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Br Cornelius

Do you accept the reality of AGW ?

Do you accept the science of anthropogenic climate change ?   50 members have voted

  1. 1. Do you accept the science of anthropogenic climate change ?


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178 posts in this topic

That graph doesn't come from that link.

Br Cornelius

who gives a....

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who gives a....

You don't understand how to discuss a point do you.

You certainly don't know how to support an argument.

This is one of your Coming Ice Age sources isn't it ??

Br Cornelius

Edited by Br Cornelius

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The Mann graph is a global average trend line.
mann's phony graph was for northern hemisphere, i'm surprised you didn't know that.

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Well Aten what do you want to dicuss about your graph, which cannot be confirmed at this stage.

That the MWP was warmer than today?

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mann's phony graph was for northern hemisphere, i'm surprised you didn't know that.

The graph which has been confirmed by multiple global proxies. Not phony by any normal definition, not your kind of phony at least.

Br Cornelius

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Would you care to share the data used for this graph?? Or at least a sorce for the graph.

it looks very much like Lamb's graph from the 60s, which was the accepted state of affairs until mann flattened it out using dodgy methods and data.

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it looks very much like Lamb's graph from the 60s, which was the accepted state of affairs until mann flattened it out using dodgy methods and data.

Thats why its been duplicated by independent teams - because they all use dodgy stats :tu:

NH_Temp_Reconstruction.gif

PS- Atu , you should read that Wiki page you misreferenced, its quite educational and clearly refutes all of the critiques of the hockey stick graph.

Br Cornelius

Edited by Br Cornelius

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Man was a causative agent in both the Medieval warm period and the Roman warm period.

Methane is an important greenhouse gas that is emitted from multiple natural and anthropogenic sources. Atmospheric methane concentrations have varied on a number of timescales in the past, but what has caused these variations is not always well understood1, 2, 3, 4, 5, 6, 7, 8. The different sources and sinks of methane have specific isotopic signatures, and the isotopic composition of methane can therefore help to identify the environmental drivers of variations in atmospheric methane concentrations9. Here we present high-resolution carbon isotope data (δ13C content) for methane from two ice cores from Greenland for the past two millennia. We find that the δ13C content underwent pronounced centennial-scale variations between 100 bc and ad 1600. With the help of two-box model calculations, we show that the centennial-scale variations in isotope ratios can be attributed to changes in pyrogenic and biogenic sources. We find correlations between these source changes and both natural climate variability—such as the Medieval Climate Anomaly and the Little Ice Age—and changes in human population and land use, such as the decline of the Roman empire and the Han dynasty, and the population expansion during the medieval period.

http://www.nature.co...NATURE-20121004

Across Europe in the early Bronze age man virtually clear felled the native forest and caused a significant change in climate as a consequence. Mans population has ebbed and flowed ever since and the climate has responded in sympathy with his population and its effects on forest cover and land use. man has been a significant influence on global climate since he invented civilization and the agricultural land use changes it brought with it. Climate has also been effected by the resurgence of forestry as mans population has crashed at various times of plague.

AGW is not new, and the signs are there for all to read - the only difference about the current era is the shear scale of land use change and the massive release of geologically stored carbon which has never happened before in mans history. This fact alone means that we are entering uncharted territory.

Br Cornelius

Edited by Br Cornelius
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Man was a causative agent in both the Medieval warm period and the Roman warm period.

http://www.nature.co...NATURE-20121004

Across Europe in the early Bronze age man virtually clear felled the native forest and caused a significant change in climate as a consequence. Mans population has ebbed and flowed ever since and the climate has responded in sympathy with his population and its effects on forest cover and land use. man has been a significant influence on global climate since he invented civilization and the agricultural land use changes it brought with it. Climate has also been effected by the resurgence of forestry as mans population has crashed at various times of plague.

AGW is not new, and the signs are there for all to read - the only difference about the current era is the shear scale of land use change and the massive release of geologically stored carbon which has never happened before in mans history. This fact alone means that we are entering uncharted territory.

Br Cornelius

that paper is a perfect example of bad science, moreover to quote and misquote something like that shows a preference for the political method over the scientific method.

http://wattsupwithth...climate-change/

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that paper is a perfect example of bad science, moreover to quote and misquote something like that shows a preference for the political method over the scientific method.

http://wattsupwithth...climate-change/

I have read the critiques of that paper but find them to be mere hand waving.

