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We have seen that funding of the science of weather modification underwent a period of rapid rise, followed by an abrupt crash. One of the leading causes of that crash, we believe, is that the program was oversold. The claims that only a few more years of research and development will lead to a scientifically-proven technology that will contribute substantially to water management and severe weather abatement, were either great exaggerations, or just false. This is largely because we greatly underestimated the complexity of the scientific and technological problems we were (and still are) faced with.
The same can be said about human impacts on global climate. There
are many scientists who are claiming that the short-term (periods of
year-to-year, or decades) variations in weather and climate are clear
evidence that we are experiencing the effects of anthropogenic
greenhouse emissions. Moreover, many claim that the `forecasts' being
made by global climate models, represent realistic expectations of
global-averaged changes in temperature and rainfall in the next decade
or century. In our opinion, both of these claims represent
overselling of the climate program. These claims appear and are
discussed in the professional literature (e.g., Schneider, 1990;
Titus, 1990a,b; IPCC, 1991; Kellogg, 1991) and in the lay press
(e.g., Brooks, 1989; Schneider, 1989; Thatcher, 1990; Bello, 1991;
Luoma, 1991; UCAR/NOAA, 1991). Titus (1990a), for example, proposes
the rerouting of the Mississippi River to save coastal Louisiana! As
an example of such extreme claims to mitigate anthropogenically caused
global warming, a 1991 National Academy Press report
(National Academy of Sciences, 1991) has
considered the insertion of 50,000 100 km 
mirrors in space to
reflect incoming sunlight. Such gross global climate engineering
represents a close analog to the exaggerated claims in weather
modification which were made in the 1960s and 1970s. Short-term
variations of weather and climate are clearly within the natural
variability of climate to the extent that we can realistically assess
it. Moreover, the models are not really `forecast' models. They are
simply research models designed to simulate the responses of
hypothesized anthropogenic changes to weather and climate, other
things being the same. Besides having many limitations in their
physical/chemical parameterizations, they are not designed to simulate
(or predict) the consequences of many other natural factors affecting
climatic change. That is because we simply do not know enough about
all the processes of importance to climatic change to include them in
any quantitative forecast system. What it amounts to is that many
scientists are grossly underestimating the complexity of interactions
among the earth's atmosphere, ocean, geosphere, and biosphere. These
problems are so complex that it may take many decades, or even
centuries, before we have matured enough as a scientific community to
make credible predictions of long-term climate trends and their
corresponding regional impacts. Even then, we may find that the
uncertainty level of those predictions due to outside (the earth)
influences may be so large that those predictions are not useful for
social planning.
