New model of man's role in climate change

Jan 24, 2011

The Roman Conquest, the Black Death and the discovery of America -- by modifying the nature of the forests -- have had a significant impact on the environment. These are the findings of Swiss scientists who have researched our long history of emitting carbon into the environment.

"Humans didn't wait for the to provoke environment and . They have been having an influence for at least 8000 years." Jed Kaplan is putting forward a new interpretation of the history of man and his environment. This professor at EPFL and his colleague Kristen Krumhardt have developed a model that demonstrates the link between population increase and deforestation. The method enables a fairly precise estimate of human-origin carbon emissions before the advent of industrialization.

The story of our influence on the climate began with the first farmers. At that time, the prevailing technology didn't allow an optimal use of the soil. "For each individual, it was necessary to clear a very large area of forest", explains Jed Kaplan. However, with time, irrigation, better tools, seeds and fertilizer became more effficient. This development was a critical factor, which would partially counterbalance the increase in population, and contain the impact of human pressure on the natural environment.

Agriculture – the story of a race for productivity

The relationship between population levels and agricultural land-use is therefore not simply proportional, as was formerly believed. In the Middle Ages, Europe had fewer forests than today, although since then the population has increased more than five fold. "The real innovation in our research has indeed been the taking into account of the improvements in farming techniques. Standard models simply state that the bigger the population, the more forest is cleared; but this doesn't correspond to the historical reality.

Ignoring the progress in agriculture, the preceding models implied that the same area of land is required to feed a European living in the fifth century as in the 20th century. This is why scientists struggled in trying to estimate the amount of CO2 produced by man before the industrial era. The work of Jed Kaplan's team now enables us – for the first time – to travel back thru time.

The influence of the Roman Empire and the Black Death on the climate

The results of this research tell a very different story from that which has been circulating up until now. They show, for example, a first major boom in carbon emissions already 2000 years before our era, corresponding to the expansion of civilizations in China and around the mediterranean.

Certain historical events, almost invisible in the preceding models, show up strongly in the data produced by the scientists. A good example is the re-growth of the forests as a consequence of the fall of the Roman Empire. The Black Death, a plague which resulted in the death of more than a third of the European population, also led to a fall in .

From the decline of the American indians to the minor ice age

Lastly, a significant decrease in emissions began in the 16th century – the one which would herald the minor ice age. Jed Kaplan has an audacious hypothesis to explain the dip in the data curve: "Thanks to the reports of the early explorers, we know that the forests were less abundant on the American continent. Then the settlers gradually eliminated the indigenous population." Threatened with extinction, these populations effectively deserted the forested areas, which – by taking up the carbon in the atmosphere – in turn set off the legendary frosts of the 19th century. "Of course, it's only a hypothesis", he concludes, "but given the data we have gathered, it's entirely plausible".

Jed Kaplan's model is not in contradiction with the previous ones on one critical point: the enormous increase in emissions from the beginning of the industrial era, and the massive use of fossil fuels. "We are just saying that our influence on the climate began a lot earlier than we thought. In 6000 BC, we were already accumulating significant quantities of carbon in the atmosphere, even though it was nothing compared to the situation today", adds the scientist. A conclusion that could turn out to be critical in the future for the improved evaluation of the decisive impact of the forests on the climate.

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Provided by Ecole Polytechnique Federale de Lausanne

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User comments : 12

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geokstr
1.9 / 5 (15) Jan 24, 2011
Well, it had to happen sooner or later.

ALL the warming events of the past can now apparently be attributed to human activity, so there is no longer any need for the warmists to plug their ears and mutter "na-na-na-na" when the Medieval Warm Period and other warmer eras are brought up. Mann will now reinsert these into his fraudulent "hockey puck" as if he never deliberately omitted them in the first place.

And the religion marches on.
GSwift7
1.7 / 5 (11) Jan 24, 2011
The work of Jed Kaplan's team now enables us, for the first time, to travel back thru time


Well, that figures; Sombody invents the time machine and the headline here is about global warming. They hardly even mention the time machine!!

ALL the warming events of the past can now apparently be attributed to human activity


Yeah, and before humans it must have been those hungry dinosaurs eating all the trees, and before them is was those hungry fish, and before them is was the hungry insects, and before them it was the hungry microbes. See it's turtles and dinosaurs and insects all the way down. See? We wouldn't even have a climate if not for living things. Imagine that; NO CLIMATE! Oh my. It would be like living on the pristine surface of the moon. Pure and beautiful, devoid of all the dirty living things. Yucky, dirty living things. Eww. I think I got some on me.
Claudius
2 / 5 (12) Jan 24, 2011
Well, the obvious answer, of course, since humans are so bad for the climate, is to eliminate the humans. Pesky creatures, but the illudium Q-36 explosive space modulator will take care of them.
Howhot
3 / 5 (6) Jan 24, 2011
Well, the obvious answer, of course, since humans are so bad for the climate, is to eliminate the humans. Pesky creatures, but the illudium Q-36 explosive space modulator will take care of them.

