Glaciers in the Arctic
From ClimateWiki
From Climate Change Reconsidered, a work of the Nongovernmental International Panel on Climate Change
Model studies indicate that CO2-induced global warming will result in significant melting of earth’s glaciers, contributing to a rise in global sea level. Global data on glaciers do not support claims made by the IPCC that most claciers are retreating or melting.
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Arctic Glaciers
Computer simulations of global climate change have long indicated the world’s polar regions should show the first and severest signs of CO2-induced global warming. If the models are correct, these signs should be especially evident in the second half of the twentieth century, when approximately two-thirds of the modern-era rise in atmospheric CO2 occurred and earth’s temperature supposedly rose to a level unprecedented in the past millennium. In this subsection, we examine historic trends in Arctic glacier behavior to determine the credibility of current climate models with respect to their polar predictions.
In a review of “the most current and comprehensive research of Holocene glaciation,” along the northernmost Gulf of Alaska between the Kenai Peninsula and Yakutat Bay, Calkin et al. (2001) report there were several periods of glacial advance and retreat over the past 7,000 years. Over the most recent of those seven millennia, there was a general retreat during the Medieval Warm Period that lasted for “at least a few centuries prior to A.D. 1200.” Then came three major intervals of Little Ice Age glacial advance: the early fifteenth century, the middle seventeenth century, and the last half of the nineteenth century. During these very cold periods, glacier equilibrium-line altitudes were depressed from 150 to 200 m below present values, as Alaskan glaciers “reached their Holocene maximum extensions.”
The mass balance records of the 18 Arctic glaciers with the longest observational histories subsequent to this time, as the planet emerged from the depths of the Little Ice Age, were studied by Dowdeswell et al. (1997). Their analysis showed that more than 80 percent of the glaciers displayed negative mass balances over the periods of their observation, as would be expected for glaciers emerging from the coldest part of the past millennium. Nevertheless, the scientists report that “ice-core records from the Canadian High Arctic islands indicate that the generally negative glacier mass balances observed over the past 50 years have probably been typical of Arctic glaciers since the end of the Little Ice Age,” when the magnitude of anthropogenic CO2 emissions was much less than it has been from 1950 onward.
These observations suggest that Arctic glaciers are not experiencing any adverse effects of anthropogenic CO2 emissions. In fact, Dowdeswell et al. say “there is no compelling indication of increasingly negative balance conditions which might, a priori, be expected from anthropogenically induced global warming.” Quite to the contrary, they report that “almost 80 percent of the mass balance time series also have a positive trend, toward a less negative mass balance.” Hence, although most Arctic glaciers continue to lose mass, as they have probably done since the end of the Little Ice Age, they are losing smaller amounts each year.
Additional evidence that the Arctic’s glaciers are not responding to human-induced warming comes from the studies of Zeeberg and Forman (2001) and Mackintosh et al. (2002), who indicate there has been an expansion of glaciers in the European Arctic over the past few decades.
Zeeberg and Forman analyzed twentieth century changes in glacier terminus positions on north Novaya Zemlya—a Russian island located between the Barents and Kara Seas in the Arctic Ocean—providing a quantitative assessment of the effects of temperature and precipitation on glacial mass balance. Their study showed a significant and accelerated post-Little Ice Age glacial retreat in the first and second decades of the twentieth century. By 1952, the region’s glaciers had experienced between 75 percent to 100 percent of their net twentieth century retreat; and during the next 50 years, the recession of more than half of the glaciers stopped, while many tidewater glaciers actually began to advance.
These glacial stabilizations and advances were attributed by the authors to observed increases in precipitation and/or decreases in temperature. For the four decades since 1961, weather stations on Novaya Zemlya, for example, show summer temperatures were 0.3 to 0.5°C colder than they were over the prior 40 years, while winter temperatures were 2.3 to 2.8°C colder than they were over that earlier period. These observations, the authors say, are “counter to warming of the Eurasian Arctic predicted for the twenty-first century by climate models, particularly for the winter season.”
Other glacier observations that run counter to climate model predictions are discussed by Mackintosh et al. (2002), who concentrated on the 300-year history of the Solheimajokull outlet glacier on the southern coast of Iceland. In 1705, this glacier had a length of about 14.8 km; by 1740 it had grown to 15.2 km in length. Thereafter, it began to retreat, reaching a minimum length of 13.2 km in 1783. Rebounding rapidly, however, the glacier returned to its 1705 position by 1794; by 1820 it equaled its 1740 length. This maximum length was maintained for the next half-century, after which the glacier began a slow retreat that continued to about 1932, when its length was approximately 14.75 km. Then it wasted away more rapidly, reaching a second minimum-length value of approximately 13.8 km about 1970, whereupon it began to rapidly expand, growing to 14.3 km by 1995.
The current position of the outlet glacier terminus is by no means unusual. In fact, it is about midway between its maximum and minimum positions of the past three centuries. It is also interesting to note that the glacier has been growing in length since about 1970. Mackintosh et al. report that “the recent advance (1970-1995) resulted from a combination of cooling and enhancement of precipitation.”
