The rapid increase in greenhouse gas (GHG) concentration over the last 50 years has produced approximately 0,64 Celsius degrees rise in global mean temperature. The most worrisome effects of global warming include severe weather and related hydro-geologic events, many of which have been already occurring. Global warming consequences are touchable also in agricultural field; species extinctions and increases in the ranges of disease vectors are actually going on. Earth’s global surface temperature strongly depends on its surface radiative properties. Solar radiation absorbed by surface, together with a natural atmospheric greenhouse effect, represents the mechanism regulating Earth’s temperature. Therefore, Earth’s albedo modification by proper surfaces would reduce the portion of solar radiation absorbed by the Earth, and consequently decreased average global temperature. Quantification of reflecting surface effectiveness has been accomplished in this work through a mathematical relation, based on the energy balance among sky, atmosphere and earth surface. The correlation between the temperature reduction and the greenhouse gases decrease in the atmosphere has been calculated on the hypothesis that the temperature increase in the last century has been caused exclusively by the GHG concentration variation occurred in the same period. It has been estimated by the proposed model that the reflecting surface area (reflecting coefficient equal to 0.9) which is required to offset the effect, in terms of global mean temperature, of introducing in the atmosphere of 1 ton of CO2eq is equal to 8 square meters. In terms of Radiative Forcing, a drop of 0.28 W/m2 is obtained for each 106 km2 of the same kind of reflecting surfaces. Comparing earlier literature models, results that one tonne of emitted CO2 offset is obtained increasing the albedo by 25% for a surface of 23 m2 using our method, of 26 m2 in Harte’s model and of 23 m2 in Berkeley study. In terms of Radiative Forcing, a drop of 0.28 W/m2 is obtained for each 106 km2 of surfaces with reflection coefficient of 0.9. Furthermore, greenhouse gas “abatement” cost through reflecting surfaces has been compared to the one obtained by the main renewable energy sources. The technologies for renewable energy sources which have been considered in this study are solar panels for the generation of thermal energy, photovoltaic panels, wind generators and hydroelectric power plants.
Analysis of Global Warming Mitigation by White Reflecting Surfaces
ROSSI, Federico;NICOLINI, ANDREA
2010
Abstract
The rapid increase in greenhouse gas (GHG) concentration over the last 50 years has produced approximately 0,64 Celsius degrees rise in global mean temperature. The most worrisome effects of global warming include severe weather and related hydro-geologic events, many of which have been already occurring. Global warming consequences are touchable also in agricultural field; species extinctions and increases in the ranges of disease vectors are actually going on. Earth’s global surface temperature strongly depends on its surface radiative properties. Solar radiation absorbed by surface, together with a natural atmospheric greenhouse effect, represents the mechanism regulating Earth’s temperature. Therefore, Earth’s albedo modification by proper surfaces would reduce the portion of solar radiation absorbed by the Earth, and consequently decreased average global temperature. Quantification of reflecting surface effectiveness has been accomplished in this work through a mathematical relation, based on the energy balance among sky, atmosphere and earth surface. The correlation between the temperature reduction and the greenhouse gases decrease in the atmosphere has been calculated on the hypothesis that the temperature increase in the last century has been caused exclusively by the GHG concentration variation occurred in the same period. It has been estimated by the proposed model that the reflecting surface area (reflecting coefficient equal to 0.9) which is required to offset the effect, in terms of global mean temperature, of introducing in the atmosphere of 1 ton of CO2eq is equal to 8 square meters. In terms of Radiative Forcing, a drop of 0.28 W/m2 is obtained for each 106 km2 of the same kind of reflecting surfaces. Comparing earlier literature models, results that one tonne of emitted CO2 offset is obtained increasing the albedo by 25% for a surface of 23 m2 using our method, of 26 m2 in Harte’s model and of 23 m2 in Berkeley study. In terms of Radiative Forcing, a drop of 0.28 W/m2 is obtained for each 106 km2 of surfaces with reflection coefficient of 0.9. Furthermore, greenhouse gas “abatement” cost through reflecting surfaces has been compared to the one obtained by the main renewable energy sources. The technologies for renewable energy sources which have been considered in this study are solar panels for the generation of thermal energy, photovoltaic panels, wind generators and hydroelectric power plants.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
