A recent paper by IPCC lead author Kevin Trenberth and Aiguo Dai:
Effects of Mount Pinatubo volcanic eruption on the hydrological cycle as an analog of geoengineering
suggests that there would be adverse effects, including drought, as a result of the use of geoengineering in order to offset greenhouse warming:
Abstract
The problem of global warming arises from the buildup of greenhouse gases such as carbon dioxide from burning of fossil fuels and other human activities that change the composition of the atmosphere and alter outgoing longwave radiation (OLR). One geoengineering solution being proposed is to reduce the incoming sunshine by emulating a volcanic eruption. In between the incoming solar radiation and the OLR is the entire weather and climate system and the hydrological cycle. The precipitation and streamflow records from 1950 to 2004 are examined for the effects of volcanic eruptions from El Chichón in March 1982 and Pinatubo in June 1991, taking into account changes from El Niño-Southern Oscillation. Following the eruption of Mount Pinatubo in June 1991 there was a substantial decrease in precipitation over land and a record decrease in runoff and river discharge into the ocean from October 1991–September 1992. The results suggest that major adverse effects, including drought, could arise from geoengineering solutions.
Jennifer Marohasy BSc PhD is a critical thinker with expertise in the scientific method.
The assumption that CO2 is a greenhouse gas (an oxymoron of the more subtle type) and thus traps heat has not been experimentally verified.
Hence this paper, which is based on this speculation, is equally a speculation.
Greenhouses work because of the principle of the interposition of a different physical phase between the radiator and the energy sink, space.
In a garden greenhouse the glass shell stops therma convection.
In the case of the earth, it is the physical presence of suspended water, (AKA clouds) that stops heat from escaping to space.
Go live in a desert, (as I do), to verify this.
As Nigel Calder said, we are simply being lied to.
Leaving the greenhouse question aside, the paper suggests that cooling the planet via geoengineering isn’t a good idea due to the effect on the weather, climate and hydrological cycle.
Louis,
the heat trapping effect of CO2 is well acknowledged, including by Paul Biggs. Maybe you should as him for the details. Denying such a basic fact of science that has been known and understood for over 100 years makes you look like a bit of a dill.
What of char in soil? Maybe you’ve dealt with it – haven’t been keeping up, bin busy taming brumbies
I’m not sure that ‘heat-trapping’ is the correct phrase, given that ‘greenhouse’ is a misnomer, as the atmopshere doesn’t behave like a greenhouse. I see the attraction of the terms for explanations to Joe public.
Personally, I don’t tend to argue about the greenhouse effect, or the enhanced greenhouse effect, just the magnitude of the enhancement, which I believe is small and not the driver of climate change.
Meanwhile, the search for an IPCC explanation of how increased CO2 results in increased temperature goes on:
http://www.climateaudit.org/?p=1851#more-1851
Even going back to IPCC 1990 is no help.
It’s not a question of what you believe – belief isn’t that scientific. Evidence is the issue.
So besides the physical theory, you have empirical measurement with radiometers, verification of spectral windows closing from space, and paleo studies.
Of course a glass barrier greenhouse isn’t correct as an analogy – recycling of longwave radiation is the issue – and sly fox Louis well knows this – I wonder why on clear nights with no clouds that the temperature doesn’t sink to -30C Louis ?
BTW it’s all still there Louis – “hand grenades indeed”
http://web.archive.org/web/20060403033506/http://lhcrazyworld.blogspot.com
http://web.archive.org/web/20050316020351/http://mangledthoughts.com/index.php?p=1736
The ‘evidence’ is what my belief is based on. Big warming is based on circumstantial evidence, climate models and theoretical calculations.
Circumstantial?
Pinxi must have had some time to watch Catalyst on ABC
http://www.abc.net.au/catalyst/stories/s2012892.htm
Char (trash burning as we know it) has become an essential part of modern Australian forestry.
I don’t reckon this is a note from Luke. All we have is an abstract.
I don’t know what is meant by geoengineering.
Luke needs to tell us what the paper is about and what geoengineering is about?
