The greenhouse effect and climate change: It’s natural, right?

How can human beings influence a system as complex as our planet’s climate?

Life on Earth is made possible by naturally-occurring greenhouse gases. Without carbon dioxide, nitrous oxide, methane, water vapor and other gasses, much of the heat from Earth’s atmosphere would escape into space and Earth would be cold and barren. The heat-trapping properties of these gases provide Earth with the greenhouse effect, wrapping our planet in a life-sustaining bubble.

So yes, the greenhouse effect is a natural part of Earth’s climate system. Yet humans are accelerating its effect, primarily through the burning of fossil fuels. Fossil fuels are so-called because they are the residue of plants and animals that lived millions of years ago that were stored underground. Carbon, an element present in all living things, is found in this residue.  When these fossil fuels, such as coal and petroleum, are burned for energy, they release the carbon back into the atmosphere in the form of carbon dioxide gas. Some of this carbon dioxide is taken up by plants, which “breathe in” the carbon dioxide and “breathe out” oxygen. Carbon is thus recycled again and again. This cycle is similar to the water cycle—no new carbon is ever created or destroyed, it just changes its form and location.

The carbon cycle is accelerated when humans transfer carbon from the ground into the atmosphere at a rate faster than plants can recycle it. This increases the amount of heat trapped inside Earth’s bubble, or biosphere. Scientists can measure the amount of carbon dioxide in the atmosphere and they can determine its sources—from plants, animals or the burning of fossil fuels.  Results of testing indicate that about one-quarter of the carbon dioxide comes from human activities.

Scientists have determined that the Earth has warmed over the past 100 years an average of 1.3 degrees Fahrenheit. Climate scientists believe that the Earth will continue to increase its average temperature through the 21st century from 2.0 to 7.0 degrees Fahrenheit if current rates of greenhouse gas emissions remain the same.

While the Earth has warmed and cooled many times as a result of changes in the Sun, volcanic eruptions, meteor impacts and continental drift, the rate at which Earth is warming this time is far greater than in the past. It is, however, possible to slow the current warming trends by reducing greenhouse gas emissions and implementing new technologies.

To learn more about climate change and its effects on Michigan, attend the MSU Extension-sponsored event “Climate Change and Water Quality: Implications for the Future” on Tuesday, June 12, 2012.  It will be held at Macomb Extension office Assembly room, 21885 Dunham Road, Clinton Township.  The program runs from 9 a.m. until 12:30 p.m.  Admission is free, but pre-registration is required. 

Visit the ANR Events Management page to register.  For more information, questions or assistance with the online registration, please call 586-469-6440.

Also, visit the onlineMSUE Bookstore to download free PDFs of climate change fact sheets.

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