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Human Effects
Humans have shown to have an effect on both the Mendenhall glacier and other glaciers around the world. Many of these glaciers are found in parks where tourism is popular therefore people have direct access to the area. For example, in Glacier National Park in Montana it is said that due to human interaction vegetation is trampled and litter from visitors is left behind resulting in pollution. Invasive non-native species are also introduced due to all of the movement near the glaciers. Pollution from car exhaust as a result of travel to and from the park also occurs. All of these scenarios negatively impact the glaciers. Since the Juneau Icefield and the Mendenhall glacier are also popular tourist locations we can expect some of the same occurrences. Other human effects on glaciers around the world include extraction of resources, where humans are taking away natural resources from these regions that their ecosystems use for survival. These human effects can all be applied to the Mendenhall glacier as it is a glacier that experiences human interaction on a daily basis so it is plausible that these same occurances could have negative impacts on this glacier as well.

Climate Change
Scientists overwhelmingly agree that earth is warming due to human activity. This warming is causing glaciers to melt quicker then they would naturally. Over the past century human activities have released large amounts of carbon dioxide and other greenhouse gases into the atmosphere. These greenhouse gases are a product of humans burning fossil fuels to produce energy. Deforestation, industrial processes, and some agricultural practices emit gases into the atmosphere as well. This emission of greenhouse gases creates a bubble around earth, trapping energy and causing the planet to warm. As temperatures rise and ice melts, water flows from the glaciers and ice caps causing the water to warm and expand. The rising temperature due to human actions is causing the glaciers to retreat at a faster rate then they would naturally.

Negative Effects of Retreat
The retreat of the Mendenhall glacier and other glaciers in the area is causing the destruction of the Juneau Icefield. The Juneau Icefield is the fifth largest icefield in North America. With its most popular attraction melting tourism is becoming less frequent in the area. This has a negative effect on the Alaskan economy as these areas are a source of revenue. To determine other negative effects of glacial retreat we are able to look at other glaciers around the world and apply negative effects they experience to the recession of the Mendenhall glacier. For many populations near glacial areas these glaciers are a source of fresh drinking water. Once these glaciers are gone the people relying on this fresh water will be out of their familiar fresh water source. For example, Anchorage is one of the most populated cities in Alaska and many people in this city rely on the Eklutna glacier for their freshwater. If the recession of this glacier continues they will be out of their main source of water. In other areas, people rely on these glaciers to nourish the ecosystem. For example, the city of San Francisco relies on the glaciers of the Peruvian Rio Santa Valley for irrigation of the land. Since the glacier is retreating so quickly it is now discharging less water than before which will eventually lead to drought in the area as it is now getting less water than it is acclimated to.

Benefits of Retreat
Although there are many negative affects of the recession of the Mendenhall glacier and glaciers in general, there are also a few positive outcomes from it as well. With the recession of the Mendenhall glacier, the Mendenhall Lake has formed. The lake is a result of the run-off from the glacier and is increasing in size as recession continues. The lake began formation in 1931 and has continued to grow since then. The lake has its own unique ecosystem and is a popular location for sport fishing; fishers can find salmon and trout in the lake. As of recently a new discovery has been made regarding the Mendenhall glacier and its recession. Within the past year, tree stumps and logs with roots and bark still attached have been appearing from under the glacier as it has been retreating. What’s even more interesting is that they are being found in their original growth position, preserved by what was believed to be a protective gravel casing covering them. By uncovering these tree stumps and logs, scientists are able to uncover information on the ecosystems past, from a pre-glacier time. Scientists observing the area are able to determine how old the trees were when they died by looking at their preserved selves now. Although it is at the cost of glacial retreat, it is fascinating what scientists are able to discover about the ecosystems past from this natural preservation.