Phlogiston and Global Warming.
This is a guest post by one of our regular commenters, Graeme No.3
Gracious acceptance of criticism is not a common human trait. In most scientists it provokes irritation, denial and antagonism. Among what their admirers call the top climate scientists, dissent seems to provoke spectacular responses. They are obsessed with CO2 as an explanation for everything. Nothing else will serve. CO2 is a greenhouse gas, CO2 causes warming, CO2 causes snow, CO2 causes strong winds; soon we will hear CO2 blamed for Man City losing the Championship.
In the early Eighteenth Century phlogiston was all the rage. When a metal corroded it was said to have lost phlogiston. When it was pointed out that rusting iron gained weight, it was explained that phlogiston had negative weight. A burning candle lost weight because it was rich in phlogiston. It was the settled science.
Until that is, Scheele and Priestley discovered oxygen, although both made convoluted work of it as neither wished to challenge settled science. Lavoisier used a closed system such as a burning candle in a bell jar, and proved that phlogiston had zero weight and zero volume. He made the obvious conclusion. Of course, we know now that the candle used up oxygen and released carbon dioxide.
Over the next 100 years settled science was shaken by overwhelming evidence of not one, but several past ice ages. Arrhenius started the ‘CO2 controls climate’ theory as an explanation for the end of ice ages, with volcanoes belching improbable amounts of CO2 and causing global warming. He was told at the time that he was wrong, but ignored the critics. He had no reverence for settled science as he had received a fourth class degree for challenging it, but extensions of that very work had earned him the Nobel Prize. For the next 60 years his theory attracted derision.
By then much more was known about the ending of an ice age. Ice cores samples showed rapid changes in temperature and CO2 levels. Arrhenius’s theory was resurrected by a group of scientists determined to prove that man was changing the climate. A rise in CO2 causes global warming, they said, which causes more CO2 (and water vapour) to evaporate from the seas. This positive feedback amplifies the effect, thus burning fossil fuels would result in global warming. Unfortunately some scientists pointed out the cores showed that the warming came before the CO2 level rose. The resulting dispute swiftly made the war between the Big Endians and the Little Endians seem small.
Needing further evidence to support their case the global warming boys noted that rapid changes seemed to occur roughly every 100,000 years in the last 900,000 although each cycle had its own idiosyncrasies in timing and magnitude of change. Going back two and a half million years, there were even more changes, roughly at 41,000 year intervals. Why the change in cycle length occurred hasn’t been settled. As these intervals were similar to 2 of the planetary cycles postulated by Milankovitch, they claimed victory. By itself the Milankovitch cycle wasn’t enough to cause rapid climate change, but some warming from it at the start would cause a rise in the CO2 level, followed by positive feedback, hence rapid global warming to an interglacial warm state.
The last warm interglacial before this one, the Eemian, was certainly warm, with lions, elephants and hippos in the Thames Valley. Early man in Yorkshire had to avoid rhinos which roamed there and as far north as the border, but not over it. Readers who’ve seen Scottish football fans will realize why a thick-skinned, belligerent animal couldn’t find a vacant ecological niche in Scotland.
Radiographic paleostudies of O18 isotopes levels from layers in the Devils Hole, Nevada seemed to add to the evidence. There was a distinct warming shown which seemingly correlated nicely with ice cores from the Antarctic, and the warm period in the terrestrial pollen record from the Netherlands, which gave the Eemian its name. The start of the warm period was changed from 120,000 years ago to align with the Milankovitch cycle start at 130,000 years ago. The geologists objected, claiming that their tests showed the relevant deposits were at least 140,000 years old. Their objections were overruled because the U/Pb method wasn’t quite accurate. Back came the geologists over the next 20 years with other tests, all giving dates between 140 & 147 thousand years ago. Geologists are the bulldog breed.
Unfortunately, the Milankovitch cycle couldn’t be that early, and a start date of 130,000 years ago and a length of 10,000 years for the Eemian became the doctrine. That left the 10,000 years before hand unexplained, and a similar length gap in the timing of this interglacial starting. Perhaps the Eemian was 20,000 years long?
Nice to have the science settled, isn’t it?
Some sceptics objected on the grounds that there was no mechanism to stop positive feedback. If warming caused more CO2 (and water vapour) which in turn caused more warming, there was at least 10 times the amount of CO2 present in sea water, and obviously no shortage of water, so positive feedback would make the oceans boil. This had never happened in the past. None of the previous interglacials was more than 3℃ warmer than at present nor higher than 300 ppm. in CO2. This has caused some to try and debate the existence of the Greenhouse effect. They claim that Loschmidt’s atmospheric paradox is sufficient explanation for the Earth’s temperature (whatever that is). They are cordially, or otherwise, invited to shut up, the Royal Society tells you so.
Some dissenters have suggested that ice ages are cold dry times associated with low solar activity and a dry, dusty atmosphere. When the sun becomes more active, it increases its overall radiance slightly, but its ultraviolet output surges. Much UV is absorbed by the atmosphere which it warms, while the rest mostly warms the oceans. This leads to a rapid increase in water vapour which is after all the most common greenhouse gas, and absorbs far more infrared than CO2. An increase in rain washes dust out of the atmosphere and decreases the amount of energy reflected, leading to yet more warmth in the atmosphere. The atmospheric circulation patterns change bringing warm air to melt snow. This further lowers the albedo, allowing the ground to warm up. This looks like a runaway effect, but the IPCC says that the output of the sun is almost constant, so the science is settled.
My modest proposal is that ice ages were ended by the arrival of aliens – I imagine them looking like miniature giraffes with blue spots and a flatulence problem. The latter would make the air in the interstellar craft, well, stifling, were it not for the use of the cold of space to condense the methane to a liquid and making it easier to store. When the storage tanks are full, they landed on Earth and discharged the methane. Methane is a potent greenhouse gas, as those who seek to convince us of our impending doom will agree. (Originally listed as 6 times stronger than CO2, this became 14 times, 25 times and 42 times. Any advance on 42? Going once, going twice….) That triggers the global warming, yet the quantity of each discharge being limited, the overall warming doesn’t exceed that seen in the ice cores or other measures.
The frequent changes in the state of the climate, the variation in timings, why the temperature rise was limited, and, assuming an increase in the price of interstellar propellant, why the switch to 100,000 year intervals occurred are better explained by this theory than any of the others. My mind is made up. Climate change is caused by farts from space hopping, blue spotted, mini giraffes. The science is settled.
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