My study provides first evidence of the real sources of the SST-anomalies which lead to the development of El Ninos: These are hydrothermal-sources, which are located for example in the Kermadec-Tonga-Arc (e.g. in the Monowai- and Macauley-Volcanic-areas), New-Hebredes-Trench-area, Nankai-Trough- and Philippine-Plate-area, Salado-Fracture-Zone, Falkland-Agulhas-Fracture-Zone, South-West-Indian-Ridge-area, Mid-Atlantic-Ridge, LFZ, Kane-Fracture-Zone and in the Pacific-Plate east of Japan, to name the important locations. The cause of El Nino-events is hydrothermal-water that rises from submarine volcanic-areas and tectonic-fractures to the ocean-surface ! On the ocean-surface this hydrothermal-water appears in the form of growing-plumes or-blobs (sea-surface-temperature-(SST)-anomalies), which then get distributed by the main ocean-currents and by surface-currents. With the NASA-Worldview-tool an analysis of the sea-surface-temperature (SST)-anomalies was done for the time-period Oct.2021 to June 2023, and for the time-periods in which the strong El Ninos from 1997/98 and 2014-16 developed. Five areas ( 1—5 ) on the ocean-floor were found where large amounts of hydrothermal-water was rising from specific areas on the ocean-floor to the surface at irregular-intervals during the mentioned time-periods ! Note: The irregular hydrothermal-activity in these five areas is a global phenomenon !! The hydrothermal-activity comes and goes in a "wave-like-pattern", which often causes activity in 3-5 areas, which are thousands of km apart, at nearly the same time ! As an example I want to mention the period 9.12.2013 to 21.12.2013 (12 days) in which the hydrothermal-activity reached a maximum level in at least four of the five areas (1-5) in this short time-period ! Note: These areas are located in the northern- and southern-Hemisphere. Changes in Earths Magnetic-Field seem to be the main cause of this increased Hydrothermal-and Volcanic-Activity ! These changes (e.g. geomagnetic-jerks) in Earths-Magnetic-Field can be caused either by internal-processes which take place near the Core-Mantle-Boundary (CMB), or they can be caused by external-events, which are strong geomagnetic-storms caused by solar-wind (space-weather). First the geomagnetic-changes (e.g. geomagnetic-jerks) seem to increase seismicity in High-Geothermal-Flux-(HGF)-areas, then with a certain delay hydrothermal-activity, especially along tectonic-fractures, is increasing, which then rises the SST and the Ocean-Heat-Content, and finally causes El-Ninos. The key to find the hydrothermal- or volcanic-sources, which cause the strong temperature-anomalies, is the precise observation of the development of every major anomaly in an animation, from the early beginning, when the first small warm-water-blob appears on the surface ! Part-2 of my hypothesis explains the probable causes of the described "global-hydrothermal-activity" in more detail !