<p>Early warning of catastrophic failure in engineering rock masses remains a challenge in rock mechanic research. Rock damage processes exhibit dynamic responses in infrared radiation temperature (IRT) signals, which have become a focal point for the identification of precursors to rock failure. Here, uniaxial compression tests on sandstone specimens with IRT and acoustic emission (AE) monitoring are conducted. Cumulative crack evolution thermogram (CCET) is proposed to characterize the spatiotemporal evolution of local damage in rock specimens based on the denoising technique of IRT. The CCET under different surface failure modes of rock is analyzed. Then, an index calculated by the CCET, named heat dissipation of crack evolution (HDCE), is defined to describe the progressive failure process of rock. Based on the critical slowing down theory, the autocorrelation coefficient and variance of the HDCE are analyzed to explore the feasibility of using them as early warning indicators for rock failure. Results indicate that the HDCE under uniaxial compression exhibits distinct critical slowing characteristics, depicting the transition from stability through criticality to instability of rock. Specifically,&#xa0;the transition of the autocorrelation coefficient and variance of the HDCE from a steady to a rapid increase indicates a critical transition in the rock state, which can serve as a precursor to rock failure. Additionally,&#xa0;the variance displays an abrupt change near peak stress (<i>σ</i>_p), an imminent failure precursor. A value of 0.511 for the autocorrelation coefficient can be defined as a reference threshold for the early warning of rock failure. The identified precursors occur at approximately 74.1% of <i>σ</i>_p. This research offers new approaches for experimental studies in rock mechanics and the early warning of hazards in engineering geology.</p>