Climate Change in Areas of the Gulf of Mexico With High Freshwater Input – A Review of Impacts and Potential Mitigation

Abstract

The Gulf of Mexico currently spans the transition from tropical to temperate coastal ecosystems but this is changing as the northern Gulf undergoes tropicalization and the entire Gulf will become tropical in this century. The objective of this paper was to review information on climate change impacts on coastal ecosystems with high freshwater input for the Gulf of Mexico and review mitigation measures for dealing with climate change. There are two high freshwater discharge areas, one surrounding the Mississippi River in the north central Gulf and one in the southern Gulf, which is associated with the Grijalva-Usumacinta River and adjacent rivers and ground water discharge from the Yucatan Peninsula. Both of these areas are characterized by extensive coastal wetlands, and in the southern Gulf, submerged aquatic vegetation. These coastal ecosystems support important natural resources, have high petroleum production, and important maritime trade. Climate change will impact both of these areas strongly. Sea level is projected to increase by a meter or more by 2100 and there will be more strong hurricanes that will be larger, have more intense rainfall, will move slower, and the rate of intensification will increase. In the north, peak Mississippi River discharge is projected to increase by 10 to 60%. In the southern Gulf, it is projected that precipitation and freshwater discharge will decrease associated with the Mesoamerican climate hotspot. Coastal management to accommodate climate change should mimic ecosystem functioning. Specific actions include protection of natural areas, full use of freshwater and sediment resources, maintain con-nections between freshwater input and coastal systems, allow inland migration of coastal wetlands, and careful management of land use changes. Keywords: Gulf of Mexico, climate change impacts, coastal ecossytems.