Direct astronomical influence on abrupt climate variability

Changes in the magnitude of millennial-scale climate variability (MCV) during Late Pleistocene occur as a function changing background state over tens thousands years, an indirect consequence slowly varying incoming solar radiation associated with changes Earth’s orbit. However, whether astronomical forcing can stimulate MCV directly (without change state) remains to be determined. Here we use comprehensive fully coupled model demonstrate that orbitally driven insolation alone give rise spontaneous oscillations under intermediate glacial conditions. Our results abrupt transition from warm interstadial cold stadial conditions triggered by precession-controlled increase low-latitude boreal summer and/or obliquity-controlled decrease high-latitude mean annual insolation, modulating North Atlantic hydroclimate sea ice–ocean–atmosphere interactions, respectively. Furthermore, contrasting effects tropical versus subpolar Atlantic, exerted obliquity or precession, result oscillatory regime, even within otherwise stable climate. With additional sensitivity experiments different glacial–interglacial backgrounds, synthesize coherent theoretical framework for stability, elaborating direct and (dual) control orbital cycles on Pleistocene. Millennial-scale arise relatively states, according analysis high- proxy records well modelling.