Impacts of Global Climate Change on Temperature and Precipitation Patterns in the Midwest and the Consequences for Soils
During the last century, human activities in agriculture, industry and technology have brought about a change in the chemical composition of the atmosphere. This change so far has not had a noticeable or discernible effect on world climate, but if these same activities continue, global climate change will become irreversible. The major contributing factor is the increase in the amount of carbon dioxide and other gasses in the atmosphere. These gasses are being cited as the cause for a "greenhouse effect" where they trap the heat of the sun and cause global climate change, specifically a warming trend on the surface of the Earth. Many different scenarios for the possibilities and extent of global climate change have been proposed, and many global climate models have been created to look at the possibilities. While there are a wealth of differing opinions, there are also some consistencies in the predictions. Among other things, climate change is expected to cause increases in average global temperatures and changes in worldwide precipitation patterns. Even though these broad consequences are agreed upon, the affects which these changes will have on the climates and ecosystems around the world is still a matter of uncertainty. However, there is some consensus for the localized effects of global change in different climatic zones of the world.
In the subboreal climate of the Midwestern region of North America, it is generally agreed that the temperature will increase an average of one to five degrees over the next ten to one hundred years (Varallyay, 1990). Also, it is expected that overall precipitation will increase and the seasonal patterns will change. These changes in the regional climate will have drastic effects in all areas of the ecosystems. One of particular concern is the possible changes in soils. With a changing climate and atmosphere, the soils, as well as the vegetation, of the Midwest would have to adapt to the new conditions.
The most direct effect of the atmospheric changes will most likely be a worldwide increase in average annual temperature. The magnitude of the changes will vary within regions. For the Midwestern area of North America, the consensus for temperature increase is one degree Celsius within the next twenty years and then approximately one degree every twenty five years after that, or an average of 0.3 degrees warmer per decade (Anderson, 1992). This is a considerable increase from the average temperature increase in the last 1000 years, which has been 0.005 degrees Celsius per decade (Ritchie, 1986). The implications for the soils, therefore, are considerable. Soils are constantly changing and developing and in the past, slow climate change has been taken into account in this development. However, the rapid temperature increases that are predicted...