Climate change is one of the most significant and complex challenges facing the world's economies. The necessity to enlarge the knowledge base regarding climate change and its impacts and to design efficient policies is widely accepted by the scientific community, the decision makers and the general public. This special issue, which will be published in two parts in the current and subsequent issue of Environment and Development Economics, is a selection of papers related to the topic of the international workshop on ‘The Economics of Climate Change and Sustainability’ organized by the Economics Department of the University of Bologna in April 2018. The papers in this special issue cover a wide range of climate-change-related topics, which include endogenous growth and overlapping generation models; climate-related financing and green bonds; demographics; location decisions; technology diffusion; quantitative relationships and experimental approaches. We hope that this special issue will provide some new insights into the economics of climate change and help to identify new directions for future research.

Environmental economics models are often too complex to be communicated in an illustrative manner. For this reason, this paper develops the Basic Climate Economic (BCE) model that features core elements of macroeconomic and climate economic modelling, while allowing for an illustrative examination of the development path. The BCE model incorporates fossil stock depletion, pollution stock accumulation, endogenous growth, and climate-induced capital depreciation. We first use graphical analysis to show the effects of climate change and climate policy on economic development. Intuition for the different model mechanisms, the functional forms, and the effects of different climate policies is provided. We then show the model equations in mathematical terms to derive closed-form solutions and to run model simulations relating to the graphical part. Finally, we compare our setup to other models of climate economics.

In an overlapping generations model with multiple steady states, we analyse the impact of endogenous environmental policies on the relevance of history and expectations for the equilibrium selection. In a polluting regime, environmental preferences cause an increasing energy tax which raises the risk that the economy transitions to the inferior equilibrium under pessimistic expectations. However, higher environmental preferences imply an earlier switch to the clean energy regime. Then, the conflict between production and environmental preferences is resolved and the prospects of selecting the superior equilibrium improve, since positive expectations become more relevant. In an empirical analysis we find that people with environmental preferences tend to have more optimistic expectations about economic development. Using these findings to analyse the steady-state dynamics implies that agents with environmental preferences support higher energy taxes and switch to clean production more quickly. Due to their optimism, the likelihood of reaching the superior stable steady state increases.

A structural model for green bonds is developed to explain the formation and dynamics of green bond prices and to address the issue of the so-called ‘greenium’, that is, the difference between the yields on a conventional bond and a green bond with the same characteristics. We provide answers to the following questions: What are the determinants of the green bond value? Do green bonds enhance the credit quality of the issuer? Are green bonds a relatively cheap tool to fund sustainable investments? We also study the effect of investors' environmental concern on portfolio allocation. Our results have direct policy implications and suggest that an improvement in credit quality could ultimately lead to a lower cost of capital for green bond issuers and that governmental tax-based incentives and an increase in investors' green awareness play a significant role in scaling up the green bonds market.

In familiar models, a decrease in the friction facing mobile factors (e.g., lowering their adjustment costs) increases a coordination problem, leading to more circumstances where there are multiple equilibria. We show that a decrease in friction can decrease coordination problems when a production externality arises from a changing stock, e.g. of pollution or knowledge. In general, the relation between the amount of friction that mobile factors face and the likelihood of multiple equilibria is non-monotonic.

This article analyzes a general equilibrium growth model with overlapping generations and (production-induced) environmental degradation. Individuals react to environmental damages through mitigation or adaptation. In the former case, they reduce production and its environmental impact. In the latter, they do not tackle the causes of the problem but rather its consequences (i.e., the wellbeing loss due to environmental degradation) by increasing defensive expenditures. Despite its simplicity, the model can generate different long-term outcomes: convergence to a stationary state following a unique trajectory or local/global indeterminacy. In the last scenario, initial conditions (history) and individual expectations matter and the model can generate coordination failures and endogenous fluctuations. Results cast doubt on solutions to environmental problems relying on the role of individual behavior change or adaptation.