This Fig 3 from 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. The paper by G. Bond can be found as a pdf by googling the title -Persistent solar influence on North Atlantic climate during the holocene. The periods of iceberg armadas through the last glacial are termed Heinrich events and the warmer periods between are termed Dansgaard-Oeschger events. I wonder if these 19C reports of iceberg fleets way north of where we would now expect in southern oceans – are the tail end of the last Heinrich event.
Yes, each one of those 30-odd flips in the abundance of Atlantic ice represents a temperature change of several whole degrees. None of them anything to do with greenhouse gas concentrations.
Yet the Paris climate treaty now claims (paragraph 17 here: unfccc.int/resource/docs/2015/cop21/eng/l09.pdf) to be able to precisely target 2 degrees warming by emitting 40 billion tonnes of CO2 a year by 2030 instead of the projected 55 billion.
However, the distinguished delegates were not 100% sure of the emission level required for a rise of 1.5 degrees. So they have tasked the IPCC to tell them this by 2018.
They slipped up a bit here though, because they also asked to be told about “the impacts of global warming of 1.5 °C above pre-industrial levels” (para 21). The delegates presumably didn’t know that most of the literature suggests net BENEFITS from such a temperature. But they needn’t worry. The IPCC is sure to get the memo and find that white is “more likely than not” to be black by 2018. They’ll need some “peer reviewed science” to back it up of course. Get ready for some extremely hairy global climate impact studies over the next couple of years!
Seabed deposition from icebergs is probably the best millennial scale paleoclimate metric we have (without going into the issues with ice cores). So I find this persuasive.
And then if cloud seeding GCRs govern the climate at millennial scale, why not other cloud seeding mechanisms at shorter timescales? The automobile catalytic converter and clean air acts over the last 80 years.
Thanks for the interesting article, Warwick, it is an antidote to the continuing Climate Madness in the Media. Was the Titanic sunk by the end of a Heinrich event?
No Nicholas – strictly I think the Heinrich events were envisaged as applying to the last ice age the period prior to the Holocene which started ~12,000 yrs BP. But the concept is maybe valid to consider those late 19C southern hemisphere iceberg fleets as part of the late stage of the Little Ice Age. Re the Titanic – without refreshing my reading – they should have been aware of risks but I thought they were too proud to slow down. How common bergs were in 1911 on that track compared to now I can not say – but I expect more common. This was from 2006 – says “..said it was the closest recorded iceberg to New Zealand since 1931.”
100 icebergs only 260km off the South Island
www.nzherald.co.nz/nz/news/article.cfm?c_id=1&objectid=10409158
I had a post on it – www.warwickhughes.com/blog/?p=71
Yes, strictly speaking these are not D-O events, but much smaller modulations during the Holocene warm period. D-O events were larger than these.
My recent paper on Ice Ages in the post above this one, suggests that the primary feedback controlling interglacial warming is actually dusty-ice albedo. Because every interglacial warming, is preceded by dust storms.
In which case, a D-O event, which has a massive 10ºc warming within 10 years, could have been caused by soot on the northern glaciers – from continent-wide forest fires. Which is why it takes a few millennia before another D-O event, because a large fuel-load has be generated first.
www.warwickhughes.com/blog/?p=4179
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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.
Ralph