Original sentence: Campbell has been predicting since 1989 ( claimed Peak then was 1990  ) that this peak will cause a catastrophic world-wide economic depression.Global oil discovery peaked in 1964 , and since the early 1980s oil production has outpaced new discoveries
Edited sentence: Campbell has been predicting since 1989 ( claimed Peak then was 1990 ) that this peak will cause a catastrophic world-wide economic depression.However, global oil discovery did peak in 1964 , and since the early 1980s oil production has outpaced new discoveries.None of this is particularly controversial; the oil industry itself is spending less than half as much on exploration as a decade ago