D Volcanoes and earthquakes are even more dangerous than in the past as around half the world's population now lives in cities. There are more than 500 active and semi-active volcanoes, about fifty of which erupt each year, and more than 500 million people now live within the range of a volcanic eruption.
An even greater number live at risk, in some degree, from earthquakes which have taken a toll of more than 1.6 million lives in the last hundred years.
E All the betting from the disaster professionals in that things will get worse.
Professor Hou Ming, of Beijing University, is a volcanologist who has been warning for years that the world has not seen the worst nature can do. The worst eruption in human history was probably Mt Tambora in 1815,in Indonesia.
It pumped so much dust into the air that it effectively cancelled the following summer in Europe and America.
But geographial evidence shows that 73,000 years ago there was a much greater eruption. "It reduced temperatures by maybe 6C in some places and the whole planet was plunged into winter for years. And there are about two of these events every 100,000 years..."