CRASHING commodities scare not only stock markets. They also strike fear into environmentalists keen to see America move towards renewable sources of energy. Barack Obama sought to bolster confidence in green power at the National Clean Energy Summit on August 24th—a day on which oil prices also fell to below $45 a barrel, their lowest for six years. Fossil fuels are both cheap and plentiful. The Dow Jones Total Coal Market index has dropped by more than three quarters in the past five years. That makes it harder for the president to wean America, which accounts for 15% of global carbon-dioxide emissions, off them.
