A scientist has attacked the inaction over a threat from a dangerous volcano in the Canary Islands which could send a tidal wave crashing against the US.
The tsunami could race across the Atlantic at the speed of a jumbo jet
Bill McGuire of the Benfield Grieg Hazard Research Centre said no one was keeping a proper watch on the mountain.
If Cumbre Vieja volcano erupts, it may send a rock slab the size of a small island crashing into the sea, creating a huge tidal wave, or tsunami.
Walls of water 300 feet high would travel to the US at the speed of a jet.
Within three hours, the wave would swamp the east coast of Africa, within five hours it would reach southern England and within 12 it could hit America's east coast.
The rock is in the process of slipping into the sea, but the trigger that sends it into the Atlantic is likely to be an eruption of Cumbre Vieja. According to Professor McGuire, Cumbre Vieja could blow "any time".
New York, Washington DC, Boston and Miami would be almost wiped out by the tsunami generated by the insecure rock falling into the Atlantic.
"Eventually, the whole rock will collapse into the water, and the collapse will devastate the Atlantic margin," said Professor McGuire, of the Benfield Grieg Hazard Research Centre.
"We need to be out there now looking at when an eruption is likely to happen...otherwise there will be no time to evacuate major cities."
The two or three seismographs designed to pick up signs of movement in the rock could not detect a volcanic eruption weeks in advance, McGuire said.
He urged the governments of Spain and the US to fund monitoring of the volcanically active La Palma - a project he said could be achieved relatively cheaply.
Professor McGuire and other experts speaking at a news conference on natural disasters on Monday said the global community needs to monitor and develop strategies to cope in the face of a catastrophe such as the one that Cumbre Vieja could cause.
Global Geophysical Events, or "Gee Gees", as they are nick-named, are not being taken seriously enough, they say.
However, good progress is being made in reducing the threat of asteroid impacts, researchers said.
Since 9/11 we have become acutely aware of the threat of terrorism. Governments worldwide are battening down the hatches and ratcheting up the security.
The global community needs to monitor the risk posed by Gee Gees, scientists claim
But some scientists believe we are ignoring threats with similar, or greater, potential to devastate human populations.
Giant walls of water that can devastate coastal cities, volcanoes so big that their ash crushes houses 1,500km (932 miles) away, giant earthquakes and asteroid impacts. These are very rare events and, if we are lucky, nothing like them will happen in our lifetimes.
But in the longer term, Gee Gees may be our undoing if we do not take action, say researchers. Careful preparation could potentially save thousands of lives, they say.
Volcanoes and earthquakes are relatively common occurrences, but Gee Gees are on an altogether different scale.
The last "super volcanic eruption" was back in April 1815, when Tambora in Indonesia exploded violently in what was the largest eruption in historic time.
The eruption column reached a height of about 44 km (28 miles), ash fell as far as 1,300 km (800 miles) from the volcano - and an estimated 92,000 people were killed.
Global governments are not entirely ignoring the threat of Gee Gees, however.
Some think the greatest danger to humanity comes from asteroids, but steps are underway to tackle the threat.
The European Space Agency (Esa) and Nasa are planning missions to test how the course of asteroids and comets can be altered by an impact.
Esa's mission Don Quijote will send a spacecraft crashing into the surface of a space rock to measure the effects. In 2005, Nasa's Deep Impact will monitor the outcome of blowing a hole in comet Tempel 1.
Scientists hope this will help them learn how to destroy or deflect an asteroid on a collision course with Earth.
Work funded by the US government is swiftly tackling the threat posed by asteroids
According to Benny Peiser, of Liverpool John Moores University, UK, the threat of cosmic mega disasters will be essentially "abolished within 30 years".
"A quiet and largely unnoticed technological revolution is dramatically accelerating the rate at which near-Earth asteroids (NEAs) are discovered," he said.
In 1995 we knew about 300 NEAs, today we know about 3,000 - and within 20 years we could be aware of 90% of all nearby space rocks, he says.
"For the first time in the history of evolution we are closing this window of vulnerability."