At the half-way point Carswell point to six things he hadn’t previously known:
1. Over the past million years, way before industrial man came along, the climate has often changed very significantly, very quickly.
2. When climate changes, the shift is from being warm and wet to cold and dry. Or vice-versa. If global temperatures are rising, it’s most likely getting wetter, not drier.
3. Warm-wet climates are generally better for life on earth than cold-dry climates.
4. CO2 levels have been far, far higher in the past – yet CO2 levels in the atmosphere don’t seem to have been a significant driver of climate in the past.
5. Human activity accounts for a relatively tiny portion of global CO2 emissions. To quote Plimer, “One [submarine] hot spring can release far more CO2 than a 1000 mW coal-fired power station”. There are many, many thousands of such springs.
6. Plimer suggests that the really significant drivers of climate change are the sun, ossiclations in the earth’s orbit, and volcanic emissions of sulphur dioxide. Indeed, the 1784 eruption of Laki in Iceland put 150 million tonnes of SO2 into the atmosphere – which wiped out crops and caused famine in the northern hemisphere for a couple of years.
The major aim of the Pilmer’s Heaven & Earth is to provide to put the human influence on climate in perspective (both in magnitude and time scale), along with the limits of what we know. For instance on p.112 Pilmer says that a 1% change in the cloud cover could account for the entire C20th warming, whilst on p.115 we find that we can only measure cloudiness to an accuracy of 1%.
The broad sweep of the book is sufficient (to reasonable people) to put on hold any new policies to combat climate change. In particular any policy trying to negate runaway global temperatures. Pilmer shows the earth has a number of powerful forces affecting climate that gives fairly wide fluctuations over millions of years, but also countervailing forces (negative feedback) that gives sufficient stability to sustain life.
However, those who are about to read the book should be aware of the lack of an editor. The following can criticisms can be made
– Pilmer uses every possible criticism available. So the temperature rise of the last century could be explained by a number of factors.
– The case for the influence of climate on human history may be over stated, but still raises questions on the current orthodoxy.
– There are a number of errors or exaggerations, that will be used as an excuse to dismiss the book. See George Monbiot in the Guardian at http://www.guardian.co.uk/environment/georgemonbiot/2009/aug/05/climate-change-scepticism. Some of the “errors” may be a matter of opinion, but they only counter points 4 and 5.
– It is written in a polemical style, that may confirm the belief of the doubters, but will not gain many converts from the AGW true believers. It is repetitive, introduces new topics at random and gives too many, poorly supported, examples.
On the evidence to page 223, there is scope at least for a second edition. More plausibly, for a journal is better able to draw together the diverse bits of information than one person working alone. Pilmer’s book is more than sufficient to undermine the case for delivering the human race into poverty and serfdom to “save the planet” to the unbiased person weighing the arguments. Sadly, policy-makers are being railroaded in one direction by political techniques more akin to the USSR than modern democracies.