The Shadow
While world leaders are proclaiming that mankind’s most serious threat is climate change, formerly referred to as global warming, scientists cannot deny that the Earth’s temperature has been warmer in the past.
In fact, during the Medieval Warm Period lasting approximately from 900 AD to 1300 AD (some scientists list the period as 950 AD till 1250 AD), the Earth was as much as 1.8 degrees Fahrenheit warmer than the temperatures that were recorded from 1960-1990.
While most scientists agree that carbon dioxide emissions are contributing to the greenhouse effect that is causing the Earth’s temperature to heat up, the same scientists must concede that the rise in the Earth’s temperature during the Medieval Warm Period was natural-driven, not human-driven.
Many in the scientific community have come to believe that the warming that occurred during the European Middle Ages that enabled England to support vineyards via temperatures that were warmer than the Earth’s temperatures that were recorded from 1960-1990 was an anomaly.
The belief is that the natural drivers of the Medieval Warm Period were less volcanic activity, an increase in solar radiation and stronger trade winds pushing warmer water toward Asia, resulting in wetter conditions in Australasia and changing weather patterns in China.
What came to be known as the North Atlantic Oscillation brought warmer winters and wetter conditions to the North American continent and in Northern Europe.
Winter weather was impacted in Greenland, North Africa and Northern Asia. The melting of Arctic sea ice and land ice combined with the warming of the North Atlantic to enable Vikings to sail to Greenland and Iceland where they settled.
In the territory that became the U.S., the South and Southwest experienced severe drought while the Pacific Northwest and what is now Canada suffered from extreme flooding.
South America and Central America experienced an extreme drought that dried up Lake Titicaca, the world’s highest lake that straddles the border of Peru and Bolivia, extending 120 miles in length and 50 miles in width.
The Mayan and the Incan civilizations were negatively impacted by the drought that also dried up some freshwater runoffs close to the ocean.
The Medieval Warm Period changed eco-systems and altered human societies without any pollution from factories, motor vehicles, aircraft, and other machines that rely on fossil fuels.
Thus, a question looms for scientists to ponder. Will the reduction of greenhouse gases that mankind is releasing into the atmosphere prevent climate change as predicted, or will natural forces drive the Earth’s temperature higher once again as it did during the Medieval Warm Period?
Following the Medieval Warm Period, regional cooling took place in the North Atlantic from 1300 AD till 1860 AD, hardly a period of time during which mankind’s pollution could be blamed by scientists for the regional climate change that saw the Earth’s temperature plunge as much as 3.6 degrees Fahrenheit in Europe and North America.
