What is climate change?
Weather changes all the time. The average pattern of weather, called climate, usually stays pretty much the same for centuries if it is left to itself. However, the earth is not being left alone. People are taking actions that can change the earth and its climate in significant ways. Carbon dioxide is the main culprit. The single human activity that is most likely to have a large impact on the climate is the burning of “fossil fuels” such as coal, oil and gas. These fuels contain carbon. Burning them makes carbon dioxide gas. Since the early 1800s, when people began burning large amounts of coal and oil, the amount of carbon dioxide in the earth’s atmosphere has increased by nearly 30%, and average global temperature appears to have risen between 1° and 2°F. Carbon dioxide gas traps solar heat in the atmosphere, partly in the same way as glass traps solar heat in a sunroom or a greenhouse. For this reason, carbon dioxide is sometimes called a “greenhouse gas.” As more carbon dioxide is
Why is it important to distinguish between weather and climate? Many people use the words weather and climate as if they mean the same thing. They do not. It is important to understand the difference in order to understand the idea of climate change. Everyone knows what weather is. It’s what is going on in the atmosphere at a particular place and time. Weather is measured in terms of wind speed, temperature, humidity, atmospheric pressure, cloudiness, and precipitation. In most places, weather changes from hour-to-hour, day-to-day, and season-to-season. The word climate refers to the average pattern of weather in a region. An example may help. If on a day in July, you are asked, “What’s the weather been like in New Orleans?” you might answer, “Today it’s clear and cool, but yesterday was hot and muggy.” On the other hand, if you are asked, “What’s the climate like during the summer in New Orleans?” it would be correct to answer, “In the summer it’s hot and muggy.” The fact that on a pa
