The Mid-Pleistocene Transition (MPT) marked a shift towards extended glacial periods and amplitudes, while its underlying mechanisms are still disputed. Here, we present a new conceptual model, capable of reconstructing global ice volume over the past 2.6 Ma, including a shift in frequency and amplitude during the MPT. We find that a long-lasting, gradual trend in the Earth-climate system is most favourable in reconstructing the MPT and that it started over 2 Ma.