Mobility Planet Care

192: Ships that cool ocean waters


Of climate catastrophes, hurricanes have caused by far the most damage. The cost of an average hurricane is US$21.6 billion and total damage from hurricanes hitting the U.S. between 1980 and April 2018 totals US$862 billion.


Prevent hurricanes by cooling the warming ocean waters that allow and encourage them to form.

While casualties from hurricanes since 1900 have numbered from a handful of fatalities to deaths in the low hundreds, Hurricane Katrina in 2005 is by far the costliest and most devastating storm in U.S. history, causing 1,833 deaths and an estimated US$160 billion in damage.

After observing the damage wrought by Katrina, Stephen Hugh Salter, an emeritus professor of engineering design at Scotland’s University of Edinburgh, began to study how to disperse hurricanes.

For ocean temperatures, the magic number for hurricane formation is 26.5° C (79.7° F). So what if you could nudge that number down early on and reduce the risks and intensities of ensuing storms?

To cool the surface of the ocean, Salter invented a wave-powered pump that would move warm surface water down to depths as far as about 650 ft. (200 m.).

It would be made from a 150 – 330 ft (50- 100 m.) diameter ring of thousands of tyres lashed together to support giant plastic tubes which extend 300 ft (100m) deep into the ocean.

The naturally working pumps would be located in “hurricane alley”, the warm corridor in the Atlantic through which the most damaging storms typically develop and pass. Salter estimated that about 150-450 of these structures would be required. They would drift around and send out radar signals so that no one would collide with them.

What became known as the “Salter Sink” was first presented to the US Government in 2005 at a post-Katrina US Homeland Security meeting on hurricane suppression.

It was picked up and developed by Intellectual Ventures, a Seattle-based new tech company led by former Microsoft chief technology officer Nathan Myhrvold. Despite devastating hurricanes such as Dorian (September 2019) which destroyed the Bahamas, the Salter Sink” system has still not been trialled except with 1/100 scale wave tank tests.

Stephen Salter’s other tactic for fighting hurricanes is making clouds a tiny bit brighter using aerosols, harnessing a phenomenon called the Twomey effect.

Twomey observed that for clouds containing the same amount of moisture, the clouds with smaller suspended water droplets reflect more sunlight.

The increased sunlight reflectance in the sky would keep the waters below from warming up to the hurricane threshold while also curbing evaporation, thereby reducing the atmospheric moisture needed to make a storm.

Working with John Latham, Salter proposes a fleet of around 1,500 unmanned Rotor ships, or Flettner ships, that would spray mist created from seawater into the air at a rate of approximately 1760 ft3 (50 m³) per second over a large portion of Earth’s ocean surface.

The large-scale test would affect an area of 10,000 km². The power for the rotors and the ship could be generated from underwater turbines. Subsequent researchers determined that transport efficiency was only relevant for use at scale, and that for research requirements, standard ships could be used for transport.

Salter estimated that it would cost US$40 million to construct a prototype cloud seeding system but has not been able to find any public or private takers.

Despite this, since 2012, a Marine Cloud Brightening Project (MCBP) team has been meeting on a weekly basis at a lab in Sunnyvale, California. In 2017 Salter held talks with major Scottish engineering firms Ferguson Marine Port, Glasgow and Clyde Blowers about building his spray vessel ‘weather machines’. A prototype is still to be built and tested.

“If we can put them in the right place at the right time, 300 ships spraying 10 cubic m. a second would put sea surface temperature back to where they used to be.  We would need a few thousand is we are criminally stupid enough to double CO₂.” Said Salter in 2019.

Meanwhile, a wind engineering team led by Arindam Gan Chowdhury and Andrew W. Conklin at the International Hurricane Research Center (IHRC) and College of Engineering and Computing (CEC) at Florida International University has been working at a full-scale large 12-fan “Wall of Wind (WoW) facility, testing building materials and designs against Category 5 hurricane-strength winds on the Saffir-Simpson Hurricane Wind Scale.

The Wall began with two fans, then six fans and finally twelve fans able to simulate wind-driven rain. Current WoW projects, funded by federal and state agencies and by private industry, are offering focus and leadership in the urgently needed hurricane engineering research and education from an integrative perspective to quantify and communicate hurricane risks and losses, mitigate hurricane impacts on the built environment, and enhance sustainability of infrastructure and business enterprise, including residential buildings, low-rise commercial buildings, power lines, traffic signals, etc. s.

The team has a patent pending for a new type of roofing material. Additionally, recommendations made as a result of Wall of Wind testing were published in the 2010 Florida Building Code. The new code provisions are geared toward decreasing the vulnerability of roofs and rooftop equipment.

Discover Solution 193: underground rivers and hydro dams

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