Weather and Climate Engineering

I have been asked to prepare a position paper on “From Cloud Seeding to Geo-engineering: History and Prospects” for a workshop on “Perturbed Clouds in the Climate System” organized by the Frankfurt Institute for Advanced Studies (FIAS) to be held in Frankfurt, Germany in March 2008. I think it is appropriate to share with the weather modification community the main points of this position paper. I will first highlight the areas of greatest progress in weather modification research noting the major successes and failures. I will emphasize how difficult it has been to establish a “cause and effect” with regard to cloud seeding and that a major obstacle has been to establish that seeding clouds causes an effect that is greater than the natural variability of the cloud systems. That is the signal to noise ratio is generally quite low. I will also point out that the cloud seeding community has had to deal with unforeseen consequences of seeding, in some cases with perceived or real negative or damaging responses.

Next I turn to climate engineering which I define as a subset of the overall scheme of geoengineering dealing specifically with modifying the climate of Earth. This will include an overview of hypothesis for engineering the climate system by modifying the earth's albedo with reflecting aerosols, orbiting mirrors or scattering particles, high altitude balloons, absorbing aerosols in the stratosphere, and altering the ocean, ice, and land-surface albedo. I will conclude by noting the lessons learned from cloud seeding and how many of these lessons are parallel to what we might anticipate from climate engineering; included in that discussion will be the potential for unforeseen consequences of our actions.

Finally I urge the weather modification community to consider entraining climate engineering into an overall national program in weather and climate engineering. I think there may be strong political support to develop a well-funded national program that includes both weather engineering research and climate engineering research. I suggest the best home for such a program would be NASA as it is noted for its successes in solving major engineering problems. The two areas of weather engineering that should be given the highest priority are enhancement of water resources in the Colorado River basin and engineering hurricanes. The area that should be given the highest priority of research in climate engineering is emulating volcanoes in producing long-lasting lower stratospheric aerosols.