And Louis, it is a bit boring to keep harping on about what is and is not a greenhouse gas. I have heard all that stuff before from you… but what is geoengineering?
Jennifer: but what is geoengineering?
howz this
http://nwtasmania.yourguide.com.au/detail.asp?class=news&subclass=general&story_id=1042341&category=general
I was just wondering what happened to our wind factory
Planetary scale engineering – i.e. technology whereby pundits have suggested we “somehow” pump a whole bunch of reflective aerosols into the atmosphere to cool the planet. (Not my idea).
Thanks. Now why won’t it work?
its much more likely the big picture will include us trying alfoil everywhere to control ST and energy transfer, radiation barriers like we once had with floating ice
porous plastic coated space blankets floating all round the briny hey
No Gavin, build our cities on water, especially in the tropical doldrums where clouds are few. Instant change from 3.5% albedo of ocean to 95% albedo for reflective roof top.
Char has also been a core output from cold fires, as produced by firestick farming and controlled burning. IT IS NOT PRODUCED BY HOT, EPA SPONSORED WILDFIRES.
Quite right Ian. For donkey’s years, some of us have been pointing out that the charcoal produced by frequent, mild burning is a significant way to sequester carbon, and improve soil fertility. The humus role is less important in Australia, although some academics still have their minds stuck in that bag.
In the ABC Quantum program I heard the distinct sound of academics leaping onto the band-wagon, following work by Lehmann on the ‘terra preta de Indio’ in Brazil. Even Pinxi must have noticed the thunder of academic boots. We will hear much more of this “amazing breakthrough”, especially now Tim Flannery is involved.
For interest, I quote from an early visitor to Perth. “The streets are of sand, mixed with charcoal, from the repeated burning of the scrub, which formerly covered the ground…” James Backhouse, 1843.
And an early botanist. “These seeds or involucres, were dug up when sinking a well on the alluvial banks of the Swan River, they were mixed with charcoal, for charcoal is invariably found in the alluvial deposits of the rivers in this country, to a depth which seems to prove that the present race of natives or others having a similar habit of annually burning the country must have inhabited these districts for a much longer period than can be ascertained by any sort of people, not excepting the Chinese.” James Drummond, 1845.
It seems Aboriginal people were engaged in widespread ‘geo-engineering’, but they put charcoal into the soil, as well as smoke into the air. There are still some academics advising politicians that frequent burning is totally bad, and we should exclude fire for decades from National Parks. We know the inevitable result. Some things take a long time to sink in, especially when there is a torrent of ideological misinformation, some in supposedly ‘refereed journals’.
A search on Google Scholar under ‘biochar’ or ‘charcoal’ will reveal considerable research on the topic. Look for Zackrisson, DeLuca, Scott, Lehmann, Sombroek, Mikan and Liang, amongst others.
Geoengineering?
I had not realised so many courtiers from King Canute’s time are re-incarnated here.
The biosphere is an epiphenomenon of the earth and it its geological processes that determine our fate – not use trying to control those processes, which we really can’t.
As for harping on a particular topic – it seems that a lie repeated often enough finally gets accepted as truth.
C’est la vie.
“Why isn’t it a good idea ” asks Jen.
Coz:
“It’s well known that particles thrown into the atmosphere by volcanic eruptions cause a global cooling effect by reflecting back sunlight.
In the case of Mount Pinatubo, global temperatures dropped by an average of 0.9 degrees Fahrenheit (0.5 degrees Celsius) the following year. But until now, no one had been able to pin down the effect that these volcanoes might have had on rainfall.
By carrying out statistical analysis on rainfall and streamflow records, the researchers were able to detect a significant drying effect after Mount Pinatubo’s eruption.
There was less rainfall over land, and a record decrease in runoff and ocean discharge into the ocean from October 1991 to September 1992, the scientists report this week in the journal Geophysical Research Letters.
It’s not clear why the sulfur particles reduce rainfall, but the team has a theory.
“First the particles block out the sun and cool off the land, making the rain move over the oceans,” Trenberth said.
“Then they cool off the oceans—and that reduces evaporation and thus global precipitation.”
