This paper presents a crop yield emulator for four major crops (maize, rice, soybean, and wheat). Trained on process-based crop model simulations, it captures yield responses to key drivers: atmospheric CO₂, temperature, water availability, and nitrogen use. The emulator closely reproduces the behavior of complex crop models and aligns well with FAO (Food and Agriculture Organization)-reported historical yields. It provides a robust and efficient method for representing agricultural outcomes in climate change impact assessments.