The glaciers completed their retreat and settled in their present positions about 1012,000 years ago. There have been other fluctuations in global temperatures on a smaller scale, however, that have sometimes been known popularly as ice ages. The 400 year period between the fourteenth and the eighteenth centuries is sometimes called the Little Ice Age. Contemporaries noted that the Baltic Sea froze over twice in the first decade of the 1300s. Temperatures in Europe fell enough to shorten the growing season, and the production of grain in Scandinavia dropped precipitously as a result. The Norse communities in Greenland could no longer be maintained and were abandoned by the end of the fifteenth century. Scientists argue that data indicate that we are currently in an interglacial period, and that
North polar ice will again move south some time in the next 23,000 years.
Read more: Polar Ice Caps - Polar Ice Caps And Geologic History
Polar Ice Caps - Polar Ice Caps And Geologic History
Polar Ice Caps - Polar Ice Caps And Geologic History
When the temperature trend in the "blade" of the hockey stick between 1850 and 2000 is examined in more detail, as shown in Figure 2, it is found that the average global temperature doesn't increase exponentially like the measurements of carbon dioxide do at Mauna Loa. The temperature increases between about 1850 and 1940, and then decreases for a 30-year period from 1940 to 1970, after which it begins to climb again. This is very peculiar if carbon dioxide is driving global temperature, because the greatest increase in output from industrial production and the associated release of carbon dioxide would have occurred during this period.
Following World War II, industrial productivity and the release of carbon dioxide climbed rapidly. Yet temperature fell, prompting many climatologists to express concern that we were heading into another ice age. Once again, the average global temperature began to warm in 1970. The temperature and carbon dioxide diagrams do not match up, as one would expect if carbon dioxide concentration is driving temperature.
Does Carbon Dioxide Drive Global Warming?
Do your own research on how ocean currents effect glaciers and the effect of sun spots on the earth's climate.