The past few years have ushered in an unprecedented, unforeseen, and largely unheralded solar energy revolution. As recently as 2005, global installed solar power capacity stood at 4.5 gigawatts (GW). Today, the figure exceeds 65 GW, which is equivalent to the capacity of about 130 average-sized coal-fired power plants.

To put recent growth of solar power in perspective it helps to look at how it has played out in particular places. Take the U.S., for example. Solar is America's fastest growing industry, and already employs more than 100,000 men and women -- more than U.S. steel production and more than U.S. coal mining. In California, which leads the nation on solar power, the number of installed solar energy systems has increased from about 500 in 1999 to more than 50,000 in 2011. These days, when you fly into a place like Oakland, you can see your plane reflected in the rooftops below.