NORMAN — Editor, The Transcript: John Baugher is correct when he
writes, “Global warming is happening” (The Norman Transcript,
Sept 25, 2012), but a simpler explanation may be more
understandable. Greenhouse gases of importance in Earth’s
atmosphere include carbon dioxide. Increased burning of fossil
fuels by humans, owing to new scientific discoveries with
advanced technologies and increased numbers of humans, has
caused this gas to increase remarkably since only 70 years ago.
The volume of CO2 in Earth’s atmosphere is now a third greater
than its highest level during the 850,000 years ended in
mid-20th century, as determined by analyses of air bubbles
trapped in ice cores. A greenhouse gas tends to block infrared
radiation, but is substantially transparent to visible light.
Solar radiation thus comes through Earth’s atmosphere but heats
the ground, which at much lower temperature than Sun, radiates
back to space mainly in the infrared range. As carbon dioxide
increases, radiation from Earth’s surface tends