How Climate Change Shapes Jumba's Past and Future

Jumba la Mtwana, a 14th-century Swahili trading settlement on Kenya’s Kilifi County coast (4°01’S, 39°44’E), stands as a testament to Indian Ocean monsoon commerce and Islamic heritage. Emerging evidence suggests that climate variability contributed both to the site’s flourishing and its abandonment in the early 15th century. Today, accelerating anthropogenic climate change poses an existential threat to these irreplaceable ruins.

Drawing on multi-decadal satellite datasets, this study documents quantified climate hazards at the site. ERA5 reanalysis data reveal a warming trend of +0.2°C per decade along the Kenya coast, with every year since 2000 recording positive temperature anomalies relative to the 1981–2010 baseline. Satellite altimetry records cumulative sea level rise of 90–100 mm since 1993, at a current rate of ~3 mm/yr, projecting potential inundation of low-lying ruins within decades. CHIRPS rainfall products (1981–2023) show a significant decline in the March–May long rains, alongside increasing variability in the October–December short rains season. NOAA AVHRR/MODIS sea surface temperature data document recurrent coral bleaching events - including 85% mortality in 1998 and 90% in 2016 - severely degrading the natural reef systems that buffer Jumba’s shoreline from wave erosion.

Under the CMIP6 SSP5-8.5 high-emissions scenario, temperatures may rise 2–3°C above present levels by 2100, with a projected 30 cm sea level rise threatening 17% of the Mombasa coastline and permanent inundation of Jumba. Urgent interventions recommended include coastal seawall construction (estimated Ksh 350 million), coral reef restoration, 3D digital preservation via photogrammetry, and integration of Jumba into Kenya’s National Determined Contributions and UNESCO heritage climate advocacy frameworks.

This study demonstrates that satellite-derived environmental monitoring can underpin heritage conservation policy, bridging physical oceanography and cultural heritage management in the context of climate justice.

KEYWORDS

Climate change; Swahili heritage; sea level rise; coastal erosion; satellite remote sensing; coral reef degradation; cultural heritage conservation; Kenya coast