The Revision of History

25 Jan 2011

AGW proponents not only adjust temperature readings from the recent past in order to draw a more prominent warming trend they are now revising history itself in order to saddle the wicked human race with further angst. According to the new history of the world the Roman Empire, the Black Death, and the colonisation of the Americas had a significant impact on climate - largely it seems by chopping down trees. So, periods of warmth in which populations expanded are interpreted as in some way bad, and conversely, espisodes of cold weather when millions of humans around the world died, mainly the poor, are classified as good - or having a good conclusion, a regrowth of forest as a result of a reduced human population. Not only that, we are informed the rot set in with the first farmers - and methane produced from cattle and sheep, pigs and goats. Farmers, it is argued, cleared the natural forest by setting fire to it to grow crops (see for example and January 22/23rd at for a similar study by different authors). It is intriguing to see how they develop their ideas and what avenues their brains walk. Apparently, the Roman Warm Period is chosen as a period when C02 levels increased. This era witnessed thriving human societies not just in the Roman world and the Middle East but in India, China and the Americas. Human population exploded - and so too did agriculture. I'm not sure if C02 levels actually increased, or it is assumed they did, but proceeding on the assumption that C02 levels increased towards the end of the Roman Warm Period why was it followed by a cool wet phase of climate in the 5th and 6th centuries AD. The two things don't add up even if a lot of people died, as they probably did as a result of plague - and we may assume there was famine, and reduced pasturage on the steppes, and a whole host of interrelated follow-ups. So, forests recovered - everywhere. What had that to do with C02 levels? Woodland also recovered after the Black Death reduced global populations - which of course coincided with a fall in carbon emissions. However, the biggest piece of historical revision is how they would reinterpret the onset of the Little Ice Age in the 17th and 18th centuries. Apparently, the indigenous Americans had cut down a lot of trees and there were all those herds of bison breaking wind, adding methane to the C02. When European colonisation arrived large numbers of indigenous Americans died out, mainly by introduced diseases. It was then the Little Ice Age kicked in. Now you know (published in Ther Holocene DOI:10.1177/0959683610386983).

On a similar kind of vein, a draft version of a paper by James Hansen is analysed by Dr Martin Hertzberg at in which, once again, palaeoclimate is being revised to suit an AGW agenda. In this instance to bolster the idea of an alarmist rise in temperature in coming years. Whereas the previous paper linked carbon emissions to global cooling events Hansen is absolutely steadfast in his belief that warming will continue - unabated. He is saying that a return to glacial conditions is overdue as earth's orbital parameters (or those of Milankovitch) indicate we should already be cooling but AGW is keeping it at bay (or something like that). Basically, he says that earth is closest to the Sun in January which should favour warmer winters and cool summers in the northern hemisphere. We are further from the Sun in summer Hansen argues and there should be less solar insolation - thus favouring the growth of glaciers and ice sheets. This isn't happening so AGW must be real, is the argument - but Hertzberg is not impressed. He says Hansen does not realise that although we are further from the Sun we are also moving more slowly and are therefore exposed to the summer Sun for a longer period of time. What this means for the Milankovitch hypothesis I don't know but Hertzberg is a co-author of a new book, Slaying the Sky Dragon - Death of the Greenhouse Gas Theory. I suppose this is a bit of an advertisement for his book and so just one example must suffice for In the News. The interpretation of the Vostok ice core in Antarctica, which goes back 400,000 years, is one argument he makes - but is he on the ball? The data displays a long term correlation between temperature and C02 atmospheric concentrations - but sceptics interpret this in one way and alarmists the opposite way. The evidence is that when human activity was characteristically low, being the Ice Ages, C02 levels were lowest when temperatures were at their coldest point in the cycle, and at their highest when warm periods had peaked (such as the Inter-Glacial episodes). So, where did earlier peaks in C02 come from, Hertzberg asks. The answer, he assures us, lies in the oceans. As oceans warm they emit dissolved C02 which is transferred to the atmosphere. When oceans cool the reverse happens - the oceans absorb more C02. Obviously, these points are arguable but in a cold glacial world vegetation would be reduced, and forest cover, so there would have been reduced amounts of C02 for the oceans to absorb. As the Ice Ages were lengthy, we might imagine there was more time for the oceans to absorb more C02 - but we might wonder. Why are ice cores in polar regions considered an ideal place to measure global C02 levels. The environment is cold and the data is saying that when, and probably where it is cold equals reduced C02 levels. Not the best place to measure C02, it could be said - or is that wrong headed?    

Finally, some glee can be had from a story on the blogosphere (see for example ). It seems that environmentalists are worried about the plight of a few fish species found only in the lakes of Cumbria - the vendace, for example. There are fish species in the lakes that are found nowhere else in the country and they have survived in isolation since the end of the Ice Age - or shortly thereafter. Apparently, they are in decline. This is a problem highlighted by genuine people with a concern for wildlife and the natural world. They may be environmentalists but they aren't the AGW alarmist brand - but their cause, presented to the Environmental Agency, has rapidly become a piece of propaganda in the hands of the bureaucrats at said agency (see also ). The newspaper claims scientists have warned that higher temperatures and lower rainfall in summer (didn't they have a flood up their last year, and a couple of years before that?) will lead to lower river flow and rising water temperatures. Hence, oxygen levels will fall so it is necessary to rescue the fish or oxygenate the water for them to survive (nothing like being pampered by a nanny). Cold water and migrating fish, including salmon and trout, are vulnerable - a decline in eel populations over the last 30 years is testimoney of that, it continues. It isn't the disappearance of ponds in the countryside, or ditches being choked by weeds and scrub, or field bottoms being drained with EU subsidies, but global warming - the catch all explanation. The bureaucracy in charge of all this at the Environmental Agency, says it is planning to plant more trees on river banks (a good thing) but for the purpose not of wildlife as such but to provide shade to keep the warming waters from getting too hot. The lead bureaucrat is then quoted as saying, climate change is one of the greatest challenges facing the world today .... blah blah and some more blah (you get the picture). No wonder people are worried about stocks of rare fish in lakes adapted to very cold water - why not move them to Scotland, and this is the plan. However, have they thought this thing through. Up in Scotland there are a lot of otters and other animals that feed on fish - will the vendace end up in the stomachs of a sea otter? What is the greater threat - living where they have always lived, through cold weather and warm weather, or left to the mercy of nature red in tooth and claw.