Brazil’s coast is experiencing rapid erosion as the Atlantic Ocean advances due to climate change.
- In places like Atafona, the sea has risen by 13 cm over the past 30 years and could rise another 16 cm by 2050.
Background:
- The Intergovernmental Panel on Climate Change (IPCC), the U.N. body for assessing the science related to climate change, reported that sea levels are rising at an unprecedented rate.
- Over the past decade, the rise has more than doubled to 0.48 cm per year, compared to an annual increase of 0.21 cm from 1993 to 2002.
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About Coastal Erosion
- Broad Definition: Coastal erosion is the process by which coastlines are eroded or worn away due to natural forces, primarily wave action, currents, tides, and human activities such as Construction, dredging etc.
- Mechanical Process of Coastal Erosion: Coastal erosion primarily occurs through four main processes:
- Corrasion: Strong waves hurl beach materials like pebbles against cliffs, gradually eroding them and creating wave-cut notches.
- Abrasion: Waves carrying sand and larger fragments wear away the base of cliffs or headlands, producing a sandpaper-like effect, particularly during storms.
- Hydraulic Action: When waves hit a cliff, they trap air in cracks.
- When the waves pull back, the trapped air bursts out forcefully, breaking off chunks of the cliff, especially since weathering has already weakened the rock.
- Attrition: Waves cause rocks and pebbles to collide with each other, breaking them down into smaller pieces.
Causes of Coastal Erosion in Brazil
- Climate Change: Rising global temperatures are causing sea levels to rise, which leads to more frequent and severe coastal erosion.
- Silting of Rivers: Rivers like the Paraiba no longer carry enough sand to replenish beaches, exacerbating erosion.
- Human Activities: Uncontrolled urbanisation, deforestation, and the over-extraction of groundwater contribute to the destabilisation of coastal areas.
- Natural Factors: Stronger tides and the natural low incline of beaches in regions like the North and Northeast of Brazil make them more susceptible to erosion.
Broader Effects Across Brazil
- Shrinking Beaches: Ponta Negra, a popular beach resort, has lost 15 metres of sand in two decades, prompting costly sand replenishment efforts by the local government.
- Amazon River Ecosystem: Saltwater intrusion due to severe droughts is threatening biodiversity at the mouth of the Amazon.
- The saltwater reaches 150 km upstream, killing freshwater fish and impacting local fisheries.
- Loss of Land: Coastal Erosion leads to the loss of beaches, dunes, and coastal wetlands, threatening homes and infrastructure near the shore.
- Disruption of Ecosystem: It disrupts vital ecosystems, such as mangroves and salt marshes, and can negatively impact coastal tourism and fishing industries.
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Potential Solutions to safeguard Brazil’s Coast
- Need for Sustainable Development: Experts emphasise that urban planning must adapt to rising seas, advocating for natural ecosystems like mangroves and sandbanks to protect coastal areas from further damage.
- Beach Nourishment: Importing sand from other locations to replenish eroded beaches. This is already being done in places like Ponta Negra.
- Building SeaWalls and Groynes: Constructing barriers to protect the coast from waves and prevent further erosion.
- Groynes are low wooden or concrete structures built to capture sediment and reduce wave energy.
October 3, 2024
