According to NASA, the climate of the earth has been changing ever since the inception of the earth (“Climate change: How do we know?”). NASA estimates that there have been about 7 cycles of sudden climate changes in the last 650,000 years alone which is too frequent, considering that the earth is about 4.543 billion years old. One of the two latest abrupt climatic changes in the prehistoric times are: The Younger Dryas, and The Akkadian collapse.
The Younger Dryas is an abrupt climate change event that occurred in about 12,800 before the present day. The Younger Dryas was experienced in Greenland, Europe, New Zealand, and North America (“Two examples of abrupt climate change”). It was evident due to the abrupt warming of the earth leading to glacial termination. The Younger Dryas climate change occurred when the Lake Agassiz discharge freshwater catastrophically leading to a thermohaline circulation (THC) shutdown. The THC shutdown reduced the northward ocean heat transport rapidly making the North America and North Europe to cool over.
The Akkadian empire existed between the Tigris and Euphrates River and which lead the agrarian revolution (“Two examples of abrupt climate change”). The empire practiced agricultural irrigation practices in the Mesopotamia region as well as rain-fed agriculture. The agricultural activities of this empire lasted for a few centuries until the empire collapsed suddenly in 4170 years before the present day. The reason for the collapse of the empire are not clear. After the collapse of the empire, all the agricultural activities ceased leading to changes in weather patterns, increasing temperatures and finally aridification.
In the modern day, abrupt climate changes are brief and smaller compared to the pre-historic climate changes mostly due to development of instruments that collect real time data. An example of current climate change is the Arctic change experienced in the 1990s (“Abrupt Climate Change: Inevitable Surprises”). The Arctic change was caused by the Arctic Oscillation (AO) and the North Atlantic Oscillation (NAO) in their positive phases which drove warmer and saline water from the Atlantic into the Arctic. This led to the melting of the Arctic sea – ice which was further aggravated by the dynamics of greenhouse warming.
- “Abrupt Climate Change: Inevitable Surprises”. The National Academies Of Science Engineering And Medicine, 2002, https://www.nap.edu/read/10136/chapter/4#25 .
- “Climate change: How do we know?”. Climate.nasa.gov. N.p., 2017. Web. 26 Apr. 2017, https://climate.nasa.gov/evidence/ .
- “Two examples of abrupt climate change”. Lamont-Doherty earth observatory. Web. 26 Apr. 2017, http://ocp.ldeo.columbia.edu/res/div/ocp/arch/examples.shtml