Earth surface temperature

CO2 acts as a greenhouse gas to affect Earth s surface temperature. Earth absorbs sunlight and then emits infrared radiation. The balance between sunlight absorbed and radiation sent back to space determines the surface temperature. A greenhouse gas absorbs infrared radiation and reradiates some of it back to the ground. By intercepting some of Earth s radiation, CO2 keeps our planet warmer than it would otherwise be. 

Besides readings of Earth s surface temperatures taken with standard glass thermometers, direct readings of atmospheric temperatures have been taken with satellites and weather balloons. In addition to direct measurements of Earth s recent temperatures, proxy measurements of temperatures from farther in the past can be derived from borehole temperature measurements, from historical and physical evidence regarding the e xtent and mass of land and sea ice, and from the bleaching of coral reefs. 

Recent space-probe and earth-based spectroscopic studies of the planet Venus suggest how much remains to be learned about the other planets. Earlier estimates of the surface temperature of Venus placed it near 60°C. The more detailed studies show, however, that two characteristic temperatures can be identified, —40°C and 430°C. The lower temperature is attributed to light emitted front high altitude cloud tops. The higher temperature is likely to be the average surface temperature. 

Concentration of carbon dioxide in the atmosphere, over the past 1000 The average change in surface temperature of the Earth from 185S to... 

Land/atmospheric interfacial processes which impact climate and biological activity on earth are illustrated in Figure 3. Emissions of carbon dioxide, methane, nitrogen dioxide, and chlorofluorocarbons (CFCs) have been linked to the transmission of solar radiation to the surface of the earth as well as to the transmission of terrestrial radiation to space. Should solar radiation be an internal process or an external driver of the hydrologic cycle, weather, and air surface temperatures Compounds of sulfur and nitrogen are associated with acidic precipitation and damage to vegetation, aquatic life, and physical structures. 

The greenhouse effect is a natural phenomenon whereby the earth s atmosphere is more transparent to solar radiation than terrestrial infixed radiation (emitted by the earth s surface and atmosphere). Consequently, the planet s mean surface temperature is about 33 K higher than the planet s radiative equilibrium temperature (the temperature at which the earth comes into equilibrium with the energy received from the sun). 

Recent revisions to the boundary conditions (ice-sheet topography and sea surface temperatures) have added uncertainty to many of the GCM calculations of the past two decades. Moreover, all of these calculations use prescriptions for at least one central component of the climate system, generally oceanic heat transport and/or sea surface temperatures. This limits the predictive benefit of the models. Nonetheless, these models are the only appropriate way to integrate physical models of diverse aspects of the Earth systems into a unified climate prediction tool. 

Fig. 1 Global mean surface temperature evolution during the last century (observed) and projected for the next century. Bars on the right show the possible range of temperature increases from different AOGCM, and also from Simple Climate Models (SCM) and Earth Models of Intermediate Complexity (EMIC). Figure taken from IPCC [1]...

Among the components of our atmosphere, the concentration of carbon dioxide is a mere 325 parts per million (ppm). In other words, 999,675 of every million molecules in the air are not CO2. (Almost all the molecules are N2 or O2.) At such a low concentration, how could CO2 possibly cause a measurable change in the Earth s surface temperature The answer lies in the role that minor atmospheric species play in the global energy balance. 

Savin, S.M. (1977) The history of the Earth s surface temperature during the pa.st 100 million years. Annu. Rev. Earth Planet. Sci., 5, 319-355. 

Walker, J.C.G. and Hays, P.B. (1981) A negative feedback mechanism for the long-term stabilization of earth s surface temperature. J. Geophys. Res., 86(C19), 9776-9782. 

An element is a substance that cannot be broken down into simpler substances by ordinary chemical means. A chemical compound is a substance made up of two or more elements that have been chemically bonded together. Scientists believe that solid sulfur compounds do not exist on Venus like they do on Earth because, at about 900° Fahrenheit (480° Celsius), the surface temperature on Venus is too hot for them to form in the first place. This temperature is well above the melting point of sulfur (235°F [ 113°C]). Therefore, instead of being incorporated into rocks, the sulfur on Venus continues to float around in the atmosphere in the form of the chemical compound sulfur dioxide (S02). 

Venus is not the only planet in the solar system that has sulfuric acid in its atmosphere. Earth has it, too. Unlike Venus, where the surface temperatures are too hot for acidic rain to reach the... 

The Net OLR, Aq (W m-2), from the ground surface to the atmosphere is given by the Stefan-Boltzmann law. The linear temperature change between the surface temperature of the Earth (Ts) and the effective temperature of the atmosphere (Te) indicates that the radiation occurs layer-by-layer through the atmosphere (Figure 9). Since the net OLR is constant through the atmosphere the net OLR through layer n is... 

The idea that microbes could migrate across the universe was supported by scientists with a worldwide reputation, such as H. von Helmholtz, W. Thomson (later Lord Kelvin) and Svante Arrhenius. This hypothesis was still accepted by Arrhenius in the year 1927, when he reported in the Zeitschrift fur Physikalische Chemie on his assumption that thermophilic bacteria could be transported within a few days from Venus (with a calculated surface temperature of 320 K) to the Earth by the radiation pressure of the sun (Arrhenius, 1927). The panspermia hypothesis, which seemed to have disappeared in the intervening decades, was reintroduced in the ideas of Francis Crick (Crick and Orgel, 1973). It still exists in a modified form (see Sect. 11.1.2.4). 

The melting process and the differentiation of the Earth s matter according to its density caused the lighter crust minerals to migrate to the outer layers of the still young Earth, whose surface temperature at that time was such that it was covered by a sea of melted rock (Wills and Bada, 2000). This separation of materials led to the layer structure of the Earth ... 

If we assume a radiation loss of the sun of 25-30% in comparison with today s values, the primeval Earth would have had a surface temperature below the freezing point of water (provided that all other factors which influence the surface temperature remained basically unchanged). 

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