A nickel‐catalyzed synthesis of trisubstituted acrylic acids from alkynes, Grignard reagents, and CO2 is reported. The reaction proceeds through carbomagnesiation of the alkyne with Grignard reagent followed by carboxylation with CO2 under mild reaction conditions in short time. Various unsymmetrical alkynes were transformed into the corresponding acid products in good yields with high stereoselectivity. The key molecule for the present global warming "CO2" must be utilized wherever it applies. Herein, CO2 is used for a nickel‐catalyzed carbomagnesiation of alkynes to produce acrylic acids.