Correcting the carbon cycle representation: How important is it for the economics of climate change?

Economic analyses of the greenhouse effect are typically carried out within the framework of computable general equilibrium models which represent the climate system by simple two box proxies based upon the pioneering work of Nordhaus. Since errors in predicting the carbon budget can imply high costs, there is some need to include more sophisticated climate models into the economics of global climate change. This paper presents a non-linear pulse representation of the process-based and data-validated Bern carbon model. Compared to the Nordhaus approach this leads to different results with respect to optimal climate policy and atmospheric carbon dioxide concentration. In particular, our results suggest that economic studies which use a Nordhaus representation of the climate system are biased towards high carbon emission and low abatement levels

Exploring the Carbon Kuznets hypothesis

The Carbon Kuznets hypothesis conjectures an inverse U–shape relation between GDP and carbon dioxide emissions. We investigate a number of empirical problems with this hypothesis by way of both econometric analysis and CGE modelling. The econometric analysis takes into account the possibility of unit root non–stationary regressors. On a panel of 107 countries covering the years from 1986 to 1998 we find evidence for unit root non–stationarity in log GDP and log emissions. Our discussion therefore focusses of potential pitfalls in estimating the Carbon Kuznets curve in the context of non–stationary panels context. We conclude that current practice in the literature fails to take these potential problems adequately into account. The second conceptual problem considered in the paper is the question of how to interpret an observed inverse U–shaped relationship. With the help of a small GCE model, we illustrate the danger of using observed GDP–emission patterns directly as a policy guide. Our model economy, where decarbonization is exogenous, demonstrates in particular that a carbon policy relating to income levels may not be appropriate even in the face of an observed inverse U–pattern between income and emissions

Localization of cyclo-oxygenase-2 in human recurrent colorectal cancer

Aim: The aim of this paper is to examine COX-2 expression in human recurrent colorectal carcinoma tissues using immunohistochemistry and quantative real-time PCR (qPCR). Methods: Colon and rectal specimens were obtained from 26 patients with recurrent colorectal carcinomas. We examined COX-2 expression in human recurrent colorectal carcinoma tissues using immunohistochemistry and quantative real-time PCR (qPCR). Results: In recurrent colorectal cancer a strong cytoplasmic and perinuclear staining of COX-2 was found. Moderate to strong immunosignals were detected in almost all of the carcinomas. We observed a strong specific staining of COX-2 in vascular endothelium. COX-2 immunoreactivity was also detected in stromal cells such as mononuclear cells, fibroblasts, and smooth muscle cells. The real-time PCR analyses demonstrated marked overexpression of the COX-2 gene in the cancer mucosa in concert with the immunohistochemistry data. Conclusion: We investigated COX-2 expression at the level of its protein as well as its messenger RNA in a series of recurrent colorectal cancers. These observations give additional information about the possibility that COX-2 could be involved in tumor promotion during colorectal cancer progression