As the weather around the world reaches new
extremes the big challenge will be to try and mitigate the effects of climate change
by changing the way we create and use energy, transport and food production. But could there
be other ways using the technology we have today to try and reduce the size and energy
of some of the more localised and destructive weather events like Tornados and Hurricanes?
and control rainfall. Controlling the weather or weather modification
as it known has long been the goal of many, from those wanting to make things better for
their fellow man but also those that want to make it somewhat worse by looking to weaponize
the weather and it’s not as if we haven’t been trying.
One of the most well-known methods of weather modification is cloud seeding, this is basically
spraying tiny particles like silver iodide, dry ice or frozen carbon dioxide, liquid propane
and more recently table salt into the clouds by planes, rockets and flares.
Although this method has been done of over 70 years there is still a lot of debate as
to how effective it really is but in what was called the most scientific study of cloud
seeding carried out so far in Wyoming over a six year period seeding mountain clouds,
it was concluded that it produced about a 10% increase in precipitation but equally
that different areas and conditions around the world could produce more or have no effect
at all. There are two basic methods, the cold rain
method, and the warm rain method. The cold rain method works in more temperate
areas where large convective clouds contain supercooled water. The seeding agents like
dry ice provides nuclei for the supercooled water to freeze around which then travel on
updrafts in the cloud picking up more water and growing larger. When they are large enough
they fall and melt into rain on the way down. If a storm is very large and has strong updrafts
they become so large that they don’t melt on the way down and fall as hail.
The warm rain methods is used in tropical areas where the clouds don’t reach the freezing
point, so a hygroscopic seed, that’s one which absorbs water like salt is used instead. The
tiny droplets coalesce as they also float on the updrafts again until they are heavy
enough to fall as rain. However, if too much seed material is used
it can have the opposite effect by creating too many seeds for the amount of water vapor
available so very few of them can grow large enough to become raindrops and here we have
another underlying issue. Natural rain requires a seed to start the
process which could be a particle of dust or pollen but our use of fossil fuels, especially
diesel and coal also creates a lot of soot which can also act as a seed, so just driving
your car or putting your heating on, you could be unintentionally seeding the clouds.
This pollution has been blamed for the loss of the snowpack in recent decades in areas
like the western US which that rely on clouds forming over mountains and the snow they deposit
and for the meltwater for their water supplies. If the clouds are seeded by pollution before
they reach the mountains there would be less snowfall and less water, so seeding clouds
over the mountains is seen as a way to bring back the snow and increase the water supply.
Another experiment using ionised particles is being trialed in the middle east in Abu
Dhabi. The idea here is that the negatively charged particles are released from Ion-emitters
and float upon convection currents and attach themselves to the natural condensation nuclei
in the clouds. Once charged they would to attract other nuclei and grow more quickly
and hopefully survive longer to produce more rain than would have possible without being
charged. So far they say it has had positive results but more research is required.
A common misconception is that cloud seeding can create rain or snow will anywhere and
from clear skies, this is false. It can only affect clouds which are already rain or snow
bearing or that just at the point of becoming so. If there are no clouds or clouds that
can not produce rain such as the very high cirrus clouds, then no amount of seeding will
make any difference. It has also been found that clouds that form over the sea are more
likely to respond to seeding compared to clouds that form inland.
Hail suppression is another reason why seeding of large thunderstorms is done in parts of
the world where hailstones routinely grow to very large sizes and cause damage to crops,
vehicles, buildings, and people. Although the exact details of how hailstones in these
storms grow are still sketchy, the idea is that seeding them will cause more of the supercooled
water to fall as rain earlier and reduce the amount that is available for hailstones to
form and thus reduce their size. In fact, is been found that the tips of the
propellers of aircraft and the airflow over their wings can also produce ice particles
from the clouds water vapor under certain conditions and unintentionally seed clouds
which could be wrongly attributed to a seeding agent.
