hi LOTS, merapi is only really in the news as it is a danger to the local population. it rarely produces explosive eruptions so is unlikely to affect the weather at all. however, i read recently that the volcanoes in the kamchatka region of russia are the ones we should worry about, then i found this today Saturday 23rd October 2010 Klyuchevskoy Volcano, Russia Explosive eruptions continue at Klyuchevskoy Volcano, Kamchatka. During the last week there has been increased activity, and ash plumes have reached a height of 30,000 ft above sea level and extended 300 km north of the volcano. The volcano is currently at the highest level RED alert. we rarely hear about these as they are in a largely unpopulated area but apparently there are several large volcanoes in this region which have the potential to all go off at once!!