There have been several ice ages in the history of the earth and from the opinions of geologists and other scientists, there will be more. An ice age is a period when significant portions or surfaces of the earth are covered by glaciers and sea ice resulting in significant lowering of the earths temperature. The portion of the earths surface that has been covered by previous ice ages has ranged between 10-30 percent of the total surface. The earth has existed for about four and a half billion years and the study of its history reveals some consistencies, one of which is periodic ice ages. But, thanks to human activities its been delayed. This has made scientists ponder the link between global warming and ice age.
Ice Age and Global Warming
From a study of previous ice ages, geologists have been able to deduce that ice ages consist of several glaciations that last for several thousands and sometimes millions of years. Glaciations are periods when the earths ice cover increases. Each glaciation has been observed to be followed by an inter-glaciation (time when the ice cover shrinks). From calculations, we are currently in an inter-glaciation because the last glaciation which was recorded in North America spanned from about 115,000 years ago to 10,000 years ago. It is known as the Wisconsin Glaciation. It is believed that the earth should have been in another ice age if not for global warming and theres evidence to confirm this.
The Earth is Overdue for the Next Ice Age
In order to understand the link between global warming and ice age, consider the following hypotheses. Scientists examine the time frames and the intervals between the different glaciations and inter-glaciations of the past ice ages in order to predict future ice ages. From these calculations, it has been deduced that the earth was already in the early parts of an ice age before human activities brought about global warming. This deduction is backed up by evidence from sea and land measurements indicating that the global temperature had been dropping due to a cooling of the atmosphere. However, the effects of global warming are thought have delayed this.
Can Global warming Cause an Ice Age?
While global warming seems to have delayed the onset of an ice age, some schools of thought believe that the current warmth the earth is enjoying cannot last forever. They believe it is just a prolonged transition into the next ice age. The reason for this is that the earth has always experienced intermittent cycles of warmth and coolness and although human activities can affect the outcome, there are several other contributory factors also involved such as the TSI (total sun irradiance).
In the end, emphasis should not really be on whether or not there are links between global warming and ice age, but rather, greater care should be given on ways to of adapting to the changes that are occurring to the earths climate.