This paper introduces endogenous and directed technical change in a growth model with environmental constraints. A unique final good is produced by combining inputs from two sectors. One of these sectors uses "dirty" machines and thus creates environmental degradation. Research can be directed...

African societies exported more slaves in colder years. Lower temperatures reduced mortality and raised agricultural yields, lowering slave supply costs. Our results help explain African participation in the slave trade, which predicts adverse outcomes today. We use an annual panel of African...

In many markets governments set minimum quality standards while some sellers choose to compete on the basis of quality by exceeding them. Such ‘high-quality’ strategies often win public acclaim, especially when ‘environmental friendliness’ is the dimension along which firms are...