The economy of Europe flourished as fisherman supplied cod to many nations as a food staple since Roman times (about 100AD). Cod could not survive in temperatures below 2 degrees centigrade. Cod was the main source of trade of Greenland, and the establishment of towns, as far north as 72 degrees latitude. That is, until most of the time between 1600 and 1830 when there became a scarcity of cod as far south as the Shetland Islands, at 60 degrees latitude, because of the Little Ice Age: an era of global cooling caused by the planets which began with increasingly cooler winters since 1444’45 and cooler summers since the summer of 1523, ending with peak cold in the winter of 1623’24 and cooler summers ending in the summer of 1831. During the 1933s, an era of global warming, cod was again caught as far north as 72 degrees latitude around the southern end of Greenland. An era of global warming had begun with increasingly warmer summers since the summer of 1831 and increasingly warmer winters since the peak of 1623.
There is evidence that the Chinese sailed around the island of Greenland. Given this fact, the water temperature in the northern ocean had to be above zero degrees centigrade. The northern latitude of Greenland is 84 degrees. Assuming 2 degrees temperature change causing the migration of cod across the 12 degrees of latitude between Greenland and Island, there would have been an additional 2 degrees warming across the 12 degrees north around the northern end of Greenland at 84 degrees latitude.
The lowest force recorded by my program was November of 394BC continuing through October of 393BC. A slightly higher low force occurred in October of 573BC. The entire millennium BC was lower than any millennium since. The next lowest force will occur in January of 2964. Between now and then we will experience global warming to 2179 and global cooling from 2179 to 2418 and then global warming similar to the 1st millennium AD.
The chart below shows the corresponding dates of the global warming with the occupation of Greenland and, perhaps, the fish economy of Greenland. The chart is a world wide view of changing temperatures, the lower the force the warmer the planets became. The winters became increasingly warmer after the fall and winter of 769. The warmest being the entire year of 1057 and most of 1058. Then global cooling began to set in that finally drove the people and the fish away from Greenland.
