Greenhouse Gases and Climate Change:
Is Carbon Dioxide a Problem?
William R. Kininmonth and George Fox
We are repeatedly told that human-induced carbon dioxide emissions
are the principal cause of the current period of global warming
and that continuing emissions will lead to dangerous climate change.
This argument, which is based on a simple but erroneous hypothesis,
is promoted by the Intergovernmental Panel on Climate Change (IPCC).
However, like predictions of imminent resource exhaustion promulgated
by the Club of Rome in 1972, it is just another false alarm.
This leaflet seeks to contribute to the scientific debate about
climate change and to a wider understanding of its economic and
The climate system is complex and although we understand many
of the causes of past climate change there continue to be significant
unknowns. We do know that the temperature of the Earth is sustained
by solar energy received mainly over the tropics. The global variations
of temperature are driven and regulated by the transport of heat
energy from the tropics to polar regions by atmospheric circulations
and by ocean currents such as the Gulf Stream.
As far as greenhouse gases are concerned we know that:
- The three major greenhouse gases that occur naturally in
the atmosphere are water vapour, carbon dioxide and ozone. Of
these, water vapour has by far the largest impact on climate.
Its quantity and distribution throughout the atmosphere change
significantly with time. Other greenhouse gases include methane,
oxides of nitrogen and chlorofluorocarbons. The direct effect
of greenhouse gases is to cool the atmosphere---these gases
emit more radiation than they absorb.
- The natural cooling of the atmosphere by greenhouse gases
and radiation processes is offset mainly by the release of latent
heat during rain formation.
- The concentration of water vapour is a maximum in the tropics
because of evaporation, particularly from the warm ocean surfaces.
Water vapour is transported around the globe by the winds.
- The Earth's surface is cooled as seawater evaporates. The
rates of evaporation and loss of latent heat from the ocean surface
increase exponentially as the temperature of the tropical ocean
rises. This puts a practical upper limit on how warm the tropical
oceans can get and explains why the warmest tropical ocean temperatures
have remained more or less constant at about 30 ºC over
the past thirty years.
- Over the tropics, deep convection and energy exchange in
the atmosphere directly link atmospheric temperatures to the
temperature of the warmest ocean surfaces. Satellite and weather
balloon data independently confirm that the tropical atmosphere
has not warmed over the past thirty years, and this stability
is consistent with the near constant temperature of the warmest
- While there is a natural upper bound to tropical temperatures,
the temperatures over middle and higher latitudes are regulated
by the rate of heat transport from the tropics. When averaged
globally, temperatures have been slightly warmer than they are
now. Also, the temperature of the Earth can cool significantly.
Changes to ocean currents can lead to cooler tropical ocean temperatures
and reduced heat transfers between the oceans and the atmosphere,
thus leading to the onset of the next ice age.
- Overall, greenhouse gases and the hydrological cycle (evaporation,
transport of water vapour and precipitation) are essential for
maintaining the Earth's surface at a temperature cooler than
it would otherwise be, and they provide a powerful negative feedback
- Carbon dioxide naturally cycles
through the atmosphere due to plant growth and decay; the total
exchange in each direction is calculated to be about 120 Gigatonnes
of carbon (GtC) per year. Over
the oceans, carbon dioxide is taken up by the cold surface waters
of the polar regions and is returned to the atmosphere by the
relatively warm upwelling waters over the tropics; the annual
rate of exchange is about 90 GtC per year.
- The annual emission of carbon
dioxide to the atmosphere resulting from human activities is
about 5 GtC per year and the human emissions are thus relatively
small compared to the natural exchange processes. Atmospheric
carbon dioxide contains about 730 GtC. Changes in natural exchanges,
as well as human activities, have led to recent increases in
atmospheric concentrations of carbon dioxide.
- Before industrialisation took place in the West during the
19th century the atmospheric concentration of carbon dioxide
was about 280 ppm. The total
concentration of carbon dioxide has risen to about 380 ppm through
changes to both natural exchange processes and human activities.
- Carbon dioxide emissions attributable to human activities
in Australia are about 1.5 per cent of the total world emissions
from human activities.
- Carbon dioxide is not a pollutant. It is basic to photosynthesis
and encourages plant, tree and marine growth. Millions of years
ago, when there was a much higher concentration of carbon dioxide
in the atmosphere than now, forest growth increased dramatically
and eventually decayed to form extensive coal deposits. (Carbon
dioxide should not be confused with carbon monoxide, an extremely
poisonous gas that will cause death in small concentrations.)
