Study expands tropical cyclone knowledge

TOLEDO, Spain, July 16 (UPI) — A Spanish-led study has linked
climate change to the newly observed development of unusual tropical
cyclones over the Atlantic Ocean.

Two very atypical tropical cyclones recently occurred. The first was
2004’s Hurricane Catarina, which made landfall over the southern
coast of Brazil. The second was Hurricane Vince in 2005 — which
formed next to the Madeira Islands in the Atlantic Ocean — the first
detected hurricane to develop over that area and the first known
tropical cyclone to make landfall in Spain.

Noting that anthropogenic climate change might be responsible for
altering the geographical areas where tropical cyclones develop, M.A.
Gaertner of the University of Castilla-La Mancha, in Toledo, Spain,
and colleagues used several regional climate models to assess new
locations of tropical cyclone occurrence.

They found an increase in cyclone intensity over the Mediterranean
Sea in climate change scenario simulations. The study, for the first
time, revealed a risk of tropical cyclone development over the
Mediterranean Sea under future climate change conditions.

The research, which involved scientists from the Max Planck Institute
for Meteorology, appears in the journal Geophysical Research Letters.

Copyright 2007 by United Press International. All Rights Reserved.
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NATURE
Vol 448|19
July 2007

BOOKS & ARTS

A lone voice in the greenhouse

The Callendar Effect: The Life and Work
of Guy Stewart Callendar (1898-1964),
the Scientist who Established the Carbon
Dioxide Theory of Climate Change

by James Rodger Fleming
American Meteorological Society: 2007.

176 pp. $34.95

Robert J. Charlson
With so much written on the subject of carbon
dioxide as a cause of climate change, it seems to
have a settled history. But the word
‘established’ in this book’s subtitle moved meto
ask who actually came up with this now
well-accepted theory, and what the basis is for
James Rodger Fleming’s claim that the subject of
his biography holds this honour.

There seems to be little doubt that in 1827 Jean
Baptiste Joseph Fourier first articulated the
idea that “light finds less resistance in
penetrating the air, than in repassing into the
air when converted to non-luminous heat”. In
the 1860s, John Tyndall showed that CO2 and water
vapour both absorb and emit infrared radiation.
Then, in 1896, Svante Arrhenius performed the
first calculations of the sen- sitivity of
Earth’s temperature to changes in
atmospheric CO2. He went on to calculate
(incorrectly) that it would take some 3,000 years
for a 50% increase of its atmospheric content at
the prevailing rate of coal consumption. He
further calculated, on the basis of the meas-
ured infrared transmission of the atmosphere by
Samuel Langley, that a 50% increase of CO2 would
warm Earth’s surface by 3.4 °C.

So how did author Fleming come to state that the
CO2 theory was established by Callendar? It seems
that this credit should be given to Fourier,
Tyndall and Arrhenius.  Callendar’s seminal
paper, ‘The Artificial Production of Carbon
Dioxide and its Influence on Temperature’, was
published in 1938, nearly half a century after
these nineteenth-century works. During the
intervening period, serious doubts had developed
about the importance of
changing atmospheric CO2 as a factor in Earth’s
climate and a cause of ice ages. Competing
theories – changes in Earth’s orbital geometry or
in solar output, the role of the oceans, the
attenuation of sunlight by volcanic dust, and
spectroscopic considerations such as water vapour
and CO2 absorbing infrared light in the same
spectral regions – had seemingly brought the
CO2-climate field into a ‘deep eclipse’.

Callendar’s 1938 paper did not include a citation
of Arrhenius’s 1896 paper, although there are
many parallels between the two.  Callendar
analysed just one set of data on atmospheric CO2
content taken at Kew, near
London, between 1898 and 1900. These data were
taken near a source of CO2 and were analytically
very
uncertain. From this analysis, he concluded that
at around 1900 the free atmosphere over the North
Atlantic region contained 274 ± 5 parts per
million (p.p.m.) of CO2. Then, after arguing that
only a small fraction of the CO2
from combustion of fossil fuels would dissolve in
the ocean, he calculated from an estimated global
production rate of CO2 the amount that he thought
would be there in 1936 (290 p.p.m.), 2000
(314-317), 2100 (346-358) and 2200 (373-396).

With a simple model of the absorption of infrared
radiation, he worked out the amount of global
warming to be expected from his predicted CO2
levels, concluding that temperature would then
have been increasing at a rate of
about 0.03 °C per decade. Callendar’s 1938
attribution of early twentieth-century warming to
CO2 increase might have been believable if global
cooling had not ensued in the 1960s and 1970s.
His result was based on many assumptions and he
used no contemporary CO2 data on which to base
his estimates. Nonetheless, his
prediction was almost correct and, along with his
1958 paper – which included large amounts of CO2
data (albeit of dubious quality) – his 1938
publication did rejuvenate the CO2 theory of
climate change.
I doubt that this amounts to establishing the
theory, but it came at a time when the fields of
geochemistry and climate dynamics were ripe for
stimulation, especially during the International
Geophysical Year (1957-58).  Shortly thereafter,
Charles David Keeling presented accurate data,
and the rest of the story is history.

Callendar’s work on climate change is just part
of the story Fleming tells about Callendar’s life
in this well written and especially well
documented book.

Robert Charlson is in the Departments of
Atmospheric Sciences and Chemistry, University
of Washington, Seattle 98195, USA.
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