MadSci Network: Environment & Ecology
Query:

Re: What are the effects of human-introduced silver iodide on the environment?

Date: Thu Dec 21 09:20:52 2000
Posted By: Dauda Ladipo, Staff, Pharmaceutical R&D, Pfizer Inc
Area of science: Environment & Ecology
ID: 976474890.En
Message:

Dear Kelly,
Cloud seeding is one of the methods used to intentionally modify weather, with examples including increasing rain or snow, making hailstorms less destructive by making the hailstones smaller, and clearing fog at airports.

Silver iodide, one of the substances used for cloud seeding, is generally regarded as a harmless material, especially in the relatively small amounts used in cloud seeding. My impression on the social justice issue is that there isn’t enough hard scientific data to support suggestions that weather modification may have the effect of bringing rain to an area by taking it away from another, even though it might seem like this could happen.

The atmosphere holds a large amount of moisture as humidity which does not fall as rain or snow even though there may be clouds present, until one or a combination of several different conditions are right for precipitation to occur. Cloud seeding seeks to start off some of these conditions and cause rain drops or snow flakes to start forming. In contrast to cloud seeding, many forms of air pollution get in the way of the formation of rain drops or snow flakes and prevent precipitation from occurring. From an environmental perspective, this is probably a more serious threat to the balance of the moisture budget than cloud seeding could be.

The science of cloud seeding has not been perfected and most of the cloud seeding that is going on is still experimental. Some cloud seeding efforts have actually reduced the amount of rainfall, rather than increase it. The consensus among observers seems to be that it is not the best solution to rainfall deficiency or water resource management problems.

The internet links below provide a lot more information on this subject. I hope my answer is useful.

Dauda Ladipo.

ENCYCLOPÆDIA BRITANNICA: weather modification
britannica.com article

MATERIAL SAFETY DATA SHEETS for Silver Iodide:
ESPI-Metals.com (pdf document)
ucsd.edu

Does Weather Modification Really Work? by Ric Jensen, Information Specialist, Texas Water Resources Institute
twri.tamu.edu

Air Pollution Is Stifling Precipitation, Study Finds Weather: Tiny particulates inhibit rain and snowfall, with major implications for the Southland, experts say. By MARLA CONE, Times Environmental Writer
latimes.com


Current Queue | Current Queue for Environment & Ecology | Environment & Ecology archives

Try the links in the MadSci Library for more information on Environment & Ecology.



MadSci Home | Information | Search | Random Knowledge Generator | MadSci Archives | Mad Library | MAD Labs | MAD FAQs | Ask a ? | Join Us! | Help Support MadSci


MadSci Network, webadmin@www.madsci.org
© 1995-2000. All rights reserved.