Geology - Google Earth Exercise 8-2

Waldron 2 1) Melt locations during the 1980s appear to be at least relatively even with the southwestern coastal area experiencing a slightly elevated rate of glacier melt. But data from 1985 shows this trend has grown more disproportionate, a slight reduction in melt rate occurred on the northeastern coastal areas and a large increase in melt rate along the southern side of the island on both coasts. By 1990 this difference in melt rate is even more pronounced, melting events were no longer constricted to the coastal areas as the entire portion of the southern side of the Waldron 3 island experienced glacial melt. However, areas that experienced the highest melting rate were the southwestern coastal areas. When viewing the 1995 data, the melting trend along the western coasts appears to have increased even more, although there was a slight reduction in melting in the northeastern areas of the island. However the 1995 data set also marks first time that significant melting spreading from the western coastal areas to the inland portion of the islands glaciers. In data from the 2000 files inland melting decreased, but all coastal areas experienced elevated melting rates. Data during 2005 shows that melting rates increased in intensity among affected areas, however there was a slight reduction in total areas affected along the eastern coast of the island, these areas in the east that still experienced melting did so at a higher rate than in the data from 2000. These melting events are influenced by several factors the largest of which is the air currents that circulate the island. The North Atlantic Ocean current brings warmer air and water up from the south Atlantic Ocean, this affects the air temperature of the air currents around the island. The Irminger air current splits off from the North Atlantic current slightly past the southern tip of Greenland and this warm air current swirls around the southern coasts and cools before reaching the northwestern portion of the island. The air currents that travel down the north eastern coast of Greenland come from significantly higher than the Irminger current and as such have enough time to cool down. This is the largest reason that the northeastern side of the island experiences melting at a slower rate than the southern coastal areas of Greenland. 2) The general trend throughout the timeline changes is a reduction in cereal crop suitability in many areas, many of which have been historically very productive. These traditionally productive areas appear to be the most impacted, such as the Mississippi River Valley and its Basin, these areas are where the bulk of American grain and feed crops are grown. Initial Waldron 4 changes between 1990-2050 show a slight increase in growing condition in northern areas such as the Canadian Pacific Northwest. However, this trend appears to be temporary as by 2080 predicts that the suitable growing locations in northern latitudes have dropped in rating, the 2080 predictions also show a significant reduction in southern growing locations as well. Data form 1961-1990 shows a high suitability for the areas around the great lakes and this high suitability extends all the way down to the Gulf Coast. By 2080 predictions show that this range has effectively been halved essentially ending in the middle of the United States, this prediction also shows a decline in suitability in growing areas along the eastern seaboard. 3) The future for South American growing season length looks incredibly poor as appropriate growing days sees a sharp decline in many areas. A sizeable portion of Brazil’s Atlantic coast appears to be experiencing extreme desertification at a rapid rate much of this is due to several dams that have been constructed along the Sao Francisco River. These dams impede seasonal flooding that sustains the local vegetation, reviewing satellite imagery through the years shows as damming and deforestation occurs along this area the desertification intensifies. This will reduce the amount of precipitation within the area and cause ambient temperatures to increase further compounding the issues within the region relating to growing season length. Central Brazil has a poor outlook as well, this is largely due to the deforestation of the Amazon Rainforest, which will also cause temperature and precipitation issues within the region. Reduced vegetation in this area could see a rise in flooding events because the soil will have little vegetation to hold moisture in the ground. Exposed earth holds little moisture and will erode at a significantly higher rate than covered soil, this will cause runoff to increase and could lead to more frequent and intense flooding events further decreasing growing season length. Waldron 5 4)There has been concern over the rapid expansion of the Sahara Desert that the areas surrounding this massive desert have been experiencing for some time now. As temperatures increase within this area precipitation rates decline and this creates a vicious cycle that is challenging to breaks. As temperatures increase and precipitation declines, vegetation around the area begins to experience a higher mortality rate and this further compounds the issue. The death of vegetation causes the barren ground to retain less moisture and increases run off during precipitation events. Barren ground does not absorb moisture as readily as covered soil and less water is able to enter the water table, human withdrawals from ground water further intensify this issue and reduce water availability for the remaining plants within the area (Rafferty, J. P. et. Al. January 29, 2020) 5) Resource wars have been waged for much of humanities known history, but recent projections have indicated that future resource wars would be more inclined to be over basic necessities such as reliable access to freshwater. Water wars could be a very real reality for many nations that are already experiencing droughts or are drought prone, including much of South America, Africa, And the Middle East. A Prime example of this would be the growing tensions between Ethiopia and the nations of Sudan and Egypt because of the construction of the Grand Ethiopian Renaissance Dam (GERD). Since Ethiopia announced that it planned to construct the GERD on the portion of the Blue Nile that passes through its borders, both Egypt and Sudan have made their concerns very clear at one point even threatening open war if they did not cease its construction (The Signal Room October 11, 2021). Recently tempers have cooled over the issue provided that Ethiopia can provide evidence that the dam will not cause the droughts and famines that restricted access to the waters of the Nile would cause as both disgruntled nations claim (The Egypt Independent September 26, 2021). Waldron 6 6)This sea level rise is largely due to the process of glacial rebound unfolding. Due to the high levels of glaciation that Canada experienced during the last ice age, the land mass partial sank under the weight of heavy glaciers. Now that the glaciers have melted and their weight has been lifted off of Canada the landmass is beginning to rise, causing their local sea levels to drop. Sea level rise in the new England region is rising because of Canadas upheaval and in part because of the glaciers melting on Greenland contributing to sea level rise. The effects of glacial rebound are more pronounced in the mid-Atlantic region because this area was lifted to higher elevations because of Canada sinking underneath the weight of its former glaciers. As the Canadian area returns to its proper placement, the mid-Atlantic sinks back to its correct position, this sinking also contributes to the sea level rise in the new England region. 7) Grand Isle and Eugene Island are experiencing rapid sea level rise because of a combination of a few ongoing environmental issues. The most concerning of which is the drastic reduction in sediment deposition from the Mississippi River, which has created the delta on which these islands sit. As the Mississippi River deposited its sediment and formed its delta, these barrier islands were created because of the high sediment load that the Mississippi once carried, however many recent human manipulations of the river have drastically reduced the sediment content of the river. There are close to 50,000 dam’s and levies on the Mississippi River and its tributaries that feed it, this has resulted in a 50% decrease in sediment content within the river, starving the region of the sediment that created it (Maloney, M, J. Et. Al. March 10, 2018). As erosion occurs there is not enough new sediment to replace what has been lost to wave action, sediment starvation within the Mississippi Delta will play a prominent role in the disappearance of the islands. Further damages to the delta complex are the shackling of the river to the north by Waldron 7 the Old River Control Complex, this facility was constructed to ensure that the meandering Mississippi remained on its current flow path through New Orleans to ensure its continued usage as a major port facility (Williams, K. February 6, 2018). The Mississippi has been trying to take a more western course, but shackling will not allow it to change to this direction, further compounding sediment issues within its delta.