That is just one paper which links past climate to mans activities. I personally think it is significantly underestimated since the current estimates of population in the Americas in precolumbian times are vastly understimated. Archeological evidence shows that significant areas of the Amazon were clear felled in pre-Columbian times and the population then crashed in post Columbian times, making an uncalculated contribution to the Medieval Warm period and Little Ice age.

Br Cornelius

Edited by Br Cornelius
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I have read the critiques of that paper but find them to be mere hand waving.

That is just one paper which links past climate to mans activities. I personally think it is significantly underestimated since the current estimates of population in the Americas in precolumbian times are vastly understimated. Archeological evidence shows that significant areas of the Amazon were clear felled in pre-Columbian times and the population then crashed in post Columbian times, making an uncalculated contribution to the Medieval Warm period and Little Ice age.

Br Cornelius

is it not more plausible that warmer climates lead to thriving civilisations and colder conditions lead to their decline, at least in times of primitive technology. in other words, confusing cause and effect (again).

this "paper" is just playing to the current agw meme, those empires only covered tiny parts of the globe, the population then was 3% of what it is today, there is no handwaving, the wattsuplink gives good reason to doubt this paper and the way it has been portrayed.

you are raising on a busted flush.

Edited by Little Fish
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The amount of land use change throughout mans history accounts for the ebb and flow of huge areas of forest, causing massive flows of carbon and methane.

There would also be an interplay with natural climate cycles which caused famine and plague.

This is based on atmospheric measurements so it is strongly reasoned. The two significant historic warm periods were caused by man.

Br Cornelius

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It lost me completely when it called radar a weather manipulation tool.

Br Cornelius

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A very interesting article about how we are playing with fire in unnecessarily shifting climate even a bit. As we shift the climate we massively increase the chances of catastrophic shifts in continental scale weather systems;

"

Gradualist arguments have assumed that Man could adapt to the effects of slow global warming, with the associated rising of sea levels and changes in agricultural growing patterns. It is likely, though, that earth’s climate does not change in such gentle rhythms. A better model than the gradualist one might be plate tectonics, where stress generally surfaces in the form of earthquakes, rather than gradual motion and shifting.

The evolutionary record is littered with sudden mass extinctions of dominant species. Often these extinctions have been caused largely by rapid climate shifts to which species were unable to adapt. And it has generally been the most dominant species that were the most vulnerable, because their dominance was based on their particular successful adaptation to the existing conditions.

The earth will always survive catastrophic change. So, too will Life. There have been past extinctions when 90% of all species died; the few that were left then repopulated the planet. This was the case with the rise of mammals, after the end-Cretaceous extinction of the dinosaurs.

Man has become dominant across Earth in a time of narrow climatic range, particularly since the Neolithic revolution, the rise of agriculture. Agriculture has allowed the remarkable exponential population increase of the past 5,000 years, relying upon a few crops that are adapted to the current climate - such as wheat, rice and corn. The daily newspaper provides many examples of the effects of normal climatic fluctuations upon Man’s food supply, (e.g. Ethiopia and North Korea) especially when "abnormal" climate is coupled with social instabilities.

Such climate fluctuations and social instabilities are only likely to increase with the coming man-made climate change.

To take, as illustration, two of several possible examples of Man’s vulnerability:

Population distribution: Upwards of one-third of the human population lives in coastal areas that would be threatened by rising sea-level. This is roughly 2 billion people. How long would it take to move this many people inland and create infrastructures capable of support?

Agriculture: Humanity has already overextended its food resources. Crops cannot pack up and move as people can. It may be possible in the gradualist scenarios that people could slowly change their agricultural patterns over time to accord with changed temperature or rainfall. It is doubtful that this could happen very successfully in a situation where there was radical change in a decade. Further, most of the world survives not based upon agri-business, but rather on settled, subsistence farming whose strength rests on the farmers having a long-developed understanding of their land and crops. Sudden change would negate this understanding.

A small-scale example of man’s inability to adjust to climate change can be seen in the steady desertification of much of the Sahel in Africa, where the Sahara has been advancing. This has led to severe dislocation, starvation and social instability. The climatic oscillations outlined above would be far more widespread and devastating than anything witnessed in Africa.

In sum, what has been called the gloom-and-doom warnings of the long-term effects of global warming may actually turn out to have been optimistic. The future could well be far more catastrophic than is generally projected."

http://dieoff.org/page127.htm

Br Cornelius

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More evidence for mans long history of changing the climate;

"

It’s a common misconception that the human impact on climate began with the large-scale burning of coal and oil in the industrial era,” says Julia Pongratz of the Carnegie Institution’s Department of Global Ecology, lead author of a new study on the impact of historical events on global climate published in the January 20, 2011, online issue of The Holocene. “Actually, humans started to influence the environment thousands of years ago by changing the vegetation cover of the Earth‘s landscapes when we cleared forests for agriculture.”