Reducing carbon dioxide emissions
due to human activities.
Replacement of coal-fired electricity production by wind power
generation has not been economical. Total wind-generated electricity
has not yet reached half of one per cent of world electricity
production and the cost per unit of wind-powered electricity generation
is up to three times the cost of production from coal-fired plant.
In addition, alternative backup power generation would be needed
for periods of low wind and for periods of high wind when the
wind generators have to be shut down.
The technology of capturing carbon dioxide emissions from power
stations and then burying this CO2 underground has been investigated.
The cost of such carbon capture and geo-sequestration from all
Australian power stations would be many billions of dollars.
Other influences on Earth's
The Earth is slowly cooling as heat from the core is conducted
to the surface. Heat is also released during volcanic eruptions
but the magnitudes of both are relatively small on the global
The main source of heat for Earth is the nuclear furnace of
the Sun. As the intensity of the Sun's radiation varies so too
will the heat received by Earth. The net heat received at the
Earth's surface also varies with the periodically changing orbital
characteristics relative to the Sun, the atmospheric aerosol concentration
(especially those aerosols released during volcanic eruptions)
and the variations of cloudiness (especially with changing cosmic
Earth's temperature cycles
The recent rate of warming and the current global average temperature
have been exceeded in the past. There is ample evidence from navigation
and colonisation records that Arctic regions at least were warmer
about 1,000 years ago, and proxy records indicate that the Earth
was warmer between 8,000 and 4,000 years ago. The current relatively
warm period that has lasted more than 8,000 years (the Holocene)
is typical of the abrupt periods of warming (interglacials) that
have punctuated the generally glacial conditions of the past several
Worldwide, the peripheries of polar ice sheets and mountain
glaciers have been melting for more than 150 years. This melting
is consistent with increased solar radiation since the early 1700s.
Solar activity has continued to increase over recent decades,
albeit not steadily.
Weather and Climate
There is no evidence of increased frequency of droughts, floods,
tropical cyclones, middle latitude storms or other violent weather
activity as Earth has warmed by about 0.6 ºC during the 20th
century. Claims that such changes will occur in the future are
conjecture based largely on the output of rudimentary computer
models. Over South East Australia the most intense heat wave since
weather records commenced continues to be the event that brought
record temperatures to Adelaide, Melbourne and Sydney, and disastrous
bushfires throughout South-Eastern Australia, in January 1939.
We rely on the Sun for warmth, and water vapour (the principal
greenhouse gas) ensures that we have a reasonably equable climate.
The effect on climate of human-induced carbon dioxide emissions
A Gigatonne of carbon (GtC) is 1000 million tonnes of carbon.
is parts per million by volume.
About the Authors
The Statement on the previous pages has been jointly prepared
- Mr William R. Kininmonth M.Sc., M.Admin., Dip. Met.---has
had a career in meteorological science and policy spanning more
than 40 years. From 1986 to 1998 he headed Australia's National
Climate Centre, monitoring Australia's changing climate and advising
government on the extent and severity of climate extremes. He
coordinated the scientific and technical review of the 1997-98
El Niño event for the World Meteorological Organization
and its input to the United Nations Task Force on El Niño.
As a member of Australia's delegations to the Second World Climate
Conference (1990) and the subsequent negotiations for the United
Nations Framework Convention on Climate Change (1991-92) he had
a close association with the early developments of the climate
William Kininmonth's book, Climate Change: A Natural Hazard
(Multi-Science Publishing Co., UK) was launched in Melbourne
in 2004. He lives in Kew, in Victoria, Australia, and can be contacted
- Mr E.C. 'George' Fox AM, B.Sc., B.E. --- a 'Professional
Engineer' with 60 years experience, including 4 years Army service
during WW2 and 25 years with English Electric Company, makers
of heavy electric power generation, distribution and utilisation
plant, locomotives and aircraft who employed 100,000 people worldwide.
He was their General Manager for India for 3 1/2 years then their
CEO for Australia for over 9 years with a 2,000 strong workforce
obtaining contracts for 5,000MW of power generating plant and
over 300 diesel electric locomotives and many other items for
governments, mines and industry around Australia. This was followed
by Directorships on 12 company Boards over more than 30 years
that involved about 15 round-the-world travels to see the world's
major coal and gas fired, nuclear and hydro-electric power stations.
He lives in Pymble, NSW, Australia.
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