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 . I like the data because it is coherent with what is known about historic climate change in the N Atlantic realm (Figure 3).
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.
Bond et al identified 3 petrological markers from sedimentary cores from three locations in the N Atlantic. 1) detrital carbonate derived from NW Greenland, 2) hematite (iron) stained grains from NE Greenland, Svalbard and Severnaya Zemlya and 3) volcanic glass from Iceland. (Figure 1). For icebergs to make the journey to well VM29, off the coast of Ireland, then the pattern of ocean circulation and winds was clearly much different then compared with today.
Figure 1 Map from Bond et al  showing bore hole locations and their complex interpretation of shifting currents and atmospheric circulation pattern.
Figure 2 shows the style of cyclical petrological marker change at the various locations. The data may appear complex but to simplify things Bond et al produced an average stack shown as the lowermost panel in Figure 2. It is this average stack that I use as the background image in the charts below. Low values equate with little IRD and a warm N Atlantic and vice versa.
Figure 2 The various mineralogical indices from the various wells that are stacked to produce the average pattern in the bottom panel.
Bond et al interpret their data in terms of shifting ocean currents and atmospheric circulation. In particular a weakening of the North Atlantic Current, strengthening of polar winds and southwards movement of the Polar Front, all enabling a more southerly dispersion of drift ice compared with today.
Comparison with CO2 and GISP2 ice core
Global average temperature is the main historic control over atmospheric CO2, at least for the last 2.6 million years. There is no evidence for Bond cycles either varying with or causing CO2 to change (Figure 3). Thus we must concluded that Bond cycles are neither caused by changes in global average temperature; nor do they cause CO2 to vary. As already noted, Bond et al favoured cyclical changes in the pattern of ocean and atmosphere circulation. This may have periodically brought extreme cold winter conditions to Europe whilst perhaps bringing milder winters to other parts of The Globe.
Figure 3 Bond cycles compared with CO2 and historic climate cycles in Europe. While Bond et al counted 9 cycles (grey numbers starting at 0), I count 10 giving a mean cycle length of 1200 years. LIA = Little Ice Age; MWP = Medieval Warm Period; DA = Dark Ages; RWP = Roman Warm Period. There is no obvious connection between Bond Cycles and global CO2. Note that the way Bond et al plot their data, time is passing from right to left and warm is down and cold is up.
It may be expected that the forces causing changes in drift ice dispersion may also affect temperatures on Greenland. Figure 4 does indeed show cyclical change in temperature on the Greenland Summit (GISP2 ice core) with a similar pattern to that presented by Bond. There are offsets between peaks and troughs that can most likely be explained by different time scales and time scale calibrations.
Figure 4 Temperature data from the Greenland summit shows a similar pattern of cyclical variance to the Bond cycles although some peaks and troughs are offset.
10Be is a cosmogenic isotope formed in the atmosphere by the action of galactic cosmic rays on oxygen and nitrogen. Beryllium is a solid, alkaline earth element. Hence when gaseous O or N gets converted the Be falls out of the sky in precipitation.
There are two main factors that control the concentration of 10Be in snow and ice: 1) the precipitation rate and 2) the rate of production of 10Be in the atmosphere. In the following charts, the concentration of 10Be has been corrected for precipitation rate  hence the residual reflects the production rate in the atmosphere.
The combined magnetic fields of the Sun and the Earth partially shields the Earth from cosmic rays. Hence changes in the magnetic field strength, particularly of The Sun, is considered to be the main variable controlling the production rate of 10Be. Magnetic field strength also correlates with sunspot numbers, hence when we talk about low sunspot numbers, like we have right now, we are also talking about low magnetic field strength and greater exposure to cosmic rays.
Figure 5 Variations in 10Be and Bond cycles. 10Be data ref .
Figure 5 shows quite strong coherency between 10Be and the Bond Cycles suggesting that changes to The Sun’s magnetic field is somehow implicated in shaping the patterns of atmospheric and ocean currents. More on processes later.
Dansgaard–Oeschger (D-O) events are cyclical temperature excursions observed in the GISP2 ice core. If we look at a deeper / older section of GISP2 we see that 10Be also correlates with these Dansgaard–Oeschger events. But we also see many more events recognisable in the 10Be data than are obvious from the temperature record. Although closer inspection of the T record does show they are present, for example see 10Be event 15.
Figure 6 Temperature and 10Be profiles from deeper/older levels of the GISP2 ice core, same references as before. Chart from an earlier Energy Matters post [ref 4].
I count 20 D-O 10Be events in 23,ooo years giving a mean cycle length of 1150 years, remarkably similar to the duration of the Bond cycles. The solar cycle that actively changed climate in the N Atlantic during the Holocene also impacted climate during the last glacial but with much more punctuated outcomes.
