 14km per year.

It is also losing mass extremely fast, with its front end retreating 5km back up its fjord this year alone. The glacier “drains” about 4% of the ice sheet, dumping tens of cubic km of fresh water in the North Atlantic. This gives it significant influence not just on global sea level rise but on the system of ocean circulation which drives through the Arctic.

“We've seen a 5km retreat of the terminus, we've see an almost 300% acceleration in the flow speed and we've seen about a 100m thinning of the glacier - all occurring in the last one or so years,” said Dr Gordon Hamilton, of the Climate Change Institute at the University of Maine.

“These are very dramatic changes.” And they are not confined to Kangerdlugssuaq. He was speaking here at the American Geophysical Union Fall Meeting. Helheim Glacier, just to the south of Kangerdlugssuaq, is exhibiting similar changed behaviour. It is flowing only slightly slower at 12km per year - the equivalent of half a football field a day.

Hamilton thinks a couple of factors may be triggering the quick melt. The observed recent increase in summer surface melting on the Greenland Ice Sheet is producing large quantities of liquid water which, if it percolates down to the base of the glacier, can lubricate its flow over rocks towards the ocean.

And if that same warming is bringing higher-temperature sea waters into contact with the front of Kangerdlugssuaq and Helheim, this could explain their rapid retreat. If other large glaciers in the region are seen to go the same way, it could begin to “pull the plug” on Greenland, said Dr Hamilton.

“The model predictions for sea level rise do not include the effects of rapid changes in ice dynamics” he added. “We're seeing now that this component might be extremely important. And what it suggests is that the predictions for both the rate and the timing for sea level rise in the next few decades will be largely underestimated.”

But, during the year and a half since the BBC ran its story, both the Helheim glacier as well as the Kangerdlugssuaq glacier have slowed down and stopped recessing. In fact, Helheim glacier has advanced in the past year such that it is currently within observed, documented, historical limits. Ian Howat and colleagues published an article in Science magazine in the spring of 2007 describing this turn of events:


They write:

The calving fronts of both glaciers appeared relatively stable from the mid-20th century until 2002, when [Helheim glacier] retreated over 7 km in 3 years. This was followed by a 5-km retreat of [Kangerdlugssuaq glacier] during the winter of 2004-5. These retreats are much greater than the 1 to 2-km seasonal fluctuations previously observed and followed a sustained period of low-elevation ice thinning. Retreats were concurrent with accelerated ice flow. This acceleration increased rates of mass loss by 28 and 15 Gt/yr at [Kangerdlugssuaq glacier] and [Helheim glacier], respectively, between 2000 and 2005, representing >40% of the ice sheet’s increase in mass loss…

[On the Kangerdlugssuaq glacier] [t]hinning moved inland between 2005 and 2006, with a peak thinning of 68 m at about 26 km, but with virtually no thinning at the front. Average thinning over the glacier during the summer of 2006 declined to near zero, with some apparent thickening in areas on the main trunk [emphasis added]…

 

 

[On the Helheim glacier] [b]etween the summers of 2005 and 2006, the rate of thinning decreased within 20 km of the front, reaching zero at the front and increasing to 50 m/year 25 km from the front. During this period, the glacier advanced 4 km as a floating or near-floating tongue to near the 2003–2004 front position. It appears that the front of this floating tongue may have regrounded in summer 2006, contributing to the deceleration and the region of compression [emphasis added].
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Helheim glacier, central eastern Greenland coast. Recent and historical terminations are indicated. From September 1999 (peach line) to May 2001 (orange line) the Helheim glacier advanced slightly, pushing its calving front beyond its location in 1972 (green line). A slow retreat that began in 2001 was followed by a rapid, headline-grabbing retreat from 2004 to August 2005 (black line). Thereafter, the glacier stopped receding and began advancing again. By August 2006, the calving front had advanced beyond its location in 1933 (blue line) and is again approaching its summer 2004 location.

Ultimately, Howat et al. caution:

The highly variable dynamics of outlet glaciers suggest that special care must be taken in how mass-balance estimates are evaluated, particularly when extrapolating into the future, because short-term spikes could yield erroneous long-term trends.

A bit further to the north of Helheim and Kangerdlugssuaq glaciers, Britannia glacier—carefully mapped out in the early 1950s by a Great Britain expedition, is shown, in recent satellite photographs to currently be larger and further reaching that when it was first visited.

 

 

Left: the current position of the Britannia glacier as captured from a satellite photo available from Yahoo Maps. Right: A detailed map of the position of the Britannia glacier produced from photographs and ground survey done in 1954 (Hamilton et al., 1956). Currently, the Britannia glacier, as well as a smaller side glacier, is advanced beyond its 1954 terminus (red circles)

The recent warm temperatures in the regions surrounding Greenland has led to a general pull back of the peripheral glaciers there. But the pullback is from the advanced positions established in the early 1990s after a 40-year period of cooling in Greenland. Previous to that, from the late 19th to the mid-20th century, a rapid and prolonged warming occurred over Greenland during which time a significant glacial recession occurred when most of Greenland’s outlet glaciers rapidly retreated from the Little Ice Age maxima. The glacial recession associated with the warming observed in Greenland over the past 10 to 20 years is returning the glaciers to their mid-20th century positions. This recession is neither unusual nor unprecedented when viewed outside the context of the past 10 years and instead, within the context of the past 100 years—most of which was dominated by natural variability.

 

References:

Ahlmann, H. W., 1946. Researches on snow and ice, 1918-1940. The Geographical Journal, 107, 11-25.

Chylek, P., et al., 2006. Greenland warming of 1920-1930 and 1995-2005. Geophysical Research Letters, 33, L11707, doi:10.1029/2006GL026510.

Hamilton, R. A., et al., 1956. British North Greenland Expedition 1952-4: Scientific Results. The Geographical Journal, 122, 203-237.

Howat, I. M., et al., 2007. Rapid changes in ice discharge from Greenland outlet glaciers. Science, 315, 1559-1561.

Yde, J. C. And Knutsen, N. T., 2007. 20th century glacier fluctuations on Disko Island, Greenland. Annals of Glaciology, 46, in press.



III. Arctic Sea Ice and Polar Bears

It is a little known fact that the Arctic habitat of the polar bear has been as warm as or warmer than present for the better part of the last 9,000 years. And the polar bears survived.

Polar bears, Ursus maritimus, inhabit much of the Northern Hemisphere’s arctic regions. They evolved into a separate species about 200,000 years ago. According to the website polarbearsinternational.org (http://www.polarbearsinternational.org/bear-facts/polar-bear-evolution/:

Scientists believe that the polar bear is a descendant of the brown bear. It is thought to be the most recent of the eight bear species.

The polar bear probably first appeared roughly 200,000 years ago, during the Pleistocene. The polar bears of that time period were much larger than they are today, as were many other species.

Scientists believe that the polar bear evolved from a group of brown bears that became isolated by glaciers in an area near Siberia. The stranded bears underwent a rapid series of evolutionary changes in order to survive on the ice. Today's polar bear is superbly adapted to life in the Arctic… [A]daptations include a longer neck, useful in keeping the polar bear's head above water when swimming; warm, thick fur; and huge paws, which help spread the bear's weight on thin ice and are useful in swimming.

