Jawa's North Coast Faces Escalating Environmental Degradation Amidst Erosion and Subsidence

The North Coast (Pantura) region of Jawa is experiencing escalating environmental degradation. Research by the Indonesian National Research and Innovation Agency (BRIN) indicates that erosion dominates 65.8% of the coastline, stretching from Serang Regency in Banten to Situbondo Regency in East Jawa. Tubagus Solihuddin, a researcher at BRIN's Climate and Atmosphere Research Center, explains that the widespread erosion is due to the fact that most of Jawa's Pantura coast is composed of unconsolidated alluvial and deltaic deposits. These geological characteristics, coupled with a coastal morphology dominated by low relief and plains less than ten meters above sea level, exacerbate erosion. Concurrently, accretion is occurring in 34.2% of areas, leading to the emergence of new land. However, erosion is also progressing in coastal deltas, which are natural centers of sedimentation, attributed to upstream development activities. Specifically, canalization, river course diversions, and dam construction are cited as factors that halt sediment supply to river mouths. The impacts of erosion are severe. In the Pantai Bahagia area of Muara Gembong District, Bekasi Regency, West Jawa, seawater has intruded up to four kilometers inland. This has not only permanently submerged public infrastructure and residents' homes but also inundated over 1,000 hectares of community fish ponds. Similar situations are occurring in Tanjung Pontang, Serang; Legonkulon, Subang; and Demak, Central Jawa, where seawater has encroached 5-6 kilometers inland, submerging rice fields and settlements. The North Coast of Jawa faces a dual threat from simultaneous sea-level rise (SLR) and land subsidence. The trend of SLR averages 0.41-0.42 centimeters per year, with its cumulative impact over the period of 1993-2025 being significant.