Clearing forests releases carbon dioxide into the atmosphere when the trees and other vegetation are burned or when they decay. The rise in atmospheric carbon dioxide resulting from deforestation is recognizable in ice cores from Greenland and Antarctica before the fossil-fuel era.

.......

But human history has had its ups and downs. During high-mortality events, such as wars and plagues, large areas of croplands and pastures have been abandoned and forests have re-grown, absorbing carbon dioxide from the atmosphere.

Pongratz decided to see how much effect these events could have had on the overall trend of rising carbon dioxide levels. Working with colleagues at the Max Planck Institute for Meteorology in Germany and with global ecologist Ken Caldeira at Carnegie, she compiled a detailed reconstruction of global land cover over the time period from 800 AD to present and used a global climate-carbon cycle model to track the impact of land use changes on global climate. Pongratz was particularly interested in four major events in which large regions were depopulated: the Mongol invasions in Asia (1200-1380), the Black Death in Europe (1347-1400), the conquest of the Americas (1519-1700), and the Fall of the Ming Dynasty in China (1600-1650).

“We found that during the short events such as the Black Death and the Ming Dynasty collapse, the forest re-growth wasn’t enough to overcome the emissions from decaying material in the soil,” says Pongratz. “But during the longer-lasting ones like the Mongol invasion and the conquest of the Americas there was enough time for the forests to re-grow and absorb significant amounts of carbon.”

The global impact of forest re-growth in even the long-lasting events was diminished by the continued clearing of forests elsewhere in the world. But in the case of the Mongol invasions, which had the biggest impact of the four events studied, re-growth on depopulated lands stockpiled nearly 700 million tons of carbon absorbed from the atmosphere. This is equivalent to the world’s total annual demand for gasoline today.

"

http://carnegiescien...ing_co2_buildup

Br Cornelius

Edited by Br Cornelius

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From the grand-daddy of the theory;

Forest clearing

Agriculture emerged around the eastern Mediterranean some 11,000 years ago, then shortly afterwards in China, and several thousand years later in the Americas. Farming can release greenhouse gases in various ways: clearing forests liberates lots of stored carbon as the wood rots or is burned, for instance, while flooded rice paddies release methane just as wetlands do.

To find out more about early farming, Ruddiman began to dig around in studies of agricultural history. These revealed that there was a sharp rise in rice cultivation in Asia around 5000 years ago, with the practice spreading across China and south-east Asia. Here at least was a possible source for the unexpected methane rise.

In Europe, people had begun clearing forests to grow cereal crops such as barley and wheat 7500 years ago (see graphic). There is no firm figure for the total extent of this forest clearance, but Ruddiman says it could have been vast. One pointer to this is the Domesday Book, which documents the 11th century census of England ordered by William the Conqueror. "There were 1.5 million people and they had cleared 85% of the forest," Ruddiman says.

http://climatechangepsychology.blogspot.ie/2008/09/william-ruddiman-and-ice-age-that-never.html

Br Cornelius

"

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Collapse of the native American population after Columbus caused Little Ice Age;

"

Recovery of forests following the collapse of human populations in the Americas after the arrival of Europeans may have driven the period of global cooling from 1500-1750 known as the Little Ice Age, report researchers speaking at the annual meeting of the American Geophysical Union in San Francisco.

By some estimates, diseases introduced by Europeans may have killed more than 90 percent of population on the New World within a century of first contact. The rapid depopulation led to large-scale abandonment, and subsequent reforestation, of agricultural lands in the Americas. Analyzing charcoal found in soils and lake sediments at sites across the Americas, Richard Nevle and Dennis Bird found evidence to suggest that this forest regeneration sequestered enough carbon to trigger global cooling.

"We estimate that the amount of carbon sequestered in the growing forests was about 10 to 50 percent of the total carbon that would have needed to come out of the atmosphere and oceans at that time to account for the observed changes in carbon dioxide concentrations," said Nevle, a visiting scholar in the Department of Geological and Environmental Sciences at Stanford.

.....

The researchers say their data lines up better with the historic climate record than other theories proposed to explain the Little Ice Age, including changes in sunlight and an increase in volcanic activity in the late 16th century.

