However:Also, by some reconstructions, the little ice age didn't end until about the year 1750, when the industrial revolution was significantly increasing CO2 emissions.
Emphazis minePre-industrial carbon dioxide levels hovered around 280 ppm until 1850.
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Exactly what is your explanation of Heinrich Events? It is obviously closely linked to the millennial cycle and both need a simultaneous explanation. My best guess is that the Labrador current gains in strength and height due to an increase in the Gulf Stream reaching the Arctic basin.The thing is we are talking about are ice rafting events off the coast of Ireland.
A lot of things have to come together for that to happen.
Besides being cold enough, the currents have to shift significantly.
Remember, a warm Gulf Current flows from the south towards Ireland/Britain.
All the evidence they found was for iceburgs from Greenland.
So, either the Gulf current would have to shift away and it'd have to be so cold that an iceburg could survive it in for a long time.
My impression is that neither of these happened during the little ice age.
The Labrador Current flows south eastward Wikipedia Labrador Current. The idea that I had would be an increase in the strength of this current due to an additional Arctic current during Heinrich Events. The size of the icebergs is also a crucial factor. Perhaps the trans-Atlantic route was not a direct one, but rather a southeast course which is then later picked up by the stronger Gulf Stream and carried northeast.Heinrich Events involved the Laurentide ice sheet and occurred relatively infrequently between 7 to 15 thousand years. Since the Laurentide ice sheet is history, we are not about to see any more Heinrich events.
These more modern 1.47K events involved the Greenland ice sheet. The last once occured around the year 597 (according to the paper).
For one to occur again, there would have to be enough ice burgs with cool enough sea temperatures for them to reach the area just east of Ireland.
Correct me if I'm wrong, but the Labrador current flows south westward doesn't it?
So, for an ice burg to get to Ireland, either the gulf current would have to cool, or it would have to shift direction so that ice burgs could travel direct.
Here we show that an intermediate-complexity climate model with glacial climate conditions simulates rapid climate shifts similar to the Dansgaard–Oeschger events with a spacing of 1,470 years when forced by periodic freshwater input into the North Atlantic Ocean in cycles of 87 and 210 years. We attribute the robust 1,470-year response time to the superposition of the two shorter cycles, together with strongly nonlinear dynamics and the long characteristic timescale of the thermohaline circulation.
This seems at odds with the above paper. The Bond cycle suggests the mechanism is independent of glacial or interglacial conditions. It's a tricky one, for sure.There is some evidence that this cycle may also be present in the Holocene
but does not trigger DO events then [Bond et al., 1997], possibly because the Atlantic ocean circulation is not close to a threshold in a warm climate [Ganopolski and Rahmstorf,2001]. The so-called ‘‘little ice age’’ of the 16th–18th century may be the most recent cold phase of this cycle. The origin of the ‘‘mystery 1,500 year cycle’’ is thus one of the key issues in climatology that needs to be explained.