Bond Events, Dansgaard-Oeschger events, Climate Cycles, and stuff

Pretty much everyone agrees that the warming we’ve seen over the last 130 year or so is on the order of .7C. The argument is over what caused it and where it’s going.

So then what would one make of increases, and declines, that are ten times (or more) greater and that happen in 1/10th the time (or less?) (Also see 1500 year cycles.)

WUWT have a nifty post covering some of these events and there’s more good stuff in the comments.

“Recent scientific evidence shows that major and widespread climate changes have occurred with startling speed. For example, roughly half the north Atlantic warming since the last ice age was achieved in only a decade, and it was accompanied by significant climatic changes across most of the globe. Similar events, including local warmings as large as 16°C, occurred repeatedly during the slide into and climb out of the last ice age. Human civilizations arose after those extreme, global ice-age climate jumps.”

“The new paradigm of an abruptly changing climatic system has been well established by research over the last decade, but this new thinking is little known and scarcely appreciated in the wider community of natural and social scientists and policy-makers.” (“Abrupt Climate Change – Inevitable Surprises”, Committee on Abrupt Climate Change, National Research Council of the National Academy of Sciences, 2002, ISBN: 0-309-51284-0, 244 pages, Richard B. Alley, chair.)

The rest: On “Trap-Speed”, ACC and the SNR

Vostok Ice Core, Antarctic: (click to enlarge)

 

At the recent end of the climate cycle there is the Younger Dryas event. The Earth was emerging from the last ice age, things were warming up, and the it rapidly dropped into full=blown ice age conditions for another 1200 years.

Apparently the recovery was pretty rapid, too.

What caused it? No one knows. Some have an impact hypothesis, and there’s an idea that giant glacial lakes flooded the Northern Atlantic with fresh water, cutting off all circulation, leading to the cooling. The problem is that the lake outflow seems to have been blocked by ice. From the comments:

This one has been out there for some time and keeps being repeated, but Thomas V Lowell showed that the St Lawrence River was blocked by ice during the Younger-Dryas. [Revised Deglacial Chronology of the Laurentide Ice Sheet and Implications for Catastrophic Meltwater Discharge as Triggers for Abrupt Climate Change,” Eos Trans AGU 86 (52) Fall Meet. Supple., Abstract (2005): F1234″ — This from “Sudden Cold” by climatologist Rodney Chilton (2009)]

…

A second study that involved a simulation of meltwater originating from the Laurentide Ice Sheet did not produce any appreciable meltwater during the entire 15,000 to 8,000 BP interval. [T.C. Moore (2000)]

…

The northern route at least appears to have suffered the same fate as the St. Lawrence in also being blocked by ice until well after the Younger-Dryas ended. [Thomas V. Lowell, ibid]

Fun stuff.

 

The End is Nigh

The  UK’s Royal Society, worried about the loss of major amounts of grant money, has stated that Global Warming will cause more volcanoes. Anything to increase the alarm, even if it means flushing one’s credibility. From the Telegraph:

And he warned: ”The rise you may need may be much smaller than we expect. Looking ahead at climate change, we may not need massive changes.

”One of the worries is that tiny environmental changes could have these effects.”

Hmmm…. sounds like these people belong with certain cultists. Haven’t they been DoomSaying for over 2,000 years? And with a perfect record of error (100% wrong, every time) how could we not trust the cultists this time?

(Cartoon by We Blog Cartoons.)

Guess it’s time to move off-planet into those tightly controlled moon bases the RS is (probably not) designing.

WUWT also has a few, well deserved, snarky remarks

NumberWatch has a list of a few other things caused by global warming.

The End is Nigh!

Ok, to be fair, I don’t know if it was the society that made the claim or the “scientists” publishing their papers in the Society’s journal(s.) Does the RS include a disclaimer with their published papers, such as, “This paper does not necessarily reflect the view of…”  If so, then perhaps there is some credibility left.

On volcanoes and warming – various commenters (elsewhere) have made an interesting point. Since much of the ash ejected from a volcano is from melting ice hitting the magma (with explosive results,) so then if there is no ice atop the volcano here will be a lot less ash and a less destructive explosion. Yet another reason that global warming is a good thing. Without all that ice the Iceland eruption would have been a lot less interesting.

Ok, I have new respect for the RS, given this report by a band of real loonies.

1500 Year warming Cooling Cycles

While reading some stuff on volcanoes and climate change, specifically Toba, I came across this Wiki article on Dansgaard-Oeschger events. D-O events are warming periods that appear in the Greenland ice cores. Temps warmed by as much as 8C over periods of around 40 years, then dropped again over the next couple hundred years.In the current interglacial these are referred to as Bond events.

These cycles don’t appear in the Antarctic ice cores, or if they do then they’re very subtle. This makes sense if the D-O events are caused by northern oceanic changes.

The little ice age of ~400 to 200 years ago has been interpreted by some as the cold part of a D-O cycle, putting us in a period of warming climate (Bond et al.. 1999).