greenhouse gases have been of serious global concern to environmentalists. enteric ruminal fermentation and manure are seen to be responsible for global warming. based on a better understanding of positive tan-nin effects on ruminant nutrition, the feeding value of browse trees and shrubs containing tannin, their roles on methanogenic rumen microbes in overcoming the production of enteric ferme...

Emissions of a broad range of greenhouse gases of varying lifetimes contribute to global climate change. Carbon dioxide displays exceptional persistence that renders its warming nearly irreversible for more than 1,000 y. Here we show that the warming due to non-CO(2) greenhouse gases, although not irreversible, persists notably longer than the anthropogenic changes in the greenhouse gas concent...

Intense climate-related disasters—floods, storms, droughts, and heat waves—have been on the rise worldwide. At the same time and coupled with an increasing concentration of greenhouse gases in the atmosphere, temperatures, on average, have been rising, and are becoming more variable and more extreme. Rainfall has also been more variable and more extreme. Is there an ominous link between the glo...

[1] The African Sahel experienced severe drying between the 1950s and the 1980s, with partial recovery since. We compare Sahel rainfall in the 20th century, pre-industrial, and increased greenhouse gases (GHG) simulations produced for the Intergovernmental Panel on Climate Change (IPCC). The simulations forced by 20th century concentrations of aerosol and GHG reproduce (i) a global change in SS...

©1999–2004 CHOICES. All rights reserved. Articles may be reproduced or electronically distributed as long as attribution to Choices and the American Agricultural Economics Association is maintained. Choices subscriptions are free and can be obtained through http://www.choicesmagazine.org. The articles in this issue by Reilly and Alig et al. have focused primarily on the potential impacts of cli...

Trends in surface temperature over the last 100, 50, and 30 yr at individual grid boxes in a 5° latitude– longitude grid are compared with model estimates of the natural internal variability of these trends and with the model response to increasing greenhouse gases and sulfate aerosols. Three different climate models are used to provide estimates of the internal variability of trends, one of wh...

Introduction The Department of Energy (DOE) Energy Information Administration estimates atmospheric greenhouse gas releases may exceed 8 billion metric tons by the year 2010 heightening its international environmental concern. Carbon dioxide will dominate the greenhouse gases (Kane and Klein, 1997) and the majority of these results from the use of fossil fuels. With viable replacement of fossil...

South Asian emissions of fossil fuel SO(2) and black carbon increased approximately 6-fold since 1930, resulting in large atmospheric concentrations of black carbon and other aerosols. This period also witnessed strong negative trends of surface solar radiation, surface evaporation, and summer monsoon rainfall. These changes over India were accompanied by an increase in atmospheric stability an...