Vulnerability, Impacts and Adaptation of Coastal Zones to Global Change - Vulnerability of Coastal Ecosystems and Adaptation - page 157

ecosystems can have repercussions on marine food systems and
constitute a threat to the health of local and regional communities,
affecting many activities, including tourism. Nevertheless,
encouraging progress has been made to control and reduce the
presence of persistent organic pollutants, radioactive substances, oil
pollution and oil spills.
The construction of dams and other infrastructures on drainage
basins and coastal plains, on a global scale, has reduced significantly
the transport of sediments into coastal zones. This sediment deficit
intensifies coastal erosion and threatens ecosystems, in particular
mangroves. The large-scale extraction of sand, gravel or pebbles from
rivers, estuaries and coastal zones for the building sector often
contributes to coastal erosion.
4.5. Vulnerabilities of humans and natural coastal systems
A system's vulnerability to climate change depends on present and
future impacts and on its capacity to adapt. When considering the
vulnerability of human coastal systems, its three components,
described in section 4.1.1, should be considered. The third component,
namely the institutional, legislative, judicial and cultural activities, is
essential to promote the climate change adaptive capacity that will be
analyzed in section 4.6. The impacts on the first component - built
environment, transport and industrial infrastructures and port
facilities - result mainly from flooding, from land loss due to GMSL
rise and from damage caused by extreme weather events, such as
tropical cyclones and strong extratropical storms, heavy rains, extreme
drought and heat waves. All these climate factors also have impacts on
health, the availability of freshwater water and the food security of
coastal populations.
The vulnerability of coastal anthroposystems to climate change is
also increasing due to non-climate factors, such as, population growth,
urbanization and high rates of subsidence caused by human activities
in several low elevation coastal regions, in particular the deltas of the
Nile, the Ganges and the Mekong. Projections based on socio-
economic scenarios indicate that the global population exposed to a