The Global Climate Change daily constantly evolving throughout  history. From  ice ages, where ice covered significant portions of the Earth to interglacial periods where winter climate caused ice to melt almost entirely - the climate has continuously changed. Through most of this period, ther is no written Climate Data

Scientists have been able to piece together a picture of the Earth's global climate change dating back decades to hundreds of thousands of years ago by analyzing a number of different parameters.  Measures of climate such as ice, boreholes tree rings, glacier lengths,  and by studying changes in the Earth's orbit around the sun. This has allowed researchers to gain an insight into Historica Temperatures.

During the last 2,000 years, the climate change has been relatively stable. Scientists have identified three departures from this stability, known as the Medieval Climate  (also referred to as the Medieval Warm Period), the Little Ice Age and the Industrial Era:

·    The Medieval Climate: Approximately between  900 and 1300 AD, evidence suggests Europe, Greenland and Asia’s winter climate experienced relative warmth. While historical temperatures accounts and other evidence document the warmth that occurred in some regions, the geographical extent, and timing of the warmth during this period is still uncertain. The American West experienced very dry conditions around this time.

·    The Little Ice Age: A wide variety of evidence supports the global existence of a "Little Ice Age" (this was not a true "ice age" since there were no major ice sheets) between about 1500 and 1850. Average temperatures were possibly up to 2ºF colder than today, but varied by region.