Br Cornelius

Edited by Br Cornelius

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I have read the critiques of that paper but find them to be mere hand waving.

That is just one paper which links past climate to mans activities. I personally think it is significantly underestimated since the current estimates of population in the Americas in precolumbian times are vastly understimated. Archeological evidence shows that significant areas of the Amazon were clear felled in pre-Columbian times and the population then crashed in post Columbian times, making an uncalculated contribution to the Medieval Warm period and Little Ice age.

Br Cornelius

The idea that clearing of forest land was a major contributor to past warming/cooling needs a little work. It ignores the fact that when trees are cut, the land is revegetated almost immediately (Full canopy closure following slash-and-burn in the Amazon takes only four years; in America, cutover sites have to be replanted to pine in the first year, or oak sprouts take the site.). It also ignores the fact that most of Europe's type-conversion occurred during the eighteenth century; America followed along about a hundred years behind, when global temperatures were dropping (The low-point was in 1909.). Most warming has occurred since 1909.

Doug

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The idea that clearing of forest land was a major contributor to past warming/cooling needs a little work. It ignores the fact that when trees are cut, the land is revegetated almost immediately (Full canopy closure following slash-and-burn in the Amazon takes only four years; in America, cutover sites have to be replanted to pine in the first year, or oak sprouts take the site.). It also ignores the fact that most of Europe's type-conversion occurred during the eighteenth century; America followed along about a hundred years behind, when global temperatures were dropping (The low-point was in 1909.). Most warming has occurred since 1909.

Doug

The history of the South American agricultural civilizations shows they clear felled and mainted clear areas of forest for long periods. They were highly sophisticated agriculturalists and not like the slash and burn farmers we see there now. This fact has been almost lost because the regrowth of apparently "pristine" rainforest was so comprehensive that it left almost no traces of the agricultural civilizations remains that came before . These facts are attested to be analysis of subtle differences in forest composition and soil profile across vast regions of the rainforest. It is estimated that there is virtually no area of South American forest which has not been cleared at some time by man.

The same is true of stone age Europe. Ireland's native scots pine forest was driven to extinction by the early neolithic farmers, and this was long term and stable land use change as they converted vast areas of land to enclosed field systems. These were abandoned when they helped cause significant climate change on the west coast which favoured peat bog formation and the field systems now lie burried more than 6meters down in peat bogs.

The Céide Fields in county Mayo attests to the change brought about by neolithic farmers. It is commonly said that no stone in Ireland hasn't been touched by the hands of man, and there is are no pristine wild space and there hasn't been for many thousands of years.

Mans ability to change his environment has been vastly underestimated. These changes in land use help to account for some of the climate vriability which have been characturized as the Roman Warm Period, the Medieval Warm period and the Little Ice age. I think you are behind the curve on this one Doug.

Br Cornelius

Edited by Br Cornelius

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The same is true of stone age Europe. Ireland's native scots pine forest was driven to extinction by the early neolithic farmers, and this was long term and stable land use change as they converted vast areas of land to enclosed field systems

Scots pine is an early-successional stage tree. Climax species suppress it. The existence of an old-growth stand of Scots pine is evidence of a previous land-clearing disaster, usually a fire.

I'm not saying that didn't happen, but I wonder about the assumptions made by these articles.

Doug

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Scots pine is an early-successional stage tree. Climax species suppress it. The existence of an old-growth stand of Scots pine is evidence of a previous land-clearing disaster, usually a fire.

I'm not saying that didn't happen, but I wonder about the assumptions made by these articles.

Doug

My point is that increasingly it is shown that man makes prefound changes to his environment through agricultural practices at a very early stage of his development. He has been shown to be very wasteful of natural resources when they are abundant and this shows up in both the maginitude and isotopic profile of atmospheric gases in ice cores. It is only in the very recent archeological analysis that these significant land use changes are becoming evident and the main land use changes happened in the very earlist neolithic periods.

Br Cornelius

Edited by Br Cornelius

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ok, so why do the solar activity proxies match very well with past temperature reconstructions, i'm sure everyone agrees that it would be idiotic to suggest that myans and romans had an influence on the sun's activity, or does the agenda driven unfalsifiable han-roman-myan hypothesis just assume this is all coincidence:

http://upload.wikime..._labels.svg.png

http://upload.wikime...0_years.svg.png

http://cyclesresearc...11000-yr-sm.png

you're now raising on a busted flush whilst jumping the shark.

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