Super Chimney concept by Michael PesochinskyA 5 km high Super Chimney
Michael Pesochinsky proposal is to buil super tall chimney to facilitate heat exchange in the atmosphere as a remedy to Global Warming.
illustration from Michael Pesochinsky website http://www.superchimney.org/
How the super-chimney will cool the atmosphere?
The super-chimney will cool the Earth atmosphere by facilitating the heat exchange, and this is the most important aspect of the super-chimney. If we think of Global Warming, we should understand that the phenomenon is caused not by the planet receiving more heat but rather by increasing the heat capacity of the atmosphere due to the greenhouse gases. Respectively, the super-chimney will change the amount of heat exhaled by the planet. It will accelerate the rate of the heat exchange in atmosphere, which will result in the reduction of the Earth atmosphere temperature.
There are three cooling mechanisms for air: convection, conduction and radiation. Without getting into fine details, for our planet it means the following: the planet at large receives and looses energy only via radiation, thus radiation actually is deciding factor on how much heat the planet receives. As for the air processes within the atmosphere, convection and conduction are the two determinative powers.
Normally, heat radiation comes from sun and then it is partially absorbed by the atmosphere while it travels through. Then the heat radiation is partially absorbed by the planet surface. The other part of heat radiation is reflected back into space. The reflected heat travels back through the atmosphere and naturally, part of it is again absorbed by the atmosphere. The super-chimney will facilitate air convection by bringing masses of warm air at high altitude, resulting in the warm air coming out of the super-chimney exit. When the heat from the air radiates out it will be already at high altitude thus the amount of energy reabsorbed by the atmosphere will be less, because there will be a thinner layer of air for heat to travel through. Therefore, more heat will be leaving the atmosphere, thus, reducing the atmosphere temperature.
Additionally, as it was explained above, the super-chimney will create rain and clouds. Clouds will be reflecting some sunlight thus, additionally cooling the atmosphere by reducing the total amount of sun radiation received by the planet.
According to the Michael Pesochinsky's calculations, it will take 10 super-chimneys to offset the heat surplus in the Earth Atmosphere, which causes Global Warming.
There are many factors to analyze. However, it is clear that in principle, the super-chimney will facilitate heat exchange and, given the enormous amount of air coming through the super-chimney, it will have effect on the heat balance of the Earth atmosphere. According to Kiehl3, annually Earth receives 492 W/m2 of radiation combined (direct solar and due to the green house effect) . Global Warming is attributed to the fact that the Earth is presently absorbing 0.85 ± 0.15 W/m2 more than it emits into space4 (Hansen et al. 2005). So the planet absorbs approximately 0.2% of radiation energy more than it should to maintain constant temperature.
According to Wikipedia, Earth surface heat captured by the atmosphere. More than 75% can be attributed to the action of greenhouse gases that absorb thermal radiation emitted by the Earth's surface. The atmosphere in turn transfers the energy it receives both into space (38%) and back to the Earth's surface (62%), where the amount transferred in each direction depends on the thermal and density structure of the atmosphere. 5 The super-chimney will emit air at the 5000m, which is roughly the point in the atmosphere where half the amount of air is below and half is above. Thus, it can be assumed that re-absorption will be cut in half. So, instead of normal distribution we will have ~70 % of energy lost to space and only 30% reabsorbed into atmosphere. In other words, the air, which will go through the super-chimney, will loose 30% more heat than a normal air.
According to the above calculation 127,292, 000 kg of air will go through the super-chimney every second. In a year it comes to 4x1015kg . According to the National Center for Atmospheric Research, "The total mean mass of the atmosphere is 5.1480×1018 kg...”.
Therefore, annually 7.7 ×10-4 of the whole atmosphere will go through the super-chimney. As shown above, that air will lose 30% more heat than normal air. Thus, the whole atmosphere will lose 2.31×10-4 or 2.31×10-2% more heat than it would otherwise. Since the planet absorbs approximately 0.2% of radiation energy more than it should to maintain constant temperature, we can aproximate that 10 super-chimneys will offset Global Warming.