Dirk Willenbockel

Climate change effects on agriculture: Economic responses to biophysical shocks

Significance Plausible estimates of climate change impacts on agriculture require integrated use of climate, crop, and economic models. We investigate the contribution of economic models to uncertainty in this impact chain. In the nine economic models included, the direction of management intensity, area, consumption, and international trade responses to harmonized crop yield shocks from climate change are similar. However, the magnitudes differ significantly. The differences depend on model structure, in particular the specification of endogenous yield effects, land use change, and propensity to trade. These results highlight where future research on modeling climate change impacts on agriculture should focus. Agricultural production is sensitive to weather and thus directly affected by climate change. Plausible estimates of these climate change impacts require combined use of climate, crop, and economic models. Results from previous studies vary substantially due to differences in models, scenarios, and data. This paper is part of a collective effort to systematically integrate these three types of models. We focus on the economic component of the assessment, investigating how nine global economic models of agriculture represent endogenous responses to seven standardized climate change scenarios produced by two climate and five crop models. These responses include adjustments in yields, area, consumption, and international trade. We apply biophysical shocks derived from the Intergovernmental Panel on Climate Change’s representative concentration pathway with end-of-century radiative forcing of 8.5 W/m2. The mean biophysical yield effect with no incremental CO2 fertilization is a 17% reduction globally by 2050 relative to a scenario with unchanging climate. Endogenous economic responses reduce yield loss to 11%, increase area of major crops by 11%, and reduce consumption by 3%. Agricultural production, cropland area, trade, and prices show the greatest degree of variability in response to climate change, and consumption the lowest. The sources of these differences include model structure and specification; in particular, model assumptions about ease of land use conversion, intensification, and trade. This study identifies where models disagree on the relative responses to climate shocks and highlights research activities needed to improve the representation of agricultural adaptation responses to climate change.

MODELS OF MILITARY EXPENDITURE AND GROWTH: A CRITICAL REVIEW

This paper reviews some of the theoretical and econometric issues involved in estimating growth models that include military spending. While the mainstream growth literature has not found military expenditure to be a significant determinant of growth, much of the defence economics literature has found significant effects. The paper argues that this is largely the product of the particular specification, the Feder–Ram model, that has been used in the defence economics literature but not in the mainstream literature. The paper critically evaluates this model, detailing its problems and limitations and suggests that it should be avoided. It also critically evaluates two alternative theoretical approaches, the Augmented Solow and the Barro models, suggesting that they provide a more promising avenue for future research. It concludes with some general comments about modelling the links between military expenditure and growth.

WTO challenges and efficiency of Chinese banks

After joining the World Trade Organisation (WTO) in December 2001, China was given 5 years to completely open up its banking market for international competition. Chinese banks have been renowned for their mounting nonperforming loans and low efficiency. Despite gradual reforms, the banking system is still dominated by state ownership and encapsulated monopolistic control. How to raise efficiency is a key to the survival and success of domestic banks, especially the state-owned commercial banks. Two important factors may be responsible for raising efficiency: ownership reform and hard budget constraints. This article uses a panel data of 22 banks over the period 1995 to 2001, and employs a stochastic frontier production function to investigate the effects of ownership structure and hard budget constraint on efficiency. Empirical results suggest that nonstate banks were 8–18% more efficient than state banks, and that banks facing a harder budget tend to perform better than those heavily capitalized by the state or regional governments. The results shed important light on banking sector reform in China to face the tough challenges after WTO accession.

Climate change impacts on agriculture in 2050 under a range of plausible socioeconomic and emissions scenarios

Previous studies have combined climate, crop and economic models to examine the impact of climate change on agricultural production and food security, but results have varied widely due to differences in models, scenarios and input data. Recent work has examined (and narrowed) these differences through systematic model intercomparison using a high-emissions pathway to highlight the differences. This paper extends that analysis to explore a range of plausible socioeconomic scenarios and emission pathways. Results from multiple climate and economic models are combined to examine the global and regional impacts of climate change on agricultural yields, area, production, consumption, prices and trade for coarse grains, rice, wheat, oilseeds and sugar crops to 2050. We find that climate impacts on global average yields, area, production and consumption are similar across shared socioeconomic pathways (SSP 1, 2 and 3, as we implement them based on population, income and productivity drivers), except when changes in trade policies are included. Impacts on trade and prices are higher for SSP 3 than SSP 2, and higher for SSP 2 than for SSP 1. Climate impacts for all variables are similar across low to moderate emissions pathways (RCP 4.5 and RCP 6.0), but increase for a higher emissions pathway (RCP 8.5). It is important to note that these global averages may hide regional variations. Projected reductions in agricultural yields due to climate change by 2050 are larger for some crops than those estimated for the past half century, but smaller than projected increases to 2050 due to rising demand and intrinsic productivity growth. Results illustrate the sensitivity of climate change impacts to differences in socioeconomic and emissions pathways. Yield impacts increase at high emissions levels and vary with changes in population, income and technology, but are reduced in all cases by endogenous changes in prices and other variables.