While brown bears hibernate in winter, polar bears do not. During an Arctic winter, there is no shortage of food, as seals are still available.

Since becoming a separate species 200,000 years ago, polar bears have survived large climate changes from ice age cold to interglacial warmth, including two lengthy periods (lasting several thousands of years each) when Arctic temperatures were significantly warmer than today. The fact that polar bear’s exist as a species today is the strongest evidence available that warming temperatures will not lead to their ultimate demise.

But these facts don’t dissuade global warming alarmists who cry that anthropogenic climate change will push the polar bear to extinction. In fact the (fictitious) plight of a lone polar bear is featured in Al Gore’s “documentary” An Inconvenient Truth. In an animated sequence, a presumably tired-of-swimming polar bear struggles to pull himself out the water onto a small chuck of ice, which subsequently breaks apart beneath him. The scene then widens to show the poor bear in the middle of a vast iceless sea, with no land in sight, left to swim on or drown trying.

In another apparent effort to alarm the public, Gore adviser, Dr. James Hansen, incorrectly implied coming extinction of polar bears in context of the mid Pliocene warm period of about 3 million years ago in an interview for a newspaper article (March 19, 2006 ). Such claims are highly problematic because the polar bear is a fairly recent species evolving from brown bears only some 250,000-200,000 years ago.

Polar bear expert, Dr. Mitch Taylor of Canada, confirms the robust resiliency of polar bears under the wide range of climatic and ice conditions having occurred in the past 250,000 years.

“Polar bears are believed to have evolved from grizzly bears during the Pleistocene era some 200-250,000 years ago. Polar bears are well developed as a separate species by the Eemian interglacial approximately 125,000 years ago. This period was characterized by temperature fluctuations caused by entirely natural events ... Polar bears obviously adapted to the changing environment, as evidenced by their presence today. ... This fact alone is sufficient grounds to reject the petition. Clearly polar bears can adapt to climate change. They have evolved and persisted for thousands of years in a period characterized by fluctuating climate. No rational person could review this information and conclude that climate change pre-destined polar bears to extinction.”

Furthermore, alarming claims by Gore and Hansen about species extinctions in general are clearly unsupported according to a new paper by Professor Daniel Botkin and 18 colleagues in the prestigious BioScience (March 2007 issue, vol. 57, 227-236) finding that "Current projections of extinction rates are overestimate[d]".

Even further alarmism has been brought to bear on the U.S. Fish and Wildlife Service who, despite its initial hesitation, is now considering listing the polar bear as an endangered species under the guise that global warming is going to wipe-out their sea ice habitat and thus potentially push the polar bear to the verge of extinction. While this scenario stands against historical evidence, it nevertheless plays in the hearts of sentimentalists worldwide making it a perfect climate alarmist’s tool for spreading disinformation about the impacts of anthropogenic fossil fuel use.

Here is how the Center for Biological Diversity (http://www.biologicaldiversity.org/swcbd/species/polarbear/index.html) describes their efforts at forcing action at the U.S. Fish and Wildlife Service:

On February 16, 2005 — the same day the Kyoto Protocol entered into force without the participation of the United States — the Center for Biological Diversity filed a scientific petition with the U.S. Fish and Wildlife Service to list the polar bear as a threatened species under the Endangered Species Act. Polar bears are at risk of extinction because global warming is causing catastrophic environmental change in the Arctic, including the rapid melting of sea ice. Because the bears are deeply dependent on the sea ice for their survival, they stand to become the first mammals in the world to lose 100 percent of their habitat to global warming.

On December 15, 2005, the Center and our partners NRDC and Greenpeace sued the Bush administration for ignoring our petition. In response, on February 9, 2006, the U.S. Fish and Wildlife Service issued a positive 90-day petition finding for polar bears, opened a 60-day comment period, and initiated a status review of the species. Finally, on December 27, 2006, the administration announced a proposed rule to list the polar bear as threatened. Comments will be accepted on the proposal until April 9, 2007, and the administration must make a final listing determination by January 9, 2008.

Because all listing decisions under the Endangered Species Act must be made on the basis of the best available science, the current rulemaking for polar bears would have to concede the severity of the global warming crisis, acknowledging the fact that a rapid, dramatic reduction in greenhouse gas emissions is necessary to prevent the extinction of the species.

Protection under the Endangered Species Act will provide concrete help to polar bears and could revolutionize American climate policy. Since U.S. resistance to curbing greenhouse gases has allowed other countries to shirk their responsibilities as well, major changes in American policy are likely to have a powerful domino effect, catalyzing change in climate policy worldwide. The polar bear’s protected status will require a new level of environmental review before oil and gas development continue in polar bear habitat in the American Arctic. Even more critically, because it is illegal to harm threatened species or jeopardize their survival, the polar bear listing could mean that all U.S. industries emitting large quantities of greenhouse gases — and requiring a federal permit to do so — will come under the purview of the Endangered Species Act. From polluting power plants in the Midwest to auto manufacturers, a vast array of industries may have to clean up their acts to give the polar bear a chance to survive.

The Center for Biological Diversity makes their ultimate goal clear, it is not about saving the polar bear, but wanting to “revolutionize American climate policy,” which is to say gain control of energy policy and choices.

Other scientists and groups are just as eager to ignore climate history and jump aboard the polar-bears-are-doomed express.

New York University’s Scienceline, a blog site written by grad students in NYU’s Science, Health and Environmental Reporting Program (http://scienceline.org/2007/02/05/health_driscoll_polarbears/), quotes Deborah Williams, president of Alaska Conservation Solutions, an environmental organization devoted to fighting global warming, as stating “There is no evidence [polar bears] can survive on land without sea ice.” (Williams even goes as far as to suggest that global warming is leading to previously undocumented cases of cannibalism among polar bears—anything, it seems for attention)

Obviously, these individuals and organizations are willfully ignorant of what paleoclimatologists overwhelmingly tell us about the past climate of the Arctic and its polar bear denizens.

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A. Early Holocene

There is a plethora of scientific evidence that demonstrates that for a multi-thousand year period lasting from about 9,000 to 4,000 years ago, the Arctic was much warmer than present day temperatures.

 

The Fourth Assessment Report (AR4) of the Intergovernmental Panel on Climate Change includes this graphic from its paleoclimate chapter (Chapter 6). It depicts the extent and magnitude of the temperatures since the end of the last ice age, about 12,000 years ago. The y-axis of the chart is latitude (north is upwards) and the x-axis is time before present (in thousands of years, going backwards to the left). The colored lines and rectangles indicate spatial and temporal extent of temperature anomalies, yellows and reds are periods that were warmer than the pre-industrial period (which itself was about 0.5ºC-0.8ºC cooler than present), and blue shading represents periods cooler than the pre-industrial. Notice that north of about 30ºN, that there were many places and periods lasting many thousands of years, that were likely as warm or warmer than present—including vast areas of the far north (Arctic), including Greenland and North Eurasia.

