<p>Environmental disasters are a crucial issue in the economic policy agenda. Policy makers, however, appear rather short-sighted when dealing with decisions aimed at preventing them. This paper contributes to the assessment of the consequences of such myopic behavior on social welfare. To this end, we develop a stylized multi-period model addressing a social planner’s choice of the level of environmentally harmful emissions that, accumulating in the environment, may trigger an exogenous environmental disaster if an uncertain threshold is exceeded. We explore two alternative scenarios, depending on how far-sighted the social planner is in its decision making process. Uncertainty about the threshold triggering the environmental disaster is not fully revealed, unless the disaster takes place, but the environment has a positive absorption rate, so that a social planner, choosing emissions in a myopic way (i.e., period by period), can in any given period obtain information on “risk free” emissions in subsequent periods, if the threshold is not exceeded. In other words, the social planner can engage in “dangerous learning” in each period. As a result, social welfare may be larger if the social planner is short sighted than when she is far-sighted (i.e., if she commits to an emission path at the beginning of the planning horizon). Overall, our paper highlights the complex interplay between the planning horizon, learning, and disaster severity in potentially shaping environmental policy.</p>