Detection and parameterization of forest fires is a task traditionally performed by polar-orbiting sensors, mainly advanced very high resolution radiometer (AVHRR) advanced along track scanning radiometer (AATSR), bispectral infrared detection (BIRD), and Moderate Resolution Imaging Spectroradiometer (MODIS). However, their time resolution is a problem to operate in real time. New geostationary sensors have proven their capacity for Earth observation. GOES, MSG, and MTSAT are already operative with time resolutions below 30 min. The international community feels that a real-time global observation network may become a reality, which is the aim of the Global Observations of Forest Cover and Land Cover Dynamics (GOFC/GOLD) FIRE Mapping and Monitoring program, focusing internationally on decision-making concerning research into global change. This paper shows the operation in real time by the MSG SEVIRI sensor over the Iberian Peninsula. For fire detection, a temporal gradient of temperature 3.9 ¿m is used, which is more efficient at eliminating incoming false alarms from solar reflection. Capacity to detect hot forest fires below 0.3 ha in Mediterranean latitudes has been analyzed along with the conditions in which it is possible to apply the MODIS methodology to establish the fire radiative energy (FRE) by means of experimental relation. We found that in this case, fire size can introduce maximum differences of 40% in FRE for small-scale fires. The capacity of this sensor is shown in different cases that have greatly impacted Spain and Portugal because of the loss of human life.