Timing and intensity of temperature deviation from pre-industrial levels. (source: IPCC, AR4, Chapter 6, p. 462)

The North Eurasia data comes from a paper by UCLA’s Glen MacDonald published back in 2000. Here is how the abstract of that paper reads:

 

Radiocarbon-dated macrofossils are used to document Holocene tree line history across northern Russia (including Siberia). Boreal forest development in this region commenced by 10,000 yr B.P. Over most of Russia, forest advanced to or near the current arctic coastline between 9000 and 7000 yr B.P. and retreated to its present position by between 4000 and 3000 yr B.P. Forest establishment and retreat was roughly synchronous across most of northern Russia. Tree line advance on the Kola Peninsula, however, appears to have occurred later than in other regions. During the period of maximum forest extension, the mean July temperatures along the northern coastline of Russia may have been 2.5° to 7.0°C warmer than modern. The development of forest and expansion of tree line likely reflects a number of complementary environmental conditions, including heightened summer insolation, the demise of Eurasian ice sheets, reduced sea-ice cover, greater continentality with eustatically lower sea level, and extreme Arctic penetration of warm North Atlantic waters. The late Holocene retreat of Eurasian tree line coincides with declining summer insolation, cooling arctic waters, and neoglaciation.

To summarize MacDonald’s results, he finds that for a period lasting somewhere around 5,000 years, the summer temperatures along the northern coastline of Russia may have been 2.5 to 7.0ºC warmer than present, and such a warming was associated with reduced sea ice, among other things.

If today’s level of Arctic warming, which has only lasted for about a decade or so, is pushing sea ice to shrink rapidly, then it would seem reasonable to think that a much warmer period lasting several thousands of years certainly did the same and even more so.

While MacDonald’s work is fairly recent, the idea that Arctic temperatures during the mid-Holocene were much warmer than our current era, and that this warming was accompanied by significant ice retreat is anything but new.

 

style="line-height: 150%;"> Noted early-20th century British meteorologist and climate historian Dr. C.E.P. Brooks, wrote an article in 1949 for the Swedish scientific journal Geografiska Annaler entitled “Post-Glacial Climatic Changes in the Light of Recent Glaciological Research.” Dr. Brooks describes the early 20th century glacial recession in an historical context:

 

 

style="margin: 0in 0.25in 0.0001pt; text-align: justify;"> We now [in 1949] seem to have entered this stage of unstable ice-sheet and glaciers. We know little about the extent of the floating ice-cap before the 19th Century, but the voyages of the Norsemen to Greenland in the early Middle Ages are strong evidence that up to about 1300 there was much less ice than at present in the East Greenland Current. The glaciological evidence shows that regions in Iceland and Norway are being laid bare which have been ice-covered for more than 600 years, but which were at one time cultivated. The retreat has evidently not yet reached the stage which it formerly maintained for several centuries, and it may be expected to continue until either the reduced polar ice-cap reaches a new position of stability, or until some meteorological “accident” reverses the trend and ushers in a new period of re-advance.

 

 

style="margin: 0in 0.25in 0.0001pt; text-align: justify;">

 

 

style="margin: 0in 0.25in 0.0001pt; text-align: justify;"> A still more advanced stage in the process of retreat was reached in the Post-glacial “Climatic Optimum” [~9,000 to 4,000 years ago], when the Arctic was so warm that peat-bogs could grow in Spitsbergen. It is not unlikely that during this period there was no permanent ice-cap in the Arctic; merely a winter ice-cap which largely disintegrated each summer [emphasis added].

 

And what effect did this multi-millennial warming have on the polar bears? Well, one thing is for sure, their existence today proves that they didn’t go extinct!

The most likely explanation is that they modified their behavior to adapt to the changing conditions, probably by spending more time on land foraging, hunting, and denning than they would during cooler, icier periods. There is evidence that these are precisely the kinds of adaptations that the bears are making to best cope with today’s warming climate. For instance, In May 2007, an AP article (http://www.tahoebonanza.com/article/20070502/Environment/105020027) reported that “More pregnant polar bears in Alaska are digging snow dens on land instead of sea ice, according to a federal study, and researchers say deteriorating sea ice due to climate warming is the likely reason.” So instead of perishing, the polar bears will adapt as best they can, as they always have.

{mospagebreak}

 

style="line-height: 150%;"> The early Holocene wasn’t the only period of extended warmth and greatly reduced sea ice that the polar bears managed to survive through. Another long much-warmer-than-present period occurred during the warm period in between the last two ice ages (known as the last interglacial).

 

A recent project was created to pull together available data on past environments in the Arctic. The Circum-Arctic Paleo Environments (CAPE) is an activity within the International Geosphere-Biosphere Program that aims to facilitate international syntheses of Arctic records. The 25-member CAPE-Last Interglacial Project Members team recently published an article characterizing the Arctic warmth during the time of the last interglacial (LIG). The work “Last interglacial Arctic warmth confirms polar amplification of climate change” was published early in 2007 in the scientific journal Quaternary Science Reviews. Many previous works indicate that Earth was warmer during the LIG than for any other period within the past 250,000 years. However, few detailed quantitative reconstructions of the period exist. The CAPE research group quantitatively estimated circum-Arctic summer air and sea surface temperatures for the LIG as reconstructed from terrestrial- and marine-based proxy records detailed in previous research conducted by a large body of scientists. The group emphasized temperatures in summer because they “exert the dominant control on glacier mass balance” and summer temperature is “the most effective predictor for most biological processes.”

The group found evidence that the LIG persisted for 10,000 to 12,000 years and that Arctic summer air temperatures during the LIG were 4 to 5ºC above present for much of the region. The warming seems to have occurred rapidly, peaking in the early portion of the LIG. The group contends that Arctic summer temperatures were warm enough “to melt all glaciers below 5 km elevation, except the Greenland ice sheet, which was reduced by ca 20-50%.” In regard to Arctic Ocean sea ice, the group states that the margins of the permanent ice “retracted well into the Arctic Ocean basin” and the ice was of an extent that was smaller than during the highly publicized ice retreat of the Holocene. When examining evidence of vegetation changes, the group concluded that “boreal forests advanced to the Arctic Ocean Coast across vast regions of the Arctic currently occupied by tundra.” In fact, across most of northern Russia, they report that forests were displaced northward by as much as 400 to 1000 km.
Regional maximum LIG summer Arctic temperature anomalies (ºC) relative to present. (taken from Cape Project Members report, 2006). Temperature across large portions of the Arctic were several degrees above present day values.
{mospagebreak}

The CAPE’s review of the evidence clearly shows an extended Arctic warm period lasting at least 2,000 years during which time glacier and sea ice was much reduced and the limits of the great boreal forests were pushed much further northward, to the shores of the Arctic Ocean. The Arctic environment was a substantially different place than we know it today. Yet, despite these major environmental changes, polar bears managed to adapt and survive.

