The three essay are concerned with the uncertainty and risks that pervade the economy, influence investors and affect policymakers. The first essay shows that monetary policymakers consider events and contingencies to make decisions, and concludes that short-lived regime switches corrupt the descriptive power of linear Taylor-type rules, although these describe well the contours of the Fed's behaviour. The second essay focuses on the role of global and domestic factors for macroeconomic fluctuations in Brazil. The estimates of a VAR model reveal that global risk aversion is an important determinant of the volatility of Brazilian series and affects the monetary policy transmission channel. The third essay builds on the idea that, contrary to the predictions of IRBC models, the degree of international consumption smoothing is low. After a review of the literature addressing the puzzle, it investigates the relationship between external debt and consumption smoothing in a sample of developing countries