In another study of the Arctic, Humlum et al. (2005) evaluated climate dynamics and their respective impacts on high-latitude glaciers for the Archipelago of Svalbard, focusing on Spitsbergen (the Archipelago’s main island) and the Longyearbreen glacier located in its relatively dry central region at 78°13’N latitude. In reviewing what was already known about the region, Humlum et al. report that “a marked warming around 1920 changed the mean annual air temperature (MAAT) at sea level within only 5 years from about -9.5°C to -4.0°C,” which change, in their words, “represents the most pronounced increase in MAAT documented anywhere in the world during the instrumental period.” Then, they report that “from 1957 to 1968, MAAT dropped about 4°C, followed by a more gradual increase towards the end of the twentieth century.”
With respect to the Longyearbreen glacier, their work reveals it “has increased in length from about 3 km to its present size of about 5 km during the last c. 1100 years,” and they say that “the meteorological setting of non-surging Longyearbreen suggest this example of late-Holocene glacier growth represents a widespread phenomenon in Svalbard and in adjoining Arctic regions,” which they describe as a “development towards cooler conditions in the Arctic” that “may explain why the Little Ice Age glacier advance in Svalbard usually represents the Holocene maximum glacier extension.”
Climate change in Svalbard over the twentieth century was a rollercoaster ride, with temperatures rising more rapidly in the early 1920s than has been documented anywhere else before or since, only to be followed by a nearly equivalent temperature drop four decades later, both of which climatic transitions were totally out of line with what climate models suggest should have occurred. The current location of the terminus of the Longyearbreen glacier suggests that, even now, Svalbard and “adjoining Arctic regions” are experiencing some of the lowest temperatures of the entire Holocene or current interglacial, at a time when atmospheric CO2 concentrations are higher than they have likely been for millions of years. Both of these observations are at odds with what the IPCC claims about the strong warming power of atmospheric CO2 enrichment.
Bradwell et al. (2006) examined the link between late Holocene fluctuations of Lambatungnajokull (an outlet glacier of the Vatnajokull ice cap of southeast Iceland) and variations in climate, using geomorphological evidence to reconstruct patterns of glacier fluctuations and using lichenometry and tephrostratigraphy to date glacial landforms created by the glacier over the past four centuries. Results indicated that “there is a particularly close correspondence between summer air temperature and the rate of ice-front recession of Lambatungnajokull during periods of overall retreat,” and that “between 1930 and 1950 this relationship is striking.” They also report that “ice-front recession was greatest during the 1930s and 1940s, when retreat averaged 20 m per year.” Thereafter, they say the retreat “slowed in the 1960s,” and they report “there has been little overall retreat since the 1980s.”
The researchers also report that “the 20th-century record of reconstructed glacier-front fluctuations at Lambatungnajokull compares well with those of other similar-sized, non-surging, outlets of southern Vatnajokull,” including Skaftafellsjokull, Fjallsjokull, Skalafellsjokull, and Flaajokull. In fact, they find “the pattern of glacier fluctuations of Lambatungnajokull over the past 200 years reflects the climatic changes that have occurred in southeast Iceland and the wider region.”
Bradwell et al.’s findings suggest that twentieth century summer air temperature in southeast Iceland and the wider region peaked in the 1930s and 1940s, and was followed by a cooling that persisted through the end of the century. This thermal behavior is about as different as one could imagine from the claim that the warming of the globe over the last two decades of the twentieth century was unprecedented over the past two millennia. Especially is this so for a high-northern-latitude region, where the IPCC claims CO2-induced global warming should be earliest and most strongly expressed.
References
Bradwell, T., Dugmore, A.J. and Sugden, D.E. 2006. The Little Ice Age glacier maximum in Iceland and the North Atlantic Oscillation: evidence from Lambatungnajokull, southeast Iceland. Boreas 35: 61-80.
Calkin, P.E., Wiles, G.C. and Barclay, D.J. 2001. Holocene coastal glaciation of Alaska. Quaternary Science Reviews 20: 449-461.
Climate Change Reconsidered: Website of the Nongovernmental International Panel on Climate Change. http://www.nipccreport.org/archive/archive.html
Dowdeswell, J.A., Hagen, J.O., Bjornsson, H., Glazovsky, A.F., Harrison, W.D., Holmlund, P., Jania, J., Koerner, R.M., Lefauconnier, B., Ommanney, C.S.L. and Thomas, R.H. 1997. The mass balance of circum-Arctic glaciers and recent climate change. Quaternary Research 48: 1-14.
Humlum, O., Elberling, B., Hormes, A., Fjordheim, K., Hansen, O.H. and Heinemeier, J. 2005. Late-Holocene glacier growth in Svalbard, documented by subglacial relict vegetation and living soil microbes. The Holocene 15: 396-407.
Mackintosh, A.N., Dugmore, A.J. and Hubbard, A.L. 2002. Holocene climatic changes in Iceland: evidence from modeling glacier length fluctuations at Solheimajokull. Quaternary International 91: 39-52.
Zeeberg, J. and Forman, S.L. 2001. Changes in glacier extent on north Novaya Zemlya in the twentieth century. Holocene 11: 161-175.
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