**5. Conclusions**

Coasts along Northeast Brazil and northern Colombia are beautiful environments. Being popular tourist destinations as well as desirable living areas, these coasts can be very valuable economically. Tourism along the coast, particularly at sandy beaches, constitutes a large income for the two countries. The increasing of urban activities in these areas also induces to the installation of many key structures to the functioning of the urban and economic life, such as harbors. For instance, the areas are very vulnerable to numerous natural and anthropogenic stressors.

The present study showed examples of the coastal environmental degradation caused by these stressors in two areas of northeast Brazil and three areas of northern Colombia. The erosion of the beaches in Brazil and Colombia and the collapse of sea cliffs of Canoa Quebrada, Brazil, cause damage to the population, either through the alteration of marine ecosystems or through the reduction of artisanal fishing, leisure, and recreation spaces or the reduction of fishing activities, vacation, and tourism. It leads to heavy losses to economic activity, such as job losses, decrease in the income and tax generation, and real estate depreciation.

In such a context, it is necessary to better plan the occupation and uses of these coastal areas, in order to promote a sustainable development. Specifically, it is necessary to consider the fact that easterly trade wind has significant influence along the coastal area of both countries. It results in a dominating easterly approaching wave occurring over 95% of the time and then, in a unidirectional longshore transport, which has to be carefully considered in the moment to introduce equipment, structures, and housing in the shoreline. Considering that trade winds are in action in tropical areas, these findings should be applicable to many other tropical coasts.