C. Polar Bears Today

 

style="line-height: 150%;"> Despite claims by activists, it is generally believed that the global population of polar bears is increasing, from 5,000 in the 1940s via 10,000 to 15,000 in the mid-1970s to 20,000 to 25,000 today. Much of this increase has been credited to stricter hunting regulations. However, it is critical to note that the increase also occurred during a time of warming temperatures in the Arctic—proof that polar bears can flourish in a changing (warming) environment. A recent survey of polar bear populations across Canada (home to about 2/3rds of the world’s polar bears) found that of the 13 distinct populations there, only two are documented to be in decline while some others are strongly increasing. For instance, polar bear biologist Mitch Taylor has documented an increase in the population of bears that are found in the Davis straight region of eastern Canada from approximately 850 individuals in the mid-1980s to about 2,100 now. “There aren’t just a few more bears. There are a ... lot more bears,” Dr. Taylor told the Christian Science monitor in a May 2007 article (http://www.csmonitor.com/2007/0503/p13s01-wogi.html?page=1). University of Alberta scientist Andrew Derocher counters that the population of bears in the western Hudson’s Bay region has at the same time dropped by 22%, falling from 1,194 in 1987 to 935 in 2004. “They are declining due to global warming and changes in when the ice freezes and melts in Hudson Bay,” said Derocher. But this conclusion was recently challenged in the scientific literature by a team led by Nunavat government scientist M.G. Dyck. In a viewpoint article published in the journal Ecological Complexities entitled “Polar bears of western Hudson Bay and climate change: Are warming spring air temperatures the ‘ultimate’ survival control factor?” Dyck and colleagues summarize:

 

 

style="margin: 0in 0.25in 0.0001pt; text-align: justify;"> Long-term warming of late spring (April–June) air temperatures has been proposed by Stirling et al. (1999) as the ‘‘ultimate’’ factor causing earlier sea-ice break-up around western Hudson Bay (WH) that has, in turn, led to the poorer physical and reproductive characteristics of polar bears occupying this region. Derocher et al. (2004) expanded the discussion to the whole circumpolar Arctic and concluded that polar bears will unlikely survive as a species should the computer-predicted scenarios for total disappearance of sea-ice in the Arctic come true. We found that spring air temperatures around the Hudson Bay basin for the past 70 years (1932–2002) show no significant warming trend and are more likely identified with the large-amplitude, natural climatic variability that is characteristic of the Arctic. Any role of external forcing by anthropogenic greenhouse gases remains difficult to identify. We argue, therefore, that the extrapolation of polar bear disappearance is highly premature. Climate models are simply not skilful for the projection of regional sea-ice changes in Hudson Bay or the whole Arctic. Alternative factors, such as increased human–bear interaction, must be taken into account in a more realistic study and explanation of the population ecology of WH polar bears. Both scientific papers and public discussion that continue to fail to recognize the inherent complexity in the adaptive interaction of polar bears with both human and nature will not likely offer any useful, science-based, preservation and management strategies for the species.

 

D. Summary

So, the next time that you see Al Gore’s photo collection of decaying glaciers and animations of polar bears drowning as the distance between icebergs and the shore is too far to swim, or desperate pleas from environmental organizations with ulterior motives to declare the polar bear as “threatened” under the Endangered Species Act, think of the conditions during the early Holocene and during the last interglacial period—natural periods in Earth’s history when the conditions in the Arctic were much milder than those of today. In fact, during the majority of the past 9,000 years, the climate of large portions of the Arctic was likely warmer and less icy than it is currently. Further, consider that during the last several decades of Arctic warming, worldwide polar bear numbers have increase by some 50% or more. And finally, remember that today’s very existence of the polar bear is the strongest evidence available that these creatures are extremely adaptable to large-scale variations in their natural climate and habitat. These are facts that climate alarmists don’t want you know.

References:

CAPE Project Members, 2006. Last interglacial Arctic warmth confirms polar
amplification of climate change. Quaternary Science Reviews, 25, 1383-1400.

Dyck, M. G. et al., 2007. Polar bears of western Hudson Bay and climate change: Are warming spring air temperatures the “ultimate” survival control factor? Ecological Complexities, in press.

 

style="line-height: 150%;"> Intergovernmental Panel on Climate Change, 2007. Fourth Assessment Report. Chapter 6, Paleoclimate.

 

MacDonald, G. M., et al., 2000. Holocene tree line history and climate change across northern Eurasia. Quaternary Research, 53, 302-311.
{mospagebreak}

 

style="line-height: 150%;"> IV. Arctic Permafrost and Methane

 

 

style="line-height: 150%;"> Another scare story coming out of the Arctic is that Arctic warming will release untold amounts of the potent greenhouse gas methane into the atmosphere from widespread melting of the Arctic permafrost. However, a douse of cold water was recently thrown to this alarmist scenario.

 

 

style="line-height: 150%;"> The alarmist theory of Arctic permafrost goes something like this.

 

Permafrost is a sink for carbon dioxide and other greenhouse gases such as methane. Basically, the soils of the high latitudes froze at the beginning of the last ice age, and when they froze, they entrapped very large amounts of organic material (carbon rich grasses, animal remains, soil material) in the frozen permafrost. As the permafrost thaws, carbon trapped within the once-frozen soils is released largely as methane, and as this methane is mixed into the global atmosphere it will cause even more warming which feeds back onto itself and causes more permafrost melting and more methane release and more warming.

The entire process is described by many as a time bomb that is going off before our very eyes. The bomb is not just causing the world to warm at a more rapid pace, but the melting permafrost is also routinely connected to the destruction of forests (recall Gore’s pictures of “drunken forests” in An Inconvenient Truth), collapse of homes and other structures (e.g., pipelines), erosion of coastal areas and hillsides, disruption of animal habitats, etc.

On this particular point, observations by Professor Syun-Ichi Akasofu, founding director of the International Arctic Research Center of the University of Alaska Fairbanks, are noteworthy:

[People] say permafrost is melting, and houses are collapsing. What happens is that, when permafrost is in the area, housing is cheap and the land is cheap. When people build a house directly over the permafrost, and then warm the house in the wintertime, and the ice underneath melts and the house collapses, that's a man-made effect! [sic.]

In addition, Gore’s methane bomb was recently factually defused in an article appearing in Geophysical Research Letters entitled “Near-surface permafrost degradation: How severe during the 21st century?” by Georg Delisle, a scientist from Germany’s Federal Institute for Geosciences and Natural Resources (the central geoscientific authority providing advice to the German Federal Government in all geo-relevant questions).

The final sentence of the abstract states “Based on paleoclimatic data and in consequence of this study, it is suggested that scenarios calling for massive release of methane in the near future from degrading permafrost are questionable.”

Delisle acknowledges that warming is occurring in the Arctic regions and that the warming will undoubtedly impact the permafrost of the high latitudes. The author notes, however, that many numerical models used to simulate the impact of warming on permafrost deal only with the upper 10 feet of the earth’s surface. The previously-used models do not take into account the cooling effect of deeper and colder zones that interact thermodynamically with the active layer near the surface. Delisle also exposes other assumptions of previous models that are “in clear conflict with field evidence.” In other words, the models driving lurid headlines and political anxiety get it wrong, again.

