Arctic Climate Impact - Case Study Example

How might the geomorphological processes and periglacial landforms of the arctic change as a result of climate change over the next 50 years? The condition of the climate has been a major factor in the occurrence of landform changes and processes and, certainly, in its investigation. This happens across all types of topography and location across the globe. The reason for this is simple, all the variables that characterize climate such as the temperature, precipitation, wind and seasonality all contribute to the acceleration and deceleration of processes that transform a geographical area. There is a direct relationship between landforming processes and climate as demonstrated in the way landscapes have changed over time due to climatic conditions. The scientific evidence points to several landforms today, which have revealed much of the past and present climates. Pielou (1994) referred to the so-called “thermal memory” of the earth in order to highlight this, that some of the memories are available for inspection. (p35) For instance, by drilling several holes in the arctic coastal plains of Alaska, the ground temperature was measured at a sequence of depths. It is one of the widely accepted beliefs among the climatic geomorphologists that the studies undertaken within some climatic types introduce a certain degree of control. According to Pitty (1971) the climate studies addresses the difficulty in comparing the characteristics of different areas due to the inescapable problems that changes other than those in the object being studied. The reason for this is that geomorphology has since been closely linked to geography, as it is by geographical search that the natural situation which affords the only realistic controls on a landform problem or changes will be discovered. (p68) This paper will examine the expected changes that will occur on the geomorphological and periglacial landforms of the Arctic within the next 50-year period in light of the climate fluctuations today. Background: Climate Change Furthermore, the interaction of the variable forces of wind, precipitation, temperature, humidity, including solar radiations, are the climatic forces that have shaped and will shape the world’s bio-regions. According to Hough, climate, “pervades and influences water, plants, wildlife and agriculture. It is the fundamental force that shapes local and regional places and is responsible for the essential differences between them.” (p189) The prime control of climate is the heat given out by the sun and that some of this heat creates energy for the atmospheric heat engine which controls the nature of pressure, wind and climatic belts. (Goudie 2001, p46) This underscores how climate change, characterized by global warming could drastically affect the geomorphological processes and periglacial landforms in the Arctic. Climate is also pivotal in the abundance or scarcity of water, which along with the other climatic forces, affects the speed of soil formation, directly and indirectly, as well as the thermal weathering, freeze-thaw action and other weathering processes. In view of the recent large-scale changes in the climate is significant in the study of the geomorphological processes and periglacial landforms of the Arctic today because it will complicate how such processes will occur. If the current landscapes reveal the patterns in the landforming processes of the past, then it would be easy to determine the future patterns when the climate fluctuations and its effects are investigated. Presently, changes in climate were most distinct in the Arctic for these past three decades. Warming is the most significant of these, disturbing the ecology of the region and, expectedly, its topography in the near future. Recent studies found that Arctic sea ice extent has reduced by 10 percent since 1970 and ice has become thinner and the fraction of the multiyear ice has decreased and this situation is expected to worsen due to the fact that the general circulation models (GCMs) consistently predict that future climate change in the circumpolar Arctic region will be markedly warmer and wetter than the present, with fluctuations in temperature and other climatic variables. (Philipps, Springman and Arenson 2003, p12) According to Thompson and Perry (1997), the primary problem issue in the discourse on climatic geomorphology is the determination of the extent to which climate, including its spatial and temporal variations, control the geomorphic processes as well as the extent to which these processes create a range of distinctive landforms. (p90) However, since this paper is only concerned with one zone, which is the Arctic, the task of identifying the geomorphological changes in the next 50 years in the region becomes simple especially when changes are classified according to the climatic forces such as temperature, precipitation and wind. Temperature Temperature changes have the most obvious effect in the Arctic. It affects the freezing point of water, with direct responses in the expansion or contraction of the cryosphere. (Thompson and Perry, p90) Periglacial landforming processes, wrote Stephens (1990), depend to a greater extent on low temperatures which promote freezing of water in winter, and warmer temperatures which lead to some thawing in summer. (p114) The immediate effect of this occurrence is that freezing and thawing eventually result to the accelerated physical weathering of bedrock and the development of a range of distinctive landforms associated with frozen ground. And so technically, there are several variables that produce distinctive landforms: physical weathering of bedrock, mass movement processes on slopes and permafrost are among these variables. As previously mentioned, fluvial activity is one of the dominant processes in periglacial land transformation. The freezing of water, in particular, in rock, soil, and sediment gives rise to several other processes such as frost shattering, heaving, thrusting and cracking. The ground ice or the ice in frozen ground, for example, has a fundamental influence upon periglacial geomorphology. Then, there is permafrost which, continuously and discontinuously, consist some 25 percent of the Earth’s land surface. (Huggett 2003, p237) Precipitation and Fluvial Variable Climate change brings about a number of hydrologic shifts that affects Arctic lakes, rivers, including seasonal flow patterns, ice cover thickness and duration, and the frequency and severity of extreme flood events. The Arctic Climate Impact Assessment (2005) maintained that in the present climate, most streams and rivers originating within the Arctic have a naval regime in which snowmelt produces high flows and negligible flow that occur in winter while in other areas, such as in some Canadian and Russian islands, Greenland, and Svalbard, ice melt from glaciers can now sustain flow during summer, whereas other streams normally could produce summer flow only in the event of periodic rainstorm events or unless they are fed by upstream storage in lakes and