A newly unearthed missive from Lenny Bernstein, a climate expert with the oil firm for 30 years, shows concerns over high presence of carbon dioxide in enormous gas field in south-east Asia factored into decision not to tap it
Tugboats tow the oil tanker Exxon Valdez off Bligh Reef in Prince William Sound 05 April 1989
Tugboats tow the oil tanker Exxon Valdez off Bligh Reef in Prince William Sound 5 April 1989. Exxon became aware of climate change as early as 1981, according to a newly discovered email. Photograph: Chris Wilkins/AFP/Getty Images