计量经济分析 = Econometric analysis

Here we present the results from an intercomparison of multiple global gridded crop models (GGCMs) within the framework of the Agricultural Model Intercomparison and Improvement Project and the Inter-Sectoral Impacts Model Intercomparison Project. Results indicate strong negative effects of climate change, especially at higher levels of warming and at low latitudes; models that include explicit nitrogen stress project more severe impacts. Across seven GGCMs, five global climate models, and four representative concentration pathways, model agreement on direction of yield changes is found in many major agricultural regions at both low and high latitudes; however, reducing uncertainty in sign of response in mid-latitude regions remains a challenge. Uncertainties related to the representation of carbon dioxide, nitrogen, and high temperature effects demonstrated here show that further research is urgently needed to better understand effects of climate change on agricultural production and to devise targeted adaptation strategies.

/pdf/assessing-agricultural-risks-of-climate-change-in-the-21st-4f6wucb9x8.pdf

Assessing agricultural risks of climate change in the 21st century in a global gridded crop model intercomparison

https://www.thelancet.com/pdfs/journals/lancet/PIIS0140-6736%2815%2960854-6.pdf?code=lancet-site

Health and climate change: policy responses to protect public health

This paper assesses the current state of evidence on the impact of trade policy reform on poverty in developing countries. There is little empirical evidence addressing this question directly, but a lot of related evidence on specific aspects. We summarize this evidence using an analytic framework addressing four key areas: economic growth and stability; households and markets; wages and employment and government revenue. Twelve key questions are identified and empirical studies and results are discussed. We argue that there is no simple generalizable conclusion about the relationship between trade liberalization and poverty, and the picture is much less negative than is often suggested. In the long run and on average, trade liberalization is likely to be strongly poverty alleviating, and there is no convincing evidence that it will generally increase overall poverty or vulnerability. But there is evidence that the poor may be less well placed in the short run to protect themselves against adverse effects and take advantage of favorable opportunities.

/pdf/trade-liberalization-and-poverty-the-evidence-so-far-59kawhxtwc.pdf

Trade Liberalization and Poverty: The Evidence So Far

Asymmetric price transmission has been the subject of considerable attention in agricultural economics. It is not only important because it may point to gaps in economic theory, but also because its presence is often considered for policy purposes to be evidence of market failure. In this paper we survey the literature on asymmetric price transmission. A wide variety of often conflicting theories of, and empirical tests for, asymmetry co-exist in this literature. We classify the different types and causes of asymmetric price transmission and describe the econometric techniques used to quantify it. We also briefly review the results of empirical applications. Outstanding methodological problems and suggestions for future research are discussed. Our main conclusion is that the existing literature is far from being unified or conclusive, and that it has often been largely method-driven, with little attention devoted to theoretical underpinnings and the plausible interpretation of results. Hence, much interesting theoretical and empirical work remains to be done.

/pdf/asymmetric-price-transmission-a-survey-3v8r9bdhwc.pdf

Asymmetric Price Transmission: A Survey

The high food prices experienced over recent years have led to the widespread view that food price volatility has increased. However, volatility has generally been lower over the two most recent decades than previously. Variability over the most recent period has been high but, with the important exception of rice, not out of line with historical experience. There is weak evidence that grains price volatility more generally may be increasing but it is too early to say.

/pdf/food-price-volatility-2xkl7ulz67.pdf

Food price volatility

This paper is concerned with the impact of food scares, principally the BSE crisis in the UK, and focuses on price transmission in vertically related markets. We show that if market power has an effect on the farm-retail margin, this determines the specification of the cointegrating relationship and thus provides a test of market power. The results for the UK beef chain suggest that we cannot reject the importance of market power. The impact of the BSE crisis on farm prices is found to be more than double that on retail prices, thus corroborating public concerns regarding a differential impact of food scares on retailers and producers.

Food scares, market power and price transmission: the UK BSE crisis

This paper focuses on the extent to which price changes occurring at the farm-level are transmitted to the retail sector. A price transmission elasticity is derived which is shown to depend on the degree of market power in the food industry and the nature of the food industry's processing technology. The offsetting role of the processing technology and market power in determining the extent of price transmission are highlighted. A case-study reports values for the price transmission elasticity for the US beef and pork sectors.

Processing Technology, Market Power and Price Transmission

There has been a long-held belief that there is an association between economic growth and increased levels of international trade. However, more recent work has questioned this hypothesis and the re-opening of the debate has identified two key areas of contention. One is the extent to which the effects of openness are conditional on factors omitted from the core regression relationship and hence how the hypothesis is tested. The other is the meaning and measurement of openness and liberalisation. This paper addresses both these areas by exploring the nature of heterogeneity in growth performance among liberalising countries using a difference-in-difference approach. The results show that, while in aggregate there appears to be a positive but small impact of trade liberalisation on growth, this masks a huge range of responses. Empirical analysis of this heterogeneity shows that a one-size-fits-all policy is not necessarily the most effective, and suggests a case-by-case approach is more appropriate.

https://papers.ssrn.com/sol3/Delivery.cfm/twec_1101.pdf?abstractid=1136499&mirid=1&type=2

C. W. Morgan

Papers

Food price volatility

Food scares, market power and price transmission: the UK BSE crisis

Processing Technology, Market Power and Price Transmission

Trade Liberalisation and Economic Growth

The impact of food scares on price adjustment in the UK beef market