Strong reduction of sulfur emission from shipping since 2020 provides a rare opportunity to examine the response of climate system to anthropogenic forcing. Using a global climate model, this study estimates a global aerosol effective radiative forcing of 0.13 W m-2 from ship emission reduction. This emission reduction leads to a global mean warming of 0.04 K in 2020-2049 with larger warming at regional scales. The warming may not be evident at present day because of the climate variability, but can represent a significant fraction (17%) of the remaining warming to 1.5 K target.