Former geologist hailed energy development as indispensible to democracies
Activist attorney has led charge for state legal action against 'Big Oil'
'We're destroying huge amounts of land for a system that, at best, is 20 percent efficient'
Green group denies need to register as foreign agent
Data was collected before details of plan were released
'Overhauling transportation systems in the United States'
Sanders says 'climate change is the single greatest threat facing our planet'