Wednesday, February 26, 2014

A Tiny Puzzler

So between the Weasel, the Variable and the Physics there has been much discussion of the greenhouse effect, and, of course, a lot of confusion, much from the confused, which Eli has on occasion tried to unscramble, but Eli has a puzzler that probably has appeared on Watts in some form or other

Given a bounded (e.g. it stops), isothermal (Eli is in denial about gravity here, the Bunny knows, but this is a thoughtful experiment) will adding additional greenhouse gases cool or heat the system?


Anonymous said...

"will adding additional greenhouse gases cool or heat the system?"

RF alone tends to warm the surface of the 'system' and cool the upper reaches of the 'system' -

Since additional RF works in part to add surplus energy to the surface but reduce net energy aloft, some of RF is negated by convection.

'Convective adjustments' of 1D models appear reasonable, but convective exchange is driven in large part by horizontal motions ( which are not captured by 1D models ). Necessarily in the GCMs, convection is parameterized, making it about as reliable as summer thunderstorm forecasts.

Old school


Arthur said...

Eli - your question seems incompletely defined?

"Given a bounded, isothermal will adding additional greenhouse gases cool or heat the system?"

??? Not sure what that's supposed to mean???

KAP said...

If it's bounded, adding any gas will increase the pressure and hence the heat of the system.

Windchasers said...

Agreeing with Arthur here; the question is ill-posed. A bounded, isothermal... what?

And just as relevant - what is causing the system to be bounded and isothermal?

Boro Nut said...

Surely any tiny increase in temperature will be overwhelmed by the cooling effect afforded by the mega-fronds that will instantly burst from every crack and crevice. I'm sure I read that on the National Academies website. Or WhatTwatsRupTo. One or the other, I forget.

And Then Theres Physics said...

Eli, if I understand what you're asking in your thought experiment, then adding GHGs will neither heat nor cool the system.

Aaron said...

Isothermal is isothermal, and the change in temperature is zero. An example is our solar system bounded and confined at a radius of 1 light-year, and including the Sun, Mercury, Venus, Earth, Saturn, Jupiter, and etc.

Formation of greenhouse gases on Earth will not affect the average temperature of the Solar System in any significant way. Greenhouse gases are added to the system, but the system remains isothermal during the period of stupidity. Gravity is not significant. Energy is not created or lost, but its distribution in the system changes, i.e., Earth becomes warmer, and certain other components of the system cool.