• Bond event

    Bond event

    • Bond events are North Atlantic ice rafting events that are tentatively linked to climate fluctuations in the Holocene. Eight such events have been identified. Bond events were previously believed to exhibit a quasi ~1,500-year cycle, but the primary period of variability is now put at ~1,000 years.

      Gerard C. Bond of the Lamont–Doherty Earth Observatory at Columbia University, was the lead author of the 1997 paper that postulated the theory of 1470-year climate cycles in the Late Pleistocene and Holocene, mainly based on petrologic tracers of drift ice in the North Atlantic. However, more recent work has shown that these tracers provide little support for 1,500-year intervals of climate change, and the reported ~1,500 ± 500-year period was a statistical artifact. Furthermore, following publication of the Greenland Ice Core Chronology 2005 (GICC05) for the North GRIP ice core, it became clear that Dansgaar-Oescher Events also show no such a pattern. The North Atlantic ice-rafting events happen to correlate with episodes of lowered lake levels in the Mid-Atlantic region, USA, the most weak events of the Asian monsoon for at least the past 9,000 years, and also correlate with most aridification events in the Middle East for the past 55,000 years (both Heinrich and Bond events).

      For reasons that are unclear, the only Holocene Bond event that has a clear temperature signal in the Greenland ice cores is the 8.2 kyr event.

      Most Bond events do not have a clear climate signal; some correspond to periods of cooling, but others are coincident with aridification in some regions.

      No. Time
      (AD, BC)
      0 ≈ −0.5 ka ≈ 1500 AD See Little Ice Age;
      1 ≈ −1.4 ka ≈ 600 AD See Migration Period;
      2 ≈ −2.8 ka ≈ 800 BC Late Bronze Age collapse may have been triggered by drought in the Eastern Mediterranean.
      3 ≈ −4.2 ka ≈ 2200 BC See 4.2 kiloyear event; collapse of the Akkadian Empire and the end of the Egyptian Old Kingdom.
      4 ≈ −5.9 ka ≈ 3900 BC See 5.9 kiloyear event;
      5 ≈ −8.2 ka ≈ 6200 BC See 8.2 kiloyear event;
      6 ≈ −9.4 ka ≈ 7400 BC Erdalen event of glacier activity in Norway, as well as with a cold event in China.
      7 ≈ −10.3 ka ≈ 8300 BC
      8 ≈ −11.1 ka ≈ 9100 BC transition from the Younger Dryas to the boreal.

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    • Bond event