Bond Cycles and the Role of The Sun in Shaping Climate
Bond cycles are defined by petrological tracers from core samples in the N Atlantic that link to the pattern of drift ice distribution. They provide a record of shifting ocean currents and winds, in particular periodic weakening of the North Atlantic current and strengthening of the Labrador current. These cycles shape what we perceive as climate change in the circum North Atlantic realm, for example the Little Ice Age and Medieval Warm Period. They leave a small mark on global average temperatures that are difficult to resolve in the proxy temperature records
Bond Cycles correlate with cosmogenic 10Be suggesting that variations in solar and terrestrial magnetic field strength somehow link to changes in atmospheric circulation and ocean currents. My favoured explanation is changes in solar spectrum that accompany changes in the magnetic field.
With tens of thousands of papers published in climate science, it is possible to pick any 50 and come up with almost whatever narrative one wants. In this post I focus on evidence from ice rafted debris (IRD) dispersed in the N Atlantic from drift ice as presented by Bond et al 2001 [1]. I like the data because it is coherent with what is known about historic climate change in the N Atlantic realm (Figure 3).
Bond Data
Glaciers entrain rocks and rock fragments from the bedrock across which they grind and when they enter the sea to become icebergs and begin to slowly melt this detritus rains down to the sea bed (see inset photo up top). This ice rafted debris (IRD) can tell us something about where the icebergs came from. If the fragments are of granite or schist then this does not tell us anything specific about the source since granite and schist is common in many bedrock areas. But if the fragments are of volcanic glass, then they can only come from Iceland in the North Atlantic realm.
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