h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Almost 100 years ago, Churchill decided that oil was the best way to go for military vessels. Could a well-informed and persuasive engineer go back in time and try to argue him away from this position?

Also, people sailed around the wing using sails. Could this technology be brought back, possibly with refinements?

There have been some refinements, but they haven't really caught on.
(Examples: http://www.ecomarinepower.com/en/marine-renewable-energy-for-shipshttp://www.sciencedaily.com/releases/2015/02/150227084559.htmhttp://youtu.be/zWZrnoNaTxQ )

(I put spaces between those links, but some removed them.)

>Almost 100 years ago, Churchill decided that oil was the best way to go for military vessels. Could a well-informed and persuasive engineer go back in time and try to argue him away from this position?<

Not in my view. Oil is just so much more portable than coal that - specifically for military purposes - there is no comparison.
If we hadn't done it then someone else would and that could (probably would) have led to a military disaster (that's definitely the thinking of the time).

One biggie about oil of course is that if my thing happened and WW1 was either stopped or delayed then we have an Ottoman (islamic) empire rather than a British/French/US coalition in charge of the biggest oil fields on earth. Where would we be then...?
A different place certainly... better? Who knows.

"The original question was how would you best use it to benefit mankind?"

Clearly nobody cares about benefitting mankind. Only themselves.



"I wonder what the most effective/efficient thing one could do to derail our lasting reliance on fossil fuels might be? [...] What small change and when would have the greatest effect on our climate given such a temporal opportunity?"

Kill Henry Ford and Thomas Edison.

I wonder what the most effective/efficient thing one could do to derail our lasting reliance on fossil fuels might be.

Nuclear holocaust

Nope... too much bykill. A targeted bioweapon would be more efficient.

No, see, then sixty million years from now all of us would become oil and gas and flammable stuff. The next sapient race to come along would just make the same mistake.

A meal of beans and broccoli *already* makes me turn into gas . No need to wait 60 million years.