Delisle instead presents “a unidimensional long term permafrost temperature model of general application” “which is fully capable of incorporating all relevant thermal processes within the active layer and the permafrost, and between the permafrost and the non frozen ground below. The model space is made up of 600 layers with a minimum spacing of 10 cm within the active layer and the uppermost ‘permafrost zone’.” Rather than look at only 10 feet into the surface as was done by previous models, the new model goes 100 yards into the surface, and is deemed as more realistic.

With the improved model, Delisle reports that continuous permafrost in Alaska and Siberia will survive over the next 100 years, even if a significant warming takes place. Further, he states that “Based on this result and on the presented analysis, it appears that all areas north of 60°N will maintain permafrost at least at depth. North of 70°N, surface temperature values today are in general below -11°C. These areas should maintain their active layer. It appears unlikely that almost all areas with near-surface permafrost today will lose their active layer within the next 100 years” as concluded by others. Delisle claims that the new model is far more consistent with field measurements and far more realistic in terms of including the energy flux component from the deeper and colder core.

Delisle adds a zinger at the end of his article stating:

A second, rarely touched upon question is associated with the apparently limited amount of organic carbon that had been released from permafrost terrain in previous periods of climatic warming such as e.g. the Medieval Warm Period or during the Holocene Climatic Optimum. There appear to be no significant CH4-excursions in ice core records of Antarctica or Greenland during these time periods which otherwise might serve as evidence for a massive release of methane into the atmosphere from degrading permafrost terrains.

In other words, the ice cores that have long been relied upon to show the chemical fluctuations in the atmosphere over many tens of thousands of years into the past—the ones that are used to related changes in atmospheric greenhouse gases such as carbon dioxide and methane to changes in global temperatures—fail to capture a large methane release during previous warm periods during the Holocene. This finding suggests that warmer temperatures in the Arctic—recall that Arctic temperatures were as warm as or warmer than present for several thousand years during the Climatic Optimum lasting from approximately 9,000 to 4,000 years ago—did not prompt a massive release of methane from permafrost melting.

The recent paper by Schaefer and colleagues in Science, also reported lack of evidence supporting the “catastrophic methane emissions from melting permafrost” scenario:

[O]ur ?13CH4 record support neither catastrophic nor gradual clathrate emissions at the YD-PB [roughly 12.2 to 11.2 thousand years ago] transition." And this transition period has been estimated to have undergone perhaps as large as 28?C (!) changes in winter temperatures or about 16?C in annual-mean temperatures by Broecker in a 2006 paper in Global and Planetary Change. Such a large change in temperatures around the Greenland and Arctic region will not likely to be soon surpassed under any future man-made emission scenarios.

 

style="line-height: 150%;"> In fact, there is no evidence in the atmospheric record of methane concentrations to indicate that the current warm-up is causing a significant methane release from melting permafrost. In fact, the build-up of methane in the atmosphere has been dramatically slowing since the early 1980s, and is now quite close to zero on a year-over-year basis. This behavior of methane is documented (among other places) in a recent paper by Khalil and colleagues from Oregon Graduate Institute entitled “Atmospheric Methane: Trends and Cycles of Sources and Sinks” appearing in the journal Environmental Science and Technology.

 

 

style="line-height: 150%;"> Khalil et al. start their article noting “Methane concentrations in the atmosphere have more than doubled over the last century, raising concerns that it is contributing to global warming and will continue to do so in the future,” but then continue “Although these past increases were alarmingly rapid, subsequent measurements showed a persistent slowdown in the trends to nearly zero at present.”

 

They continue:

It is apparent that there are ups and downs, but these are superimposed on a systematically declining rate of accumulation. The slowdown of methane trends has been known and discussed for a long time; however, it is particularly noteworthy that the decrease of the methane trend is not a new phenomenon, but rather it has occurred from the time that systematic measurements were first taken. Most probably it started even before then. Since fluctuations are superimposed on a generally decreasing trend, there have been years in recent times when methane has not increased at all or has even fallen slightly relative to the previous year. This has attracted more interest than in the past when there were similar short-term down turns but on the whole methane still increased over previous years. The recent incursions of the trend into negative territory are therefore part of a much longer term process.

 

style="margin: 0in 0.5in 0.0001pt;"> Global average monthly atmospheric concentration of methane (CH4) as compiled in Khalil et al. (2007). The rate of the atmospheric build-up of methane has slowed dramatically and now approaches zero.

 

 

 

style="margin: 0in 0.5in 0.0001pt;"> The annual trend in atmospheric methane concentration as compiled by Khlail et al. (2007). The trend has been declining since the early 1980s and currently approaches zero.

 

 

style="line-height: 150%;"> Khalil and colleagues summarize their findings thus:

 

 

style="margin: 0in 0.25in 0.0001pt; text-align: justify;"> The present data set spans more than two decades. It shows that both methane emissions and its lifetime may have been constant over this period. To quantitatively explain the decreasing trends of methane it is not necessary to look for decreasing sources or increasing OH [hydroxyl radical]. During the time of the measurements if either has changed the other must also have changed by a proportionate amount to account for the observed trends. Moreover, while such circumstances may have occurred, if the sources have increased in the past they would have no environmental consequences such as increased global warming, because the extra amounts put into the atmosphere would be the same amounts that would have to be taken out by the increased OH to be consistent with the observed concentrations of methane during the last two decades. The concentrations behave exactly as if the sources and sinks had been constant. A confirming aspect of this apparent constancy of sources and sinks is that the trend has been decreasing for the last two decades until the present when it has reached near zero, thus attracting renewed attention. The major agricultural sources such as rice agriculture and cattle have little or no potential for large increases in the future and have already shown reduction in emissions from some regions. Seeing that the total source has remained constant for at least the last two decades, it is questionable whether human activities can cause methane concentrations to increase greatly in the future. This prediction is within the lower range of the IPCC SRES scenarios. [emphasis added]

 

The implications for this are two-fold. First the IPCC future scenarios for atmospheric methane concentrations are likely to be in error on the high side.

 

style="line-height: 150%;"> The great majority of projections of future methane concentrations as put forth by the Intergovernmental Panel on Climate Change (IPCC) likely err on the high side as the build-up rate of atmospheric methane concentration has slowed for the past 30 years and now is near zero.

 

 

style="line-height: 150%;"> Secondly, there is absolutely no indication at all that global methane emissions have increased (from sources such as permafrost melting) during the past 30 years despite the global warming that has taken place. This finding, coupled with the results from Delisle that a massive methane release from future permafrost melting is not anticipated, is strong indication that alarmist scare stories about Arctic warming leading to a runaway greenhouse effect are simply ungrounded in the best available science.

 

References:

Broecker, W. S., 2006. Abrupt climate change revisited. Global and Planetary Change, 54, 211-215.

Delisle, G. 2007. Near-surface permafrost degradation: How severe during the 21st century? Geophysical Research Letters, 34, L09503, doi:10.1029/2007GL029323.

