THE BIRTH OF CLIMATE
CHANGE
WHILE FOURIER REALIZED THAT THE ABSORPTION OF outward-
going infrared
heat energy is the key to what became known as the greenhouse effect, he
did not propose what the source of this absorption was. Nor did he provide
quantitative estimates of what it might be.
The quantitative science underlying the greenhouse effect began with
Irish physicist John Tyndall, who was born just around the time Fourier was
beginning to ponder the question of what governed the Earth’s temperature.
In the late 1840s he and a colleague, who both taught at an English
boarding school, had the good sense to move to Germany to study. German
universities were far ahead of Britain in experimental science at the time.
By the time Tyndall returned in 1851, he was well prepared to begin a
career in experimental chemistry and physics, where his early work focused
on magnetism, one of the subjects of greatest interest at the time. In 1853 he
obtained a professorship at the Royal Institution, led by Michael Faraday,
one of the greatest experimental physicists of the nineteenth century, whose
work established the modern theory of electromagnetism. A decade later,
upon Faraday’s retirement, Tyndall was appointed his successor.
A lifelong interest in mountain climbing and glaciology led Tyndall to
explore the heating effects of sunlight and study the earlier work of Fourier
and others proposing that the absorption of infrared light by the atmosphere
might ultimately heat the Earth’s surface. Ever the experimentalist, in 1859
Tyndall began a decade-long set of experiments on the absorption of
thermal radiation by different gases.
He began experiments in May of that year with a setup that consisted of a
known heat source, a tube containing the gas he wanted to study, and at the
end of that an object called a thermopile, which converts thermal energy
into an electrical signal he could measure. By measuring the thermal energy
, emanating from the tube, he could determine how much energy was
absorbed by the gas.
Incidentally, this was an early application of what is called absorption
spectroscopy, which, turned on its head, was ironically essentially the same
tool used by Keeling to first accurately measure the fraction of CO2 in the
atmosphere. Tyndall helped first determine the absorption properties of
CO2, and his work was followed by a century of more refined studies. When
Keeling did his work, he could compare the absorption of infrared radiation
by atmospheric samples to the known absorption properties of test samples
with predetermined CO2 fractions to determine the CO2 fraction in the
atmosphere. A hundred years earlier, Tyndall actually used his own method
to invent a system for measuring the CO2 fraction in human breath, a
method that is still in use today.
Returning to Tyndall, by the end of May, he enthusiastically reported his
results to the Royal Society:
With the exception of the celebrated memoir of M. Pouillet on
Solar Radiation through the atmosphere, nothing, so far as I am
aware, has been published on the transmission of radiant heat
through gaseous bodies. We know nothing of the effect even of
air upon heat radiated from terrestrial sources.
By June 10 he had firmly established the experimental physics of the
greenhouse effect. As he put it in a Royal Society lecture, regarding solar
heat:
when the heat is absorbed by the planet, it is so changed in quality
that the rays emanating from the planet cannot get with the same
freedom back into space. Thus the atmosphere admits of the
entrance of solar heat; but checks its exit, and the result is a
tendency to accumulate heat at the surface of the planet.
Tyndall studied the infrared absorption by nitrogen, oxygen, water vapor,
carbon dioxide, ozone, and methane, among other gases in the atmosphere,
and was the first to get quantitative data on this absorption. His chief result
was that the main gases, oxygen and nitrogen, did not have any significant
absorptions, but that water vapor is the strongest absorber of infrared
CHANGE
WHILE FOURIER REALIZED THAT THE ABSORPTION OF outward-
going infrared
heat energy is the key to what became known as the greenhouse effect, he
did not propose what the source of this absorption was. Nor did he provide
quantitative estimates of what it might be.
The quantitative science underlying the greenhouse effect began with
Irish physicist John Tyndall, who was born just around the time Fourier was
beginning to ponder the question of what governed the Earth’s temperature.
In the late 1840s he and a colleague, who both taught at an English
boarding school, had the good sense to move to Germany to study. German
universities were far ahead of Britain in experimental science at the time.
By the time Tyndall returned in 1851, he was well prepared to begin a
career in experimental chemistry and physics, where his early work focused
on magnetism, one of the subjects of greatest interest at the time. In 1853 he
obtained a professorship at the Royal Institution, led by Michael Faraday,
one of the greatest experimental physicists of the nineteenth century, whose
work established the modern theory of electromagnetism. A decade later,
upon Faraday’s retirement, Tyndall was appointed his successor.
A lifelong interest in mountain climbing and glaciology led Tyndall to
explore the heating effects of sunlight and study the earlier work of Fourier
and others proposing that the absorption of infrared light by the atmosphere
might ultimately heat the Earth’s surface. Ever the experimentalist, in 1859
Tyndall began a decade-long set of experiments on the absorption of
thermal radiation by different gases.
He began experiments in May of that year with a setup that consisted of a
known heat source, a tube containing the gas he wanted to study, and at the
end of that an object called a thermopile, which converts thermal energy
into an electrical signal he could measure. By measuring the thermal energy
, emanating from the tube, he could determine how much energy was
absorbed by the gas.
Incidentally, this was an early application of what is called absorption
spectroscopy, which, turned on its head, was ironically essentially the same
tool used by Keeling to first accurately measure the fraction of CO2 in the
atmosphere. Tyndall helped first determine the absorption properties of
CO2, and his work was followed by a century of more refined studies. When
Keeling did his work, he could compare the absorption of infrared radiation
by atmospheric samples to the known absorption properties of test samples
with predetermined CO2 fractions to determine the CO2 fraction in the
atmosphere. A hundred years earlier, Tyndall actually used his own method
to invent a system for measuring the CO2 fraction in human breath, a
method that is still in use today.
Returning to Tyndall, by the end of May, he enthusiastically reported his
results to the Royal Society:
With the exception of the celebrated memoir of M. Pouillet on
Solar Radiation through the atmosphere, nothing, so far as I am
aware, has been published on the transmission of radiant heat
through gaseous bodies. We know nothing of the effect even of
air upon heat radiated from terrestrial sources.
By June 10 he had firmly established the experimental physics of the
greenhouse effect. As he put it in a Royal Society lecture, regarding solar
heat:
when the heat is absorbed by the planet, it is so changed in quality
that the rays emanating from the planet cannot get with the same
freedom back into space. Thus the atmosphere admits of the
entrance of solar heat; but checks its exit, and the result is a
tendency to accumulate heat at the surface of the planet.
Tyndall studied the infrared absorption by nitrogen, oxygen, water vapor,
carbon dioxide, ozone, and methane, among other gases in the atmosphere,
and was the first to get quantitative data on this absorption. His chief result
was that the main gases, oxygen and nitrogen, did not have any significant
absorptions, but that water vapor is the strongest absorber of infrared