In the case of the Agung and El Chichón eruptions, there was no detectable reduction in global precipitation. That’s probably because these volcanoes didn’t have quite as much oomph as Mount Pinatubo, experts say.
The findings should ring alarm bells for those considering pumping sulfur into the skies—and creating a solar shield—as a solution to global warming, the researchers warned. (Get the basics on global warming.)
“Our results suggest that major adverse effects, including drought, could arise from such ‘geoengineering’ solutions,” Trenberth said.
Not everyone agrees that these findings rule out a solar shield. ” .. ..
More at http://news.nationalgeographic.com/news/2007/08/070817-volcano-warming_2.html
“Geo” means “earth” so geoengineering is a bit of a malapropism, eg geofabric is material used to contain earth.
But what the heck, these cyber warriors wouldnt know a bee from a bulls foot.
Geology is the science and study of the solid matter that constitute the Earth, a geologist studies geology and geotechnology is the science and engineering of soil, rock, and the fluids they contain.
Great – time for a diversionary dust up with Rog. Always fun.
Wiki says:
Earth science (also known as geoscience, the geosciences or the Earth Sciences), is an all-embracing term for the sciences related to the planet Earth. It is arguably a special case in planetary science, being the only known life-bearing planet. There are both reductionist and holistic approaches to Earth science. The major historic disciplines use physics, geology, geography, METEOROLOGY, mathematics, chemistry and biology to build a quantitative understanding of the principal areas or spheres of the Earth system.
http://en.wikipedia.org/wiki/Earth_Sciences
Of course it may have been doctored by right wing extremists. What does Britannica say?
http://www.abc.net.au/news/stories/2007/08/24/2013984.htm
Of course the correct term is terraforming:
The terraforming (literally, “Earth-shaping”) of a planet, moon, or other body is the hypothetical process of deliberately modifying its atmosphere, temperature, or ecology to be similar to those of Earth in order to make it habitable by humans. The term is sometimes used broadly as a synonym for planetary engineering in general.
http://en.wikipedia.org/wiki/Terraforming
Although we know that right wing extremists aka denialist fascist nazi types that inhabit this blog actually want to undertake veneraforming – make Earth more like Venus ! That’s veneraforming Rog not VD.
“theoretical calculations” says Paul Biggs.
Theoretical calculations are what powers 99% of current science, IMHO. Are you yearning for the days long gone of purely empirical science?
Paul
at least we agree on that. The whole issue of “deniers” is true, I think, as long as people such as Louise continually restate the patently false as fact. The real issue is, what will the magnitude of warming be due to the greenhouse/enhanced greenhouse effect. If we can at least all move on to that stage of the debate, it will be much more rational.
The evidence is growing for the precipitation process having control over climate sensitivity to CO2 – a sort of planetary thermostat that prevents runaway warming – otherwise the earth would have been either very hot, or very cold due to CO2 in the past – it wasn’t . The IPCC will need to revise downwards their upper estimates of climate sensitivity to CO2.
I have a new, submitted climate sensitivity paper in my possession, based on AR4, which is on the low side.
Talking of the IPCC, a submitted paper has tested the IPCC consensus of WG1 scientists, with a survey:
18% said that IPCC AR4 WG1 overstates the role of CO2, 17% said the role of CO2 was underestimated, the remaining 65% agreed to some extent with AR4 WG1, the largest group, 47% were largely in agreement with AR4 WG1. Around 97% agreed that anthropogenic CO2 is an important part of the climate system, and had contributed to some extent to the observed average global warming.
I’ll do a more detailed post on this if/when the paper is published.
Paul,
Not being mischievous (well, only slightly) but I suspect a survey of wise ones in Ye Middle Ages would have found that 99.99% thought the Sun went around the Earth, and the Earth was a flat disk. If they thought otherwise, they probably didn’t dare say so.
There is a big difference in the two situations being referred to. One was opinion based on ignorance, one is opinion based on scientific research.
