The link is here Modulation of Ice Ages via Precession and Dust-Albedo Feedbacks.
His earlier paper was discussed – Albedo regulation of Ice Ages, with no CO2 feedbacks. And on a related subject I posted – Some climate sanity after Paris COP21 blabfest – drawing attention to The book “The Chilling Stars” by Henrik Svensmark & Nigel Calder sums up 12,000 years of Holocene cosmic & solar driven “climate change” in the North Atlantic. Ralph tells me he is in touch with Henrik Svensmark.
Paper Abstract
We present here a simple and novel proposal for the modulation and rhythm of ice ages and interglacials during the late Pleistocene. While the standard Milankovitch-precession theory fails to explain the long intervals between interglacials, these can be accounted for by a novel forcing and feedback system involving CO2, dust and albedo. During the glacial period, the high albedo of the northern ice sheets drives down global temperatures and CO2 concentrations, despite subsequent precessional forcing maxima. Over the following millennia CO2 is sequestered in the oceans and atmospheric concentrations eventually reach a critical minima of about 200 ppm, which causes a die-back of temperate and boreal forests and grasslands, especially at high altitude. The ensuing soil erosion generates dust storms, resulting in increased dust deposition and lower albedo on the northern ice sheets. As northern hemisphere insolation increases during the next Milankovitch cycle, the dust-laden ice-sheets absorb considerably more insolation and undergo rapid melting, which forces the climate into an interglacial period. The proposed mechanism is simple, robust, and comprehensive in its scope, and its key elements are well supported by empirical evidence.
Gail Coombs has posted an informative comment at my first blog article on Ralphs work –
www.warwickhughes.com/blog/?p=4019
I hope it is OK to reprint her comment here – see how it comes out –
A link to Ralph Ellis’s paper was just posted at another blog. I read the paper, finding the link to dust intriging. I do however have a few points Ralph Ellis might wish to consider.
#1. Since the northern hemisphere, especially at high latitudes, is the critical factor, the Greenland ice cores are more appropriate when looking at the effect of decreasing solar insolation during the Holocene. Unlike the Antarctic ice cores, the Greenland and other northern temperature proxies show an accelerated decrease in temperature during the last few thousand years with an overall decrease of ~ 3C. (1) (2) (3) (4) (5)
Modern warm period
#2. Warwick Hughes has very kindly posted information written by Dr. Zbigniew Jaworowski (6). Lucy Skywalker has also posted information by Jaworowski and others.(7) The long and short of it is the CO2 record as now accepted by establishment science is as tainted by politics as the temperature record. CO2 was never as low as the air bubbles in the ice cores show because the CO2 migrated out of the air bubbles into the water within the ice structure. Whole samples of crush ice yield much higher results. (C3 plants like trees starve at 220 ppm. This number too was ‘adjusted’ to fit the political narrative with carefully contrived studies as support.)
#3. This does not however negate dust as a major forcing. Instead of plants dying because of straight CO2 starvation they die due to drought, exacerbated by the low levels of CO2. C4 plants evolved to deal with this duall stress. Thus the Wisconsin Ice Age had major deserts (8)
EUROPE –Europe had a large ice sheet covering Scandinavea, then steppe-tundra – dry, cold climates a bit further south and in southern Europe, a dry, almost semi-desert steppe.
ASIA — Central Asia had a large area of extreme desert conditions surrounded by semi-desert. Siberia was much more arid than today, with steppe-tundra and polar desert Ice masses were found in north-western Siberia.
NORTH AMERICA — Alaska was a polar desert extending across the far north of Canada to the southern edge of Greenland. In the USA and Canada the southern edge of the ice sheet was mostly tundra, dry tundra or semi desert.
SOUTH AMERICA — South America had temperate desert and semi-desert, mainly in the south.
