More than 120 scientists, engineers, analysts and economists from 30 countries were hunkered down here for the 40th annual conference on "planetary emergencies.' The term was coined by Dr. Antonino Zichichi, a native son and a theoretical physicist who has made Erice a hub for experts to discuss persistent, and potentially catastrophic, global challenges. The participants were not particularly optimistic. They presented data showing that the boom in biofuels was depleting Southeast Asian rain forests, that "bot herders'