"Rising atmospheric CO2 is the most obvious and startling expressions of our impact on the global environment," study corresponding author and University of
Current carbon dioxide levels last seen 14 million years ago phys.org - get the latest breaking news, showbiz & celebrity photos, sport news & rumours, viral videos and top stories from phys.org Daily Mail and Mail on Sunday newspapers.
The last time carbon dioxide in the atmosphere consistently matched today's human-driven levels was 14 million years ago, according to a large new study Thursday that paints a grim picture of where Earth's climate is headed.