Differential Climate Sensitivity of Egypt's Major Vegetable Crops: Quantifying Yield Elasticities to Temperature, Humidity, and Rainfall (2000-2025)

Climate change imposes quantifiable pressure on agricultural productivity in water-scarce regions such as Egypt. This study measures the differential climate sensitivity of Egypt's two major vegetable crops—tomatoes and potatoes—using 26 years of time-series data (2000–2025). Time-series regression analysis reveals significant climate change: maximum temperatures increased 0.144°C annually (12.7% cumulative over 26 years), minimum temperatures increased 0.211°C annually (32.1% cumulative), while relative humidity declined 0.260 percentage points annually and rainfall declined 0.008 mm annually. Multiple regression elasticity analysis with mixed log-linear specification—wherein humidity and rainfall are log-transformed (ratio-scaled) while temperatures are in linear form (interval-scaled)—demonstrates striking differential crop vulnerabilities. Tomato yield exhibits positive elasticity to humidity (+2.80% per 1% humidity increase; p < 0.01) but faces vulnerability due to declining atmospheric moisture. Potato yield shows pronounced negative temperature elasticity (−3.25% per 1°C maximum temperature; p < 0.01) and negative rainfall elasticity (−5.53% per 1% rainfall increase; p < 0.05), while minimum temperature warming provides partial compensation (+2.09% per 1°C; p < 0.05). The combined net effect of asymmetric temperature warming on potato yield approaches zero, indicating stagnant productivity without adaptive intervention. Results showed the necessity of crop-specific climate adaptation strategies, including heat-tolerant variety selection, optimized irrigation management, and adjusted planting schedules to sustain food security in Egypt's arid agricultural context.