Khalil, M.A.K., C.L. Butenhoff, and R.A. Rasmussen, 2007. Atmospheric Methane: Trends and Cycles of Sources and Sinks. Environmental Science and Technology, available on-line (10.1021/es061791t).

Schaefer, H., et al., 2006. Ice record of ?13C for atmospheric CH4 across the younger-dryas-preboreal transition. Science, 313, 1109-1112.

{mospagebreak}

V. Antarctica Ice Mass: Growing into the Future

 

style="line-height: 150%;"> Both models and observations indicate that the mass of Antarctica’s ice sheets should continue to increase into the future as warming temperatures lead to enhanced atmospheric moisture and increased snowfall. The net result is a negative contribution to future global sea level.

 

 

style="line-height: 41.35pt; page-break-after: avoid; vertical-align: baseline;"> I

 

 

style="line-height: 150%;"> It has been long held that a warming climate in the regions surrounding Antarctica would enhance snowfall there, lead to snow and ice accumulation, and ultimately result in a negative contribution to sea level rise (in other words, continued snow and ice build up on the Antarctic continent would result in a lowering of sea levels). This idea has been reflected in each and every report of the Intergovernmental Panel on Climate Change (IPCC). For instance, in the IPCC’s First Assessment Report, published in 1995, they summarize the expectations from Antarctica in a warming climate as “On the whole, the sensitivity of Antarctica to climate change is such that a future warming should lead to increased accumulation and thus a negative contribution to sea level change.” In the IPCC’s Fourth Assessment Report, released in 2007, 12 years after their initial report, they state that “General Circulation Models indicate that the Antarctic Ice Sheet will receive increased snowfall without experiencing substantial surface melting, thus gaining mass and contributing negatively to sea level.” In fact, under every IPCC future emissions scenario, the expected Antarctic contribution to sea level rise in the 21st century is negative.

 

 

style="line-height: 150%;"> However, with the March 2006 Science article by researchers Isabella Velicogna and John Wahl, this idea was (purportedly) turned on its head.

 

 

style="margin: 0in 0.25in 0.0001pt; text-align: justify;"> The [IPCC] report predicted that the Antarctic ice sheet will probably gain mass during the 21st century because of increased precipitation in a warming global climate. Recent radar altimeter measurements have shown an increase in the overall thickness of the East Antarctic Ice Sheet’s (EAIS’s) interior during 1992–2003. However, the IPCC prediction does not consider possible dynamic changes in coastal regions, and radar altimetry provides only sparse coverage of those areas. Detailed interferometric synthetic-aperture radar and airborne laser altimeter surveys of glaciers along the edge of the West Antarctic Ice Sheet (WAIS) show rapid increases in near-coastal discharge during the past few years. The overall contribution of the Antarctic ice sheet to global sea-level change thus depends on the balance between mass changes in the interior and those in coastal areas. The gravitational survey of Antarctica provided by the Gravity Recovery and Climate Experiment (GRACE) satellites and discussed in this paper is a comprehensive survey of the entire ice sheet and is thus able to overcome the issue of limited sampling….

 

 

style="margin: 0in 0.25in 0.0001pt; text-align: justify;">

 

 

style="margin: 0in 0.25in 0.0001pt; text-align: justify;"> Using measurements of time-variable gravity from the [GRACE] satellites, we determined mass variations of the Antarctic ice sheet during 2002–2005. We found that the mass of the ice sheet decreased significantly, at a rate of 152 ± 80 cubic kilometers of ice per year, which is equivalent to 0.4 ± 0.2 millimeters of global sea-level rise per year. Most of this mass loss came from the West Antarctic Ice Sheet.

 

 

style="line-height: 150%;"> This result, reported by Velicogna and Wahl, indicated that instead of gaining ice, Antarctic was instead rapidly losing ice and contributing to sea level rise. However, while big attention was being paid to its suggested implications (a future warming would lead to a sea level rise much greater than expected), little attention was being paid to the fact that the study only covered a period of three years (2002-2005)—a period far too short to reliably determine long-term tendency or behavior of the balance of Antarctica’s mass of snow and ice.

 

 

style="line-height: 150%;"> In fact, longer-term studies that better illustrate the trend and variability of Antarctica’s amount of snow and ice, find overall increases in ice mass as well as multi-year variations in ice accumulation that could explain Velicogna and Wahl’s results.

 

 

style="line-height: 150%;"> For instance, over the short term, variations in snowfall amounts from year-to-year can explain the reported mass loss from 2002-2005. Andrew Monaghan and colleagues, made this point abundantly clear in a paper they published in Science less than six months after the Velicogna and Wahl study was published. Monaghan et al. investigated the behavior of snowfall over the Antarctic continent and examined both its long-term and short-term variability. They found that a short-term decrease in snowfall during the time period examined by Velicogna and Wahl could explain their results. Monaghan et al. wrote:

 

 

style="margin: 0in 0.25in 0.0001pt; text-align: justify;"> Interannual and interdecadal snowfall variability must be more seriously considered when assessing the rapid ice volume changes that are occurring over Antarctica. With regard to interannual variability, consider a recent estimate of Antarctic ice sheet mass loss that is the equivalent of 0.4 ± 0.2 mm year-1 GSL [global sea level rise] rise for 3 years (2002–2005) from satellite-derived time-variable gravity measurements [made by Velicogna and Wahl]. Antarctic-wide annual snowfall accumulation decreased by about 25 mm y-1 WEQ [water equivalent], or about 0.86 mm year-1 GSL rise, between calendar year 2002 and 2003, suggesting that the gravity fluctuations could be heavily influenced by interannual snowfall variations.

 

 

style="line-height: 150%;"> Over the longer term, recent papers continue to show overall snow and ice mass gain in Antarctica. Davis et al., 2005 reported that ice mass gain over the East Antarctic Ice Sheet likely exceeded ice mass loss from the West Antarctic Ice Sheet, indicating a net gain in mass over the entire Antarctic continent. Wingham et al. reported an overall increase of 27 ± 29 Gt per year during the same time period. Wingham et al. explained “Mass gains from accumulating snow, particularly on the Antarctic Peninsula and within East Antarctica, exceed the ice dynamic mass loss from West Antarctica.”

 

 

style="margin: 0in 0.5in 0.0001pt; line-height: 150%;"> Elevation change in the Antarctic Ice Sheet, 1992-2003, as derived by Wingham et al., 2006.

 

 

style="line-height: 150%;"> Finally, in a recent careful study of geological evidence around the George VI Ice Shelf by the Antarctic Peninsular, James Smith and colleagues from British Antarctic Survey and elsewhere confirmed that "The absence of a currently extant ice shelf during this time interval [i.e., early Holocene around 9600 to 7730 years BP] suggests that early Holocene ocean-atmosphere variability in the AP [Antarctic Peninsula] was greater than that measured in recent decades."

 

 

style="line-height: 150%;"> The bottom line for the Antarctic ice sheet is that over the long term, increased precipitation in the form of snow should accompany warming temperatures. There may be shorter term variability that will be overlaid on this long-term trend, but, currently, our best scientific understanding is that the long-term ice accumulation will dominate shorter-term loss variations, with the net result being a small sea level drawdown resulting from climate processes taking place over Antarctic during the course of the 21st century.

