Flares for combustion of associated petroleum gas (APG) are the main sources of thermal impact on landscapes during the exploitation of oil deposits. The object of this study is the Volga–Uralian steppe region producing 22% of the volume of Russian oil, which leads to the formation of high volumes of combusted APG. Our research was aimed at identification of the real amount of active sources of APG combustion and assessment of thermal pollution of ambient landscapes. On the basis of special analysis of Landsat satellite images, 112 thermal points are detected on the key territory of 77 000 km2. It is established that one active flare increases the temperature of the surface and surface air layer by more than 8° in a radius of 30 to 350 m from the open fire. Operation of one flare results in a temperature increase over an area of 0.085 km2, on average, supporting the formation of so-called heat islands. APG combustion of 112 flares can increase the temperature in an area of >10 km2. This process leads both to heating of areas of the atmosphere and pollution of vast areas. A smoking gas trail from one flare can reach 11 km in length and can disperse up to 3 km in width spanning an area of >30 km2. The formation of areas of microclimate changes is one of the effects of APG combustion.