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The main biophysical impacts of sea level rise and increased variable rainfall are increased coastal erosion, more extensive coastal inundation, higher storm surge flooding, salinisation of surface and ground waters, and loss of wetlands (cf. Second IPCC Assessment Report).

Other impacts of climate change could induce dramatic changes in water resources, energy resources – through inundation of oil-producing deltaic zones and modifications in dams inducing changes in hydropower production - and oceanic circulation, particularly upwellings, but also exacerbate drought and desertification. The main coastal ecosystems at risk are mangroves and coral reefs. Mangroves are strictly dependent on the sea level variations and also on the rainfall and salinity so it is expected that they will migrate or die if lateral shifting is not possible or if salinity is too high. However, other factors like the topography of the area but also the rate of sedimentation will be of importance in the response of mangroves to sea level rise. 

The following impacts of climate change on the main economic activities present in the coastal zones are identified by the scientific community:

  • Fisheries will be affected through the degradation/loss of ecosystems such as mangroves which act as spawning, breeding and nursing grounds for a number of fish species, and through changes in sea surface temperature and also the intensity and location of upwellings that will modify species distribution;
  • Agriculture will be affected – sometimes positively - by changes in CO2 atmospheric concentration, temperature and rainfall that will modify the geographical distribution of agro-ecological zones in relation with the sensitivity of most of the crops to climatic parameters. In the coastal zones, sea level rise will also induce a salinization of soils, surface and ground waters that will necessarily affect agricultural lands. Permanent flooding will mean a loss of agricultural lands in a number of coastal zones;
  • Coastal infrastructures (such as roads and harbours) will be at risk by sea level rise induced coastal erosion and inundation. For the same reasons coastal towns and villages will be threatened and some coastal populations will be displaced;
  • Tourism, which is mainly dependent on beaches (sun and sand), will be affected by an acceleration of coastal erosion due to sea level rise that will reduce the number of appropriate sites for beach-based tourism. Tourism infrastructure along the coast will also be impacted, as will a number of heritage sites.

These threats have been then acknowledged by the Third Assessment Report of the Intergovernmental Panel on Climate Change (IPCC), which stated that “Tropical and subtropical coastlines, particularly in areas that are already under stress from human activities, are highly susceptible to global warming impacts.”

Other GEF initiatives working in this field: