The world is overdue a major "space storm" which could knock out communications satellites, ground aircraft and trigger blackouts, leading to a "global Katrina" and causing hundreds of billions of pounds of damage, the scientists said.
A massive eruption of the sun, they claimed, would send waves of radiation and charged particles to Earth, damaging the satellite systems, airline navigation and phone networks, the Daily Mail reported.
If the storm is powerful enough, it could even crash stock markets and cause power cuts that last weeks or months, the experts said.
According to the scientists, the chances of a disruption from space are getting stronger because the sun is entering the "most active period" of its 11-year natural cycle, and the next period of maximum activity is expected in 2013.
"The issue of space weather has got to be taken seriously. We've had a relatively quiet period of space weather -- but we can't expect that quiet period to continue," Professor John Beddington, chief scientific adviser of Britain, told the annual meeting of the American Association for the Advancement of Science (AAAS) in Washington.
He said: "At the same time over that period the potential vulnerability of our systems has increased dramatically, whether it is the smart grid in our electricity systems or the ubiquitous use of GPS in just about everything we use these days.
"The situation has changed. We need to be thinking about the ability both to categorise and explain and give early warning when particular types of space weather are likely to occur."
Jane Lubchenco, administrator of the US National Oceanic and Atmospheric Administration, said: "It's reasonable to expect there will be more (solar storm) events. The watchwords are predict and prepare."
Solar storms are caused by massive explosions on the sun. They release waves of X-rays and ultraviolet radiation which smash into the Earth within minutes, disrupting radio signals and damaging the electronics of satellites.
They are followed 10 to 20 minutes later by a burst of energetic particles which cause even more havoc with satellites -- and then 15 to 30 hours later by supercharged plasma which collides with Earth's magnetic field.
The plasma create the aurora -- or Northern Lights, for example -- and can induce electrical currents in power lines and cables.
The world got a taster of the sun's explosive power last week when a major solar eruption caused spectacular aurorae and disrupted radio communications.
The first major solar flare was recorded in 1859. In 1972, a similar storm cut off telephone communication in Illinois, while another one caused blackouts across Quebec in Canada in 1989.