Well, yes – consensus isn’t proof, but it’s interesting nevertheless, the conclusion can be drawn that the relative role of CO2 compared to other human influences is an open scientific question, and a significant minority (15-20%) think the role of anthropogenic CO2 is exaggerated by the IPCC.
So we’re now having “survey driven science” ? Jeez. Let’s have some surveys on what we all think of medical science perhaps. Anyone can play.
“Then they cool off the oceans—and that reduces evaporation and thus global precipitation.”
Good. So we are agreed that warming is a good thing in general.
If you don’t actually ask the individual scientists involved in the IPCC what their views are, then claims of consensus are based on the views of a few lead authors.
Anyway Luke, the paper has a well known blogging, pro-AGW climate modeller as one of the authors.
‘the Earth was a flat disk’ – Davey Gam
The invention of the myth that everyone in the Middle Ages thought the Earth was flat can be laid at the feet of Washington Irving and his popular novel, The Life and Voyages of Christopher Columbus, published in 1828.
Respected western scholars of the Middle Ages such as Clement, Origen, Ambrose, Augustine, Isodore, Albertus Magnus and Aquinas all accepted the Earth was a globe nor did they consider the matter to be in doubt. The few fringe writers who suggested otherwise, like Cosmas Indicopleustes were derided as uneducated. Islamic scholars of the period such as Ibn Hazm, Ibn al-Jawzi, Ibn Khaldun, Ibn Abbas and Ibn Taymiya were also agreed that the planet was a globe.
The Mappa Mundi and the manuscript of Macrobius’s commentary on the Dream of Scipio, amongst many other sources all show the earth as a globe and the most influential astronomy textbook of the 13th century and required reading by students in all Western European universities was titled, On the Sphere of the World.
In view of the number of Creationists still around today, the misconception that the Sun went around the Earth is not so surprising….
“Wiki says”
bit like “Simon says”
peer reviewed hmmm?
Fact is the argument is based on bogan terminology, Lukes strong suit.
another Californian buzz word, ‘holistic’
Wiki says:
Bogan (pronounced /ˈbəʉ.gn̩/, rhyming with slogan) is Australian and New Zealand English slang, usually pejorative, for a person who is, or is perceived to be uncouth, unsophisticated or of a lower-class background. According to the stereotype, the speech and mannerisms of “bogans” indicate poor education and uncultured upbringing. ‘Bogans’ usually reside in economically disadvantaged suburbs (often outer metropolitan) or rural areas.
Well I guess Rog would be more likely to be a an old bodgie.
Wiki says:
Bodgies and Widgies refer to a youth subculture that existed in Australia and New Zealand in the 1950s, similar to the Teddy Boy culture in the UK or Greaser culture in the US.
The males were called Bodgies and the females were called Widgies. Bodgies were well-known for their often loutish behaviour. On February 1, 1951 the Sydney Morning Herald wrote on its front page:
What with “bodgies” growing their hair long and getting around in satin shirts, and “weegies” cutting their hair short and wearing jeans, confusion seems to be arising about the sex of some Australian adolescents.[1].
Wiki says, Wiki says..
..everybody is talking Wiki
http://wikiscanner.virgil.gr/
Well,
As everyone in the AGW camp knows, the CO2 molecule orients itself in the direction of gravity–so that these molecules allow the Sun’s radiation into Earth’s gravity well, but don’t allow Earth to let the heat back out into space.
These molecules are so powerful that even when human emissions of CO2 comprise 0.00125 percent of the atmosphere, they are able to prevent the next Ice Age.
Which is impending. NASA amended its heat tables, and it turns out, the “hot time” was back in the 1930s.
Will CO2 save us from the “cold death” of civilizations which are near to the poles? Those who complain of too many humans on the planet would be glad of death on such a wide scale.
“orients itself in the direction of gravity” – heheheheheheheheheeeeee hehehe ehehehehe heeh hehehe
Oh ROTFL to the max – yes is that right?
“they are able to prevent the next Ice Age” …
Yes grasshopper – CO2 molecule is big heapum powerful magic. Interestingly 0.00125 is also the amount of grey matter in Schilly’s cranium.
