Although fire is considered an important factor in global vegetation evolution and climate change, few high-resolution Miocene fire records have been obtained worldwide. 

Recently, two independent micro-charcoal–based fire records from the northern Tibetan Plateau were analyzed; both show similar trends in micro-charcoal concentrations through time, with low abundances in the warmer Middle Miocene Climate Optimum (18–14 Ma) followed by a continuous increase throughout the late Miocene (14–5 Ma) cooling.  

Scientists' detailed statistical analyses show that the micro-charcoal concentration trend is highly positively correlated to the trend in oxygen isotopes (δ¹⁸O, r = 0.94) and xerophytic species (%_Xero, r = 0.95).  

Scientists propose that the intensified fire frequency on the Tibetan Plateau mainly originated from the forest-steppe ecotone as a result of the continuous aridification in winter driven by the global cooling and decreased atmospheric pCO₂ that occurred during 18–5 Ma, with a secondary control by the tectonic activity of the northern Tibetan Plateau. 

The study entitled “Miocene fire intensification linked to continuous aridification on the Tibetan Plateau” was published in Geology.