In this paper, we investigate how different levels of entrance fees affect donations for a public good, a natural park.

To explore this issue, the researchers conducted a stated preference study focusing on visitors’ preferences for donating money to raise funds for a protected area in Costa Rica given different entrance fee levels. The results reveal that there is incomplete crowding-out of donations when establishing an entrance fee.

On 31 March, the Intergovernmental Panel on Climate Change (IPCC) released its latest report on the impacts of climate change on humans and ecosystems (see go.nature.com/ad5v1b). These are real risks that need to be accounted for in planning for adaptation and mitigation. Pricing the risks with integrated models of physics and economics lets their costs be compared to those of limiting climate change or investing in greater resilience.

This paper concerns optimal redistributive non-linear income taxation in an OLG model, where people care about their own consumption relative to (i) other people's current consumption, (ii) own past consumption, and (iii) other people's past consumption. We show that both (i) and (iii) affect the marginal income tax structure whereas (ii) does not. We also derive conditions under which atemporal and intertemporal consumption comparisons give rise to exactly the same tax policy responses.