söndag 25 juli 2010
Chilling Greenhouse Gases?
In the earlier post CO2 Cooling we pondered the question if more GreenHouse Gases GHG (like water vapor) will warm or cool the Earth surface?
Let's consider a simplistic (but possibly relevant) argument: Let's agree that without any atmosphere an isotherm Earth would have a blackbody temperature of 255 K as given by
Stefan-Boltzmann-Planck's Law. What would the temperature be with a fully opaque atmosphere effectively extending an isotherm Earth to include the atmosphere. Right: Again 255 K.
The real atmosphere is something in between fully transparent and fully opaque with
an Earth surface temperature of 288 K. Apparently we cannot say a priori that making the atmosphere more opaque by adding GHG will warm the Earth surface: Adding too much would cause cooling.
Simplistic, yes, but anyway relevant?