In a one-state one-control variable Quadratic Linear Problem, I examine the effect of an increase in the multiplicative uncertainty on the use of the control variable. In contrast with previous studies, this model considers a stochastic constant term in the transition equation. I found that the...

In this essay, it is shown that in the Hoel and Karp (2001) model of global warming, the optimal response of taxes for a stock pollutant with mutiplicative uncertainty is opposite when the control variable is pollution taxes instead of emissions. In this case, the election of control variable...