But this hasn’t stopped many countries around the world from trying it. China has invested
heavily in cloud seeding and even used it to try and keep the opening and closing ceremonies
of the 2008 Beijing Olympics rain and smog-free. Whilst China says that they have had great
success it also has some of the most polluted skies in the world further confusing the results.
Its been reported that they had deployed over solid fuel 500 burners on the high slopes
of Tibetian plateau to pump out silver iodide in an experiment to increase the amount of
snow and rain across a 1.6 million square km area that eventually feeds in to the Yellow,
Yangtze, Mekong rivers even though in the west silver iodide is increasingly seen as
a pollutant and therefore is not used much. But as they say, one man’s pitchfork is another
man’s weapon of war and so it was with cloud seeding in the Vietnam war when the US carried
out the secret CIA sponsored operation Popeye from 1967 to 1972 under the auspices of weather
reconnaissance. This was an attempt to increase the length of the monsoon season with cloud
seeding with the intention of causing damage due to extra rainfall to roads, river crossings,
inducing landslides and generally making life more difficult with year-round mud for the
Vietcong along the Ho Chi Minh Trail, the main route for transporting men and arms to
the South but which also covered parts of Cambodia, Laos, as well as Vietnam. Only after
the programs existence was leaked in 1971 did operations cease in 1972 after details
of it were published in the New York Times. This highlights the issue that the effects
of increased rainfall don’t stay in the area where the seeding took place or the rain
fell. Flash floods along river courses could happen far from the rainfall and even in other
countries. So if we could affect rainfall then we should
be able to affect storms and the biggest of all, the tropical cyclone or hurricanes. Project
cirrus was a collaboration between the US Army Corp and General Electric to drop crushed
dry ice or frozen carbon dioxide from a modified bomber into the rainbands of a hurricane in
1947, this is actually the basis of all modern cloud seeding.
The theory was that the dry ice would cause a new eyewall to form which would be larger
than the old one, this would reduce the pressure gradient and weaken the hurricane. After the
seeding, the storm which was traveling westwards did a quick turn and made landfall near Savannah,
Georgia. People blamed the change of direction on the seeding and legal action for the damage
caused was threatened which stopped further trials for over 10 years. Later it was discovered
that a similar storm had done the same thing in 1906 and that the 1947 storm was probably
already turning before the seeding started, this stopped the legal action.
Project Stormfury was a further attempt weaken hurricanes run by the US government from 1962
to 63. Again this used cloud seeding but this time with silver iodide which mimics the effect
of the dry ice whilst being easier to handle and longer-lasting. This was to try and make
the supercooled water in the hurricane to freeze and disrupt the it’s inner structure.
However, it was found that most hurricanes didn’t have enough supercooled water and
that unseeded hurricanes changed in the same way a seeded one was expected to, pretty much
making the project redundant. In the 1959’s, nuking hurricanes into submission
was seriously considered. The idea was that if you exploded a high yield weapon above
the eye, the huge uplift of air seen in the fireball would suck in cool air and disrupt
the storms convention currents. But there are some serious drawbacks with
this, the most obvious being it would spread highly radioactive isotopes through the wind
and rain over a wide area. The second issue is that hurricanes are heat engines, they
get their energy from the warm moist air above the ocean so adding more heat from the blast
would probably make it stronger rather than weaker.
The third problem is the sheer amount of energy already being released a hurricane which is
in a typical one is the equivalent to a 10 megaton weapon being detonated every 20 minutes,
so a succession of bombs would be needed to have the required have any effect. As hurricanes
are just air and water vapor the blast shock wave would have little effect on it’s structure
and what water vapor that might be superheated from the initial X-Ray bust would condense
back again a short time after adding more heat in the process.
So if you can’t stop them when they are large, maybe you could stall them when they
are developing and just storms at sea. For a hurricane to develop the sea temperature
must be above 26.5C. Around 80 tropical depressions form in an average year in the Atlantic but
only about 5 to 10 will become hurricanes, so which ones do you go for.
Instead of trying to figure out which might become a hurricane why not affect them all.
