From Mensagenda - April 2007

The Future: The Greenhouse Effect

by Mary Abbey

What’s going to happen because of global warming — the increase in average world temperature due to human activity? The simple answer is that things will change! Will we like the changes? If you are a summer person, some of the effects may not seem too bad. If you are a winter person, the story may be different. Will our lifestyles have to change? I’d say probably, but we can reduce the need for dramatic differences. So, let’s discuss the likely changes due to our warming planet.

First of all, our climate is changing and will continue to change. Remember that climate is the average weather of an area, so we’re talking about changes that we’ll notice in our weather. Our winters will be shorter. There will be an increase in extremely warm days and a decrease in extremely cold days. The daily temperature range will be reduced because nights will be warmer. Precipitation patterns will change. The warmer atmosphere will encourage more evaporation. That means that some areas will get more rain, coming in heavier rainfalls, and some areas will get less rain, resulting in drought. More intense storms are likely with greater storm damage. We may see stronger or more frequent El Nino events. Overall, the changes will be greater the farther an area is from the equator.

The greatest climate changes will occur in the arctic. There will be maximum warming in the high northern latitudes in late autumn and winter. There will be greater evaporation and more precipitation, rain or snow. These changes will occur because of the new conditions that will exist in that environment with the ice caps melting.

The ocean level will rise. There are two main reasons for this. The first is the melting of ice on Greenland and in western Antarctica. The second, and most important, is thermal expansion. When a material warms up, the molecules move faster and occupy a greater space. The ocean waters will expand as more thermal energy is absorbed. Estimates of rise vary greatly from a few feet to several meters. Undoubtedly, our continental outlines will change as low-lying areas become flooded. Populations in coastal cities will have to move farther inland.

As cities along our coasts face inundation, other areas of the world will be facing difficulties associated with a lack of drinking water. Melting mountain glaciers and a reduction in winter snows will mean less-reliable water resources throughout the year. Shifting weather patterns may benefit some areas while other areas will experience greater stress due to dwindling water supplies.

Changing weather patterns will affect what can live successfully in an area. The agriculture industry will have to adapt farming practices to the new conditions. Natural ecosystems will adjust, but many species will not be able to survive the quickly changing circumstances. Other species will expand their territories, including the disease vectors. What we take as normal, balanced communities of living organisms will change.

I learned most of this information about five years ago as I was preparing for a class. I did not expect to see these results anytime soon, but much is happening now. Before I discuss the changes we are already seeing, I’d like to delve into feedback mechanisms and other processes that affect global warming. So, until next time, enjoy the weather, warmer or colder than normal.