Here is my attempt to explain why.
You said:

You only get to win when the "other guy" admits that he has lost.

That is the reason why the "L" brothers have not answered many direct questions from me.
If they ignore my questions they do not need to admit that they have lost.

You can lead this horse to water, but you can't make him think...

Unfortunately I do not know how to read the thoughts of people.
I am familiar with electronic terminology. Power measured in Watts = Voltage times Current. (W=E*I) If there is one volt across a load that draws one amp of current, then the power that is being dissipated is one watt.

One watt is one joule (the SI unit of energy) per second.

1W = 1J/S = 1kg*m2/s3 = 1 newton meter per second
In electrical terms, 1Watt = 1Volt * 1Amp.

If that calculation is wrong then let me know because the electric company uses a derivative of that called a Watt hour. I may need to argue about my electric bill;-)

In any case, had RL specified that the calculation must contain the detonation velocity and must be displayed in “newton meters per second” I would have done that.
(or alternately asked someone to do it for me:-)

Anyone with a basic scientific or mathematical education can work out the detonation velocity of a cube of TNT and hence the DURATION of the explosion. From this comes POWER (rate of doing work) not ENERGY (Amount of work done [or technically, do-able - but now we're into thermodynamics which gets messy...])

snip

While we're at it, Johannes, why is it so much more difficult to build an Uranium bomb than a plutonium bomb?

It depends on what you mean by “more difficult,” as I understand it, the uranium bomb was constructed before the plutonium bomb was built.
So; was the uranium bomb built first because it was more difficult, I wonder why they would do that?

If you mean that it is “more difficult” to achieve a chain reaction in uranium, than plutonium, then I suspect that it has to do with the half life or energy level of the respective atoms.

The total energy released in fission varies with the precise break up, but averages about 200 MeV* for U-235 or 3.2 x 10-11 joule. That from Pu-239 is about 210 MeV* per fission.

http://www.world-nuclear.org/education/phys.htm

And which one will heat the Earth's atmosphere more?

Here again it depends on what you mean by the word ”heat.”
Do you consider all forms of electromagnetic energy as forms of “heat?”
Do you consider “heat” only as motion of molecules?

Do you consider the infrared energy that comes from the sun as “heat” or is it heat only after the energy causes the molecules to move faster?
Why does impinging infrared energy cause molecules to move faster?
Is your “heat” related to something nuclear like:

Pu-239 is fissile in the same way as U-235, i.e. with thermal neutrons.

When atomic nuclei absorb gamma rays, does the nucleus gain energy?
If a nucleus of an atom gains energy, can it be said that it is “hotter” as a result?

In the following quote: It points out that ”activation products are formed wherever neutrons impact on any other material,” is the “other material” “hotter” after the neutrons impact them.

Apart from transuranic elements in the reactor fuel, activation products are formed wherever neutrons impact on any other material. Activation products in a reactor (and particularly its steel components exposed to neutrons) range from tritium (H-3) and carbon-14 to cobalt-60, iron-55 and nickel-63. The latter four radioisotopes create difficulties during eventual demolition of the reactor, and affect the extent to which materials can be recycled.

If I knew your answers to the above questions I might be able to give you the answer that you are looking for.

But since I do not know how you think, I will answer your question by saying that if there are two identical masses of uranium and plutonium, the energy from the plutonium is expelled at a “faster” rate and possibly distributed into a greater area since the expelled neutrons move faster, so “if” the energy content of each is the same at the beginning of the “comparison experiment“, then the plutonium activity will be deleted earlier but the total energy from both will amount to the same quantity.
Under such conditions both materials expend the same amount of energy, therefore both heat the atmosphere the same amount, the thing is that if you ask which one heats the atmosphere more in one hour or one day, then there would be a different answer for each material.

Analogue would be to ask which is heavier, a ton of bricks or a ton of feathers.
Another would be to ask; which is brighter, a candle that burns for 4 days or a flash bulb of a camera?

I tried to give you a non-mathematical answer, after all, why should I use my brain for mathematics, we can always ask RL to explain such problems to us by using math. :-)

Part of my answer is conjecture, so if I am wrong, please correct the errors.

The quotations are from: http://www.world-nuclear.org/education/phys.htm

All except this last one:

When I tell any truth it is not for the sake of convincing those who do not know it, but for the sake of defending those who do.

William Blake (1757–1827), English poet, painter, engraver. Public Address (written c. 1810; published in Complete Writings, ed. by Geoffrey Keynes, 1957)