What are the consequences for nature?

According to a study conducted by VU Amsterdam university, parts of low-lying nature reserves on Bonaire – the saliñas, Lac Bay, and the islet of Little Bonaire – will become permanently flooded as a result of the rising sea level by as early as 2050. The sections below explain how climate change will impact freshwater availability, land ecosystems, coastal erosion, and marine ecosystems.

Freshwater availability

In the Caribbean region, the supply of freshwater is already limited on account of the increasing demand and changes in land use. Climate change will result in decreased rainfall and rising temperatures. This poses the risk of reducing the freshwater supply even further. Salinisation is adding to this risk. As a result of sea level rise, tidal action, waves, and storm surges, seawater is encroaching further and further inland, which is gradually salinising both the soil and the water.

Sint Maarten

Sint Maarten has two freshwater bodies: Little Bay Pond and Fresh Pond. This water is vitally important for various bird species, the fish population, molluscs, and small invertebrates. These two ponds are already affected by pollution. Changes in precipitation patterns, more severe storms, and higher temperatures would threaten their survival.

Salt lakes and caves

Climate change could also impact the salt plains and saliñas. Saliñas are salt lakes or salt bays that are closed off from the sea by a barrier of dead coral. They are important for various seagrass species, fish, crustaceans, and birds such as flamingos, terns, and sandpipers. Normally, the saliñas contain saline water, but during the rainy season, the water may turn almost fresh. Changes in precipitation patterns may compromise the volume of freshwater, which is harmful to the natural environment. Furthermore, salinisation and sea level rise may jeopardise freshwater caves, which are home to bats, shrimps, and a wide range of crustaceans.

Land ecosystems

In combination with storm surges, large differences between low and high tide, and higher waves, sea level rise can exacerbate coastal erosion. In addition, the cloud forests and rainforests of Sint Maarten, Sint Eustatius, and Saba are vulnerable to radical weather differences. Rising temperatures would cause the cloud forests of Saba and Sint Eustatius to grow higher, which would increase their exposure to extreme weather such as drought and hurricanes. This would render the lower-lying, drier areas more susceptible to wildfire. Furthermore, the islands could be at risk of a greater influx of exotic, non-indigenous plant and animal species. Indigenous species on islands are vulnerable in that respect.

Coastal erosion and marine ecosystems

Coastal and marine ecosystems are vitally important for the tourism industry. In addition, they constitute the habitat of countless animal species, and they protect the islands from damage caused by erosion, storm surges, and sea level rise.

Ocean acidification

The higher CO₂ concentration in the atmosphere is causing ocean acidification, which is jeopardising molluscs and echinoderms, such as starfish, sea urchins, and sea cucumbers. Acidification is also jeopardising coral reefs, along with the fish and other animal species that are dependent on the coral.

Disappearance of seagrass

Seagrass is vulnerable to climate change too. For example, seagrass beds are affected by rising water temperatures and by a decrease in sunlight as a result of deteriorating water quality. According to experts, the worldwide volume of seagrass beds is declining by 7 per cent a year. Across the globe, 29 per cent of all seagrasses have already disappeared.

Disappearance of coral reefs

Ocean acidification, deteriorating water quality, and rising water temperatures pose the main threats to coral reefs. According to the World Wildlife Fund, almost half of all coral has disappeared over the past thirty years. An increase in coral bleaching has already been observed. According to the IPCC, half of all coral reefs in the world could be suffering from heat stress by around 2080. By 2074, coral bleaching could become increasingly serious in the Caribbean region. Even in a low-emissions scenario, coral bleaching in the Caribbean will start by 2030. More details are provided in the Coral reef health narrative in the Climate Impact Atlas for the BES islands.

Disappearance of mangrove forests

Mangrove forests serve as the breeding and feeding ground for countless animal species. In addition, they protect against coastal erosion and storms. Normally, they are quite resilient to sea level rise, but the combination of, inter alia, climate change, urbanisation, and tourism renders them vulnerable.