There have been several ideas to cool the ocean surface in the area where they develop
using wave-powered pumps, also known as ocean plowing to either move warm surface water
downwards or cool deep water upwards. The issue here is that you would need thousands
of them covering a vast area and in small scale tests many of these pumps were damaged
by the waves. Another idea which is used in Norway to stop
the buildup of ice in fjords is to pump air into the deep water. As the air bubbles rise
to the surface, they bring up the deeper salty water which stops the ice from forming. If
this was done in the warm ocean waters it could bring up the deeper cooler water to
cool the surface depriving the storms of the heat energy to grow into hurricanes.
Again the same issue applies in that you would need thousands of these solar-powered pumping
plants covering a large area to have any effect. Yet another idea is to make the clouds themselves
more reflective by spraying seawater into them. This would reflect more of the sun’s
energy back into space and cooling the sea below. This has been suggested to help combat
global warming and if this was done around the equator not only would it reduce the amount
of available energy for storms to form but also it would help cool the poles as there
the whole point of the atmospheric and ocean currents is to distribute the heat imbalance
form the equator to the poles. However, there is also the law of unintended
consequences on the sea life and the new weather patterns that would become established if
we were artificially cool large areas of the oceans.
Tornados are the other deadly storms but these are quite different from hurricanes, for one
they are much smaller with an average width of 0.8 km and give very little notice when
the form, the funnel clouds lasting from a few minutes to a couple of hours but in that
time they can do tremendous amounts of damage to anything they encounter.
Unlike hurricanes, Tornados nearly always form overland from large rotating thunderstorms
or supercells. These and require cold dry air over warm humid air and an unstable atmosphere,
something which happens regularly over the great planes of the central US in an area
called tornado alley. Because they form in a different way to hurricanes,
primarily due to the difference between the cool dry air and the warm moist air masses
and the lateral winds which provide the spin to get them going there have been several
theories as to how they might be controlled. One was from the physicist Bernard Eastlund,
who if you have seen the video we did on HAARP was the man behind the idea of the giant ionospheric
heater in Alaska that could create heat the ionosphere to create a lens to focus the suns
energy on to an area may be hundreds of kilometers away.
Well the Thunderstorm Solar Power Satellite which he called it, would be a giant solar
collector that would generate electricity and convert that into microwaves which would
be focused on to thunderstorms to heat the cool rainy downdrafts and disrupting the convection
currents within the storm cell. This might sound far fetched but if you also
watched our previous video about spacebased electrical power generation then you’ll
know they are already trailing the microwave power link technology and the satellite-based
solar generators, so it might not be far fetched for long.
But there are problems with this, firstly the solar power station and microwave transmitter
would need to be in geostationary orbit to stay above the area and to have a 24 hour
supply of sunlight for its power. But that would place them over the equator rather than
the central US. At 36,000km away the beam would be very wide at up to 10km across and
not focused enough to pick out the small area of the cool air in rear flank downdraft of
thunderstorms were most tornados start, if you heat up the already warm air it might
just make any tornados stronger. If the satellite was in a low earth orbit
at 400Km, then the beam could be a lot tighter and stronger but it would be traveling around
the earth once every 90 minutes with only a few minutes over a potential target. Getting
the satellite to be over a storm at the right time and in daylight for its power would be
down to luck rather than planning. You would also have to avoid the high energy microwave
from hitting people and livestock on the ground so it would have to be turned off when over
towns and villages. A variation on this is a ground-based system
with high power microwave transmitters mounted on trucks with large generators. This gets
around the problem of being close enough but you would still need many megawatts of power
so a convoy of transmitters and generators would have to track down the storms just like
storm chasers do now. They would then need to stop and set up in just a few minutes to
be effective all whilst avoiding any emerging tornados.
In the real world, this would just not be practical with current power technology and
transportation. So our best hope is better detection and prediction of where tornados
may form and maybe more underground buildings and structures that would not be affected. Accurate weather prediction has come a long
way in the last 20 years or so using a whole variety of methods from realtime updating
of data in the field to predictive modeling on supercomputers but all of this requires
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