A 66-year assessment of photovoltaic solar resource trends across Yemen

• A 66-year high-resolution analysis reveals that mean surface air temperatures in Yemen have increased by +0.25°C per decade, paralleled by a +0.26°C/decade rise in PV cell operating temperature, posing critical efficiency challenges for solar energy systems. • Despite stable national solar irradiance trends (slope ≈ 0 W/m²/year), regional PV resource potential (PVres) diverges significantly, with coastal zones showing positive trends up to +0.10 W/m²/year and inland deserts facing declines of up to −0.10 W/m²/year due to intensified dust and land degradation. • Seasonal PVres ranges from a peak of ∼264 W/m² in April to a trough of ∼201 W/m² in December, highlighting the need for energy storage systems to balance interseasonal supply and demand. • Long-term decline in wind speeds (−0.002 m/s/year) reduces passive cooling of PV modules, further compounding thermal efficiency losses in a warming climate. • Adaptive policy responses, such as coastal PV prioritization, hybrid energy systems for dust-prone interiors, and climate-informed infrastructure planning, are recommended to safeguard Yemen’s solar energy gains under escalating environmental stress. Yemen’s rapidly warming climate poses critical challenges to solar energy efficiency despite abundant irradiance. We observe pronounced warming across all thermal indices, with mean surface air temperatures rising by +0.25°C per decade ( p < 0.001), accompanied by increases in maximum (+0.21°C/decade) and minimum (+0.28°C/decade) temperatures for the period 1958 to 2024. Photovoltaic (PV) cell operating temperatures mirror this trend, climbing by +0.26°C/decade. We further found cumulative efficiency losses of 0.4 - 0.5% per°C for crystalline silicon PV modules, compounding Yemen’s energy vulnerabilities. Counterintuitively, downwelling surface solar radiation (SRAD) remains stable with a near-zero trend (slope ≈ -0.00 W/m² yr -1 ), while declining wind speeds of -0.002 ms yr -1 reduce natural cooling of PV modules. Our spatiotemporal analysis reveals stark regional contrasts whereby coastal zones exhibit stable or increasing PV resource potential (PVres; +0.10 W/m²/year), while inland deserts like the Rub’ al Khali margins show declines of up to -0.10 W/m²/year, likely driven by intensifying dust aerosols and land degradation. Nationally, PVres shows no significant long-term trend (-0.043 W/m²/year, p = 0.070), obscuring these critical regional vulnerabilities. Seasonal extremes ranging from April peaks of 264 W/m² to December troughs of 201 W/m² highlight the necessity for adaptive energy storage systems. We identify a critical paradox wherein nationally stable solar resources mask spatially divergent risks requiring high-resolution energy planning. Coastal regions emerge as optimal for PV deployment, whereas inland areas necessitate dust-resilient technologies and hybrid systems. We recommend that policymakers and development partners implement region-specific strategies combining coastal PV expansion with inland adaptive measures to mitigate efficiency losses.