North American Climate Change

Decent Essays
The Earth has not always been as it is today. Periods of climate alterations have occurred over time to land us where we stand today. Around 8200 years ago or 6200 BCE, a surprising event occurred on Earth. The Earth underwent an abrupt climate temperature change. This change is known as the 8.2 ka year event or 8200 year event which refers to the last major climate alteration, a Northern Hemisphere cooling event that occurred approximately 8,200 years before the present. This event was less severe than the Younger Dryas, a cooling event preceding the 8.2, but more severe than the Little Ice Age that occurred after. The event occurred in the Greenland Ice cores during the Holocene, a period in which the Earth had a relatively stable climate.…show more content…
The cause of the event remained a mystery for quite some time but scientists have begun to come together and converge on a consistent image of what really happened. Scientists and climatologists have estimated that the cooling event may have been caused by a major fresh water pulse into the North Atlantic as a result of the final collapse of the North American Laurentide ice sheet. The meltwater pulse is believed to have affected the North Atlantic thermohaline circulation, or MOC, reducing heat transportation in the Atlantic causing cooling in the North Atlantic waters. At about the same time, the glacial lakes Ojibway and Agassiz suddenly drained into the North Atlantic Ocean and Hudson Bay. The total amount of freshwater that was displaced and emptied into the North Atlantic and Hudson Strait remain uncertain, but estimates of the volume extend from a lower bound of 1–2 × 1014 m3 to a higher bound of 5 × 1014 m3. The cooling of the 8.2-kilo year event was temporary, however, the sea-level rise from the meltwater pulse was a permanent effect. This large amount of fresh water discharge created a significant fingerprint in sea-level heights, acting as a catalyst for the decline in meridional overturning circulation or MOC. MOC is also known as the “conveyer belt” because it is the process of surface waters in the high latitudes being cooled and becoming denser which then…show more content…
This decrease in methane was a result of the collapse of the North American Laurentide ice sheet where a large concentration of methane was trapped under the ice. When the ice sheet collapsed, methane was released and no longer trapped. There is also evidence from ocean sediments that parts of the tropics became drier as a result of the 8.2 ka event. The shrinking and deterioration of the tropical wetlands in a drier climate could also explain the 10-15% drop in atmospheric methane that resulted from the event. This event relates to what I have learned in class because it covers concepts on glaciers/ice sheets, water movements, natural processes, and relativity. Glaciers are essentially massive ice that float under their own weight. The size of glaciers can vary but for the most part they are very large and provide water for about 1/3 of the world’s population. They are the biggest storage of fresh water, which explains the extent to which the North Atlantic was filled following the collapse of the North American Laurentide ice sheet. When the ice sheet collapsed, it initiated a freshwater pulse that sufficiently freshened the North Atlantic surface waters, which caused the cooling event. In class, we have also reviewed the concept that everything is related. The collapse of the North American Laurentide ice sheet led to a melt water pulse,
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