What have the Romans ever done for us?

Microdot reader required

UPDATE: WUWT reports that the climate angle was spliced in at the last minute…

“Apart from the sanitation, medicine, education, wine, public order, irrigation, roads, the fresh water system and public health, what have the Romans ever done for us?” *

Given us warmer weather, that’s what!

Just as we must get rid of the Medieval Warm Period, the inconvenient Roman Warm Period must also be dealt with, and here’s a novel way of doing it: claim that it was man-made. In a single stroke, the RWP is scrubbed from the list of “natural warmings” that the planet has experienced in recent history, helping the Cause by demonstrating that it too was anthropogenic. The ABC reports:

A period covering the heyday of both the Roman Empire and China’s Han dynasty saw a big rise in greenhouse gases, according to a new study.

The finding challenges the view that human-made climate change only began around 1800.

A record of the atmosphere trapped in Greenland’s ice found the level of heat-trapping methane rose about 2000 years ago and stayed at that higher level for about two centuries.

Methane was probably released during deforestation to clear land for farming and from the use of charcoal as fuel, for instance to smelt metal to make weapons, says lead author Celia Sapart of Utrecht University in the Netherlands.

“Per capita they were already emitting quite a lot in the Roman Empire and Han Dynasty,” she says of the findings by an international team of scientists published today in the journal Nature (link to abstract). (source)

But the per capita emissions are irrelevant in terms of climate, since it is absolute concentrations that will affect greenhouse warming. The population, as the article goes on to say, was about 300 million, barely 4% of what it it today, and without any industrialisation apart from burning charcoal. I will leave it to you to consider the likelihood of such a tiny agrarian population having a significant effect on the climate.

The ABC’s coverage is similarly disingenuous. I’m not going to pay thirty bucks for the full article in Nature (if anyone has access, I would be grateful for a PDF – Update: PDF received from a generous reader – thank you!), but eyeballing the tiny graphics published with the abstract (see above) seems to indicate that centennial scale changes in CH4 mixing ratio in the Roman period were in the order of a 20-40 parts per billion (that’s billion with a b). How the ABC can call this a “big rise in greenhouse gases” is unfortunately yet more evidence of agenda-driven journalism. It’s a tiny fraction compared with the industrial rise in CH4, which took mixing ratios to over 1800 ppb, yet the paper claims it is responsible for the significant warming that occurred around the time of the Roman empire?

However, if we could blame the RWP on the Romans, then we can subtract it from the natural warming column and add it to the AGW column. Nice try.

* Monty Python Life of Brian:


Roman and Medieval periods warmer than today

Cooling trend?

Another story you won’t see anywhere on the ABC, firmly stuck in its groupthink mode and working itself up into a lather plugging a litany of dire and alarmist statements from a symposium on coral reefs, which has predicted, amongst other things, rises in sea levels of 1.7m by the next century (far exceeding even the “gold standard” IPCC projection).

I wonder if a “coral reef symposium” would get any media interest at all if it didn’t follow the well worn-path of alarmism and links to man-made climate change? Probably not.

And why, I wonder, did the ABC choose not to report on a paper published in the peer-reviewed journal Nature Climate Change that showed the Roman and Medieval periods were actually warmer than the present, without any help from man-made CO2? Because it doesn’t fit the rusted-on groupthink, maybe?

A new study measuring temperatures over the past two millennia has concluded that in fact the temperatures seen in the last decade are far from being the hottest in history.

A large team of scientists making a comprehensive study of data from tree rings say that in fact global temperatures have been on a falling trend for the past 2,000 years and they have often been noticeably higher than they are today – despite the absence of any significant amounts of human-released carbon dioxide in the atmosphere back then.

“We found that previous estimates of historical temperatures during the Roman era and the Middle Ages were too low,” says Professor-Doktor Jan Esper of the Johannes Gutenberg-Universität Mainz, one of the scientists leading the study. “Such findings are also significant with regard to climate policy.” (source)

They certainly are. But don’t expect such policies to change anytime soon.

Warmist journal New Scientist does its best to prop up the consensus and wheels out Michael “Stick” Mann to rubbish the results:

The finding does not change our understanding of the warming power of carbon dioxide. In fact, it shows that human CO2 emissions have interrupted a long cooling period that would ultimately have delivered the next ice age. [So we’ve stopped an ice age? I would have thought that was probably quite good news…]

Esper says temperature reconstructions will have to be redone because past studies probably underestimated temperatures during the medieval warm period and other warm periods going back to Roman times. The further back in time, the greater the underestimate would be.

But others have doubts. [Michael] Mann argues that Esper’s tree-ring measurements come from high latitudes and reflect only summer temperatures. “The implications of this study are vastly overstated by the authors,” he says. (source)

Because when you’re an activist first and a scientist second, like Mann and the rest of the Hockey Team, your mind is firmly closed to even the possibility of contradictory evidence.

Link to paper here.

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