To Archive List PageThe Greenhouse Effect
Some actual facts and figures about greenhouse gases and the relative amounts produced by the natural world and human race

The politicians' case for a human cause for climate change is based on propaganda, not evidence, because facts can get in the way of raising new taxes. Here are some actual facts:

Q. What causes a greenhouse effect?
sun red skyA. Planets absorb heat from sunlight and also radiate heat into space. A greenhouse effect occurs when more heat is retained by some of the gases in the atmosphere than is radiated into space.
   The classic example of a runaway greenhouse effect in the Solar System is the planet Venus, which has a thick, heat-absorbing atmosphere and a surface temperature which reaches 460 deg.C. in places.

Q. Is Earth experiencing the greenhouse effect?
A. Possibly. The science of planetary dynamics is not far enough advanced yet to offer a definitive answer.

Q. How much of the gases which cause a greenhouse effect is produced by human activity, e.g. farming, manufacturing, power generation and transportation?
A. Just 0.28%. Human activity creates a negligible amount of greenhouse gases compared to the amounts produced naturally on Earth. Which means that spending vast amounts of money on preventing the release of small amounts of greenhouse gases will have little or no detectable effect on the global climate.

Q. Which gases in the atmosphere cause the greenhouse effect?
A. Water, carbon dioxide, methane, nitrous oxide, chlorofluorocarbons (CFCs) and a number of other miscellaneous gases.

Q. We hear so much about carbon dioxide; is it really the head bad guy as far as the greenhouse effect is concerned?
A. The various 'greenhouse gases' all have a different capacity for retaining heat. Methane has a Global Warming Potential 21 times higher than carbon dioxide. The corresponding figure for nitrous oxide is 310. But both gases are present in the atmosphere as much lower concentrations than carbon dioxide. The table below shows the greenhouse contributions of the main greenhouse gases. The Global Warming Potential percentages were obtained by multiplying their atmospheric concentration by the appropriate GWP factor:

Greenhouse gas % Global Warming Contribution % Natural Source % Human Source
 Water vapour95.000


 Carbon Dioxide3.618




 Nitrous Oxide0.950


 CFCs, misc. gases0.072




The figures in the above table will probably look quite different from the ones trotted out by the people making a living out of the global warming industry, 'scientists' and politicians alike. This is because reputable climatologists always include water vapour in their calculations while special interest groups and many news reporters leave water vapor out 'because it is customary for them to do so'.

If water is left out of the calculations, the total human contribution to a greenhouse effect rises from 0.28% to 5.53%, which gives dishonest politicians [Tautology? Ed.] out to raise taxation levels 20 times more room to wriggle and bamboozle their voters.

The Kyoto Protocol calls for mandatory carbon dioxide reductions of 30% from developed countries. If this requirement were to be extended to every country in the world, it would reduce the total human greenhouse contribution from carbon dioxide by about 0.035%. This is a negligible amount and well within the year-to-year variations of the natural world.

A final thought . . .

The carbon conmen blame the fall in global temperatures between 1940 and 1970 on the effect of soot particles, aerosols and other pollutants in the atmosphere reflecting sunlight before it could be absorbed by greenhouse gases and causing global cooling.
   But they can't explain why we are not experiencing a similar cooling effect now, at a time when China and other developing nations are chucking billions and billions of tons of these reflective pollutants into the atmosphere.

When politicians talk about reducing human-produced carbon dioxide, the amounts involved are fractions of a fraction of one per cent of the greenhouse gases produced naturally.
   Making such reductions will have no measurable effect on the Earth's climate.

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