 However, during El Niño events, trade winds are weaker, causing decreased upwelling in the equatorial regions as the divergence of water north and south of the equator is not as strong or as prevalent.The coastal upwelling zones diminish as well since they are wind driven systems, and the wind is no longer a very strong driving force in these areas.As a result, global upwelling drastically decreases, causing a decrease in productivity as the waters are no longer receiving nutrient-rich water.