Nuclear storm warnings?

White House Science Advisor John Holdren and Sir John Beddington, Science Advisor to British Prime Minister David Cameron, in a recent joint article "Celestial Storm Warnings" published in the New York Times, warned that a solar flare from the Sun could cause a great geomagnetic storm, with catastrophic consequences for the United States and the world.  A great geomagnetic storm would generate a powerful electromagnetic pulse (EMP) that could destroy electronic systems and collapse all the critical infrastructures--power grids, communications, transportation, banking and finance, food and water--that sustain modern civilization, and the lives of millions.  Holdren and Beddington write reassuringly that "work to protect our societies is well underway.[sic]"