Reprinted from “My Pages,” Hackaday.io
Updated 08-12-2024
Last update 12-26-2024
An exploration of
possible modern uses of clear-weather atmospheric electricity.
The idea: On clear,
calm days, release tiny, negatively charged sulfur particles near ground level
(but no lower than 25 cm) and wait for them to rise into the stratosphere on
the sky voltage. They should then oxidize to a sulfuric acid aerosol, which is
a powerful climate cooling agent if present in the stratosphere. The
stratosphere begins 8 km above the surface in the arctic and 16 km above the
surface in the tropics (mode= 12 km). At the surface, the electric field of the
sky voltage has an intensity of 100 to 200 volts/m, earth negative, with the
maximum occurring at 18:00 UTC, no matter where you are. It is part of the
global atmospheric electric circuit, which is powered by thunderstorms and
other electrified clouds. Solid sulfur can be negatively charged by friction, a
process called tribocharging. Tribocharging is already used in one type of
powder coating technology.
A network of
photochemical reactions given here https://doi.org/10.1073/pnas.1620870114 (scheme 1) suggests that elemental sulfur
will change into sulfuric acid aerosols in the atmosphere. (The scheme is
presented as applying to anoxic conditions, but in the text, it is presented as
describing current knowledge of atmospheric sulfur chemistry.) A fly in the
ointment is that an irreversible step is shown going from gaseous S8 to solid
S8, and I want reversible, so I am still searching for a rigorous chemical
precedent for the supposed transformation. DOI:10.1126/sciadv.abc3687 figures 5B and S4, shows that when
suspended in an aqueous solution at pH 6, solid sulfur generates sulfate when
irradiated at 280 nm (shortest-wavelength end of the UVB range). That precedent
isn’t rigorous either but it is helpful in addressing the question of providing
sulfur in solid elemental form.
If stratospheric
temperatures are too low to permit useable oxidation rates, microwave heating
using ground-based projectors could be tried. (Such projectors could also be used for in-flight recharging of high-flying drones that deliver substances into the upper atmosphere.)
To charge negatively,
the Teflon tube that is standard on a triboelectric gun will have to be replaced by a
tube made with an electron donor, or else corona charging used instead of
triboelectric charging. I calculate that to rise in the atmospheric electric field, a
particle needs a charge to mass ratio ("specific charge") greater
than 50 millicoulomb/kilogram, which may be another factor requiring corona
charging.
The figure of 50 mC/kg
was derived by dividing g, the gravitational acceleration at the Earth's
surface (about 10 m/s2), by 200 V/m, and multiplying by 1000 to get
the units used in studies of powder-coating physics (and the units analysis
checks out).
Extrapolating from
data in Meng et al., 2008, http://dx.doi.org/10.1088/0022-3727/41/19/195207 , 2.3-micron-diameter sulfur
particles corona charged at 90 kV should fly. However, a ten-fold smaller
sulfur particle will have a ten-fold greater specific charge, giving some
margin to allow for discharging on the way up.
The diameter of the
sulfur particle injected into the stratosphere is unrelated to the diameter of
the eventual sulfuric acid droplets it produces upon oxidation in the
stratosphere, because one reaction intermediate, sulfur dioxide, is gaseous.
At this time, my best
guess as to how fast the particles would rise is 3 cm/s (because I believe I
have seen it), which will take them up to the stratosphere in four to five
days.
Ideal release
conditions are low barometric pressure (i.e., rising airmass) but no
clouds. This need not be a contradiction in terms if the rising air is dry to
begin with. For example, dry polar air warmed by contact with arid ground
should rise without cloud formation.
However, thus far, my
calculations have not addressed the fact that the sky electric field weakens
with height. At an altitude of 12 km, it is only 5 V/m, versus 100-200 V/m at
sea level. The altitude effect will cause the particles to stop ascending and
start concentrating at a particular altitude (a possibly useful effect)
where gravitational and coulombic forces are in equilibrium, but is it
stratospheric? Unfortunately, no. Even reducing particle diameter 10-fold to
0.23 microns (which uses up our margin for discharge) only gives 4.5 km, less
than the minimum height of the stratosphere, 8 km. So, we don't get there,
unless we stand on a mountain top in Greenland, but we get interestingly close
with what is only the first scheme contemplated. My source for the dependence
of electric field on height is figure 20-7a in https://www.ngdc.noaa.gov/stp/space-weather/online-publications/miscellaneous/afrl_publications/handbook_1985/Chptr20.pdf
The weakening of the
Earth’s gravity with height is no help, because if you go up to 12 km, the
difference is only one-half of one percent.
The problem of
particles discharging en route is far from trivial, but charged dust particles
suspended in air at ground level lose charge with a half-life of about 4 days
( https://doi.org/10.1093/pnasnexus/pgac220 ), independent of composition, which is
not too discouraging, but the loss will be faster at altitude, where air
ionization by cosmic rays is more intense.
We could use electrons
as an ion scavenging agent, to be released under the aerosols as a way to
continuously guard the ascending aerosols from cation recruitment, which is the
main mechanism of neutralization of negatively charged airborne particles according
to the previous citation. Electrons (as hydrated hydroxide anions) could be
injected into the air by smoke-detector-type Americium discs sitting on top of
three-meter-high grounding stakes driven into the ground. The ground is
360 kV negative relative to an imaginary capacitor plate in the ionosphere.
