Abstract: A computer-implemented method for estimating a quantity of gas flared at a gas flaring site includes obtaining a short-wave infrared, SWIR, estimation image of the gas flaring site. The estimation image is acquired by a spaceborne image sensor and includes pixels representing a radiation measured in the SWIR wavelength band. The estimation image is segmented by detecting pixels which represent flared gas heated atmosphere, thereby obtaining a segmented estimation image. A surface of flared gas heated atmosphere is determined based on the segmented estimation image, and the quantity of flared gas is determined based on the surface of flared gas heated atmosphere, by using a model associating surfaces of flared gas heated atmosphere with corresponding quantities of flared gas quantities.