Assessing the effect of climate change on upwelling ecosystems is essential to be able to predict the future of marine resources. The zones concerned by this upwelling of cold deep water, which is very rich in nutrients, provide up to 20 % of global production of fish. Since the 1990s, the theory adopted by the majority of the scientific community affirmed that these phenomena were intensifying. The rising temperatures of the air masses above the continents were expected to quicken the trade winds, which would in turn increase the upwellings, thereby cooling the surface water. But this theory has been contradicted by the recent work of researchers from the IRD and its partners.