Climate Change Economics

Unmitigated climate change is projected to reduce average U.S. corn yields. Many of these projections rely on stable model coefficients, which may not hold in practice. We investigate the assumption of spatio-temporal stability of weather coefficients in regressions of U.S. Corn Belt yields during 1950–2014 and examine their implications for climate change projections. We reject the null hypothesis of time-constant weather shock coefficients for roughly one-third of sample counties and find that smoothly evolving parameters contribute to near-term prediction deterioration. We next estimate a dynamic econometric model that accounts for nonstationarities, outliers, and smoothly evolving parameters. Though average yields are projected to decline through 2050, there is considerable uncertainty when bootstrapping from a set of 30 downscaled climate models for both the RCP 4.5 and RCP 8.5 scenarios. Long-tailed distributions suggest a small number of counties could experience only small short-term yield decreases. Projections from a static analogue of our dynamic model have distributions with thinner tails, less dispersion, and higher means.

The Paris Agreement states that from 2020 developed countries will mobilize at least USD 100 billion per year to support climate action in developing countries. The attainment of this objective involves decisions by donor countries about the channel and destination of climate finance disbursements. This paper explores how the spending conditions associated to different disbursement options can affect the opportunities for donors to expand their exports. In particular, using a Multiregional Input-Output Model, it finds that donors have an economic incentive for choosing bilateral channels that enable to tie aid to the detriment of multilateral ones, such as the Green Climate Fund. On the other hand, local content requirements imposed by recipient countries do not substantially affect donors’ exports, since they do not reduce intermediate exports, which represent a relevant share of the total exports generated by the mitigation and adaptation actions analysed.

We assess the extent to which Carbon Capture and Storage (CCS) and R&D on this abatement technology are part of a socially efficient solution to the problem of climate change. For this purpose, we extend the intertemporal model of climate and directed technical change developed by Acemoglu et al. (2012) [The environment and directed technical change. American Economic Review, 102(1), 131–166] to include a sector responsible for CCS. We show that two types of solutions exist: a renewable energy regime where current CCS technology is only temporarily used but never further developed; and a fossil energy regime where CCS is part of a long-term solution and is further developed at about the same rate as fossil energy technology. Our computations show that for current estimates of the marginal cost of CCS, the renewable energy regime clearly dominates the fossil fuel energy regime.

The difference in land use modeling approaches is an important uncertain factor in evaluating future climate scenarios in global economic models. We compare five widely used land use modeling approaches: constrained optimization, constant elasticity of transformation (CET), the additive form of constant elasticity of transformation (ACET), logit, and Ricardian. We demonstrate that the approaches differ not only by the extent of parameter uses but also by the definition of conversion cost and the consideration of comparative advantage implied by land heterogeneity. We develop a generalized hybrid approach that incorporates ACET/logit and Ricardian to account for both conversion cost and comparative advantage. We use this hybrid approach to estimate future climate impacts on agriculture. We find a welfare loss of about 0.38–0.46% of the global GDP. We demonstrate that ignoring land heterogeneity or land conversion costs underestimates climate impacts on agricultural production and welfare.

The economic welfare effects of climate change on global agriculture will be mediated by several complex biophysical and economic processes. For a given emissions scenario, these include: (1) the response of the climate system to anthropogenic forcing, (2) the response of crop yields to climate system and carbon dioxide changes, given baseline improvements in crop yields, (3) the response of agricultural markets to crop yield changes, and (4) the economic welfare implications of such market responses. In this paper, we use information about the first two processes from available climate-crop model comparison studies to analyze implications for the third and fourth processes. Applying the range of crop yield changes in a Global Integrated Assessment Model (GCAM) highlights several important economic relationships. First, we find a consistent relationship between global cropland area and yield change that is approximately orthogonal to the relationship between regional cropland area and yield change. Second, we find that the change in economic welfare, expressed as total surplus change per unit economic output, peaks during the 21st century. Third, we find that, at the global level, changes in yield affect both producer surplus and consumer surplus. Specifically, surplus changes to producers and consumers are always opposite in sign, although which economic actors gain or lose varies with the sign of yield change for any given commodity. Taken together, these results contribute to a growing body of research on climate-induced changes on agriculture by highlighting several economic relationships that are robust to differences in the underlying biophysical responses.

This paper examines the impacts of the EU Emissions Trading System (ETS) on the environmental and economic performance of Norwegian plants. The ETS is regarded as the cornerstone climate policy in the EU and Norway, but there has been considerable debate regarding its effects due to low quota prices and substantial allocation of free allowances. The rich data allow us to investigate potential effects of the ETS on several important aspects of plant behavior. The results indicate a weak tendency of emissions reductions among Norwegian plants in the second phase of the ETS, but not in the other phases. We find no significant effects on emissions intensity in any of the phases, but positive effects on value added and productivity in the second phase. These positive effects may be due to the large amounts of free allowances, and that plants may have passed on additional marginal costs to consumers.