Some factors that contribute to the growth of coastal cities are as follows: 

Urbanization: Nowadays, about 54% of the world population lives in urban areas. According to the United Nations, of all the current 7.7 billion inhabitants, 40% live within 100 km of the coast. That is 3.08 billion people living in coastal areas and a market of1.66 billion people incoming to a coastal city. 

‍Population growth: The current world population of 7.7 billion people is expected to increase to 9.7 billion by 2050; this means a 2 billion increase in population. At current rates, there will be an extra 800 million people depending on innovative coastal developments. 

Productivity: Coastal environments are the ones that contribute most to a country's economy. This drives the increasing demand for coastal land and reclaimed land. Innovation in the traditional land reclamation systems has high potential to contribute to the location's productivity where it is implanted. ‍

Migrations: The World Bank estimates that the percentage of the global population living in coastal areas could reach 50% or higher by 2050. Nowadays, at today's population, it is 40%.Moreover, inequalities regarding employment opportunities, especially between the northern and southern hemispheres, make northern countries desirable destinations for many migrants. 

Tourism industry: Worldwide, at2016 levels, the world was experiencing a tourism population of over 1.2billion visitors per year. Cities like New York itself host about 60 million visitors a year. This industry increases land demands to absorb this temporary but constant population. 

City Sprawl: The sprawl of cities uses land that provides ecosystem services such as wetlands to combat sea-level rise or forests for climate adaptation. In a coastal city, the threshold between land and sea pushes growth more intensively towards the mainland.