“Back in 1930s” … Ahem .. and now ? January this year had the largest positive temperature anomaly every observed for the globe. That is, “global” warming peaked this year.
“Civilisations which are near the poles ” – like the great penguin civilisation .. .. .. hehehehehehehehehe heheh ROTFL again.
Luke,
I am not entirely convinced that ROTFL is a cogent response to NASA’s correction of temperature data, nor that the acronym you offer disproves the (in)ability of CO2 molecules to selectively heat the Earth.
But, since you consider ROTFL to be convincing, I will say ROTFL to you.
Now we are all convinced, on your measure of convincingness.
Not.
Schillsbo – you crack me up. I don’t anyone who could pen so much utter stupidity in such a small space. An all time classic. Louis is an amateur compared to you.
Anyway all jokes aside – the real non-sepo world doesn’t care if you guys have found a 0.02C problem in your weather station. You’re all smoking too much hooch anyway.
January this year had the largest positive temperature anomaly every observed for the globe. That is, “global” warming peaked this year.
Schiller
once again, you refuse to argue science or engage in rational debate. Derision is your only stock in trade. It’s a complete waste of time and I wonder why you bother. Luke provides numerous references to scientific literature, but it is completely ignored by you.
SJT,
I mention the revisions to NASA’s dataset, Luke responds with ROTFL, but you say *I’m* the derisive one.
I guess this means there must be derisive datasets, but credible kiddie-acronyms.
You’ve convinced me. You might imagine what you’ve convinced me *of*.
What 0.03C on the previous? And only for the USA. – take a hike Schillsbo. But I’d rather talk about your CO2 gravity ideas. Wow !
IS there a graph of the average temperature anomaly for Australia over the last 20 years or so?
I ask because it is becoming more and more apparent that the US anomalies are caused at least in part by non compliance with WMO, siting and exposure of meteorological instrument specifications.
Aus temperature network is uncontaminated by such concerns, and would serve as an excellent stand alone test case of the relevance of the world figures.
http://www.bom.gov.au/cgi-bin/silo/reg/cli_chg/timeseries.cgi?variable=tmean®ion=aus&season=0112
The Australian Annual Mean Temperature Anomoly
Talk of “geoengineering” to mitigate the so-called greenhouse effect of anthropogenic CO2 and other trace gases reminds me of Mr.Bean’s disastrous attempts to conceal the effects of his sneeze on ‘Whistler’s Mother”.
‘Gaud’ help us all.
“Geoengineering” also makes me wonder. We can’t do anything to stop CO2 being created, but we have the assumed ability to stop the effects of CO2.
Schiller, Luke provides much scientific evidence, then when he responds to your irrelevant prattle in kind, you pull him up for it. Maybe you could try responding to the serious posts he puts up in a serious way.
Now I get it, ‘geoengineering” is Lukes brainwave, his precious few minutes of fame and he is defending down to his last milliamp.
Nice to see Lukes mob come to man the fort but fact is its made of straw. Should make good compost.
That’s right Rog – repent and amend your CO2 consumption lest thee perish in God’s greenhouse hellfire.
check out the brief treatment of the char in soil idea (gav linked to catalyst). Even tim flannery said he can’t fault the idea. I’m sure the bigger brains here can though.
Here is an effect of increased CO2 which is worth considering.
http://www.aihw.gov.au/mortality/data/life_expectancy.cfm
On char – well you have to do the whole of life cycle numbers – collection of material, processing, distribution, burial. Do we have ’em? I suspect it’s not “intense” enough. So the char bit might be OK but how much CO2 to run around and do it all. Interesting though.
Particularly interesting is the dip in life expectancy for older people during the cold snap from 1960 to 1974, then the steady rise afterward.
I mean compare the two graphs.
http://www.aihw.gov.au/mortality/data/life_expectancy.cfm
Scroll down til you get to Figure 1: Expected length of life at birth and at 65 years, by sex, Australia, 1901-1910 to 2000. Then click on The Australian Annual Mean Temperature Anomoly
http://www.bom.gov.au/cgi-bin/silo/reg/cli_chg/timeseries.cgi?variable=tmean®ion=aus&season=0112
You know how the map of Africa and South America look like they fit together? Same thing here.
