The Greenhouse Effect and Global Warming - Air Pollution and Global Warming: History, Science, and Solutions - page 270

Nitrous oxide and methane absorb at the edges of the
window. An increase in the mixing ratio of any thermal-
IR-absorbing gas, regardless of whether it absorbs in
the window, increases atmospheric heating. However,
an increase in the mixing ratio of a gas that absorbs in
the window heats the air more than does an increase in
the mixing ratio of a gas that absorbs outside the win-
dow because more radiation currently passes through
the window than outside it.

12.2.2. Historical Aspects of Global Warming
The first scientist to consider the Earth as a greenhouse
was Jean Baptiste Fourier (1768-1830), a French
mathematician and physicist known for his studies of
heat conductivity and diffusion. In 1827, Fourier sug-
gested that the atmosphere behaved like the glass in a
hot house, letting through “light” rays of the sun but
retaining “dark rays” from the ground.
The first to recognize that specific gases in the atmo-
sphere selectively absorbed thermal-IR radiation was
John Tyndall (1820-1893; Figure 12.5), the English
experimental physicist who was also known for study-
ing the interactions of light with small particles (Sec-
tion 7.1.5). Around 1865, Tyndall discovered that water
vapor absorbs more thermal-IR radiation than does
dry air and postulated that water vapor moderates the
Earth's climate.

Figure 12.6. Svante August Arrhenius (1859-1927).
Edgar Fahs Smith Collection, University of
Pennsylvania Library.

The first to propose the theory of global warming
wasSwedish physical chemist Svante August Arrhe-
nius (1859-1927; Figure 12.6). In 1896, he suggested
that a doubling of CO 2 (g) mixing ratios, which could
occur due to the rapid increase in coal combustion since
the beginning of the Industrial Revolution in the eigh-
teenth century, might lead to temperature increases of
5 ◦ C(Arrhenius, 1896). This estimate is higher than
recent estimates that a doubling of CO 2 (g) will result
in a 2 ◦ Ctemperature rise, but the theory is still consis-
tent. Arrhenius also theorized that reductions in CO 2 (g)
caused glacial periods to occur. This theory was incor-
rect because changes in the Earth's orbit have been
responsible for glacial maxima. The decrease in CO 2 (g)
mixing ratios during a glacial period is an effect rather
than a cause of temperature changes.

12.2.3. Leading Causes of Global Warming
Carbon dioxide is the leading cause of global warm-
ing (Table 12.3), which is the temperature change of
the lower atmosphere above and beyond that from the
natural greenhouse effect. The second leading cause
of historic near-surface global warming may be par-
ticulate black carbon and its associated brown carbon
(Jacobson, 2000, 2001b, 2010b; Chung and Seinfeld,

Figure 12.5. John Tyndall (1820-1893). Edgar Fahs
Smith Collection, University of Pennsylvania Library.