The government expects to present it to fellow G-8 members in Scotland in July.
While the international community has been eager to implement such a system, it is unclear what the international response will be to the specifics of the British proposal.
A Liberal Democrat member of the British Parliament, Lembit Opik, considers himself an eager backer of the plan.
"This is important news to me, because for the last four years I have been campaigning to get the British government to raise this issue at a G-8 summit," he says. "Many times, they have told me that they are not planning to do so. But, at last, it seems that they have considered the danger, and they have decided to act upon in. It's very good news."
The British plan calls for the establishment of a global system that would comprise monitoring stations around volcanoes and earthquake zones. It would also deploy sea buoys to warn against tsunamis. And it should watch the sky to spot asteroids or comets that might be on a collision course with Earth.
Opik notes that some parts of the world are already covered by local systems. But he says the international community at last realizes there is a need for a global network.
"My guess is that the Christmas tsunami and the many, many thousands of people who died there have been the event which has caused the British government to act on this now," Opik says. "I always was afraid that it would take a natural disaster to actually happen before we got the investment. Well, the natural disaster has happened, and now hopefully the investment will follow."
Opik says the British government estimates the costs of its proposal at between $200 million and $300 million -- a figure that he says is not prohibitive.
"The investment that we make in predicting earthquakes -- and indeed volcanoes and potential asteroid impacts -- will pay for itself if even one serious event is predicted," he says. "So in that sense, it's always been politics rather than the price tag which has got in the way. The most important thing to recognize is that this will actually be much cheaper in the long term than the investment that is required at the front."
Experts from around the world gathered in Japan in January to discuss ways to prevent a repeat of the massive loss of life in December's Indian Ocean tsunami tragedy through an early-warning system. At that conference, UN experts announced their plans to set up a global early-warning system to alert particularly vulnerable communities. And country representatives attending the conference pledged millions of dollars for such a project.
U.K. scientists have known about the British plan for some time, partly because they have advocated it and partly because they were consulted about it.
"It is not a surprise," says Steve Blake, a senior lecturer at the Earth sciences department at the Open University in Milton Keynes. "I am aware that there have been discussions about asteroid impacts and very large volcanic eruptions. The scientific community have been advising the government about those, and trying to convince them that it's something for them to consider. So, in that sense it's not a surprise. It's pleasing that they're doing something."
Blake says technological advances make such a system much more attractive than it might have been even a few years ago. That makes the early-warning system arguably overdue.
"Satellite technology is one way in which remote volcanoes can be regularly looked at, and seismic instruments are very, very important," he says. "But other techniques that measure the deformation of the ground or the temperature of the surface provide useful information as well. Having a long record of an area is also important. Sometimes earthquakes stop and then start up again. So, the only answer is really intense monitoring."
Opik says that while the expert public and a number of institutions are increasingly receptive to the global monitoring system, not everyone fully understands the danger yet.
"I think it would be sensible for the government to discuss these proposals in parliament, because I am not sure that many British politicians fully understand the dangers," he says. "We really have the technology, the experts, the astronomers, and the know-how to maybe make the world a bit safer. It would be great to see the politicians from all parties supporting this."
That discussion is now on its way. The British government's Natural Hazard Working Group says its plan should be made public in a few weeks. If it gets the go-ahead, it will face a crucial test when G-8 members are asked for their support in July.