Financial Times: The US should aim to generate all of its electricity from zero-carbon energy sources within a decade, Al Gore, the former vice-president, urged on Thursday. In a speech in Washington he argued that only by making such a commitment could the US solve the pressing problems of the high oil price, the export of jobs abroad and climate change. “Our dangerous over-reliance on carbon-based fuels is at the core of all three of these challenges – the economic, environmental and national …