Perhaps the true urgency of global warming is to avoid extended payouts to pensioners.
“Geoengineering not the answer to global warming”
Really? I thought all the AGW greenie-whoppers wanted us to change the atmosphere and the biosphere.
Hunh. What’s left? Sand and gravel?
Lamna Nasus,
If I can squeeze a word in. I found your historical note interesting. I stand corrected on Ye Medieval Wise Ones. But how did they know it was a globe? Pretty good thinking, given their lack of technical support. Might you launch a thread on environmental history? I love that stuff. Could be a good basis for any attempts at ‘geoengineering’. In fact, probably essential. Thanks.
P.S. Lamna, Is ‘creationism’ accepted as a ‘consensus’, only challeneged by ‘denialists’?
Davey
we have always had extremely intelligent people throughout history, they just didn’t always have the infrastructure and institutions to do what we are capable of today behind them. I remember reading about one ancient mathematician who deduce that the earth was round and the earth orbited the sun by using the most basic instrument, a stick stuck in the ground and observing it’s the shadow it cast.
You thought wrong, again. Maybe you could just listen and think for a change.
Dave: I wonder if the ancient Greeks had a problem like we have today with modern fires in parts of the Mediterranean
Gavin,
I don’t think so. One new element in Greece is, I believe, eucalyptus plantations. Also, in the past Greek villagers burnt more often for agricultural and pastoral purposes, and gathered leaf matter for animal bedding. Urbanisation has reduced that, as village life declines, so fuels have built up.
The Israeli ecologist Naveh has described the past role of regular burning by shepherds in the eastern Mediterranean lands. He claims that the Bible and Talmud mention the prevalence of fire at least 30 times with 15 different species and types, and in connection with forests 6 times.
In the late 1950s there were anti-terrorist (EOKA) operations in the Cyprus mountains. A large fire killed 19 people. The army blamed escaping terrorists, EOKA blamed army mortar bombs. The real cause was the suppression of traditional maquis burning by shepherds, so the government could plant pines. ‘Geoengineering’?
Virgil, in the Aeneid described ‘the scattered fires, set by the shepherds in the woods, when the wind is right’.
I am sure the ancient Greeks did have trouble with immature, bossy people like SJT. At least Luke is witty, and occasionally funny.
Gavin,
I have just dug out a reference. Liacos, L.G. (1973) Present Studies and History of Burning in Greece, Proceedings of Tall Timbers Fire Ecology Conference, Tallahassee, Florida. He, too, quotes from Virgil (Georgics) “Often, too, it has been useful to fire barren fields, and burn the light stubble in crackling flames; whether it be that the earth derives thence hidden strength and rich nutriment, or that in the flame every taint is baked out and the useless moisture sweats from it, or that the heat opens fresh paths and loosens hidden pores, by which the sap may reach the tender blades, or that rather hardens the soil and narrows the gaping veins, that so the searching showers may not harm, or the blazing sun’s fierce tyranny wither it, or North wind’s piercing cold.”
Sounds like geoengineering to me. Was there contact between Ancient Greeks, Romans, and Aborigines? Could be a new book for Tim Flannery.
Dave; some interesting links, note I was tracking blue gum again
Eucalyptus – EU studies
.
http://www.blt.bmlfuw.gv.at/vero/veroeff/0797_Eucalypt_introduction_e.pdf
Forest litter – obliqua
http://www.blackwell-synergy.com/doi/abs/10.1046/j.1440-169x.1999.00988.x?journalCode=aec
Gavin,
There is a well written article by Oliver Rackham ‘Fire in the European Mediterranean’ (Aridlands Newsletter No 54. Nov/Dec 2003). It is available on-line, free of charge. Oliver mentions village depopulation as a cause of recent fierce fires. The villagers were ‘geoengineers’ through stubble burning, shepherding etc.
