We model the optimal reaction of a public PAYG pension system to demographic shocks. We compare the ex-ante first best and second best solution of a Ramsey planner with full commitment to the outcome under simple third best rules that mimic the pension systems observed in the real world. The...

We study the sustainability of pension systems using a life-cycle model with distortionary taxation that sets an upper limit to the real value of tax revenues. This limit implies an endogenous threshold dependency ratio, i.e. a point in the cross-section distribution of the population beyond...

Increasing longevity causes an upward trend in the dependency ratio in many countries. This raises concerns about the financial sustainability of social security schemes, and reform initiatives and proposals abound. It is shown that a fundamental policy choice inevitably arises since a given...

We analyze the short and long run effects of demographic ageing - increased longevity and reduced fertility - on per-capita growth. The OLG model captures direct effects, working through adjustments in the savings rate, labor supply, and capital deepening, and indirect effects, working through...

We study the environmental and economic effects of public abatement in the presence of multiple stable steady-state ecological equilibria. Under shallow-lake dynamics (SLD), the isocline for the stock of pollution features two stable branches, a good and a bad one. Assuming that the ecology is...

Demographic trends in most developed economies are characterized by rising longevity and decreasing birthrates. These trends endanger the sustainability of the current public pension systems. Therefore social security reform proposals are on the agenda in many countries. This paper demonstrates...

Over the next four decades, increasing old-age dependency ratios exert an enormous upward pressure on welfare spending in most developed countries. As this is mainly due to existing unfunded public pension schemes, many countries have embarked on far-reaching reforms in this area, strengthening...