Human societies have nearly always done each other the maximum damage they could according to their technological development. The 20th century was not a regression, just standard operating procedure, and provides no extra reason for pessimisim.
The world is big and complex, making it all too easy to point to negative developments as a seeming answer to optimistic analysis. However, there is no denying that humankind has achieved fantastic progress in the last couple of centuries across a broad front -- and, in fact, there are powerful reasons why that happened, and can be expected to continue operating. (A more thorough analysis of these points can be found in my own 2009 book, The Case for Rational Optimism.)
To quote Wikipedia "Ridley was non-executive chairman of the UK bank Northern Rock from 2004 to 2007, in the period leading up to the bank's near-collapse." maybe this is why he has little to say about the financial crisis.