In the Philippines, CI collaborated with partners to conduct a climate change vulnerability assessment of the Verde Island Passage (VIP), focused specifically on marine and coastal areas. The 1.14 million-hectare VIP is part of the Sulu-Sulawesi Seascape and located within the globally significant Coral Triangle, an area considered the center of the world's marine biodiversity. As such, VIP has a wealth of coastal marine resources including highly diverse coral reefs, mangrove forests and seagrass meadows. The abundant fish and another marine life support over 1.7 million people living in coastal areas in the provinces surrounding the Passage, whose livelihoods include fishing, aquaculture, and tourism.
The vulnerability assessment identified the main climate change impacts that will be felt in the Verde Island Passage, as well as the consequences of those impacts and the recommendations for adaptation:
Climate change impacts
- Changes in sea surface temperature: Sea surface temperature varies among years, but an increase of 0.06°C/decade over the last 100 years and 0.2°C/decade for the past 20 years has been observed. Increases are most pronounced in bays with low circulation.
- Changes in sea level rise: As sea water temperature increases, it expands, resulting in sea level rise. Over the last five years, sea level surrounding the Verde Island Passage has been increasing at 0.5 to 1.0 mm per year.
- Changes in storm frequency and intensity: Between 1952 and 2008, 160 typhoons passed within 200 km of the Verde Island Passage. With increasing sea surface temperatures, predictions are that the number and intensity of storms are likely to increase.
- Changes in rainfall patterns: Rainfall shows high variability in the Verde Island Passage, but a general increase has been recorded in the region.
- Changes in ocean acidification: As the ocean absorbs the excess carbon dioxide (CO2) from emissions released into the atmosphere, the acidity of the ocean increases.
Consequences of those impacts
- Many fish species are predicted to be pushed farther offshore due to increased sea surface temperature. In addition, higher temperatures will reduce upwelling, resulting in lower ocean productivity and food for pelagic fish species
- Fish larvae development will be reduced by increasing sea surface temperature and loss of mangrove habitat. Those impacts, exacerbated by salinity changes from sea level rise and increased rainfall, are predicted to reduce fish production by 13-20%
- Rising sea surface temperature will increase coral bleaching and mortality. A loss of 3-20% in live hard coral cover is expected
- Ocean acidification will have a negative effect on coral growth and cause reef degradation which will be enhanced by increases in storm events
- Loss of coral diversity, growth, and cover may occur offshore due to sea level rise, and inshore due to detrimental effects on water quality from increased rainfall
- Destruction of mangrove forests is likely to result from increased storm events and decreased seedling production, survivorship, and regeneration of mangroves, leading to forest degradation, may result from increased sea surface temperature and
- Sea level rise and increased rainfall may result in seagrass loss due to light limitation, both in deep and shallow areas
- Extreme heat stress from increased sea surface temperature may impede seagrass growth and reproduction and increased storm intensity and rainfall can cause physical removal and burial of seagrass in sediment runoff, as well as affect salinity, causing shifts to more tolerant seagrass species
- Damage to fishing infrastructure such as boats, fishing equipment, aquaculture ponds, and seaweed farms are likely from increased intensity of storms
- A reduced inshore fish harvest, especially impacting municipal fishers, is likely with degradation of seagrass and mangrove habitats resulting from increased sea surface temperature, sea level rise, and rainfall. A reduced finfish harvest resulting from declining fish populations and diversity may lead to possible food shortages
- Reduced tourism and livelihood may result from coral reef degradation, and loss of charismatic species and inshore habitats as a result of all aspects of climate change
- Entire villages may be damaged and flooded with serious consequences for human safety and property loss due to sea level rise and an increase in rainfall and storm frequency and intensity
- Increased storms and flooding due to sea level rise may result in destruction of tourist boats and coastal results and cause interruptions to commercial operations, causing a loss of production and livelihood
- More vector-borne diseases and toxic algal blooms are likely to result from increased sea surface temperature as well as increased flooding from sea level rise, and increased rainfall and storm events
- More frequent flooding may contribute to pollution from industry and water contamination from wastewater
- Saltwater intrusion and flooding caused by sea level rise and increased rainfall and storm events may degrade agricultural lands and aquaculture ponds and affect freshwater availability
- Reduced marine snails and bivalves available for harvest may result from increased ocean acidification, affecting their growth and ability to build shells, thereby negatively affecting food availability
Recommendations for adaptation
- Review existing national and local policies, programs and plans to ensure that they include strategies to address climate change impacts and incorporate ecosystem monitoring and evaluation
- Use best management practices for fishing on coral reefs, seagrass beds, and mangrove forests, and increased enforcement against illegal and destructive practices (e.g. dynamite fishing, push nets)
- Establish marine protected areas (MPA) to reduce current impacts, preserve biodiversity, and sustain fisheries, increasing the resilience and adaptive capacity of marine ecosystems to address current future climate change impacts
- Protect natural mangroves, seagrass, and coral habitats that act as natural coastal defence mechanisms, reducing erosional processes and buffering storms and other extreme weather events
- Diversify livelihood opportunities of coastal resources-dependent communities to reduce climate change vulnerability and promote sustainable practices
- Implement more aggressive enforcement and regulation strategies to prevent illegal and destructive practices, including blast fishing, cyanide fishing, and shark fin fishing.
DOWNLOAD: Climate Change Vulnerability Assessment for the Verde Island Passage