AFRICA — Africa was about half extreme desert surrounded by a strip of semi-desert. Much of the rest was grassland followed by savanna
AUSTRALIA — Central Australia was a large area of extreme desert with drifting sand dunes surrounded by semi-desert. To the north was grasslands. A land bridge connected Australia and New Guinea; this was apparently covered in open grasslands or scrub.
This landscape especially as the Great Year headed toward summer and those northern deserts thawed a bit produced plenty of dust.
#4. What is quite interesting is the switch from the dusty Wisconsin Ice Age to a non-dusty Holocene happened within a few years according to Dr. Richard B. Alley. This would indicate a major switch in climate possibly having to do with the oceans warming/increased solar insolation/monsoons rains suddenly encouraging plant growth. One only has to see a desert after a rain to understand how quickly the change can happen.. (9)
Dr. Richard B. Alley observations:
“‘You did not need to be a trained ice core observer to see this,’ recalled Alley. ‘Ken Taylor is sitting there with the ECM and he’s running along and his green line is going wee, wee, wee, wee – Boing! Weep! Woop! And then it stays down.’ Dust in the windy ice age atmosphere lowered the acidity of the core to a completely new state. ‘We’re just standing there and he just draws a picture of it,”‘Alley said.”
…and then it was Alley’s turn at the ice. “It slides across in front of me and I’m trying to identify years: ‘That’s a year, that’s a year and that’s a year, and – woops, that one’s only half as thick.’ And it’s sitting there just looking at you. And there’s a huge change in the appearance of the ice, it goes from being clear to being not clear, having a lot of dust.”
FROM:
Climate Crash: Abrupt Climate Change and What it Means for our Future by John D. Cox, (John Henry Press, an imprint of the National Academies Press, ISBN: 0-309-54565-X, 224 pages, 2005),
REFERENCES:
(1) climate.envsci.rutgers.edu/robock/MillerArctic.pdf
(2) adsabs.harvard.edu/abs/2007AGUFMPP11A0203F
(3) www.sciencedirect.com/science/article/pii/S0033589411001256
(4) www.sott.net/article/279874-The-End-Holocene
(5) edmhdotme.wordpress.com/2015/06/01/the-holocene-context-for-anthropogenic-global-warming-2/
(6) www.warwickhughes.com/icecore/
(7) www.greenworldtrust.org.uk/Science/Scientific/CO2-ice-HS.htm
(8) www.esd.ornl.gov/projects/qen/nerc.html#maps
(9)Monsoons
www.sciencemag.org/content/308/5723/854.abstract
hol.sagepub.com/content/23/8/1123.abstract
www.sciencemag.org/content/324/5925/377.abstract
Wazsah. Thanks for you comments, which I will try to answer.
>>#1. Greenland ice cores are more appropriate
>>when looking at the effect of decreasing solar
>>insolation during the Holocene.
Yes, and no. Unfortunately, the Greenland cores only go back 100 kyrs, so they only contain one interglacial. So if you are looking for trends and cycles, you have to use the Antarctic cores.
.
>>C3 plants like trees starve at 220 ppm.
Not sure about that. The study we used claimed that the critical CO2 concentration was 150 – 160 ppm. This is why we invoked upland regions, where the CO2 concentration is lower. And surprisingly, in my fig 11 the upland land area at 160 ppm equivalent, suits the vegetation models very closely. We end up with about 30% die-back of global flora, which is enough to generate the observed dust levels.
.
>>Instead of plants dying because of straight CO2
>>starvation they die due to drought
But if you look at my fig 7, which is an average of all the paleoclimatic models, there was no massive drought. But yes, C3 plants do need more moisture in low CO2 conditions, so moisture may have been a contributing factor.
.
>>the switch from the dusty Wisconsin Ice Age to
>>a non-dusty Holocene happened within a few years
>>according to Dr. Richard B. Alley
The regrowth was caused by the increase in CO2. As soon as the CO2 increased, the plants regenerated, and the dust immediately stopped. It seems quite clear from this, that CO2 was the controlling agent of dust.
Cheers,
Ralph