The public has not been made aware of all information regarding global warming. This is unfortunate because when we hear “global warming” we have come to assume this means human-caused warming. In truth we are unable to distinguish between natural warming and human-caused warming.
What we do know is, there is a gradual increase in the average temperature of Earth. S. Fred Singer and other climatologists have done extensive research on historical global temperature variation. By using proxy thermometers, e.g., ice cores from Greenland, and written records they have found that global temperature exhibits a 1,500-year heating/cooling cycle.
Indeed, records show that during the Middle Ages Mediterranean crops were growing as far north as Germany. Alaskan glaciers have been warming for hundreds of years, not just since the Industrial Revolution.
I urge everyone who has accepted the popular notion that man is responsible for global warming to search out literature by climatologists such as: S. Fred Singer, Roy Spencer, Dennis Avery, David Hart and Tim Ball.