Frank, you silly retard, the experiment has been done repeatedly with the whole of the Earth's atmosphere. And when vast amounts of GHGs were added rapidly, the weather, indeed, went 'apeshit'.
Methane Catastrophe
Permian global warming would have had several additional consequences. It would have increased the rate of evaporation, making the continents more dry even while making the atmosphere more humid. It also would have increased the amount of water that the atmosphere could hold, and, because water itself is the dominant greenhouse gas, that water would have contributed to still further global warming. Cloud cover would have increased, but the role of clouds in determining climate is a matter of continuing discussion and much serious investigation among scientists, because clouds on one hand increase Earth's albedo (thus reflecting more solar radiation back into space) and cool the planet, and, on the other, increase the amount of warmth trapped beneath them. It is still unknown whether, on balance, clouds contribute more to planetary warming or cooling, though the answer is sure to be different for different types of clouds. As we have already seen, some clouds -- polar stratospheric clouds -- may have helped warm the polar regions at the beginning of the Eocene.
More water vapor in the atmosphere, however, would have meant more precipitation, and this precipitation would have come in the form of more severe storms. Some continental areas therefore may have been subject to a kind of double whammy: drying out more because of increased evaporation, and then periodically getting hit by powerful storms. This is a prescription for drought punctuated by flash floods and rapid erosion, and would have imposed difficult living conditions on the many of the creatures of the affected areas. Other areas simply received more precipitation, which ameliorated harsher climates and made arid climates less so (Retallack, 2003).
In South Africa's Karroo Basin, the additional precipitation may have been responsible for changing river dynamics and altering meadering rivers (which sweep in great curves across their valleys) to braided rivers (which are comprised of many interwoven strands). Although numerous factors control the specific shapes of rivers, the amount of flow is an important one, and braided rivers tend to indicate higher flow rates than meandering ones. The major extinction of terrestrial plants, whose root systems tend to anchor soils, is also a likely factor in altering river shape (Ward, 2000).
Though the study of the effects of warming on terrestrial species (the Thomas, 2004, study) examines only present-day global warming, its application to the end-Permian is obvious. While the initial triggering mechanism is different -- the anthropogenic production of carbon dioxide in the present versus direct oceanic warming and indirect CO^2-induced global warming caused by Traps volcanism at the end of the Permian -- the effects would have been the same. The atmosphere warmed, and the ocean and the terrestrial surface with it. Huge numbers of species were not able to survive the changed conditions, and they died.