 

 

style="line-height: 150%;"> References:

 

 

style="line-height: 150%;"> Davis, C. H., et al., 2005. Snowfall-driven growth in East Antarctic Ice Sheet mitigates recent sea-level rise. Science, 308, 1898-1901.

 

 

style="line-height: 150%;"> Monaghan, A. J., et al., 2006. Insignificant change in Antarctic snowfall since the International Geophysical Year. Science, 313, 827-831.

 

 

style="line-height: 150%;"> Smith, J. A., et al., 2007. Oceanic and atmospheric forcing of early Holocene ice shelf retreat, George VI Ice Shelf, Antarctica Peninsula. Quaternary Science Reviews, 26, 500-516.

 

 

style="line-height: 150%;"> Velicogna, I., and J. Wahl, 2006. Measurements of time-variable gravity show mass loss in Antarctica. Science, 311, 1754-1756.

 

 

style="line-height: 150%;"> Wingham, D. J., et al., 2006. Mass balance of the Antarctic ice sheet. Philosophical Transactions of the Royal Society A, 364, 1627-1635.

 

 

style="line-height: 150%;"> {mospagebreak}

 

 

style="line-height: 150%;"> VI. Sea Level Rise

 

 

style="line-height: 150%;"> Scare stories of rapidly rising sea levels, with a magnitude exceeding many feet per century, inundating coastlines and forcing the redistribution of coastal communities as a result of increasing atmospheric levels of carbon dioxide are exaggerations of our best scientific knowledge.

 

 

style="line-height: 150%;"> The Intergovernmental Panel on Climate Change (IPCC) in its Fourth Assessment Report (AR4), projects a median sea level rise of 14 inches from its middle-of-the-road future emissions scenario (A1B). The full range of IPCC AR4 sea level rise projections, encompassing all of its various SRES emissions scenarios is 7.1 to 23.2 inches.

 

 

style="margin: 0in 0.5in 0.0001pt;"> Range of sea level rise projections (and their individual components) made by the IPCC AR4 for its six primary emissions scenarios. Notice that the primary component is thermal expansion (red crosses), and that the contribution from Antarctica is expected to be negative (dark blue crosses) and that the contribution from Greenland is expected to be only slightly positive (light blue crosses).

 

 

style="margin: 0in 0.5in 0.0001pt;">

 

 

style="margin: 0in 0.5in 0.0001pt;">

 

 

style="line-height: 150%;"> The IPCC sea level rise projections stand in sharp contrast to the scare stories being put forth by Dr. James Hansen and others who contend that modest future warming will result in rapid disintegration of the Greenland and Antarctic ice sheets resulting in a sea level rise within the coming century that may exceed several meters. Hansen and his fellow believers, both prior to and following the IPCC’s release of its Fourth Assessment Report (AR4) have leveled harsh criticism of the IPCC for playing things too conservatively when it came to their projections of sea level rise. However, the IPCC lead authors staunchly defend their report’s conclusions.

 

 

style="line-height: 150%;"> For instance, IPCC AR4 lead author Dr. Richard Alley testified before the House Committee on Science and Technology, Feb. 8, 2007, concerning the state of scientific knowledge of accelerating sea level rise and pressure to exaggerate what it known about it. Dr. Alley told the Committee:

 

 

style="margin: 0in 0.25in 0.0001pt; text-align: justify;"> This document [the IPCC AR4] works very, very hard to be an assessment of what is known scientifically and what is well-founded in the refereed literature and when we come up to that cliff and look over and say we don’t have a foundation right now, we have to tell you that, and on this particular issue, the trend of acceleration of this flow with warming we don’t have a good assessed scientific foundation right now. [emphasis added]

 

 

style="line-height: 150%;"> The reason that Hansen and others are clamoring that the IPCC was too conservative in their estimates is a processes known as “dynamic ice changes.” Dynamic changes are the ones that are not due to the slower processes that determine ice sheet characteristics such as snowfall and ablation, but instead are due to as-of-yet unmodellable rapid changes in ice sheet outlet glaciers from processes such as basal lubrication and melting from beneath ocean-ending glacial tongues. However, the studies of dynamical ice changes are very limited in their temporal scope and thus are unreliable for assessing actual long term trends. And as we have seen for at least two major outlet glaciers in Greenland, the reported speed-ups have ended and glacial advance and thickening has begun. Whether these glacial surges will increase in the future is simply impossible to know. However, even when the IPCC attempts to take future dynamical changes into consideration in their sea level rise projections, they only arrive at small additional increases:

 

 

style="margin: 0in 0.25in 0.0001pt; text-align: justify;"> Further accelerations in ice flow of the kind recently observed in some Greenland outlet glaciers and West Antarctic ice streams could substantially increase the contribution from the ice sheets. For example, if ice discharge from these processes were to scale up in future in proportion to global average surface temperature change (taken as a measure of global climate change), it would add 0.1 to 0.2 m to the upper bound of sea level rise by 2090 to 2099. In this example, during 2090 to 2099 the rate of scaled-up Antarctic discharge would roughly balance the expected increased rate of Antarctic accumulation, being under A1B a factor of 5 to 10 greater than in recent years.

 

 

style="line-height: 150%;"> In other words, even when considering possible dynamical ice flow increases in the future, the IPCC still finds that they may only add about 3.9 to 7.9 inches to sea level rise estimates by the year 2100 (a far cry from Hansen’s several meters). These IPCC calculations are supported by the fact, as reported by Shepard and Wingham in Science, the current sea level rise contributed by the recent rate of ice loss from Greenland and Antarctica is about 0.014 inches per year or about 1.4 inches per century. So even if the current rate of dynamic ice loss increases by 10 times during the coming century, the added sea level rise over the course of a century will amount to little more than a foot. And considering (as we have shown) that natural year-to-year fluctuations in snowfall can explain the recent short-term reported increase in Antarctic mass loss, and in Greenland, some of the major glaciers that were advancing rapidly have suddenly slowed, there is little reason to think that significant increases in dynamical ice flow will be instigated anytime soon, if at all.

 

 

style="line-height: 150%;"> References:

 

 

style="line-height: 150%;"> Shepard, A., and D. Wingham, 2007. Recent sea-level contributions of the Antarctic and Greenland ice sheets. Science, 315, 1529-1532.

 

 

style="line-height: 150%;"> Intergovernmental Panel on Climate Change, 2007. Fourth Assessment Report. Chapter 10, Global Climate Projections.

 

 

style="line-height: 150%;"> VII. Summary

 

 

style="line-height: 150%;"> Climate change is currently ongoing in the earth’s polar regions. In fact, it has been seemingly forever. Key to current policy initiatives is the “attribution” question – whether the change is due to anthropogenic alterations to the earth’s atmosphere composition or primarily to ages old natural fluctuations beyond human control.

