Global Atmospheric Change
People and Climate Changes
Life on Earth has been possible because of the very special characteristics of our atmosphere. The planet is warm enough to support life, thanks to the presence of certain gases in the lower atmosphere. The atmosphere also absorbs almost all of the potentially damaging radiation produced by the sun before it reaches the surface. Our atmosphere contains elements necessary for life—nitrogen, carbon and oxygen—as well as abundant water vapor to maintain the water cycle.
Human actions, particularly during the last several decades, are changing the composition of Earth’s atmosphere. Since the industrial revolution, people have been removing stored carbon from Earth in the forms of coal, crude oil and natural gas, and burning it to make heat. In the process, water vapor, carbon dioxide and small amounts of other substances are produced. Other activities, such as clearing land (by burning) for agriculture, also have added CO2 to the atmosphere. As a result, levels of carbon dioxide in the lower atmosphere have increased from around 260 parts per million (ppm) by weight to more than 350 ppm.
Carbon dioxide is one of the gases responsible for trapping heat near Earth’s surface and lower atmosphere. Many scientists believe that increases in the amounts of CO2 and other greenhouse gases, such as methane (CH4), will lead to warmer temperatures on Earth. Even minor increases in the surface temperature of the planet could have far-reaching effects. Major climactic patterns of winds, temperature and rainfall could change drastically. This would impact water resources, coastlines, agriculture, forests, energy production and patterns of disease.
Climate, the characteristics of weather in a particular region over long periods of time, determines which kinds of plant and animal life are present, which crops can be grown, how people construct their houses and, to a great extent, people’s clothing and diet. The climate of any given region depends on its distance from the equator, altitude and rainfall patterns.
Even slight changes in the world’s climate affect human health and well-being in countless ways.
The release of chemicals known as CFCs (chlorofluorocarbons) is contributing to changes in the atmosphere that will affect climate and human health and well-being. Freon and other CFCs are greenhouse gases that increase the amount of heat trapped near the surface of Earth. In addition, chlorine molecules released by these chemicals in the stratosphere break apart the ozone molecules responsible for shielding Earth from ultraviolet radiation.
Over the last decade, the amount of ozone in the stratosphere has decreased (especially in the polar regions)—leading to greater risks of skin cancer for people and also damaging vital populations of plants, animals and marine life.
Keywords: atmosphere | carbon monoxide | climate | CO2 | Earth | ecology | energy | environment | fossil fuel | global change | greenhouse gas | health | ozone | pollution | radiation | skin damage | solar energy | sun | sunscreen | UV light | weather | lesson
- Illustration © Baylor College of Medicine\M.S. Young.
- Moreno, N., Tharp, B., and Dresden, J. (2011) The Science of Global Atmospheric Change Teacher’s Guide. Baylor College of Medicine: Houston. ISBN: 978-1-888997-75-0.
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Funded by the following grant(s)
My Health My World: National Dissemination
Grant Number: 5R25ES009259
The Environment as a Context for Opportunities in Schools
Grant Number: 5R25ES010698, R25ES06932
Foundations for the Future: Capitalizing on Technology to Promote Equity, Access and Quality in Elementary Science Education