Over the last few decades, empirical economists have experienced what Angrist and Pischke (2010) call a “credibility revolution”. Today, empirical economists take the quality of research designs far more seriously than twenty years ago. Unfortunately, however, many policy practitioners tend to overstate the value of experimental studies that are ill-designed, overlooking the pitfalls of experimental approaches and the advances in other areas of empirical research. This article reviews the pros and cons of structural versus reduced-form approaches to causal inference in a simple conceptual framework that is easy enough for practitioners. I argue that an informed policy decision requires credible evidence not only on causal relationships but also on the economic mechanisms underlying such relationships. My view is that economic theory plays a non-marginal role in virtually all empirical studies in economics, including those that rely on field experiments, and structural and reduced-form approaches are complements in producing credible evidence toward better-informed policy making. I reinforce this view by reviewing some of the recent empirical studies in the environmental economics literature.

Reduction and elimination of plastics have become a global trend by the growing impact of marine plastic pollution and climate change. Most of the plastic debris in the ocean is household waste, mainly from food containers and packaging transported to the ocean through rivers. Asian countries have strengthened controls on trade of waste after China's waste import ban. Under these circumstances, reviewing waste management is a common important issue to all countries. In addition to the traditional government regulations and market-based approaches, this paper discusses the role of public awareness and the social license to operate (SLO) in managing waste to the ocean.

In the context of growing inequality and poverty caused by neoliberalism and of the climate crisis, a cascade of proposals for an anti-austerity Green New Deal, the radical integration of environmental and economic policies, has been made in the United States and Europe since 2018. According to these proposals, huge investments for transitioning into zero carbon society should be made much earlier than suggested by conventional proposals, paying attention to the fair transition of employment and to the redress of any injustice regarding wealth, race, gender, generation, etc. In addition, based on anti-austerity economic theories, the investment should not mainly be financed through tax increases, but by mobilizing huge private resources such as pension funds, and, in countries with monetary sovereignty, also via deficit spending.