Significant reduction of the Loop Current in the 21st century and its impact on the Gulf of Mexico

Abstract

This study examines the potential impact of future anthropogenic global warming on the Gulf of Mexico (GoM) by using a downscaled high‐resolution ocean model constrained with the surface forcing fields and initial and boundary conditions obtained from the IPCC‐AR4 model simulations under A1B scenario. The simulated volume transport by the Loop Current (LC) is reduced considerably by 20–25% during the 21st century, consistent with a similar rate of reduction in the Atlantic Meridional Overturning Circulation. The effect of the LC in the present climate is to warm the GoM, therefore the reduced LC and the associated weakening of the warm LC eddy have a cooling impact in the GoM, particularly in the northern basin. Due to this cooling influence, the northern GoM is characterized as the region of minimal warming. Low‐resolution models, such as the IPCC‐AR4 models, underestimate the reduction of the LC and its cooling effect, thus fail to simulate the reduced warming feature in the northern GoM. The potential implications of the reduced warming in the northern GoM on pelagic fish species and their spawning patterns are also discussed.