BRING IT ON SOB!
Mandan
2.6 / 5 (5) Jan 24, 2011
I was reading articles back in the 1980s in Discover Magazine as a graduate student in ancient history about the beginning of human impact on the environment through the use of various forms of controlled burning-- burning grasslands by late Paleolithic/Mesolithic hunter/gatherers to encourage new grass growth and increase their food animal herd numbers; increases in burning wood as fuel and for urban-scale cooking in the Bronze and Iron Ages; then later exploiting coal deposits which I clearly remember being correlated with the warming during the Middle Ages, even arguments that this may actually have blunted a return to active glaciation and ice sheet advance.

So this is far from being something new, and even further from being conveniently "made up" findings for the benefit of climate researchers in clear retreat from the stunningly brilliant onslaughts of those who hold the keys to the true truth. Now give me a bunch of one star ratings and move on, the usual suspects. ICU,2
dollymop
5 / 5 (2) Jan 25, 2011
At an AIA archaeology lecture about 5 years ago, we learned about a dig in Jordan. These people had no writing yet - but they did fire pottery - even their houses were egg shaped whitewashed ceramic - very cool. And they did have flocks of goats. They cut a lot of wood for their kilns, and the goats ate the baby tree shoots, so no new trees could grow. Eventually they changed the local climate by killing off all the trees - and their culture collapsed.
Skeptic_Heretic
4 / 5 (4) Jan 25, 2011
Why would the skeptics be arguing against land change, which happens to a larger extent and more often due to nature itself, being a major factor in climate change? You're just cutting the legs out on your own argument. The changes his model show simply account for the incredibly small percentage of change due to man in the past, which isn't significant enough to explain climate fluxuation in the past but allows us to account for more of the unexplained noise.
Claudius
1 / 5 (10) Jan 25, 2011
Here's the latest on this from Mother Nature Network: "Was Genghis Khan history's greenest conqueror?"

"The Mongol invasion scrubbed nearly 700 million tons of carbon from the atmosphere, according to new research."

"... the Mongol Empire, about 22 percent of the world's total land area had been conquered and an estimated 40 million people were slaughtered by the horse-driven, bow-wielding hordes. Depopulation over such a large swathe of land meant that countless numbers of cultivated fields eventually returned to forests."

So there you have it again: killing humans is a good way to reduce warming due to human activity. So not only does Jim Hanson want a global dictatorship modeled on China to address global warming, but genocide seems to be part of the anti-global-warming paradigm. After all, China has probably killed at least 80 million of its citizens, doing even a better job than Genghis Khan or even the depopulation of the Native Americans.
Claudius
1 / 5 (10) Jan 25, 2011
On further reflection, perhaps that is why the modern Chinese don't need emissions controls and are building 2 to 3 coal fired power plants a week. They got a big carbon offset by murdering 80 million of their people.
Ass
1.6 / 5 (7) Jan 25, 2011
I thought this must be a joke, but I can't spot it. (1)Models can show anything since the modeler gets to choose the parameters and inputs. (2) Simultaneity does not show connection (famous examples: Ice cream sales "causes" rabies, old maids "cause" failure of clover crops.) (3)Neither the zoo-geographic nor archaeological examples are correct, (4) it is not logical to assume humans cause global climatic change, even now. Add in volcanic activity, extra-terrestrial dust and debris, deep ocean disturbance bringing methyl hydrates,---all sorts of things. You don't know? Neither does anyone else.
We sure as hell aren't helping.
erich_knight
1.8 / 5 (5) Jan 30, 2011
The Columbian Encounter and the Little Ice Age: Abrupt Land Use Change, Fire, and Greenhouse Forcing - Annals of the Association of American Geographers

Dr. Dull's recent work brings even more support, related even closer to practices of Terra Preta soils in the Amazon. The BC, charcoal & pollen evidence is hard to ignore The pieces of anthropogenic climate change fall into place.

The re-growth of Neotropical forests following the Columbian encounter led to terrestrial biospheric carbon sequestration on the order of 2 to 5 GtC, contributing to the well-documented decrease in atmospheric C recorded in Antarctic ice cores from about 1500 through 1750. From charcoal in lake bed studies it documents increased biomass burning and deforestation during Ag and population expansion in the Neotropics from 2500 to 500 years BP, corresponding with atmospheric carbon loading and global warming 1100 to 650 years BP.
dollymop
5 / 5 (1) Feb 01, 2011
The argument 'did man do it or did nature do it' is specious. Obviously there are natural events and cycles that cause climate change. We are still heating up since the last major ice age peak about 25,000 years ago. Equally obviously, humans are a very destructive species, since we mine, practice agriculture, produce chemicals and make physical changes to the planet on a very large scale. We can't do much about natural occurrences, but we can clean up our own act, and not overpopulate. Birth control seems a happier solution to me than letting nature take its course with plagues, that inevitably hit monocultures like us.

Cleaning up our own mess seems a no brainer. Make a clean environment to live in, as well as protect the planet - which for the foreseeable future is our only home. We either take care of it ourselves - or nature will eventually take care of it for us - and we won't like that at all. Getting re-balanced by nature is a hard road.