 

 

style="line-height: 150%;"> Of primary interest is the ongoing impact. And here, there is good news. The ice cap which covers Greenland and which contains enough water to raise global sea level some 23 feet is slow to change. Currently, the vast majority of Greenland’s glaciers have likely not retreated beyond their historical limits established in the 1950s—a period not marked by an unusual rate of sea level rise. Several major outlet glaciers that a few years ago were retreating rapidly and dumping an extra 43 Gt/year of ice into the sea (>40% of Greenland’s ice input total increase since 2000) have dramatically slowed and are regaining their equilibrium.

 

 

style="line-height: 150%;"> In Antarctica, climate models backed by long-term observations suggest that with a warming climate, Antarctica will gain snow and ice as an increase in precipitation is projected there. This will lead to a negative contribution to future sea levels from the Antarctic continent as a whole. The most scientifically-sound projections, made by the IPCC in their 2007 Fourth Assessment Report, are for a median sea level rise of 14 inches by the year 2100. This is a full order of magnitude less than the alarmist predictions by certain prominent scientists. Predictions of runaway greenhouse warming from methane released by permafrost melting have been shown to be improbable and without past precedent. And the very existence of polar bears today is proof of this species’ ability to adapt to climate changes, including conditions of significantly higher temperatures and reduced sea ice. For at least two protracted periods several thousand years in length the Arctic environment of the polar bear has been warmer and more ice free than the current one.

 

 

style="line-height: 150%;"> Many of these facts are not found in the mass media or in alarmist claims. In those settings, they are forgotten or ignored. But these facts are real, and they are readily available in the scientific literature—oftentimes directly available via the World Wide Web, not even requiring a visit to repository library. These facts tell a story with which many people are unfamiliar, a story that recognizes that the earth’s climate is changing, that a variety of human activities to some degree have a role in the changes, and that future climate changes will be modest – possibly even cooling. This contrasts with the scare stories that dominate the major media outlets portending immediate, large-scale ecological disruptions and social upheavals as a result of human-induced climate changes stemming from our energy uses.

 

 

style="line-height: 150%;"> It is important to explore the scientific knowledge that lies beneath the surface of many media reports; to investigate the full story. To convince oneself that she has received the complete picture and gained a better and fuller understanding of the issues. This is the only route to informed policy decisions preventing severely negative outcomes.

 

 

style="line-height: 150%;"> It is hoped that this document brings to light important facts that are often overlooked, circumscribed and ill-reported. This document is not intended to be the final word on any of the issues included within its contents, but instead to be catalyst that fuels further investigation of these and the many other topics that make up the complex subject of anthropogenic climate change and its implications for us all.

 

 

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style="line-height: 150%;"> Addendum: Antarctic Temperatures Disagree With Climate Model Predictions

 

COLUMBUS , Ohio – A new report on climate over the world's southernmost continent shows that temperatures during the late 20th century did not climb as had been predicted by many global climate models.

This comes soon after the latest report by the Intergovernmental Panel on Climate Change that strongly supports the conclusion that the Earth's climate as a whole is warming, largely due to human activity.

It also follows a similar finding from last summer by the same research group that showed no increase in precipitation over Antarctica in the last 50 years. Most models predict that both precipitation and temperature will increase over Antarctica with a warming of the planet.

 

“The best we can say right now is that the climate models are somewhat inconsistent with the evidence that we have for the last 50 years from continental Antarctica. We're looking for a small signal that represents the impact of human activity and it is hard to find it at the moment,” he said.

David Bromwich, professor of professor of atmospheric sciences in the Department of Geography, and researcher with the Byrd Polar Research Center at Ohio State University, reported on this work at the annual meeting of the American Association for the Advancement of Science at San Francisco.

“It's hard to see a global warming signal from the mainland of Antarctica right now,” he said. “Part of the reason is that there is a lot of variability there. It's very hard in these polar latitudes to demonstrate a global warming signal. This is in marked contrast to the northern tip of the Antarctic Peninsula that is one of the most rapidly warming parts of the Earth.”

Bromwich says that the problem rises from several complications. The continent is vast, as large as the United States and Mexico combined. Only a small amount of detailed data is available – there are perhaps only 100 weather stations on that continent compared to the thousands spread across the U.S. and Europe. And the records that we have only date back a half-century.

“The best we can say right now is that the climate models are somewhat inconsistent with the evidence that we have for the last 50 years from continental Antarctica.

“We're looking for a small signal that represents the impact of human activity and it is hard to find it at the moment,” he said.

Last year, Bromwich's research group reported in the journal Science that Antarctic snowfall hadn't increased in the last 50 years. “What we see now is that the temperature regime is broadly similar to what we saw before with snowfall. In the last decade or so, both have gone down,” he said.

In addition to the new temperature records and earlier precipitation records, Bromwich's team also looked at the behavior of the circumpolar westerlies, the broad system of winds that surround the Antarctic continent.

“The westerlies have intensified over the last four decades of so, increasing in strength by as much as perhaps 10 to 20 percent,” he said. “This is a huge amount of ocean north of Antarctica and we're only now understanding just how important the winds are for things like mixing in the Southern Ocean.” The ocean mixing both dissipates heat and absorbs carbon dioxide, one of the key greenhouse gases linked to global warming.

Some researchers are suggesting that the strengthening of the westerlies may be playing a role in the collapse of ice shelves along the Antarctic Peninsula.

“The peninsula is the most northern point of Antarctica and it sticks out into the westerlies,” Bromwich says. “If there is an increase in the westerly winds, it will have a warming impact on that part of the continent, thus helping to break up the ice shelves, he said.

“Farther south, the impact would be modest, or even non-existent.”

Bromwich said that the increase in the ozone hole above the central Antarctic continent may also be affecting temperatures on the mainland. “If you have less ozone, there's less absorption of the ultraviolet light and the stratosphere doesn't warm as much.”

That would mean that winter-like conditions would remain later in the spring than normal, lowering temperatures.

“In some sense, we might have competing effects going on in Antarctica where there is low-level CO2 warming but that may be swamped by the effects of ozone depletion,” he said. “The year 2006 was the all-time maximum for ozone depletion over the Antarctic.”

Bromwich said the disagreement between climate model predictions and the snowfall and temperature records doesn't necessarily mean that the models are wrong.

“It isn't surprising that these models are not doing as well in these remote parts of the world. These are global models and shouldn't be expected to be equally exact for all locations,” he said.

Contact: David Bromwich (614) 292-6692; Bromwich.1@osu.edu

Writing by Earle Holland (614) 292-8384: Holland.8@osu.edu

Robert Ferguson has 26 years of Capitol Hill experience, having worked in both the House and Senate. He served in the House Republican Study Committee, the Senate Republican Policy Committee; as Chief of Staff to Congressman Jack Fields (R-TX) from 1981-1997, Chief of Staff to Congressman John E. Peterson (R-PA) from 1997-2002 and Chief of Staff to Congressman Rick Renzi (R-AZ) in 2002. He has considerable policy experience in climate change science, mercury science, energy and mining, forests and resources, clean air and the environment. His undergraduate and advanced degrees were taken at Brigham Young University and George Washington University, respectively.

 

 

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