Coastal regionalization of mexican coasts in response to global climate change

Category Geomorphology
Group GSI.IR
Location International Geological Congress,oslo 2008
Author Nava-Sanchez, Enrique H.; Martinez-Flores, Guillermo; Murillo-Jimenez, Janette M.; Godinez-Orta, Lucio
Holding Date 08 September 2008

The Mexican coast exhibits a high diversity of environments in response to geologic, oceanographic and atmospheric processes, whose activity varies along the coasts. The Pacific coast is highly related to tectonism, which favors the development of a steep topography with some narrow coastal plains, whereas the Atlantic coast and Caribbean, presents low and plain relief, with a coastline dominated by storm surges, sea currents, and sea level changes, associated to climate changes of short and long period. The present work analyzes changes that could experience the littoral of Mexican coastal environments, as a result of climate change and its effect on coastal morphodynamics. A coastal regionalization was made considering a set of variables: (1) geomorphological: forms and processes involved in the evolution of the coastal zone and drainage basins; (2) geological: lithology, tectonic activity and subsidence; (3) climatic: precipitation and winds associated with storms and tropical cyclones; and (4) oceanographical: waves, tides and currents. From these variables the most important to consider for regionalization was the geomorphology. The identified coastal regions are, on the Pacific: (1) Pacific Coast of Baja California peninsula, (2) Eastern Coast of Baja California peninsula, (3) Coastal Plain of the Gulf of California, (4) Southwestern Cost of the Pacific, and (5) Chiapaneca Coastal Plain. On the Atlantic coast the regions are the (6) Northern Plain of the Gulf of Mexico, (7) Veracruzana Coast, (8) Southern Plain of the Gulf of Mexico, (9) Yucateca Coast, and (10) Mexican Caribbean Coast. The processes that are directly related to the climatic changes that threaten the coastal populations are: sea level rise, variations of the fluvial discharge to the coast, and increase of the coastal erosion. Effects of sea level rise on the coasts are: (1) floods, (2) sandy beach and barrier erosion, (3) fluvial flood of coastal plains, and (4) increase of salinity of estuaries and aquifers. In general, these processes will have larger effects on wetlands and low coasts (deltaic and lagoonal zones), environments that dominate the Atlantic coast; the Pacific coast will be less affected except by the Chiapaneca and Gulf of California coastal plains. The southern Pacific and Atlantic coasts of Mexico will be affected by the increment on frequency and energy of tropical cyclones, with catastrophic precipitations that vary in space and time.