With Speed and Violence Fred Pearce - Global Commons Institute

any case, seemed at first to be minor local curiosities confined to the last
glaciation, and therefore of no relevance to modern climate. But Bond had a
hunch that the two were linked in some way, and that they had a global
significance. Both, he noted, appeared to coincide with other climate
changes, such as the advances and retreat of glaciers in Europe and North
America. Like the Younger Dryas event and the climate flip 8,200 years ago,
they seemed either to push the world into a different climate mode or to be
part of such a process. Down the corridor, Bond's buddy Broecker was on
hand to suggest a possible link to the ocean conveyor. The story began to
take on a life of its own. But first the pair needed evidence to back up their
hunch.
Bond began to re-examine trays of sediment cores from the bed of the
North Atlantic that were assembled in his New York archive. Some were old
cores, taken years before by the Lamont-Doherty research vessel Verna from
beneath the waters off Ireland and the channel between Greenland and
Iceland. Others were new, drilled off Newfoundland under Bond's
supervision.
As expected, Bond found further evidence of Heinrich's rock fragments
roughly every 8,000 years or so through the last glaciation. But the marine
sediment cores also revealed lesser layers of materials normally alien to the
seabed of the North Atlantic. Most exciting of all, these lesser layers
occurred roughly every 1,500 years, and appeared to coincide with the cold
phase of the Dansgaard-Oeschger cycle in the Greenland ice cores. This was
pay dirt. Doubly so when it became clear that the iceberg armadas of the
Heinrich events occurred during unusually cold phases of the
Dansgaard-Oeschger cycle. The pattern seemed to involve a large Heinrich