Brian, This is very interesting. Are there any naturally occuring sources of chlorinated or brominated hydrocarbons? While the mechanisms may be rational, who has a credible mass balance? No matter what the scientists you reference conclude, aren't you a little skeptical of trying to use 100+ years of weather data to predict 3 billion years of weather? Steve --------------------------------------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8d To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt delivery of Technet send the following message: SET Technet NOMAIL Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ---------------------------------------------------------------------------------