Background Information: Climate Change Through History
Scientists know that there have been many climatic changes throughout the earth's history. For example, the overall temperature across the globe is at least 5.5 degrees Celsius (10 degrees Fahrenheit) higher than that of 75 million years ago. Yet, the earth has also experienced periods of significant cooling, as was the case 20,000 years ago. At that time, temperatures dropped and heavy snow and ice covered large areas of the planet.
Evidence of Climate Change
It is important to remember that even minor fluctuations can have a significant effect on the environment. However, certain human activities that have taken place during the last century have also contributed to climate change. This is particularly true in the case of the Enhanced Greenhouse Effect, which is caused by an excess of greenhouse gases generated by the use of some certain products such as aerosol sprays, refrigerators, fire extinguishers, air conditioners, cars, fertilizers, etc.
The use of certain products, which have become particularly popular during the last several decades, has led to an increase in greenhouse gas emission. For example, excess ChloroFluoroCarbons (CFCs) are emitted by refrigerators and certain types of air conditioning units. The use of aerosol products in the common spray cans also increases levels of CFCs. Certain types of fertilizers add additional nitrous oxide, while burning of fossil fuels (oil, gas, coal) increase levels of carbon dioxide.
However, these are only a few example of factors leading to changes in the climate. While scientists have been able to determine some of the causes of climate change, many are still only partially understood. Some are still a mystery. A schematic view of the components of the global climate system, their processes and interactions and some aspects that may change.
In understanding more about climate variability, then climate change and its consequences, let us look at some specific examples and events such as, the El Niño phenomenon, the Greenhouse Effect, global warming, and sea level changes.
