(FT) -- The sun is waking up from a long quiet spell. Last week it sent out the strongest flare for four years -- and scientists are warning that earth should prepare for an intense electromagnetic storm that, in the worst case, could be a "global Katrina" costing the world economy $2,000bn.
Senior officials responsible for policy on solar storms -- also known as space weather -- in the US, UK and Sweden urged more preparedness at the annual meeting of the American Association for the Advancement of Science in Washington.
"We have to take the issue of space weather seriously," said Sir John Beddington, UK chief scientist. "The sun is coming out of a quiet period, and our vulnerability has increased since the last solar maximum [around 2000]."
"Predict and prepare should be the watchwords," agreed Jane Lubchenco, head of the US National Oceanic and Atmospheric Administration. "So much more of our technology is vulnerable than it was 10 years ago."
A solar storm starts with an eruption of super-hot gas travelling out from the sun at speeds of up to 5m miles an hour. Electrically charged particles hit earth's atmosphere 20 to 30 hours later, causing electromagnetic havoc.
Last week's solar storm may have been the biggest since 2007, but it was relatively small in historical terms.
It caused some radio communications problems and minor disruption of civil aviation as airlines routed flights away from the polar regions, said Dr Lubchenco.
A more extreme storm can shut down communications satellites for many hours -- or even cause permanent damage to their components. On the ground, the intense magnetic fluctuations can induce surges in power lines, leading to grid failures such as the one that blacked out the whole of Quebec in 1989.
The 11-year cycle of solar activity is quite variable and the present one is running late, with the next maximum expected in 2013.
The peak was not expected to be very strong but that should not cause complacency, said Tom Bogdan, director of the US Space Weather Prediction Center.
The most intense solar storm on record, which ruined much of the world's newly installed telegraph network in 1859, took place during an otherwise weak cycle. An 1859-type storm today could knock out the world's information, communications and electricity distribution systems, at a cost estimated by the US government at $2,000bn.
In terms of terrestrial vulnerability, the biggest change since the 2000 peak is that the world has become more dependent on global positioning system satellites -- and not just for navigation. The world's mobile phone networks depend on ultra-precise GPS time signals for their co-ordination.
© The Financial Times Limited 2011
