Dear Tom,
Since carbon dioxide is an odorless, colorless gas, as is oxygen and nitrogen, why should carbon dioxide be blamed for being a “greenhouse gas”?
Robert Long
Dear Robert,
Most of Earth’s atmosphere–almost 99 percent–consists of nitrogen (N2) and oxygen (O2), which contain two atoms bound tightly together. They do not readily absorb heat.
Molecules with three or more atoms, like water vapor (H2O), carbon dioxide (CO2), methane (CH4) and ozone (O3), comprise only about 1 percent of the atmosphere. They are the primary “greenhouse gasses” because they readily absorb and release heat and infrared energy which is reabsorbed by other greenhouse gasses. The net result is more heat retained near the Earth’s surface.
Of the greenhouse gasses, carbon dioxide is responsible for 63 percent of the Earth’s warming. Methane accounts for 23 percent.
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Tom Skilling is chief meteorologist at WGN-TV. His forecasts can be seen Monday through Friday on WGN-TV News at noon and 9 p.m.
Write to: ASK TOM WHY, 2501 Bradley Pl., Chicago, IL 60618 or asktomwhy@wgntv.com (Mail volume precludes personal response.)
WGN-TV meteorologists Dennis Haller, Steve Kahn and Richard Koeneman plus weather producer Bill Snyder contribute to this page.
