In this paper, we introduce a unified Ramsey model where pollution has an impact on preferences and affects both consumption demand and labor supply. Pollution comes from production activities and is viewed as a stock variable with a strong inertia. A government is introduced and levies a proportional tax on production to finance depollution expenditure. We find two interesting results when pollution raises the consumption demand (compensation effect). First, in the long run, a higher green-tax rate increases the pollution level at the steady state (green paradox) when pollution raises the labor supply (disenchantment effect). Second, in the short run, local indeterminacy can arise through a Hopf bifurcation when pollution lowers the labor supply (leisure effect) even if pollution has a strong inertia.