Debate at the University
(Launceston campus, 3 October
"This house agrees that global warming is the biggest threat
humankind faces in the 21st Century"
William Kininmonth speaking in
Ladies and Gentlemen.
In the context
of pestilence, famine and warfare it is ludicrous to suggest
that global warming might be considered the biggest threat that
humankind faces in the 21st century.
The plague that
ravaged Europe from the middle 14th to the middle 17th centuries
is estimated to have killed between 30 and 50 percent of the
population. Pneumonia killed about 20 million people in the 1920s.
SARS, Ebola and other potential pandemics continue to hover in
Famine and disease
resulting from drought and floods killed more than 20 million
people across northern China, India, southern Africa, northeast
Brazil and the islands of the Pacific during the El Niño
of 1877. Similar numbers of people died in 1888, including about
one third of the population of Ethiopia. As recently as 1997
about one million people of Papua New Guinea were saved from
starvation by Australian aid. Famine, disease and starvation
again threaten vulnerable regions of the world as another El
Niño event develops in the equatorial Pacific Ocean. The
threat is very close to home as Australia suffers drought, water
restrictions are imposed and fire danger will be extreme this
is an ever-present danger. Australia has troops deployed under
international arrangements in Iraq, Afghanistan, East Timor and
the Pacific in an attempt to promote democracy and maintain peace.
In addition, there is civil unrest in Africa, Central and South
America and across southern and central Asia.
Against this background
of pestilence, famine and warfare the Earth's climate has warmed
over the past 200 years from the cold of the Little Ice Age.
The global population has expanded to more than 6 billion people.
There is no doubt that there is enough food being grown to feed
the global population. There are also resources available to
clothe and house the people. Regions of scarcity and deprivation
are caused by inhibiting social structures, including colonialism,
corruption and conflicting tribal allegiances. In a perfect world,
there are abundant resources to sustain the global population.
Why should we even
think that global warming is a threat to humankind in the 21st
In 1988 the UN
established the Intergovernmental Panel on Climate Change, or
IPCC, to provide guidance to governments on the likelihood of
human induced climate change. In its First Assessment Report
of 1990 the IPCC stated:
- There is a greenhouse
effect that keeps the Earth warmer than it would otherwise be.
- Carbon dioxide
is a greenhouse gas and its concentration in the atmosphere is
increasing because of human activities.
- Increasing concentrations
of carbon dioxide will enhance the greenhouse effect so as to
make the Earth warmer.
The IPCC emphasised,
however, that there were many uncertainties in our knowledge
of the climate system. The report highlighted that it was not
possible to quantify the timing, magnitude nor regional patterns
of anthropogenic global warming.
on rudimentary computer models of the climate system, the IPCC
then projected that the global average temperature would rise
3°C and sea level would rise 65 cm above 1990 values by 2100.
The IPCC issued
further assessment reports in 1995 and 2001, each claiming advances
in scientific understanding; each claiming greater confidence
that recent global warming was due to human activities and that
the warming is likely to increase. Almost exclusively, the additional
confidence was based on access to more powerful computers that
have enabled the formulation of more complex models to simulate
the climate system.
But there is no
evidence that the computer models are better representing reality.
Indeed, we could be forgiven if we concluded that computer modelling
is akin to the magician's smoke and mirrors!
The main greenhouse
gas in the atmosphere is water vapour. Its concentration and
distribution vary in space and time. Saturation and cloud formation
occurs in ascending air and clouds change the earth's local radiation
patterns even more strongly than greenhouse gases do. Representation
of water vapour and clouds in computer models is recognised as
being very difficult and a major source of error.
In contrast, carbon
dioxide is a well-mixed gas and its interaction with the Earth's
radiation fields can be calculated for cloud-free air.
We calculate that
the Earth would radiate to space at the rate of 337 W/m2 in the
absence of clouds, water vapour and carbon dioxide. If we add
standard water vapour concentrations then the radiation would
reduce to 286 W/m2. That is, the greenhouse effect of water vapour
is about 51 W/m2.
levels of carbon dioxide to the atmosphere, about 300 ppm, further
reduces radiation to space by 27 W/m2. Carbon dioxide has about
half of the greenhouse effect of water vapour.
However, 70 percent
of carbon dioxide's greenhouse effect is due to the first 50
ppm of concentration. Carbon dioxide is essentially a spent force
as far as the enhanced greenhouse effect is concerned and adding
to the concentration by industrial activities has little impact.
100 ppm of carbon dioxide added to the atmosphere since industrialisation
has increased the greenhouse effect by a little more than 1 W/m2.
A further doubling of carbon dioxide concentration to 800 ppm
by the end of the 21st century will only increase the greenhouse
effect by about 3 W/m2, a very small increase.
When we look at
the numbers in perspective, the impact of the enhanced greenhouse
effect from anthropogenic carbon dioxide is small and the threat
is a mirage.
that Earth's climate is about to cross a trigger point that will
result in runaway global warming also does not stand up to scrutiny.
distributes heat from the warm tropical surface through the atmosphere.
The buoyancy required for convective clouds mean that temperature
rises in the atmosphere are constrained by the surface temperature.
However the temperature
at the Earth's surface is strongly regulated by evaporation.
Surface evaporation increases nearly exponentially with surface
temperature and the warmest ocean temperatures are constrained
to about 30°C. Even tropical rainforests do not exceed
35°C. High afternoon temperatures are only experienced
over arid inland regions.
of the Earth's surface is ocean. Evaporation cooling will thus
constrain the surface temperature against the minor enhanced
greenhouse effect of anthropogenic carbon dioxide, much as a
canvas water bag provides cool water in a desert.
An omission in
any discussion of anthropogenic global warming is regional radiation
imbalance. Most solar radiation is received over the tropics.
In contrast, the polar regions radiate more energy to space than
the solar radiation they receive. The global radiation balance
is only maintained because of the transport of excess energy
from the tropics to the poles by the atmospheric and ocean circulations.
and the oceans are interacting fluids with natural modes of variability.
The oceans contain the thermal and mass inertia. They are the
flywheels of the climate system. However the atmosphere transports
about 80 percent of the energy to the poles and the surface winds
drive the ocean circulations.
from the interannual scale of El Niño to the multi-centennial
scale of the Little Ice Ages. This is because of the internal
variability generated by interactions between the oceans and
only respond linearly to radiative forcing and do not simulate
the internal variability of the climate system. This is highlighted
in the circular logic of the IPCC in its 2001 report. IPCC claims
that "the warming of the past 100 years is very unlikely
to be due to internal variability alone, as estimated by current
did not predict the development of the current El Niño
event that is bringing drought to Australia and spawning natural
disasters around the world. They are not capable of predicting
the next Little Ice Age.
computer models give nineteen different projections for anthropogenic
global warming for the 21st century, and they are all exaggerated.
and violence are ever present. Each is capable of killing millions
of people and destroying the social fabric of the global community.
In contrast, the
global warming of the past 200 years has been beneficial to human
society and to the biosphere. Society and ecosystems have adapted
and flourished. There is no reason to believe that life will
not continue to adapt and flourish on Earth.
cannot be considered as a threat in the 21st century, and is
certainly not the biggest threat to humankind.