Stunningly honest article in New Scientist admits that historically, warmer times have been better and that plenty of bad things happened when CO2 levels were allegedly "safe"

Climate change: The great civilisation destroyer? - environment - 06 August 2012 - New Scientist

Excavating in what is now Syria, Weiss found dust deposits suggesting that the region's climate suddenly became drier around 2200 BC. The drought would have led to famine, he argued, explaining why major cities were abandoned at this time ...When Zhang compared climate records for the last 1200 years to the timeline of China's dynastic wars, the match was striking. Most of the dynastic transitions and periods of social unrest took place when temperatures were a few tenths of a degree colder. Warmer periods were more stable and peaceful (Chinese Science Bulletin, vol 50, p 137).
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Zhang gradually built up a more detailed picture showing that harvests fell when the climate was cold, as did population levels, while wars were more common. Of 15 bouts of warfare he studied, 12 took place in cooler times. He then looked at records of war across Europe, Asia and north Africa between 1400 and 1900. Once again, there were more wars when the temperatures were lower. Cooler periods also saw more deaths and declines in the population.