For the Heinrich events, the melting of the Laurentide ice sheet is thought to be the culprit. For the Bond events, Mr. Bond speculated that the ice rafting was caused by the melting of the Greenland and Iceland glaciers. I don't know that either Mr. Bond or Mr. Heinrich proposed a mechanism for the melting. One popular hypothesis is variations in the planet's orbital path and axial tilt. The axial tilt right now, and for as long as humans have been aware of and studied the axial tilt is 23 1/2 degrees. But this can vary from 22.1 to 24.5 degrees. The eccentricities of the axial tilt and the degree of the elliptical nature of the planet's orbit determine how much solar radiation reaches the surface. We are fortunate (perhaps) in that in northern hemisphere winter, we are closest to the sun (more sunlight reaches the surface in the temperate zone) and farthest from the sun in northern hemisphere summer. The additional effect, which some may not immediately intuit is that in northern hemisphere winter we are moving faster, because we are closer to the sun, meaning winter does not last as long as summer, when we are moving more slowly in relation to our star--and therefore summer lasts longer.
The same is true of Mars, by the way, and it is more dramatic. Mars' orbit is more elliptical than ours, and that has been increasing over time. Relative to its entire orbit, it is closer to the sun in northern hemisphere winter, as compared to the Earth in relations to its entire orbit (in absolute terms, we get closer in northern hemisphere winter); in Martian northern hemisphere summer, Mars is much farther away from our star in both relative and absolute terms. The axial tilt of Mars is also a little more dramatic, ranging fr0m 20 to 25 degrees (relative to the plane of the ecliptic). The prevailing "wisdom" on this is that this is caused by the gigantic magma dome under the Tharsis plateau. Tharsis is home to three of the four largest volcanoes in our star system (as far as we know). Asria Mons, Pavonis Mons and Ascraeus Mons run from south-southwest to north-north east across the Tharsis plateau, with the southern rim of the Pavonis Mons caldera sitting right on the Martian equator. Just to the northwest of the Tharsis plateau is Olympus Mons, believed to be (with good reason for the belief) the largest volcano in our star system. It is a massive shield volcano, rising more than three times above the plain on which it sits than Mt. Everest does above sea level. It is over 500 kilometers across the base from southwest to northeast. (If the northeastern edge of the volcano rested on the southern suburbs of Paris, the southwestern edge would cover Bordeaux, more than 300 miles away--that's a pretty impressive hunk of rock.)
Understanding the effect of axial tilt and the varying elliptical nature of the orbital path of both planets will provide a wealth of information which can be useful in the study of climate change. One caveat, though--the magma dome beneath Tharsis and Olympus Mons many not have caused the change in the axial tilt and elliptical orbit of Mars. There is growing conviction that the hypothesis of the "Big Hit" may have been responsible (that a planetesimal hit Mars), just as a planetesimal hitting the Earth probably created our moon, and gave us our extreme axial tilt.
There is so much to understand in order to get a handle on what effects our climate.