Observations provided by the historical, archaeological, and palaeontological records, together with paleoclimatic data, demonstrate that climatic variability has high potential to affect biodiversity and human society . The evolution of the Earth's biota has been punctuated by global biodiversity crises often triggered by rapid warming  . These so-called hyperthermal events were marked by rapid warming of >1℃, which coincided with global disturbances of the carbon and water cycles, and by reduced oxygen and pH in seawater . Magnitudes of global temperature shifts in hyperthermal events were sometimes greater than those predicted for the current century but extended over longer periods of time. Rates inferred from paleo records that are coarsely resolved are inevitably lower than those from direct observations during recent decades, and caution must be exercised when describing the rate of recent temperature changes as unprecedented . Mass extinctions, each with greater than 70% marine species extinctions, occurred when the magnitude of temperature change exceeded 5.2℃ , albeit species extinctions occurred at lower magnitudes of warming .
IPCC
Climate Change 2022: Impacts, Adaptation and Vulnerability
IPCC Report