The Greenhouse Effect, Yes or No? A Scientific Evaluation

The concept of limited predictability is reviewed followed by simple examples illustrating the sensitivity to small changes in the initial state and/or the forcing of a nonlinear system. Limited predictability applies to almost all nonlinear systems, and the concept is therefore important to geophysical systems governed by nonlinear model equations. The limited predictability determines the upper limit to operational weather forecasts, but it will also be demonstrated that it has an impact on the determination of the effect of changes in the forcing of the system. The general strategy applied by researchers to estimate the atmospheric greenhouse effect is reviewed. It will be demonstrated that the adopted strategy, due to prescribed changes in the forcing of the climate system, is also influenced by limited predictability in the sense that predicted changes are much larger than observed changes in the temperatures at the surface of the Earth. It is therefore very unlikely that the predictions are reliable. The inclusion of the sulphuraerosol effect is also discussed with the conclusion that although these cooling agents reduce greenhouse warming, they do not behave as expected in the sulphurrich and sulphurpoor regions. Copyright Kluwer Academic Publishers 1999