Average earth surface temperature

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... 

Since the earth has temperature, it emits radiant energy called thermal radiation or planetary infrared radiation. Measurements by satellites show an average radiant emission from the earth of about 240 watts per square meter. This is equivalent to the radiation that a black body would emit if its temperature is at -19°C (-3°F). This is also the same energy rate as the solar constant averaged over the earth s surface minus the 30% reflected radiation. This shows that the amount of radiation emitted by the earth is closely balanced by the amount of solar energy absorbed and since the earth is in this state of balance, its temperature will change relatively slowly from year to year. 

An average of temperature records on the earth s surface over a year indicates that the earth s average surface temperature is about 14°C (57°F). But, the earth s 240 watts per square meter of thermal infrared radiation as measured by satellite is equivalent to the radiation emitted by a black body whose temperature is about -19°C (-3°F), not the 14°C (57°F) average measured at the earth s surface. The 33°C (60°F) difference between the apparent temperature of the earth as seen in space and the actual temperature of the earth s surface is attributed to the greenhouse effect. 

Most climate models show a climate in stable equilibrium. If the 1900 condition of 300 parts per million doubles to 600 ppm, most three-dimensional models indicate an equilibrium with an average surface temperature warming of 3.5° to 5°C (5.6° to 9°F). If the carbon dioxide content of the atmosphere doubled in one month, the earth s temperature would not reach its new equilibrium value for a century or more. 

Of the solar flux of 1 368 W/m2 reaching the upper atmosphere, 23% is absorbed by the atmosphere and 25% is reflected back into space. Earth absorbs 48% of the solar flux and reflects 4%. Radiation reaching Earth should be just enough to keep the surface temperature at 254 K, which would not support life as we know it. Why does the average temperature of Earth s surface stay at a comfortable 287 K ... 

A greenhouse gas is any component of tbe atmosphere that allows visible solar radiation to reach the Earth s surface but prevents invisible infrared radiation (beat) from escaping back into outer space. This mimics the warming action of a greenhouse. If it were not for the atmosphere s greenhouse effect, Earth s average surface temperature would be a chilly -i8°C. 

The average change in surface temperature of the Earth from 1860 to 1990. 

Several water compositions are plotted on the stability diagrams in Figure 8.2. It can be seen that at shallow Earth surface pressures and temperatures, seawater plots in the stability field of dolomite whereas solutions of average river water composition and most shallow groundwaters plot in the field of calcite. With burial of carbonate sediments and elevated P and T, the dolomite field shrinks, but subsurface fluid compositions evolve toward a composition in equilibrium with dolomite. This conclusion is probably one of the most important arguments for the formation of dolomite during deep burial diagenesis (see also Hardie, 1987). Thermodynamic considerations favor this reaction path, as well as the fact that... 

The reradiation of the absorbed energy leads to an observed warming of Earth s surface environment of about 35°C that is, an average surface temperature... 

---