John Hofmeister, former President of Shell
Is America ready to wean itself off a long-term addiction to fossil fuels?
The disastrous BP oil spill in the Gulf of Mexico has sharpened the debate about sustainable energy strategies across the developed world.
John Hofmeister was for years a big player in the global oil industry. He retired from Shell's American business recently, where he was president from 2005-2008.
Now he tells the BBC's Stephen Sackur that he is ready to talk straight about the world's looming energy crisis.
Is big oil part of the solution, or the problem?