Climate change and urbanization are the biggest challenges to be faced by humanity. Between 1950 and 2005, global carbon emissions from fossil fuel burning increased by almost 500% while the level of urbanization increased from 29% to 49%. Urban growth is one of the main factors that cause the increase of natural habitat loss on the planet, which affects the capacity of ecosystems to meet the vital needs of millions of people, including the growing number of international migrants, who are strongly directed to urban areas. Considering the trend of intensification of the effects of climate change, this study assesses the interdependence between urbanization, climate vulnerability and environmental displacement in the megacities of the world, based on the simulation of sea level rise in megacities. Although climate change is a global issue, it is also a local concern, since urban areas play a crucial role in the climate change scenario. As migration policies and urbanization are considered separately, megacities are spaces of high vulnerability, notably given the effects of climate change, and demand the development of coordinated responses to tackle them.