Technological advancements and a relative abundance of wealth (at least in the West) keep modern humans at a comfortable mental distance from their vulnerability to the elements. So when a wall of water surges up and wreaks havoc, as happened in Asia in 2004 and again in New Orleans this summer, part of our horror arises from the realization that newfangled gizmos that should have been able to predict (and help cope with) a massive natural disaster ultimately failed to do the job.

While humans will always be at the mercy of nature's most violent upheavals, geologists have noted that more careful monitoring could have mitigated the human devastation in Asia in 2004. And observers have long known that New Orleans was in a hurricane path; the city's date with destruction was only a matter of time. Extreme natural events with probabilities of occurrence far below 1 percent in any single year approach 100 percent in the long run, writes Bill McGuire, Benfield Professor of Geophysical Hazards and director of the Benfield Hazard Research Centre at University College London, in Prospect (June 2005). McGuire believes humans need to pay closer attention to the possibility of global geophysical events, or gee-gees, as he calls them.

So what catastrophes lie in wait for us? Here's a beginner's guide, based on McGuire's research, to the gee-gees of the future and how to prepare for their inevitable appearance.

Mega-tsunami (up to 10 times bigger than 2004 tsunami)
Frequency: Once every 10,000 years
Cause: Giant underwater landslide or collapse of island volcano or a giant comet hitting the ocean floor
Effect: Complete transcontinental coastal devastation. Likely annihilation of more than one dominant coastal city. Global economic upheaval.
Prevention: Careful monitoring of precarious rock formations and sea volcanoes; careful monitoring of space debris that might be headed toward the Atlantic; as much advance warning and evacuation time as possible once a shift occurs or a comet collision appears imminent.
Best Bet: Follow the animals to the highest hill and hold on tight.

Major earthquake (McGuire predicts that the next big quake will strike the heart of Tokyo)
Frequency: Once a century
Cause: Shifting tectonic plates
Effect: Widespread mayhem. If a major quake hits Tokyo, the physical damage will be local, but the global economic damage will be daunting. Tokyo is home to 30 million people (a quarter of Japan's population) and two-thirds of the country's industrial giants. While Tokyo rebuilds its financial core, other markets will take a serious hit.
Prevention: Begin looking for ways to make the planetary economy more resilient to the financial chaos that would be caused by a Tokyo quake.
Best Bet: Wise financial structuring and preparation in the world economy; personally, you should diversify your investment assets (and buy Sony products while you still can).