[ExI] how to tame hurricanes

[Anders Sandberg]

On 2013-12-15 18:32, John Clark wrote:
> Storms get their energy from the warm water on the ocean's surface, so 
> if you could cool that surface layer you could reduce the power of a 
> hurricane, one interesting idea for doing this is called a "Salter Sink".

It is a very neat idea, and I liked the rough analysis by Intellectual 
Ventures.

My big concern is that it is based on the idea that a slight decrease in 
surface water temperature is enough. Now received wisdom is that 
hurricanes cannot form below a critical temperature of 28 degrees, which 
seems to suggest that a slight tweak might reduce their incidence a fair 
bit. But first, when I read up on hurricane thermodynamics I found that 
Kerry A. Emanuel (the doyen of the field) rather clearly states that 
this is not a strict limit: this just represents a level where 
hurricanes usually don't get squashed by the trade winds. More 
seriously, once a hurricane has formed, it gains energy from heat 
released by evaporated or aerosolized water. At this point small 
temperature differences do not matter much, since a one degree 
difference is still just ~1/300 of the total heat. So it might be that 
the sinks do not have much of an effect.

In the end the only thing that can settle it is to run a proper 
hurricane model over a Salter sea, which requires either some good 
simulations or experimental outdoors work.


-- 
Dr Anders Sandberg
Future of Humanity Institute
Oxford Martin School
Oxford University