Geoscience Reference
In-Depth Information
test of a scientific examination.” He provided his own description of greenhouse
warming: “If the quantity ofcarbonic acid in the atmosphere increases, the temper-
ature of the ground and the lower atmosphere strata will be raised, till the increase
of radiation into space caused by the increase in temperature has restored the equi-
librium between gain and loss of heat.”
18
Ekholm thought that mankind's “influence on climate” might even prevent a
“future Ice Age.” If CO
2
did not rise enough from natural causes to accomplish
this goal, “Man will no doubt be able to increase the supply of carbonic acid [car-
bon dioxide] also by digging of deep fountains pouring out carbonic acid” (61).
Ekholm and Arrhenius viewed CO
2
warming as providing a double benefit: For
science, the concept solved the mystery of the ice ages. For humanity, the warming
would ward off a new ice age and provide a more equable climate.
Ekholm's article included one prescient and overlooked passage:
Radiation from the earth into space does not go directly from the ground, but on the average
from a layer of the atmosphere having a considerable height above sea-level. The greater is the
absorbing power of the air for heat rays emitted from the ground, the higher will that layer be.
But the higher the layer, the lower is its temperature relatively [
sic
] to the ground; and as the
radiation from the layer into space is the less the lower its temperature is, it follows that the
ground will be hotter the higher the radiating layer is.
(20)
This paragraph contains the essential idea that after several decades would help
to reestablish Arrhenius's theory: adding more CO
2
to the lower atmosphere and
thereby increasing absorption raises the elevation at which infrared radiation de-
parts Earth for space. It is not possible to “saturate” the atmosphere with CO
2
so
that adding more will make no difference. The more added, the higher the level at
which radiation leaves the atmosphere and the greater the warming at the surface.
But not only was this passage overlooked, so was Ekholm's entire article, in
spite of its publication in one of the leading journals of meteorology. As Chamber-
lin and the magisters of meteorology began to weigh in, Arrhenius and his “unfor-
tunate” theory did not stand a chance.