The Finn Men
For those finding it hard to believe that icebergs once dispersed IRD off the west coast of Ireland, an additional strand of evidence comes from the infrequent sightings of Finn Men (Inuit) off the northern Islands of Scotland. One such Finn Man came ashore near Aberdeen around 1728 where he died shortly afterwards . His kayak and equipment are preserved in Marischal Museum (Figure 7), adjacent to where I once studied for a PhD in isotope geochemistry.
It seems reasonable to presume that the edge of the sea ice was much closer then than today and that the Finn Men got caught on drift ice and blown southwards to the northern isles where they once again took to the sea.
Figure 7 One of several 18th century Inuit kayaks that reside in Scottish museums.
The Winter of 2010
Years ago the UK public were informed by the climate science community that our children would grow up not knowing snow. But then the winter of 2010 came along and ruined the climate science script. We all got a taste of what LIA conditions might have been like with lochs and rivers freezing over that had not frozen for very many years.
Figure 8 Not a scene from The Day After Tomorrow but the UK during the winter of 2010. Image from UK Met Office.
The observed reason for the extraordinary and prolonged cold was atmospheric circulation going into reverse with arctic winds blowing across Europe from Siberia. This took place on the back of the extreme low point of solar geomagnetic activity that took place between solar cycles 23 and 24 in 2009. Coincidence? Cycle 24 has become the weakest sunspot cycle since cycle 14 in 1906.
Figure 9 Sunspot cycle 24 is to the right. Look closely and you will see how low the number got in 2009 when the sun had no spots for many months. Image from Solar Influences Data Analysis Center.
In response to Britons freezing to death, the UK MET office published a fine paper in 2011  explaining how new data showed that changes in the spectrum of energy leaving the Sun was much larger than previously known (one of these known unknowns) and they presented a computer model that showed how change in UV could drive the observed change in atmospheric circulation and account for the abnormally cold winter of 2010.
Spectral Irradiance Monitor satellite measurements indicate that variations in solar ultraviolet irradiance may be larger than previously thought. Here we drive an ocean–atmosphere climate model with ultraviolet irradiance variations based on these observations. We find that the model responds to the solar minimum with patterns in surface pressure and temperature that resemble the negative phase of the North Atlantic or Arctic Oscillation, of similar magnitude to observations. In our model, the anomalies descend through the depth of the extratropical winter atmosphere. If the updated measurements of solar ultraviolet irradiance are correct, low solar activity, as observed during recent years, drives cold winters in northern Europe and the United States, and mild winters over southern Europe and Canada, with little direct change in globally averaged temperature. 
With the culmination of solar cycle 24 fast approaching in around 2021, we will shortly discover if low solar activity does indeed cause freezing cold winters in Europe.
This post is written as a partial response to Dr Colin Summerhayes who had a guest post on Energy Matters a couple of weeks ago that stimulated much debate . Dr Summerhayes narrative was based around the notion of the Little Ice Age being the culmination of global cooling, driven by orbital geometry and subsequently reversed by the activities of Man and in particular CO2 emissions.
Insolation peaked around 11,700 years ago, melting the great North American and European ice sheets and parts of West and East Antarctica. Since then, insolation has declined (Berger and Loutre, 2002). As a result, Earth’s climate cooled over the past 10,000 years (Marcott et al., 2013; see also the PAGES 2k Consortium, 2013, for the past 2000 years). The cooling trend culminated in the Little Ice Age of 1350-1850.
Orbital calculations show that we should remain in this cold condition for the next 5,000 years (Berger and Loutre, 2002). So, why are we not still in the Little Ice Age? 
The evidence I present here suggests that the Little Ice Age was not unique and was but one of 10 similar cold events (Bond Cycles) of the Holocene brought about not by orbital geometry and its impacts on insolation but by changes to the solar magnetic field and attendant changes in solar spectrum. The subsequent warming in the North Atlantic Realm following the Little Ice Age is but one of 10 such natural warming episodes of the Holocene brought about by changes to the North Atlantic current and atmospheric circulation patterns.
I suggest therefore that there are at least three distinct drivers of climate change 1) orbital forcing of insolation, 2) solar forcing of ocean and atmosphere circulation and 3) forcing from Manmade land use changes and emissions. In order to empirically estimate the magnitude of the latter, it is important to untangle observations of the last 150 years from the solar forced Bond / D-O cycles.
 Persistent Solar Influence on North Atlantic Climate During the Holocene Gerard Bond, et al. Science 294, 2130 (2001)
 Solar forcing of winter climate variability in the Northern Hemisphere Sarah Ineson et al; NATURE GEOSCIENCE PUBLISHED ONLINE: 9 OCTOBER 2011 | DOI: 10.1038/NGEO1282
[Inset image credit of ice bergs] http://www.navcen.uscg.gov/?pageName=iipWhereDoNorthAtlanticIcebergsComeFrom