ponds. (p379) It must be underscored that in geomorphology, water and water flow is the principal variable in controlling total denudation by dissolution and the occurrence of corrosion. The operation of running water as an agent of erosion and deposition is important in the Arctic periglacial environment. According to Bird, under current scenarios of climate change, many Arctic coastlines and several communities will be susceptible to flooding. (p169) Ford and Williams (2007) stressed that these variables not only facilitate other geomorphological processes to dominate but also contribute significantly on the Arctic morphological evolution in the next 50 years. (p401) Domack (2003) referred to the sensitivity of the Arctic lakes and freshwater systems, which lie within relatively barren fellfield, rock and ice catchments, applies critical limits on many physical environmental variables including temperature, ice extent, snow cover, underwater light availability and albedo. (p160) If climate change alters the long-term nature of breakup dynamics, the structure and function of rivers and related delta ecosystems are also very likely to be significantly altered with direct effects not just in geomorphological processes and land formations but also in-channel and riparian biological activity as well. (Arctic Climate Impact Assessment, p380) Wind As in hot deserts, the lack of vegetation cover, low precipitation and the availability of fine-grained sediments at ground surface in the Arctic facilitate deflation and Aeolian transport of silt and fine sand in some periglacial areas. In Europe, for instance, the considerable thickness of the wind-blown silt was deposited by dry easterly winds in a great swathe running from Russia to western France. (Stephens, p115) It is helpful, in this regard to explain that the geomorphological processes and land formations activities in the Arctic can be explained in terms of the interplay between the energy input for sediment transfer and the availability of sediment to be transported. (Higgitt and Lee 2001, p10) The former, as illustrated by the wind variable, is a direct function of the climate; while the latter is related to both the depletion of legacy of glacial sediment supply and the role of vegetation cover in inhibiting transfer. The deterioration of the climate to wetter and/or stormier conditions in the next 50 years or so, which also indirectly affect the natural vegetation cover and fresh sediment supplies, is expected to affect the Arctic significantly. The Case of the Frozen Ground The climatic forces could be seen best at work in the frozen ground, the periglacial phenomenon, which is divided into two classes: seasonally frozen ground, which thaws annually; and permafrost, which remains permanently frozen. Permafrost is especially relevant in the land forming processes that happens in the Arctic. The International Permafrost Association defined permafrost as the ground that remains at or below 0°C for at least two consecutive years. (Etzelmuller and Hagen 2005, p11) Although in geo-scientific literature, processes and landforms related to glaciers and permafrost are often treated separately, both are part of the cryosphere and that they often co-exist and therefore have a high potential of interaction. According to Harris and Murton (2005), interaction between permafrost and glacial phenomena depends largely on their proximity: where permafrost occurs close to glaciers, the thermal regime of the active layer is influenced in part by the surface covering of adjacent glacial ice through its effect on albedo (the total radiation from the sun that is reflected by a surface) and ground heat flux. (p1) There is the fact that glacitectonic processes are strongly influenced by water pressures beneath subglacial and proglacial permafrost, and that together they produce a complex assemblage of ground ice in glaciated frozen lowlands. In the context of climate change, permafrost becomes significant when glacier – permafrost interactions are influenced by the deglaciation of terrains in the Arctic wherein permafrost is aggrading. This ‘paraglacial’ zone, wrote Harris and Murton, is complex and occurs over a wide range of temporal and spatial scales. For example, recent assessments in the Alaskan Arctic zone demonstrate the effect of climate change as the warmer Arctic climate considerably thawed and reduced permafrost. (US National Research Council 2008, p104) Hallet et al. (2004), predicted that if the Arctic temperatures continue to rise at the current rate, which is 0.1° C/yr, the upper 10 m of ice-bearing permafrost is projected to thaw within a century due to both air warming and increased insulation from snow. (p127) Cuff and Goudie (2008) supported this finding and stressed, for his part, that permafrost stability largely depends on climate changes change, resulting to either the persistence of permafrost for over a hundred to thousands more years or to the persistence of only a few years from now. (p495) Conclusion: The Next 50 years Along with geology, climate is the prime control of the physical environment because it affects soils, vegetation, animals and the operation of geomorphological processes such as ice and wind. Specifically, for the Arctic, geomorphological activity occurs during freeze-up and breakup. It would most likely have significant effects on the geomorphological processes and land formations in the Arctic once the climatic conditions such as the extreme warming in the region alter the severity of such events as well as their timing. With all the variables considered, from all climatic changes, particularly the temperature, the Arctic is seen to lose its periglacial character over the next 50-100 years as indicated by projections of climate change. (Christiansen and Humlum (2003), p139). There is already empirical evidence that points to the fact that there has been a decline in the extent of Arctic sea ice in all seasons, with the most prominent retreat in the summer. Temperature is the most important climatic factor at play here. It has wide-ranging and far-reaching effects on almost all aspect of the Arctic environs and the geomorphological processes that transpire within. Finally, it must be underscored that the predictions on the geomorphological processes and the land formation trends, among other specific effects in the Arctic environment may still vary due to the complex nature of the interrelationships between climate forces which determine the surface and ground thermal conditions. References Arctic Climate Impact Assessment 2005, Arctic climate impact assessment. New York: Cambridge University Press. Bird, E 2010, Encyclopedia of the Worlds Coastal Landforms. Heidelberg: Springer. 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University of Chicago Press. Pitty, Alistair, 1971, Introduction to geomorphology. Norfolk: Taylor & Francis. Stephens, N 1990, Natural landscapes of Britain from the air. Cambridge University Press. Thompson, R and Perry, A 1997, Applied climatology: principles and practice. New York: Routledge. Read More