Managing uncertainty: a review of food system scenario analysis and modelling.

Complex socio-ecological systems like the food system are unpredictable, especially to long-term horizons such as 2050. In order to manage this uncertainty, scenario analysis has been used in conjunction with food system models to explore plausible future outcomes. Food system scenarios use a diversity of scenario types and modelling approaches determined by the purpose of the exercise and by technical, methodological and epistemological constraints. Our case studies do not suggest Malthusian futures for a projected global population of 9 billion in 2050; but international trade will be a crucial determinant of outcomes; and the concept of sustainability across the dimensions of the food system has been inadequately explored so far. The impact of scenario analysis at a global scale could be strengthened with participatory processes involving key actors at other geographical scales. Food system models are valuable in managing existing knowledge on system behaviour and ensuring the credibility of qualitative stories but they are limited by current datasets for global crop production and trade, land use and hydrology. Climate change is likely to challenge the adaptive capacity of agricultural production and there are important knowledge gaps for modelling research to address.

Structural Effects of a Real Exchange Rate Revaluation in China: A CGE Assessment

The misalignment of the Chinese currency exposed by the rapid build-up of China’s foreign exchange reserves over the past few years has been the subject of considerable recent debate. Recent econometric studies suggest a Renminbi undervaluation on the order of 10 to 30%. The modest revaluation of July 2005 is widely perceived as insufficient to correct China’s balance-of-payments disequilibrium and has not silenced charges that China is engaging in persistent one-sided currency manipulation. Within China there are widespread concerns regarding the adverse employment effects of a major revaluation on labour-intensive export sectors, yet the likely magnitude of these effects remains a controversial issue. The paper aims to shed light on this question by simulating the structural effects of a real exchange rate revaluation that lowers the current account surplus-GDP by 4 percentage-points using a 17-sector computable general equilibrium model of the Chinese economy.

A Dynamic General Equilibrium Analysis of Adaptation to Climate Change in Ethiopia

This study links a multi-sectoral regionalized dynamic computable general equilibrium model of Ethiopia with a system of country-specific hydrology, crop, road and hydropower engineering models to simulate the economic impacts of climate change towards 2050. In the absence of externally funded policy-driven adaptation investments Ethiopiaâ..s GDP in the 2040s will be up to 10 percent below the counterfactual no-climate change baseline. Suitably scaled adaptation measures could restore aggregate welfare to baseline levels at a cost that is substantially lower than the welfare losses due to climate change.

Global linkages among energy, food and water: an economic assessment

The resolution adopted by the General Assembly of the United Nations on 25 September 2015 is symptomatic of the water-energy-food (WEF) nexus. It postulates goals and related targets for 2030 that include (1) End hunger, achieve food security and improved nutrition, and promote sustainable agriculture (SDG2); (2) Ensure availability and sustainable management of water and sanitation for all (SDG6); and (3) Ensure access to affordable, reliable, sustainable, and modern energy for all (SDG7). There will be tradeoffs between achieving these goals particularly in the wake of changing consumption patterns and rising demands from a growing population expected to reach more than nine billion by 2050. This paper uses global economic analysis tools to assess the impacts of long-term changes in fossil fuel prices, for example, as a result of a carbon tax under the UNFCCC or in response to new, large findings of fossil energy sources, on water and food outcomes. We find that a fossil fuel tax would not adversely affect food security and could be a boon to global food security if it reduces adverse climate change impacts.

Growth effects of anticipated trade liberalization and the Baldwin multiplier

Abstract According to Baldwin (1992) [Baldwin, R.E., 1992. Measurable dynamic gains from trade. Journal of Political Economy 100, 162–174] trade liberalization induces a medium-run investment-led growth process. This note points out that Baldwins own model would actually predict a significant initial drop in investment and aggregate income, when announcement effects are taken into account.

EVIDENCE ON THE IMPACT OF TARIFF REDUCTIONS ON EMPLOYMENT IN DEVELOPING COUNTRIES: A SYSTEMATIC REVIEW

This paper analyses the evidence on the impact of tariff reductions on employment in developing countries. We carry out a systematic review of the existing empirical literature, and include both, ex post econometric evidence and ex ante Computable General Equilibrium (CGE) simulation studies. The synthesis of results suggests that the effects of tariff reductions on employment are country and trade policy specific. When looking across higher quality econometric studies that control for the endogeneity of tariffs, only a couple of studies have statistically significant results, and these suggest that employment is likely to decrease slightly in the short run following trade liberalization. This is consistent with the notion that there are winners and losers from trade policy reform. These results are in contrast with the CGE findings, which by design incorporate projections of the medium-run economy-wide knock-on effects suggested by economic theory. The synthesis of CGE studies suggests non-negative effects of trade liberalization on aggregate employment and moderate inter-sectoral labour reallocation effects.