Global climate forcing

Over the past decade, the potential for non-negligible changes in climate caused by human activity has been an issue of great concern. Very large uncertainties are associated with both estimations of possible effects on climate as well as estimations of the potential impacts of changes in climate. However, current consensus in the international scientific community is that observations suggest a discernible human influence on global climate .  

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Pinatubo), and can result in global climate forcing and stratospheric ozone depletion (Sections... 

Mann M., Bradley R.S., et al. Global-scale temprature patterns and climate forcing over the past six centuries. 1998 Nature 392 779-787. 

Schultz, M. G., Diel, T., Brasseur, G. P. and Zittel, W. (2003). Air pollution and climate-forcing impacts of a global hydrogen economy. Science, 302 (24th October, 2003). 

Table 12.1 summarizes the potential effects of HSCT emissions on stratospheric ozone and on global climate through changes in radiative forcing (Stolarski et al., 1995) as discussed in Chapter 14. Since the effect of NOj on 03 is anticipated to be the most important stratospheric issue, we focus on this here. The other issues are treated briefly where appropriate. 

For example, Fig. 14.29 shows one calculation of direct radiative forcing using a global climate model, GCM (Penner et al., 1998). Due to the preponderance of anthropogenic S02 emissions in the Northern Hemisphere, the direct radiative forcing due to sulfate... 

Kelly, P. M., and T. M. L. Wigley, Solar Cycle Length, Greenhouse Forcing and Global Climate, Nature, 360, 328-330 (1992). 

Mann, M. E., R. S. Bradley, and M. K. Hughes, Global-Scale Temperature Patterns and Climate Forcing over the Past Six Centuries, Nature, 392, 779-787 (1998). 

The results presented here focus on the present and future effect on radiative forcing due to changes in the radiatively-important chemical species (03, water vapor and CHJ associated with aircraft emissions. To address this question, we conduct uncoupled model experiments using the University of Oslo (UiO) 3-D chemical transport models (CTMs) to calculate changes in atmospheric composition and the State University of New York at Albany (SUNYA) 3-D global climate model (GCM) to calculate the radiative forcing associated with these changes. Two case studies were conducted to... 

As Mitra (2004) pointed out, the Indian oceanic experiment (INDOEX) was the first complex problem-oriented observational international program aimed mainly at studies of the aerosol-induced radiative and climatic forcing of regional and global climate that take respective feedbacks into account. The preliminary stage of the accomplishment of INDOEX began in 1996-1997, and the basic part of complex observations was accomplished in 1998-1999 with the participation of specialists from different countries (India, U.S.A., Western Europe, Mauritius, and the Maldives). The obtained results were based on the use of surface, ship, aircraft, and satellite observational means. 

Volcanic eruptions cause changes in RF from 0.2 Wm 2 to 0.5 W m 2 (these values, however, are very conditional). To analyze the possible anthropogenic impacts on global climate, estimates of the sensitivity of the climate system to external forcings are very important. Hansen et al. (1998) assumed that a change in global mean SAT with a doubled C02 concentration should constitute 3 1°C. The unreliable character of RF estimates makes it worthwhile to use different scenarios of RF changes. Developments in this field can be exemplified by the work of Tett et al. (1999). 

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