In Brazil, CI collaborated with partners to conduct a climate change vulnerability assessment of the greater Discovery Coast and Abrolhos shelf region, in the Northeast of Brazil, which focused on the marine-terrestrial interface. This area includes the Abrolhos shelf and the adjacent terrestrial watersheds of the Mucuri, Doce and Jequitinhonha rivers, and harbours the largest forest remnants within the northern part of the Atlantic Forest biome, as well as the largest and richest coral reefs in the Southern Atlantic. This region supports over 500,000 people and much employment is generated from natural systems, with nearly 20,000 people relying on fisheries and another 80,000 on tourism.
The vulnerability assessment identified the main climate change impacts that will be felt in the Discovery Coast and Abrolhos shelf region, as well as the consequences of those impacts and the recommendations for adaptation:
Climate change impacts
- Changes in annual rainfall: Decrease in annual rainfall is projected for 2050 under a dry scenario, in the northeast of the study region and in the south of the study region, but an increased in annual rainfall is projected for 2050 under a wet scenario, especially in the mid-coastal basins and in the west of the study region
- Changes in sea level rise: Increase in sea level rise between 0.18 and 0.79 m, which will lead to an increase in the velocity and intensity of waves
- Changes in ocean temperatures: Increase in ocean temperatures is expected in the study region, following the global patterns
- Increase in ocean acidification: increase in ocean acidification is expected in the study region, following the global patterns
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Consequences of those impacts
- Decline in near-shore fisheries due to the negative impacts of increased ocean temperature and ocean acidification on coral reefs but a potential increase in off-shore fisheries due to the prevalence of winter-like conditions. Tens of thousands of people in the study region depend on near-shore fisheries and will be negatively impacted if climate change reduces fish populations.
- Increase in sediments delivered to reefs, especially in their shore-adjacent inner arc of those reefs, as a result of a scenario of high future rainfall. Oceanographic impacts of climate change (increased near-floor orbital velocities) will increase and prolong sediment suspension, which will be intensified by the longer reef submission time caused by sea level rise. The primary first-order impacts of reef sedimentation are coral mortality and an ensuing collapse of fish stocks. Second-order impacts include degradation of natural beauty, tourism offerings, and fisheries whose stocks depend on reefs and related habitats for a portion of their lifecycles.
- Increase the vulnerability of coastal areas to erosion due to a combination of sea level rise and changes in wave heights and direction due to changes in ocean circulation. Sea level rise will increase the depth of water across the coast of Bahia, potentially flooding many coastal areas and habitats and increasing their vulnerability to erosion, especially during storm events. Changes in erosion patterns and flooding from sea level rise will directly impact local hotels, homes, and restaurants. Infrastructure located on or near the coastline including roads, electrical transmission lines, sewage and water infrastructure, and bridges are subject to damage. This will be exacerbated by the loss of coastal ecosystems that mitigate coastal flooding and erosion.
- Increase the feedback among local climate, fire and forest fragmentation, increasing the frequency of forest fires in the future as a result of a scenario of less rainfall and high temperatures, which would generate new forest edges and more vulnerability to further burns. Climate change may further compound these effects by interfering natural forest regeneration due to the loss of seed dispersers diversity. Climate change will affect the ability to diversify tourism in the region, as well as impacting ecosystem services such as water provision and crop pollination.
- Negative impacts on estuaries due to a freshwater squeeze resulting from an increased salinity on the seaward side, as a result of sea level rise, and a diminished freshwater discharge from upriver. The freshwater squeeze will impact fish stocks, endemic and migratory bird and turtle populations, and marine mammals. Freshwater habitat and biodiversity and fresh water availability for human consumption will be impacted due to the inland penetration of salt water wedge. Human populations, particularly communities which depend primarily or secondarily on fishing as a source of protein or income will lose employment and income if estuaries are lost to climate change. Reduction and extinction of charismatic animals will greatly diminish the ecotourism appeal and natural beauty of the study area’s coastal and marine environments.
- Decline in water yield is expected in some parts of the coast in the study region and in mountainous areas that drain to Porto Seguro, one of the most important cities for tourism in the study region. It is possible that at least 6.8 million people may be at some degree of risk of water scarcity or of decrease in water availability if forested areas located around watersheds or in areas of high fog interception are not properly protected or managed.
- Decline in areas suitable for coffee in the future, with a 53% to 56 % reduction in the future suitable area when compared to the present. The extreme south of Bahia state and the extreme north of the Espírito Santo state, which are the areas with the highest number of coffee plantations at the moment, will no longer be suitable for arabica coffee. Part of one of the most important regions for coffee production worldwide is predicted to no longer be suitable for arabica coffee. As coffee is one of the main agriculture activities in the study region, a large monetary loss (about 400 million dollars per year) is expected with the reduction in suitable areas for coffee as a result of climate change.
Recommendations for adaptation
- Implement sustainable and adaptive fisheries management
- Increase Coral reef resilience
- Strengthen coastal planning and management
- Grow the value of Forest Fragments
- Ensure freshwater availability
- Incentive the development of shaded coffee
DOWNLOAD: Climate Change Vulnerability Assessment for the Discovery Coast and Abrolhos Shelf Region