After all, geoscientists have checked the pre-industrial climate, over the past 10,000 years: this isolates natural climate drivers. According to the IPCC, natural factors hardly play any role in today’s climate so we would expect a rather flat and boring climate history.
Far from it: real, hard data from ice cores, dripstones, tree rings and ocean or lake sediment cores reveal significant temperature changes of more than 1°C, with warm and cold phases alternating in a 1,000-year cycle. These include the Minoan Warm Period 3,000 years ago and the Roman Warm Period 2,000 years ago. During the Medieval Warm Phase around 1,000 years ago, Greenland was colonised and grapes for wine grew in England. The Little Ice Age lasted from the 15th to the 19th century. All these fluctuations occurred before man-made CO2. Fritz Vahrenholt, the telegraph
No doubt manmade CO2 contributes its mite to climate change – though I suspect that changes in land use actually contribute rather more (both in actual warming and the warming of the land-based thermometers due to the Urban Heat Island effect).
But is that mite enough to justify all but the most minimal steps to reduce CO2 emissions? Well, if the total economic cost was, say, $1.00 a year for the citizens of the developed world, perhaps; but a billion or two is chump change to the greenie alarmists; the talk in Rio is in the trillions and is a complete waste of time and money.