No Change in GMST: Scenarios Explored

[carl]

GMST scenarios ..please help

Hey how you doing? Can anyone tell me 2 scenarios that could possibly lead to no overall change in GMST in this way please. I think (1) and (3) might be right?

(1) The fraction of Earth's surface covered with ice and snow decreases while the albedo of the surface (which isn't covered by ice and snow) decreases.


(2) The atmospheric CO2 concentration decreases while the solar constant increases.


(3) The volcanic aerosol content in the atmosphere increases while the atmospheric H2O concentration decreases.


(4) The volcanic aerosol content in the atmosphere decreases while the atmospheric CO2 concentration increases.


(5) The albedo of the surface (which isn't covered by ice and snow) decreases while the fraction of Earth's surface covered with ice and snow increases.

 

[Andre]

Hey how you doing? Can anyone tell me 2 scenarios that could possibly lead to no overall change in GMST in this way please. I think (1) and (3) might be right?

Well Carl, that depends if you want a political correct answer or a physical correct answer.

(1) The fraction of Earth's surface covered with ice and snow decreases while the albedo of the surface (which isn't covered by ice and snow) decreases.

No, both work in the same direction, decrease of snow cover decreases local albedo like the albedo decrease elsewhere. Note that the insolation and hence effect of albedo of the (An-)Arctic snow areas in the (local) sunless-winter is virtually non existant. No sunshine to be reflected on the snow.

(2) The atmospheric CO2 concentration decreases while the solar constant increases.

obviously a yes, politically correct, however the resulting changes in evaporation, oceanic cycles etc are highly unknown and may spoil the true answer

(3) The volcanic aerosol content in the atmosphere increases while the atmospheric H2O concentration decreases.

Both would be causing decreasing temperatures but the H2O concentration in a different way than expected in a politically correct way, it's about the high amount of 'latent' heat from evaporation - condensation that is decreasing with decreasing H2O concentration, much more than decreasing greenhouse effect.

(4) The volcanic aerosol content in the atmosphere decreases while the atmospheric CO2 concentration increases.

the politically and physically correct answer would be no, both leading to warming

(5) The albedo of the surface (which isn't covered by ice and snow) decreases while the fraction of Earth's surface covered with ice and snow increases.

That could lead to no changes but bear in mind that effect of albedo change (decrease) in low lattitudes is huge and leads to warming while the effect of high lattitude snow ice cover decrease is very minor.

 

[DEMcMillan]

I assume that GMST stands for global mean surface temperature. I encourage you to
be thoughtful about volcanic elements in your model. The term aerosol has been introduced to represent both solid and liquid bodies suspended in the atmosphere. Silicates dispersed by volcanic activity are the solids introduced directly. Aerosol is usually used to indicate sulfuric acid (sulfate). Sulfur dioxide (SO₂) is a part of volcanic spew. It must be oxidized to sulfur trioxide (SO₃) by monatomic oxygen that otherwise forms ozone. SO₃ adds water to form sulfuric acid that can easily attract more water molecules, generating heat. In the cold stratosphere the sulfuric acid particle is likely to freeze. Reagent (85%) sulfuric acid freezes at 10.3 ^oC. Atmospheric particle shape is often differentiable by its scattering reflective behavior using LIDAR. Both liquids and solids reflect and absorb light and heat as well as scatter it. Stratospheric volcanic dispersions have a roughly two year duration of this heat generation (global LS) http://vortex.nsstc.uah.edu/data/msu/t4/uahncdc.ls 1982-1984 (El Chichon) and 1991-1993 (Mount Pinatubo) that has not yet been well explained. In one of two cases (1991-1993) low troposphere temperatures fell for over two years (global LT). In 1982-1984 a modest ENSO (e) process reduced the early decline (tropical LT). http://vortex.nsstc.uah.edu/data/msu/t2lt/uahncdc.lt