Alpha particles, the main form of radiation from Americium, only travel 4.5 cm
in air, if you are worried about safety. In that distance, they make many air
cations (+) and anions (-) through molecular collisions, giving a current
of a few nanoamperes per disc (a thousand times greater than the natural
current descending into one square meter). The local fair-weather electric
field will be concentrated at the top of the pole and will pull down all the cations
while repelling the anions upward. An array of these
"radioelectrodes," possibly extending over many square kilometers,
will be needed because a fairly strong electric field will be pulling cations
in from the sides. The ozone byproduct generation (7 molecules per 100 eV of
alpha-particle energy) should be manageable. Connecting all radioelectrodes to a central station by buried wires would allow grounding independent of soil moisture and, with suitably insulated poles, would also allow non-ground DC potentials to be applied to the radioelectrodes. The latter feature would be an elegant way to control the amount of current flowing from the radioelectrodes into the lower atmosphere. Voltages far less than those needed for corona discharge would suffice.
If the effect of this
scavenging on air conductivity is uniform with height, there should be no
effect on the profile of field intensity with height. If the conductivity
change is concentrated at low altitudes, there will be. Injecting enough charge
carriers to increase the air conductivity will, in this case, tend to flatten
the profile of field strength with height, which could be advantageous and
increase the height to which particles can be lifted. My circuit model for
these conclusions was a multi-tapped voltage divider connected across a
battery.
Most of the resistance
of the air column is concentrated at low altitudes, and this is where we can
most easily reach it, so, it’s a break. Reducing this resistance should
efficiently increase the current flowing in the air column, pulling it in at
the top from the sides, thus concentrating it, thus concentrating the power
available from this source. The enhanced current will enhance the vertical
electric fields all the way up.
DISCUSSION:
Other climate
manipulations can be imagined, such as increasing the winter snowpack in Canada
and Russia by seeding supercooled clouds with ice-nucleating proteins isolated
from Pseudomonas syringae and a few other species of bacteria.
Another possibility is
carbon sequestration in fertilized wetlands, but the strong greenhouse gas
methane will be produced as a byproduct. Combining direct physical temperature
control with carbon sequestration, however, would unlock access to a simple wetlands
strategy for regaining carbon balance. Carbon sequestration in wetlands is how
the non-marine fossil carbon got into the ground in the first place, and it
will be readily available to us as peat fuel if we need it again some day, for
example, to reverse a temperature undershoot by burning some fossil fuel
again.
Our task is not to
build a cooling system, but a well-engineered control system that can either heat or cool at need. Focusing
narrowly on cooling will trigger a continental glaciation sooner or later.
Every crisis is an
opportunity, and the opportunity in this one is to build a system of global
climate control that in the future will protect us not only from climate
disasters of our own making, but also from natural climate-impacting ones like
volcanic explosions, long statistical pauses in volcanic explosions, and
changes in solar radiance (How could solar radiance change? Round up the usual
sunspots). For probably the first time in history, humans are now collectively
powerful enough to control the global climate. This is in large part due to our
presently great numbers, so population increase isn’t all bad; people not only
consume resources, but they can also do work.
Can we relax some
constraints here, given the anticipated economies of a coulombic hoist system?
Does injection have to be stratospheric, or will high tropospheric do? Will the
high-tropospheric UV flux and spectrum be adequate to convert sulfur aerosols
into sulfuric acid before they settle out? Do the light-scattering particles
have to be sulfuric acid or can they be electrified mineral dust, pollen, or
sea salt? A dominant consideration of particle injection into the high
troposphere will be avoidance of cirrus cloud formation, as these clouds have a
net greenhouse effect. Ice-nucleating particles ameliorate the cirrus cloud
problem. Such particles can consist of bismuth tri-iodide or natural isoprenoid
organics of 0.1 microns or less. Moreover, cirrus clouds originate in precisely
the dry updraft areas I previously identified as the best release sites for the
Coulombic hoist (CH), which is sixty degrees north, the northernmost boundary of the prairie provinces, so the CH lends itself to raising particles into the high
troposphere for purposes of cirrus cloud thinning. A net warming effect due to
overseeding is thought to be a possibility, however.
High-tropospheric
injections will be more reversible, if mistakes are made (and they will be),
than will stratospheric injections, because the climate effects of a pulsed
injection at this altitude last only 1 to 3 months. Geographically, the effects
will also be less than global, allowing a more pluralistic and thus acceptable
governance model, as well as offering the enticing possibility of regional
climate tweaking. Artificial heating and cooling effects at any altitude will have to be balanced between northern and southern hemispheres to avoid shifting the latitude of the monsoon rains; any such shift would cause hardship to millions of farmers and food insecurity for many more.
As to the pollution
aspects, nobody lives in the high troposphere, and acid rain from the amount of
sulfuric acid needed for climate control will be diluted over large areas and
need not be net-harmful. You can be poisoned by too much vitamin D, but that
does not mean that nobody should have any vitamin D. This type of situation is
called "hormesis," and it is quite common.
Of course, we will
have to be careful.
Because discretion is
the better part of valour.
11-18-2024: A search should be undertaken for natural Coulombic hoists or aeolian hoists already in existence that could be modified for climate control. Electric levitation is already implicated in greatly extending how far Saharan dust travels before settling out (see previous link).
I have a BSc in
Engineering Chemistry, 1977, from Queen’s University, Ontario.