Dave: I don’t entirely buy Pyne and co on this issue. We always had these levels of fire including the distant past is perhaps itself a bit of a myth based on the hope somebody can get it all back under control if only they had the authority. It’s much more likely when every body had a go with lighting fires, kids and all there wasn’t a lot left to burn in critical areas where people lived.
http://europa.eu/rapid/pressReleasesAction.do?reference=IP/05/1050
Maybe those past fire programs had more to do with frightening wild animals than resolving fuel issues. Also it’s highly likely they spread hot charcoal scratching for cooked food and that accidentally had some good impacts on soils.
Dave: one thing I have learned is we can instinctively light fires to create havoc. These days with overcrowding in urban areas fires become another form of vandalism but in rural areas it’s even more of an escape for the isolated. Hot weather like cold weather is depressing.
I think we are getting more of the hotter extremes and that’s a bait for arsonists. Frequency of this form of anti social behavior is probably on a par with natural summer wildfires now. Expect a double whammy every where in the dusty regions.
Gavin,
I think Steve Pyne would agree that when people burnt more often, there was less fuel to burn, so fires were milder. Seems obvious to you and me, but there are muddle-headed academics in Australia who say that fires have become more frequent AND fiercer. Have you read Steve’s ‘Brief History of Fire’? Humans have been ‘geoengineering’ with fire for thousands of years.
Davey and Gavin – on your theme surf-out:
How Did Humans First Alter Global Climate?
A bold new hypothesis suggests that our ancestors’ farming practices kicked off global warming thousands of years before we started burning coal and driving cars
By William F. Ruddiman
http://courses.eas.ualberta.ca/eas457/Ruddiman2003.pdf
http://www.realclimate.org/index.php/archives/2005/12/early-anthropocene-hyppothesis/
http://en.wikipedia.org/wiki/William_Ruddiman
And some informed dissent: – it’s never that simple
http://www.americanscientist.org/template/BookReviewTypeDetail/assetid/49607;jsessionid=baa9VN8tQp3jvv
Thanks Luke: I was blissfully unaware of the Ruddiman hypothesis and the RC debate.
One issue I have with any of these arguments is the NH influence. Also; our SH history starts with Cook.
The 8000 BP time line seems easy enough. I began asking about significant local events related to obvious signs say 15000-8000 years ago after guessing the age of tools, middens and occupied caves adjacent to Bass Strait.
I took a punt in the early 70’s on a long inland occupation in the rugged SW with out evidence just thinking through cultural changes that must have taken place related to sea levels fire and ice. I think it was our museum that noticed an absence of scale fish in the reports on local diets. Whatever it triggered an interest in rates of change and erosion.
My land lord tried using the tools he and his father found on the farm fringes. Early forest clearing had caused major landslides in the heads of gullies that changed streams. We had our own time lines right down to fossils. At a guess hunting round there had been with and without forests. Recent forests that built bits of Melbourne could have been young a thousand years ago because it was all tall timber to the water’s edge on white settlement.
The 1940’s tool demos proved one point, all pre historic tracks had to be made with fire.
The Little Ice Age continues to be an embarrassment to the warm-mongers.
Ruddiman suggests that the outbreak of bubonic plague (mid 1300s AD) caused farm abandonment which caused forest regrowth which caused a decrease in concentration of atmospheric CO2 (I’m not sure if this is true) which caused the Little Ice Age.
Apart from the leaps of logic and non sequiturs, the beginning of Little Ice Age predates the great bubonic pandemic by about 50 years.
Ruddiman’s proposition that the agricultural practices of relatively small human populations thousands of years ago could have altered the global climate is too far fetched to be credible – far more likely that the warming climate facilitated the development and spread of agriculture.
Thanks Luke,
What a constructive fellow you are. The Ruddiman idea is interesting, but I believe the human population was very small just after the last Great Ice Age. Their activities in forest clearing, ploughing, farting etc. might have been minuscule. However, I don’t have hard data, so will keep an open mind.
Now fire, that’s another kettle of fish. One human can burn thousands of hectares. A few thousand Nyoongars, with some help from lightning, managed to burn millions of hectares of forest and woodland on a three year cycle. Geoengineering on the grand scale.