The tundra biome exists in northern latitudes where average summer temperatures stay in the range of -1.11 to 10 degrees Celsius, and winter temperatures hover around -1.11 degrees C below zero. The land has no trees, little precipitation falls and the ground has a layer of permafrost, soil that remains frozen year round, even as the surface above it melts for a short time during the summer. Human effects on the tundra come primarily from mining and oil drilling activities and from climate change that NASA says results from greenhouse gases caused by burning fossil fuels.
Air temperatures have warmed in the far North, and as a result thunder and lightening storms that used to stay further south now occur in areas of tundra. As a result, lightening-caused wildfires have become more common. According to the National Science Foundation, the 10-year period from 2000 to 2010 saw more area burnt by wildfires in the Alaskan tundra than all the fires from the 1950s to 2000 combined.
As the tundra has warmed, the area of true tundra has receded as larger, shrubbier plants move north. Other areas in the tundra have changed from the grassy plain that makes up tundra to marshy wetlands, with tundra vegetation being replaced by wetland grasses. According to the Arctic Change website, satellite imagery shows that between 1982 and 2000, the area of tundra, based on the type of plants growing there, decreased by 18 per cent.
As temperatures have increased in the tundra, species that did not come so far north in the past now migrate to the tundra during the summer months. According to Arctic Change, ring neck ducks, for example, had never been seen at an observation station on the Canadian tundra prior to the 1980s. From that time through 2009, they commonly migrate through the tundra. Additionally, construction of pipelines, such as the Alaska pipeline, block traditional caribou migration paths. In some areas, the Alaska pipeline had to be raised so caribou could pass under it.
Such airborne pollutants as DDT and PCBs have been carried into remote areas of the Arctic tundra. The tundra serves as nesting grounds for many species of migratory birds. Pollutants like DDT can become concentrated in the systems of birds, causing thinning of their eggshells. Although DDT is banned in the United States, warmer temperatures in the tundra have led to insect outbreaks and increased use of other pesticides that may have unknown impacts on tundra wildlife.