1,184 research outputs found

    Emissions Pricing to Stablize Global Climate

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    http://globalchange.mit.edu/research/publications/2241In the absence of significant greenhouse gas (GHG) mitigation, many analysts project that atmospheric concentrations of species identified for control in the Kyoto protocol could exceed 1000 ppm (carbon-dioxide-equivalent) by 2100 from the current levels of about 435 ppm. This could lead to global average temperature increases of between 2.5° and 6° C by the end of the century. There are risks of even greater warming given that underlying uncertainties in emissions projections and climate response are substantial. Stabilization of GHG concentrations that would have a reasonable chance of meeting temperature targets identified in international negotiations would require significant reductions in GHG emissions below “business-as-usual” levels, and indeed from present emissions levels. Nearly universal participation of countries is required, and the needed investments in efficiency and alternative energy sources would entail significant costs. Resolving how these additional costs might be shared among countries is critical to facilitating a wide participation of large-emitting countries in a climate stabilization policy. The 2°C target is very ambitious given current atmospheric concentrations and inertia in the energy and climate system. The Copenhagen pledges for 2020 still keep the 2°C target within a reach, but very aggressive actions would be needed immediately after that

    Improving poverty and inequality modelling in climate research

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    As climate change progresses, the risk of adverse impacts on vulnerable populations is growing. As governments seek increased and drastic action, policymakers are likely to seek quantification of climate-change impacts and the consequences of mitigation policies on these populations. Current models used in climate research have a limited ability to represent the poor and vulnerable, or the different dimensions along which they face these risks. Best practices need to be adopted more widely, and new model features that incorporate social heterogeneity and different policy mechanisms need to be developed. Increased collaboration between modellers, economists, and other social scientists could aid these developments. We review the history and state of the art of models used in climate research, including integrated assessment models (IAMs) and national studies, and those that model mitigation and climate-change impacts. We assess how and to what extent they represent distributional impacts within countries. We argue that there is much scope to improve the representation of income distribution and poverty. Given the diversity of models, this endeavour presents fundamental challenges for some models, but possibly requires only incremental changes in others

    Efeito de tratamentos sobre a carga bacteriana de cama de aviário reutilizada em frangos de corte.

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    bitstream/item/58058/1/CUsersPiazzonDocuments467.pdfProjeto n. 03.04.35.100.0

    Solar geoengineering may lead to excessive cooling and high strategic uncertainty

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    Climate engineering-the deliberate large-scale manipulation of the Earth's climate system-is a set of technologies for reducing climate-change impacts and risks. It is controversial and raises novel governance challenges [T. C. Schelling, Climatic Change, 33, 303-307 (1996); J. Virgoe, Climatic Change, 95, 103-119 (2008)]. We focus on the strategic implications of solar geoengineering. When countries engineer the climate, conflict can arise because different countries might prefer different temperatures. This would result in too much geoengineering: the country with the highest preference for geoengineering cools the planet beyond what is socially optimal at the expense of the others-a theoretical possibility termed "free-driving" [M. L. Weitzman, Scand. J. Econ., 117, 1049-1068 (2015)]. This study is an empirical test of this hypothesis. We carry out an economic laboratory experiment based on a public "good or bad" game. We find compelling evidence of free-driving: global geoengineering exceeds the socially efficient level and leads to welfare losses. We also evaluate the possibility of counteracting the geoengineering efforts of others. Results show that countergeoengineering generates high payoff inequality as well as heavy welfare losses, resulting from both strategic and behavioral factors. Finally, we compare strategic behavior in bilateral and multilateral settings. We find that welfare deteriorates even more under multilateralism when countergeoengineering is a possibility. These results have general implications for governing global good or bad commons

    Annex 1 - Glossary

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    This glossary defines some specific terms as the Lead Authors intend them to be interpreted in the context of this report

    Differential gene expression patterns in cyclooxygenase-1 and cyclooxygenase-2 deficient mouse brain

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    BACKGROUND: Cyclooxygenase (COX)-1 and COX-2 produce prostanoids from arachidonic acid and are thought to have important yet distinct roles in normal brain function. Deletion of COX-1 or COX-2 results in profound differences both in brain levels of prostaglandin E(2 )and in activation of the transcription factor nuclear factor-κB, suggesting that COX-1 and COX-2 play distinct roles in brain arachidonic acid metabolism and regulation of gene expression. To further elucidate the role of COX isoforms in the regulation of the brain transcriptome, microarray analysis of gene expression in the cerebral cortex and hippocampus of mice deficient in COX-1 (COX-1(-/-)) or COX-2 (COX-2(-/-)) was performed. RESULTS: A majority (>93%) of the differentially expressed genes in both the cortex and hippocampus were altered in one COX isoform knockout mouse but not the other. The major gene function affected in all genotype comparisons was 'transcriptional regulation'. Distinct biologic and metabolic pathways that were altered in COX(-/- )mice included β oxidation, methionine metabolism, janus kinase signaling, and GABAergic neurotransmission. CONCLUSION: Our findings suggest that COX-1 and COX-2 differentially modulate brain gene expression. Because certain anti-inflammatory and analgesic treatments are based on inhibition of COX activity, the specific alterations observed in this study further our understanding of the relationship of COX-1 and COX-2 with signaling pathways in brain and of the therapeutic and toxicologic consequences of COX inhibition
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