Human+Impacts+(Arctic+Tundra)

=**Climate Change**= At the heart of many of the problems facing polar landscapes today is the overall heating of earth's atmosphere, otherwise known as global warming. Ice in the surrounding seas and farther North is melting at an alarming rate. When the ice melts, the darker ocean absorbs heat that the ice would have reflected back into the atmosphere or space (I1). The seas warm, more ice melts, and the greenhouse effect prevents the ice from reforming during the colder winter months. On land, these increasing temperatures also cause harm by melting permafrost stored in the ground. Permafrost is a permanently frozen layer of soil that exists year-round in polar conditions. The c old temperatures prevent carbon dioxide-heavy plants from decomposing, trapping the CO2 (and other gases like methane) and preventing it from re-entering the atmosphere in what is called a "carbon dioxide sink" (I2). However, as global warming continues unchecked, the permafrost melts, causing the decomposition of dead plant matter and the subsequent release of thousands of years of carbon dioxide into the atmosphere (I2). When permafrost melts, erosion occurs due to the lack of root systems deep enough to hold the soil in place, as seen in photo 2.

Photo 1(I3) and photo 2 (I4) depict permafrost melting and erosion.

This photo (I5) depicts the cycle of carbon within the tundra ecosystem.

Holes in the ozone layer, a result of increased levels of chlorofluorocarbons and halons (found in aerosol and refrigerants), also lead to increased radiation damage and harms the surrounding ecosystems (I6). Although most UV-B damage has so far occurred in marine systems in the Arctic and Antarctic, the growing size of the ozone hole brings the potential for harm much closer to the tundra landscape. Dangerous UV-B rays are readily absorbed into organisms' DNA, resulting in health hazards and even genetic mutations and cancers, as seen in the image below. (I7).

(I7)

Other effects of UV-B include cataracts and snow blindness, and the rays impair the ability of plants to photosynthesize, resulting in smaller, nutrient-poor plants that are more susceptible to disease (I7). With the invasion of new species into warming northern areas, the risk for disease is all the more prevalent. If sparse tundra plant species are unable to be sustained and protected, populations of lemmings, caribou, hares, and foxes will dramatically decrease from malnutrition and disease that accumulates up the food chain.

=**Human Development**= The polar grasslands contain some of the largest oil and gas reserves still remaining in the world. Many of these reserves exist offshore in continental shelf seas, but there are enough mining and drilling operations on land to have already begun disrupting the fragile tundra landscape. When a mining or drilling operation starts, towns pop up and the inhabitants establish roads and pipelines. In a landscape that has been unchanged for virtually hundreds of years, even a disturbance such as a set of footprints, or the creation of a footpath, will be visible for many years. When sunlight hits the ruts or impressions in the ground, they begin to melt, turning roads, tire tracks and digging marks into large holes, gorges or lakes (I8). Roads and pipelines have disrupted migratory patterns of caribou and reindeer and their access to feeding, denning, and calving grounds. To curb the effects of the pipelines, many have been raised in sections or entirely so that herds can pass under them.

This photo shows a pipeline cutting across the Alaskan landscape (I9).

Today, arctic regions are responsible for producing around one-tenth of the earth's oil and one-fourth of its natural gas, with 80% of this oil and gas coming from the Russian Arctic (I10). Prudhoe Bay in Alaska is responsible for 20% of the oil extracted from US Arctic oil fields (I10). The field operates in the path of the Central Arctic herd in Alaska, and although there has not been a significant change in the population as a result of the field, researchers have observed that many females are displaced from normal calving grounds and both males and females go out of their way to avoid the area (I11). One such herd is the Porcupine caribou herd, which migrates through a section of protected wilderness that has the possibility to be opened up for drilling if approved by Congress. However, these grounds are the caribou's calving grounds, and if the caribou is displaced or reroute around the drilling area, they risk becoming subject to malnutrition from eating insufficient vegetation in alternate locations (ie the coast or rough mountainsides) (I11). To see how caribou and culture interact, watch this video.

= **Air Pollution** = The Arctic circle is unique in that researchers have significant amounts of DDT, volcanic ash, soot, and other industrial pollutants in an area that does not have the capacity to produce such pollutants in such large-scale amounts. There is almost no need for DDT or other pesticides in the relatively barren environment, and sand from the Gobi desert shouldn't be creating a haze visible to the human eye in Alaska. Global wind currents and oceanic currents carry pollution primarily from Eurasia, North America, and Africa into the Arctic Circle, creating a phenomenon called the Arctic Haze. Today, the haze consists of large amounts of industrial pollutants like organochlorines and other anthropogenic materials from highly industrial areas. Soot is one of the larger issues, originating from cooking fires and coal-burning in South and East Asia respectively (I12). It perpetuates the greenhouse effect, and reduces visibility and the amount of sunlight able to reach earth. Along with, soot, dust, sand, and ash suffocate lichens and other shallow-rooted pant life. Lichens are often the first affected, and they act as biological indicator species. Photo 1 (I13) captures an image of arctic haze. Photo 2 (I14) is a diagram depicting the formation and causes of haze, which can be transposed to fit the larger cycle of pollutants through the global atmosphere which creates Arctic haze. = **Ecological Imbalances** = Human development of farms and a surplus of crops in southern winter nesting areas has disrupted the feeding patterns of migratory geese. The destruction and/or pollution of usual nesting grounds drives these geese into agricultural areas where they eat greater amounts of food, and which then allows them to increase their populations. As they migrate back north, into the polar grasslands, their increased numbers cannot be supported by the sparse tundra vegetation. (I15) (I16). Increasing polar temperatures have, unsurprisingly, led to the early thawing of lakes, ponds, and other bodies of water. This is troubling news in itself, but worse is the early hatching of mosquitoes that come with it. Mosquito populations have significantly increased over the past years, and with longer periods of warm weather, they have been able to survive into adulthood, reach larger sizes, and develop much more rapidly. Mosquitoes also tend to emerge all at once, and usually around the time that migrating herds of caribou or reindeer give birth to calves. These mosquitoes tend to attack in large groups, swarming their targets. This will drive the larger animals into snowy, less hospitable areas, preventing them from grazing as much as they need to. Researchers have observed that as insect 'harassment" increases, caribou/reindeer populations decease (I17). Females that have recently given birth are less able to flee the onslaught, providing female mosquitoes with the fresh blood supply needed to survive reproduce.    Photo 1 (I17) shows the change in growth within the mosquito population. Photo 2 (I18) shows two caribou. Photo 3 (I19) is an image of a mosquito swarm in Alaska.  Back To Home Page Foward